Zagreus 6.0 - Rewrite from Scratch #82
Conversation
|
Note Reviews pausedUse the following commands to manage reviews:
📝 Walkthrough📝 Walkthrough📝 Walkthrough📝 Walkthrough📝 Walkthrough📝 WalkthroughWalkthroughThe pull request introduces significant modifications to the chess move logic in the Changes
Thank you for using CodeRabbit. We offer it for free to the OSS community and would appreciate your support in helping us grow. If you find it useful, would you consider giving us a shout-out on your favorite social media? 🪧 TipsChatThere are 3 ways to chat with CodeRabbit:
Note: Be mindful of the bot's finite context window. It's strongly recommended to break down tasks such as reading entire modules into smaller chunks. For a focused discussion, use review comments to chat about specific files and their changes, instead of using the PR comments. CodeRabbit Commands (Invoked using PR comments)
Other keywords and placeholders
CodeRabbit Configuration File (
|
![coderabbitai[bot]](https://avatars.githubusercontent.com/in/347564?s=60&v=4){kind=small}
There was a problem hiding this comment.
Actionable comments posted: 26
🧹 Outside diff range and nitpick comments (28)
src/constants.h (1)
34-36: LGTM: SQUARES, PIECES, and COLORS constants addedThe addition of these constants improves code readability and prevents the use of magic numbers. The use of
uint8_tis space-efficient for these small, non-negative values.Consider adding comments to explain what each constant represents, especially for PIECES (6 piece types * 2 colors). This can help prevent confusion for future maintainers.
src/board.cpp (1)
1-47: Consider adding documentation and potentially missing methods.The overall structure of the file is good, with appropriate use of the Zagreus namespace and inline method implementations. However, consider the following suggestions:
- Add documentation comments (e.g., Doxygen-style) for each method to describe their purpose, parameters, and return values.
- If not defined elsewhere, consider adding constructor and destructor implementations, or explicitly delete them if not needed.
- Evaluate if there are any other essential methods for the Board class that should be implemented in this file.
Would you like assistance in generating documentation comments or identifying potential missing methods?
.github/workflows/valgrind.yml (1)
Line range hint
1-67: Suggest caching to improve workflow efficiencyThe workflow looks well-structured for running Valgrind checks and Clang sanitizers. However, to improve efficiency, consider implementing caching for dependencies and build artifacts.
Here's a suggestion to add caching:
- Add a step to cache dependencies after the "Setup CMake" step:
- name: Cache dependencies uses: actions/cache@v3 with: path: | ~/.cache/pip ~/.conan ${{ github.workspace }}/build/_deps key: ${{ runner.os }}-dependencies-${{ hashFiles('**/CMakeLists.txt', '**/conanfile.txt') }} restore-keys: | ${{ runner.os }}-dependencies-
- Add a step to cache build artifacts after the first build:
- name: Cache build uses: actions/cache@v3 with: path: | ${{ github.workspace }}/build key: ${{ runner.os }}-build-${{ github.sha }} restore-keys: | ${{ runner.os }}-build-These caching steps can significantly reduce the time needed for subsequent runs of the workflow.
.github/workflows/release.yml (2)
15-15: Approved: Using latest Ubuntu version for buildsUpdating to
ubuntu-latestensures that the workflow uses the most recent stable Ubuntu version, which is a good practice for keeping the build environment up-to-date with security patches and new features.Consider periodically testing the workflow with the next Ubuntu version (if available in GitHub Actions) to catch any potential breaking changes early. You can do this by temporarily setting up a parallel job with the next Ubuntu version in the matrix.
Line range hint
1-114: Suggestion: Consider further workflow optimizationsThe updates to the build environment and tools are good improvements. However, there might be opportunities to further enhance the workflow:
- Caching: Implement caching for build dependencies to speed up subsequent runs.
- Parallel builds: If not already doing so, consider enabling parallel builds with CMake.
- Artifact retention: Set up artifact retention policies to manage storage efficiently.
- Build matrix expansion: Consider adding more OS versions or architectures if relevant.
Here's an example of how you could implement caching for CMake:
- name: Cache CMake files uses: actions/cache@v3 with: path: | ~/.cmake build key: ${{ runner.os }}-cmake-${{ hashFiles('**/CMakeLists.txt') }} restore-keys: | ${{ runner.os }}-cmake-Add this step before the CMake configuration step in your workflow.
CMakeLists.txt (1)
Line range hint
1-226: Approved: Comprehensive CMake configuration.The CMake configuration is well-structured and provides a good range of build options. Some suggestions for further improvement:
- Consider using CMake's
target_compile_options()instead of directly settingCMAKE_CXX_FLAGSfor better encapsulation.- Evaluate the use of CMake's
FetchContentfor managing external dependencies consistently.- Consider adding an option for Address Sanitizer (ASan) separately from Undefined Behavior Sanitizer (UBSan) for more granular control.
- Implement version checking for required tools and libraries to ensure compatibility.
Here's an example of using
target_compile_options():target_compile_options(Zagreus PRIVATE $<$<CONFIG:Debug>:${DEBUG_FLAGS}> $<$<CONFIG:Release>:${RELEASE_FLAGS}> $<$<CONFIG:RelWithDebInfo,MinSizeRel>:${PROFILING_FLAGS}> )src/magics.cpp (1)
352-352: Improved type safety forinit_sliders_attacksparameterThe change from
inttoboolfor theis_bishopparameter enhances type safety and improves code readability. This modification better reflects the intended use of the parameter as a boolean flag.Consider adding a brief comment explaining the purpose of the
is_bishopparameter, e.g.:// Initialize attacks for either bishops (true) or rooks (false) void init_sliders_attacks(bool is_bishop) {src/uci-specification.txt (10)
3-3: Consider updating the specification date.The current date (April 2006) is quite old for a specification being added in 2024. It might be beneficial to update this to reflect the current implementation or add a note about the version/date of the UCI specification being used.
17-21: Clarify the newline character specification.The explanation of newline characters could be more precise. While it correctly states that newline representation can vary by OS, it might be helpful to specify the exact byte sequences for clarity (e.g., 0x0A for Unix/Linux, 0x0D0A for Windows).
🧰 Tools
🪛 LanguageTool
[uncategorized] ~20-~20: Possible missing comma found.
Context: ... If you use Engine and GUI in the same OS this should be no problem if you commun...(AI_HYDRA_LEO_MISSING_COMMA)
27-28: Define "forced mode" for clarity.The document mentions that the engine will always be in "forced mode" without explaining what this means. Consider adding a brief explanation of forced mode for better understanding.
🧰 Tools
🪛 LanguageTool
[uncategorized] ~27-~27: Possible missing comma found.
Context: ... * The engine will always be in forced mode which means it should never start calcu...(AI_HYDRA_LEO_MISSING_COMMA)
86-92: Clarify the 'setoption' command value format.The explanation of the 'setoption' command could be more explicit about the format of the 'value' parameter, especially for options that aren't simple strings or numbers. Consider adding examples for different types of options (e.g., boolean, multi-choice).
🧰 Tools
🪛 LanguageTool
[uncategorized] ~89-~89: Possible missing comma found.
Context: ...eded. One string will be sent for each parameter and this will only be sent when the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~90-~90: This word is normally spelled with a hyphen.
Context: ...lue of the option in should not be case sensitive and can inlude spaces. The substrings ...(EN_COMPOUNDS_CASE_SENSITIVE)
125-130: Specify how to represent an empty move list in the 'position' command.The 'position' command explanation doesn't explicitly state how to represent an empty move list. Consider adding this information for completeness.
🧰 Tools
🪛 LanguageTool
[uncategorized] ~127-~127: This noun is normally spelled as one word.
Context: ...ard and play the moves on the internal chess board. if the game was played from the star...(BOARD_COMPOUNDS)
[uncategorized] ~128-~128: Possible missing comma found.
Context: ... if the game was played from the start position the string "startpos" will be sent Not...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~130-~130: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...to the engine, the GUI should have sent a "ucinewgame" inbetween. * go start ca...(EN_A_VS_AN)
215-247: Maintain consistency in command explanations.The explanations for the 'copyprotection' and 'registration' commands include code snippets, which is inconsistent with the style used for other commands in this document. Consider removing the code snippets or adding similar examples for other commands to maintain consistency.
🧰 Tools
🪛 LanguageTool
[uncategorized] ~216-~216: Possible missing comma found.
Context: ... copyprotected engines. After the uciok command the engine can tell the GUI, that it w...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~218-~218: It seems that a comma is missing.
Context: ...yprotection checking". If the check is ok the engine should send "copyprotection ...(IF_COMMA)
[uncategorized] ~219-~219: Possible missing comma found.
Context: ..."copyprotection error". If there is an error the engine should not function properly...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~220-~220: Three successive sentences begin with the same word. Consider rewording the sentence or use a thesaurus to find a synonym.
Context: ...on properly but should not quit alone. If the engine reports "copyprotection erro...(ENGLISH_WORD_REPEAT_BEGINNING_RULE)
[uncategorized] ~232-~232: Possible missing comma found.
Context: ...atures. Analog to the "copyprotection" command the engine can send "registration check...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~234-~234: Possible missing comma found.
Context: ...istration ok" or "registration error". Also after every attempt to register the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~239-~239: Consider adding a comma after this introductory phrase.
Context: ...and might not use all its features. In addition the GUI should offer to open a dialog t...(IN_GENERAL_COMMA)
[uncategorized] ~240-~240: Possible missing comma found.
Context: ...on of the engine. To try to register an engine the GUI can send the "register" comman...(AI_HYDRA_LEO_MISSING_COMMA)
407-409: Provide an example for 'combo' option with multiple values.The explanation of the 'combo' option type could benefit from an example showing how multiple predefined values should be specified. This would help ensure correct implementation.
524-531: Clarify if Chess960 support is optional or mandatory for UCI compliance.The document doesn't explicitly state whether support for Chess960 is optional or mandatory for UCI compliance. Clarifying this point would help engine and GUI developers understand the requirements for full UCI implementation.
🧰 Tools
🪛 LanguageTool
[uncategorized] ~526-~526: Possible missing comma found.
Context: ...l the GUI that it is capable of playing Chess960 and the GUI has to tell the engine that...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~526-~526: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ... of playing Chess960 and the GUI has to tell the engine that is should play accordin...(REP_TELL_X)
[grammar] ~527-~527: Do not use the modal verb ‘should’ after the verb ‘be’. Did you mean “should”?
Context: ...and the GUI has to tell the engine that is should play according to the Chess960 rules. T...(BE_MD)
533-537: Provide additional examples for Chess960 castling moves.While the document explains that castling moves in Chess960 are represented as the king "taking" its own rook, it could benefit from additional examples. Consider adding examples for queenside castling or castling from non-standard starting positions to further clarify the notation.
🧰 Tools
🪛 LanguageTool
[style] ~536-~536: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...es" his own rook. Example: e1h1 for the white short castle move in the normal chess start p...(EN_ADJ_ORDER)
1-544: Overall, the UCI specification is comprehensive and well-structured.This document provides a thorough specification of the Universal Chess Interface protocol. It covers all major aspects of communication between chess engines and GUIs, including initialization, game setup, search control, and option handling. The inclusion of examples and the Chess960 extension adds valuable practical context.
While the specification is generally clear and complete, there are a few areas where minor improvements could enhance clarity and consistency:
- Updating the specification date or version.
- Clarifying some technical details (e.g., newline characters, empty move lists).
- Improving the structure of long command lists (e.g., 'go' and 'info' commands).
- Maintaining consistency in the use of examples and code snippets.
- Providing more details on Chess960 support requirements.
These suggestions aim to make the document even more user-friendly for implementers.
Would you like assistance in drafting the suggested improvements to the specification?
🧰 Tools
🪛 LanguageTool
[uncategorized] ~20-~20: Possible missing comma found.
Context: ... If you use Engine and GUI in the same OS this should be no problem if you commun...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~27-~27: Possible missing comma found.
Context: ... * The engine will always be in forced mode which means it should never start calcu...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~39-~39: Consider adding a comma before the interrupter.
Context: ... "debug joho on\n" will be undefined however. * if the engine receives a command wh...(HOWEVER_COMMA)
[style] ~50-~50: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...t as 0000. Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (for promotion) GUI...(EN_ADJ_ORDER)
[typographical] ~65-~65: Consider adding a comma here.
Context: ...e settings the engine supports if any. After that the engine should send "uciok" to ackno...(FOR_THAT_COMMA)
[uncategorized] ~89-~89: Possible missing comma found.
Context: ...eded. One string will be sent for each parameter and this will only be sent when the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~90-~90: This word is normally spelled with a hyphen.
Context: ...lue of the option in should not be case sensitive and can inlude spaces. The substrings ...(EN_COMPOUNDS_CASE_SENSITIVE)
[uncategorized] ~117-~117: Possible missing comma found.
Context: ...uld play or a new game it should analyse but also the next position from a testsu...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~119-~119: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...sitions only. If the GUI hasn't sent a "ucinewgame" before the first "position...(EN_A_VS_AN)
[uncategorized] ~120-~120: Possible missing comma found.
Context: ...uldn't expect any further ucinewgame commands as the GUI is probably not supporting t...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~122-~122: Possible missing comma found.
Context: ... reaction to "ucinewgame" can take some time the GUI should always send "isready" ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~127-~127: This noun is normally spelled as one word.
Context: ...ard and play the moves on the internal chess board. if the game was played from the star...(BOARD_COMPOUNDS)
[uncategorized] ~128-~128: Possible missing comma found.
Context: ... if the game was played from the start position the string "startpos" will be sent Not...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~130-~130: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...to the engine, the GUI should have sent a "ucinewgame" inbetween. * go start ca...(EN_A_VS_AN)
[typographical] ~135-~135: It seems that a comma is missing.
Context: ...the same string. If one command is not sent its value should be interpreted as it w...(IF_COMMA)
[grammar] ~137-~137: The singular determiner ‘this’ may not agree with the plural noun ‘moves’. Did you mean “these”?
Context: ...ove1> .... restrict search to this moves only Example: After "position s...(THIS_NNS)
[duplication] ~143-~143: Possible typo: you repeated a word
Context: ...e! This means that the last move sent in in the position string is the ponder move....(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~173-~173: Possible typo: you repeated a word
Context: ...hout being told so in this mode! * stop stop calculating as soon as possible, don't...(ENGLISH_WORD_REPEAT_RULE)
[style] ~175-~175: For a more polite and respectful tone, consider rephrasing with ‘please’.
Context: ... stop calculating as soon as possible, don't forget the "bestmove" and possibly the "ponder...(DONT_FORGET)
[duplication] ~181-~181: Possible typo: you repeated a word
Context: ...tch from pondering to normal search. * quit quit the program as soon as possible Engin...(ENGLISH_WORD_REPEAT_RULE)
[typographical] ~212-~212: Consider adding a comma here.
Context: ...ve" command is needed! Directly before that the engine should send a final "info" c...(TO_THAT_COMMA)
[duplication] ~213-~213: Possible typo: you repeated a word
Context: ...and with the final search information, the the GUI has the complete statistics about t...(ENGLISH_WORD_REPEAT_RULE)
[uncategorized] ~216-~216: Possible missing comma found.
Context: ... copyprotected engines. After the uciok command the engine can tell the GUI, that it w...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~218-~218: It seems that a comma is missing.
Context: ...yprotection checking". If the check is ok the engine should send "copyprotection ...(IF_COMMA)
[uncategorized] ~219-~219: Possible missing comma found.
Context: ..."copyprotection error". If there is an error the engine should not function properly...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~220-~220: Three successive sentences begin with the same word. Consider rewording the sentence or use a thesaurus to find a synonym.
Context: ...on properly but should not quit alone. If the engine reports "copyprotection erro...(ENGLISH_WORD_REPEAT_BEGINNING_RULE)
[uncategorized] ~232-~232: Possible missing comma found.
Context: ...atures. Analog to the "copyprotection" command the engine can send "registration check...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~234-~234: Possible missing comma found.
Context: ...istration ok" or "registration error". Also after every attempt to register the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~239-~239: Consider adding a comma after this introductory phrase.
Context: ...and might not use all its features. In addition the GUI should offer to open a dialog t...(IN_GENERAL_COMMA)
[uncategorized] ~240-~240: Possible missing comma found.
Context: ...on of the engine. To try to register an engine the GUI can send the "register" comman...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~253-~253: A comma may be missing after the conjunctive/linking adverb ‘Also’.
Context: ...nfo depth 12 nodes 123456 nps 100000". Also all infos belonging to the pv should be...(SENT_START_CONJUNCTIVE_LINKING_ADVERB_COMMA)
[typographical] ~262-~262: Consider adding a comma.
Context: ...in plies, if the engine sends seldepth there must also be a "depth" present in the s...(IF_THERE_COMMA)
[uncategorized] ~271-~271: Possible missing comma found.
Context: ... the multi pv mode. for the best move/pv add "multipv 1" in the string when you ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~272-~272: Possible missing comma found.
Context: ...tring when you send the pv. in k-best mode always send all k variants in k strings...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~282-~282: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ...bound. * upperbound the score is just an upper bound. * currmove cu...(REP_BE_JUST)
[grammar] ~299-~299: Possibly, a comma is missing after an introductory clause, the verb inflection is not correct, or a question mark is missing. Did you mean “string, command” or “string commands”?
Context: ...isplayed be the engine, if there is a string command the rest of the line will be interprete...(IF_DT_NN_VBZ)
[uncategorized] ~301-~301: Did you mean “I”?
Context: ...efuted by the line ... , i can be any number >= 1. Example: af...(I_LOWERCASE_PREMIUM)
[style] ~312-~312: This phrasing could be wordy, so try replacing it with something more concise.
Context: ... can be omitted. If is greater than 1, always send all k lines in k strings...(MORE_THAN_EXCEEDS)
[uncategorized] ~326-~326: Possible missing comma found.
Context: ...nge the default value. For all allowed combinations see the examples below, as some combin...(AI_HYDRA_LEO_MISSING_COMMA)
[grammar] ~327-~327: The singular determiner ‘this’ may not agree with the plural noun ‘tokens’. Did you mean “these”?
Context: ...xamples below, as some combinations of this tokens don't make sense. One string wi...(THIS_NNS)
[typographical] ~332-~332: Consider adding a comma after ‘Usually’ for more clarity.
Context: ...he semantics of this option is fixed. Usually those options should not be displayed i...(RB_LY_COMMA)
[uncategorized] ~339-~339: The preposition ‘of’ seems more likely in this position.
Context: ...= Hash, type is spin the value in MB for memory for hash tables can be changed, ...(AI_HYDRA_LEO_REPLACE_FOR_OF)
[style] ~343-~343: As an alternative to the over-used intensifier ‘very’, consider replacing this phrase.
Context: ...ll engines! So the engine should use a very small hash first as default. * = Nalim...(EN_WEAK_ADJECTIVE)
[style] ~352-~352: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ype check this means that the engine is able to ponder. The GUI will send this whene...(BE_ABLE_TO)
[style] ~368-~368: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ould be false by default, The engine is able to limit its strength to a specific Elo nu...(BE_ABLE_TO)
[typographical] ~377-~377: After the expression ‘for example’ a comma is usually used.
Context: ...n analysing or playing a game. For example when playing it can use some kind of le...(COMMA_FOR_EXAMPLE)
[typographical] ~378-~378: The word “otherwise” is an adverb that can’t be used like a conjunction, and therefore needs to be separated from the sentence.
Context: ...set to false if the engine is playing a game, otherwise it is true. * = UCI_Opponent, t...(THUS_SENTENCE)
[uncategorized] ~384-~384: Did you mean Garry Kasparov, the chess player?
Context: ...n name UCI_Opponent value GM 2800 human Gary Kasparov" "setoption name UCI_Opponent valu...(EN_SIMPLE_REPLACE_GARY_KASPAROV)
[duplication] ~385-~385: Possible typo: you repeated a word
Context: ... "setoption name UCI_Opponent value none none computer Shredder" * = UCI_Engi...(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~481-~481: Possible typo: you repeated a word
Context: ... is supporting it, tell the engine that is is // searching on a game that it hasn't s...(ENGLISH_WORD_REPEAT_RULE)
[uncategorized] ~526-~526: Possible missing comma found.
Context: ...l the GUI that it is capable of playing Chess960 and the GUI has to tell the engine that...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~526-~526: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ... of playing Chess960 and the GUI has to tell the engine that is should play accordin...(REP_TELL_X)
[grammar] ~527-~527: Do not use the modal verb ‘should’ after the verb ‘be’. Did you mean “should”?
Context: ...and the GUI has to tell the engine that is should play according to the Chess960 rules. T...(BE_MD)
[style] ~536-~536: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...es" his own rook. Example: e1h1 for the white short castle move in the normal chess start p...(EN_ADJ_ORDER)
src/main.cpp (1)
23-23: Consider removing unused parameters frommainSince
argcandargvare no longer utilized withinmain, you might simplify the function signature toint main()to reflect that no command-line arguments are processed.Apply this diff to update the function signature:
-int main(int argc, char *argv[]) { +int main() {src/move_gen.h (1)
36-40: Consistent Naming ConventionsEnsure that the naming conventions for the move generation functions are consistent across the codebase. If other functions use a specific naming style (e.g.,
generate_pawn_movesvs.generatePawnMoves), aligning these functions' names will improve code readability and maintainability.src/board.h (1)
40-40: Consider using a specific type for the 'square' parameterIn
getPieceOnSquare(int square), consider using a more specific type instead ofintfor thesquareparameter. Ifsquareis expected to be within a specific range (e.g.,0to63for a chessboard), using a fixed-width unsigned integer likeuint8_tor defining a type alias (e.g.,SquareIndex) can enhance type safety and prevent invalid values.src/move_gen.cpp (3)
30-33: Offer assistance in implementing TODOs for pawn movesThe
generatePawnMovesfunction has several TODOs:
- Implement en passant.
- Handle promotions.
- Move attacks to table lookup.
- Implement
GenerationTypelogic using a mask.Would you like assistance in implementing any of these features? I can help generate code or provide suggestions to address these TODO items.
110-110: Offer assistance in implementing TODO for knight movesThe
generateKnightMovesfunction includes a TODO to move to table calculations. Using precomputed attack tables can enhance performance.Would you like assistance in implementing precomputed attack tables for knight moves? I can help provide code or discuss strategies for generating and utilizing these tables.
28-127: Consider adding unit tests for move generation functionsAdding unit tests for
generatePawnMovesandgenerateKnightMoveswill help ensure correctness and facilitate future development and refactoring.src/bitwise.cpp (3)
5-5: Update the copyright year to reflect 2024.Since the code is being rewritten in 2024, consider updating the year to reflect the current year only.
Apply this diff:
- Copyright (C) 2023-2024 Danny Jelsma + Copyright (C) 2024 Danny Jelsma
22-22: Ensureconstants.his necessary.Verify that all constants used in this file are defined in
constants.hand remove any unnecessary includes to improve compilation time.
222-222: Ensure there's a newline at the end of the file.For POSIX compliance and to avoid compiler warnings, the file should end with a newline character.
src/uci.cpp (2)
37-37: Address the pending setup implementationThere's a TODO comment indicating that additional setup is required in the
doSetupmethod. Completing this implementation is essential for the engine's correct initialization.Would you like assistance in implementing the necessary setup steps? I can help provide solutions or open a GitHub issue to track this task.
261-261: Implement multithreading for concurrent input handlingThe TODO comment suggests that activities unrelated to UCI input reading should be performed in a separate thread to allow the engine to read input even while thinking. Implementing multithreading will help achieve this requirement and improve responsiveness.
Would you like assistance in implementing a threading mechanism to handle UCI input and engine processing concurrently? I can help outline a solution or open a GitHub issue to track this task.
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (66)
- .github/workflows/ctest.yml (1 hunks)
- .github/workflows/release.yml (3 hunks)
- .github/workflows/valgrind.yml (1 hunks)
- .idea/.gitignore (1 hunks)
- CMakeLists.txt (2 hunks)
- senjo/BackgroundCommand.cpp (0 hunks)
- senjo/BackgroundCommand.h (0 hunks)
- senjo/CMakeLists.txt (0 hunks)
- senjo/ChessEngine.cpp (0 hunks)
- senjo/ChessEngine.h (0 hunks)
- senjo/EngineOption.cpp (0 hunks)
- senjo/EngineOption.h (0 hunks)
- senjo/GoParams.h (0 hunks)
- senjo/Output.cpp (0 hunks)
- senjo/Output.h (0 hunks)
- senjo/Parameters.cpp (0 hunks)
- senjo/Parameters.h (0 hunks)
- senjo/Platform.h (0 hunks)
- senjo/README.md (0 hunks)
- senjo/SearchStats.h (0 hunks)
- senjo/Thread.cpp (0 hunks)
- senjo/Thread.h (0 hunks)
- senjo/UCIAdapter.cpp (0 hunks)
- senjo/UCIAdapter.h (0 hunks)
- src/bitboard.cpp (2 hunks)
- src/bitboard.h (2 hunks)
- src/bitwise.cpp (2 hunks)
- src/bitwise.h (2 hunks)
- src/board.cpp (1 hunks)
- src/board.h (2 hunks)
- src/constants.h (2 hunks)
- src/engine.cpp (0 hunks)
- src/engine.h (0 hunks)
- src/evaluate.cpp (0 hunks)
- src/evaluate.h (0 hunks)
- src/features.cpp (0 hunks)
- src/features.h (0 hunks)
- src/magics.cpp (2 hunks)
- src/main.cpp (2 hunks)
- src/move.h (2 hunks)
- src/move_gen.cpp (1 hunks)
- src/move_gen.h (2 hunks)
- src/move_picker.cpp (1 hunks)
- src/move_picker.h (2 hunks)
- src/movegen.cpp (0 hunks)
- src/movelist_pool.cpp (0 hunks)
- src/movepicker.cpp (0 hunks)
- src/pst.cpp (0 hunks)
- src/pst.h (0 hunks)
- src/search.cpp (0 hunks)
- src/search.h (0 hunks)
- src/timemanager.cpp (0 hunks)
- src/timemanager.h (0 hunks)
- src/tt.cpp (0 hunks)
- src/tt.h (0 hunks)
- src/tuner.cpp (0 hunks)
- src/types.h (2 hunks)
- src/uci-specification.txt (1 hunks)
- src/uci.cpp (1 hunks)
- src/uci.h (1 hunks)
- src/utils.cpp (0 hunks)
- src/utils.h (0 hunks)
- tests/ep_tests.cpp (0 hunks)
- tests/eval_tests.cpp (0 hunks)
- tests/perft_tests.cpp (0 hunks)
- tests/see_tests.cpp (0 hunks)
💤 Files with no reviewable changes (43)
- senjo/BackgroundCommand.cpp
- senjo/BackgroundCommand.h
- senjo/CMakeLists.txt
- senjo/ChessEngine.cpp
- senjo/ChessEngine.h
- senjo/EngineOption.cpp
- senjo/EngineOption.h
- senjo/GoParams.h
- senjo/Output.cpp
- senjo/Output.h
- senjo/Parameters.cpp
- senjo/Parameters.h
- senjo/Platform.h
- senjo/README.md
- senjo/SearchStats.h
- senjo/Thread.cpp
- senjo/Thread.h
- senjo/UCIAdapter.cpp
- senjo/UCIAdapter.h
- src/engine.cpp
- src/engine.h
- src/evaluate.cpp
- src/evaluate.h
- src/features.cpp
- src/features.h
- src/movegen.cpp
- src/movelist_pool.cpp
- src/movepicker.cpp
- src/pst.cpp
- src/pst.h
- src/search.cpp
- src/search.h
- src/timemanager.cpp
- src/timemanager.h
- src/tt.cpp
- src/tt.h
- src/tuner.cpp
- src/utils.cpp
- src/utils.h
- tests/ep_tests.cpp
- tests/eval_tests.cpp
- tests/perft_tests.cpp
- tests/see_tests.cpp
✅ Files skipped from review due to trivial changes (1)
- .idea/.gitignore
🧰 Additional context used
🪛 LanguageTool
src/uci-specification.txt
[uncategorized] ~20-~20: Possible missing comma found.
Context: ... If you use Engine and GUI in the same OS this should be no problem if you commun...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~27-~27: Possible missing comma found.
Context: ... * The engine will always be in forced mode which means it should never start calcu...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~39-~39: Consider adding a comma before the interrupter.
Context: ... "debug joho on\n" will be undefined however. * if the engine receives a command wh...(HOWEVER_COMMA)
[style] ~50-~50: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...t as 0000. Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (for promotion) GUI...(EN_ADJ_ORDER)
[typographical] ~65-~65: Consider adding a comma here.
Context: ...e settings the engine supports if any. After that the engine should send "uciok" to ackno...(FOR_THAT_COMMA)
[uncategorized] ~89-~89: Possible missing comma found.
Context: ...eded. One string will be sent for each parameter and this will only be sent when the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~90-~90: This word is normally spelled with a hyphen.
Context: ...lue of the option in should not be case sensitive and can inlude spaces. The substrings ...(EN_COMPOUNDS_CASE_SENSITIVE)
[uncategorized] ~117-~117: Possible missing comma found.
Context: ...uld play or a new game it should analyse but also the next position from a testsu...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~119-~119: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...sitions only. If the GUI hasn't sent a "ucinewgame" before the first "position...(EN_A_VS_AN)
[uncategorized] ~120-~120: Possible missing comma found.
Context: ...uldn't expect any further ucinewgame commands as the GUI is probably not supporting t...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~122-~122: Possible missing comma found.
Context: ... reaction to "ucinewgame" can take some time the GUI should always send "isready" ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~127-~127: This noun is normally spelled as one word.
Context: ...ard and play the moves on the internal chess board. if the game was played from the star...(BOARD_COMPOUNDS)
[uncategorized] ~128-~128: Possible missing comma found.
Context: ... if the game was played from the start position the string "startpos" will be sent Not...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~130-~130: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...to the engine, the GUI should have sent a "ucinewgame" inbetween. * go start ca...(EN_A_VS_AN)
[typographical] ~135-~135: It seems that a comma is missing.
Context: ...the same string. If one command is not sent its value should be interpreted as it w...(IF_COMMA)
[grammar] ~137-~137: The singular determiner ‘this’ may not agree with the plural noun ‘moves’. Did you mean “these”?
Context: ...ove1> .... restrict search to this moves only Example: After "position s...(THIS_NNS)
[duplication] ~143-~143: Possible typo: you repeated a word
Context: ...e! This means that the last move sent in in the position string is the ponder move....(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~173-~173: Possible typo: you repeated a word
Context: ...hout being told so in this mode! * stop stop calculating as soon as possible, don't...(ENGLISH_WORD_REPEAT_RULE)
[style] ~175-~175: For a more polite and respectful tone, consider rephrasing with ‘please’.
Context: ... stop calculating as soon as possible, don't forget the "bestmove" and possibly the "ponder...(DONT_FORGET)
[duplication] ~181-~181: Possible typo: you repeated a word
Context: ...tch from pondering to normal search. * quit quit the program as soon as possible Engin...(ENGLISH_WORD_REPEAT_RULE)
[typographical] ~212-~212: Consider adding a comma here.
Context: ...ve" command is needed! Directly before that the engine should send a final "info" c...(TO_THAT_COMMA)
[duplication] ~213-~213: Possible typo: you repeated a word
Context: ...and with the final search information, the the GUI has the complete statistics about t...(ENGLISH_WORD_REPEAT_RULE)
[uncategorized] ~216-~216: Possible missing comma found.
Context: ... copyprotected engines. After the uciok command the engine can tell the GUI, that it w...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~218-~218: It seems that a comma is missing.
Context: ...yprotection checking". If the check is ok the engine should send "copyprotection ...(IF_COMMA)
[uncategorized] ~219-~219: Possible missing comma found.
Context: ..."copyprotection error". If there is an error the engine should not function properly...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~220-~220: Three successive sentences begin with the same word. Consider rewording the sentence or use a thesaurus to find a synonym.
Context: ...on properly but should not quit alone. If the engine reports "copyprotection erro...(ENGLISH_WORD_REPEAT_BEGINNING_RULE)
[uncategorized] ~232-~232: Possible missing comma found.
Context: ...atures. Analog to the "copyprotection" command the engine can send "registration check...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~234-~234: Possible missing comma found.
Context: ...istration ok" or "registration error". Also after every attempt to register the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~239-~239: Consider adding a comma after this introductory phrase.
Context: ...and might not use all its features. In addition the GUI should offer to open a dialog t...(IN_GENERAL_COMMA)
[uncategorized] ~240-~240: Possible missing comma found.
Context: ...on of the engine. To try to register an engine the GUI can send the "register" comman...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~253-~253: A comma may be missing after the conjunctive/linking adverb ‘Also’.
Context: ...nfo depth 12 nodes 123456 nps 100000". Also all infos belonging to the pv should be...(SENT_START_CONJUNCTIVE_LINKING_ADVERB_COMMA)
[typographical] ~262-~262: Consider adding a comma.
Context: ...in plies, if the engine sends seldepth there must also be a "depth" present in the s...(IF_THERE_COMMA)
[uncategorized] ~271-~271: Possible missing comma found.
Context: ... the multi pv mode. for the best move/pv add "multipv 1" in the string when you ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~272-~272: Possible missing comma found.
Context: ...tring when you send the pv. in k-best mode always send all k variants in k strings...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~282-~282: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ...bound. * upperbound the score is just an upper bound. * currmove cu...(REP_BE_JUST)
[grammar] ~299-~299: Possibly, a comma is missing after an introductory clause, the verb inflection is not correct, or a question mark is missing. Did you mean “string, command” or “string commands”?
Context: ...isplayed be the engine, if there is a string command the rest of the line will be interprete...(IF_DT_NN_VBZ)
[uncategorized] ~301-~301: Did you mean “I”?
Context: ...efuted by the line ... , i can be any number >= 1. Example: af...(I_LOWERCASE_PREMIUM)
[style] ~312-~312: This phrasing could be wordy, so try replacing it with something more concise.
Context: ... can be omitted. If is greater than 1, always send all k lines in k strings...(MORE_THAN_EXCEEDS)
[uncategorized] ~326-~326: Possible missing comma found.
Context: ...nge the default value. For all allowed combinations see the examples below, as some combin...(AI_HYDRA_LEO_MISSING_COMMA)
[grammar] ~327-~327: The singular determiner ‘this’ may not agree with the plural noun ‘tokens’. Did you mean “these”?
Context: ...xamples below, as some combinations of this tokens don't make sense. One string wi...(THIS_NNS)
[typographical] ~332-~332: Consider adding a comma after ‘Usually’ for more clarity.
Context: ...he semantics of this option is fixed. Usually those options should not be displayed i...(RB_LY_COMMA)
[uncategorized] ~339-~339: The preposition ‘of’ seems more likely in this position.
Context: ...= Hash, type is spin the value in MB for memory for hash tables can be changed, ...(AI_HYDRA_LEO_REPLACE_FOR_OF)
[style] ~343-~343: As an alternative to the over-used intensifier ‘very’, consider replacing this phrase.
Context: ...ll engines! So the engine should use a very small hash first as default. * = Nalim...(EN_WEAK_ADJECTIVE)
[style] ~352-~352: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ype check this means that the engine is able to ponder. The GUI will send this whene...(BE_ABLE_TO)
[style] ~368-~368: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ould be false by default, The engine is able to limit its strength to a specific Elo nu...(BE_ABLE_TO)
[typographical] ~377-~377: After the expression ‘for example’ a comma is usually used.
Context: ...n analysing or playing a game. For example when playing it can use some kind of le...(COMMA_FOR_EXAMPLE)
[typographical] ~378-~378: The word “otherwise” is an adverb that can’t be used like a conjunction, and therefore needs to be separated from the sentence.
Context: ...set to false if the engine is playing a game, otherwise it is true. * = UCI_Opponent, t...(THUS_SENTENCE)
[uncategorized] ~384-~384: Did you mean Garry Kasparov, the chess player?
Context: ...n name UCI_Opponent value GM 2800 human Gary Kasparov" "setoption name UCI_Opponent valu...(EN_SIMPLE_REPLACE_GARY_KASPAROV)
[duplication] ~385-~385: Possible typo: you repeated a word
Context: ... "setoption name UCI_Opponent value none none computer Shredder" * = UCI_Engi...(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~481-~481: Possible typo: you repeated a word
Context: ... is supporting it, tell the engine that is is // searching on a game that it hasn't s...(ENGLISH_WORD_REPEAT_RULE)
[uncategorized] ~526-~526: Possible missing comma found.
Context: ...l the GUI that it is capable of playing Chess960 and the GUI has to tell the engine that...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~526-~526: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ... of playing Chess960 and the GUI has to tell the engine that is should play accordin...(REP_TELL_X)
[grammar] ~527-~527: Do not use the modal verb ‘should’ after the verb ‘be’. Did you mean “should”?
Context: ...and the GUI has to tell the engine that is should play according to the Chess960 rules. T...(BE_MD)
[style] ~536-~536: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...es" his own rook. Example: e1h1 for the white short castle move in the normal chess start p...(EN_ADJ_ORDER)
🪛 cppcheck
src/uci.cpp
[performance] 343-343: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 351-351: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 359-359: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 406-406: Function parameter 'values' should be passed by const reference.
(passedByValue)
🔇 Additional comments (55)
.github/workflows/ctest.yml (3)
Line range hint
1-33: LGTM! Workflow update looks good overall.The update to Clang 18 and the overall structure of the workflow are appropriate. With the suggested improvements, this workflow should provide a robust CI process for the project.
24-24: Verify compatibility with Clang 18 and update documentation.The Clang version has been updated from 17 to 18. While this keeps the project up-to-date with the latest compiler version, it's important to consider the following:
- Ensure that the codebase is compatible with Clang 18. There might be new warnings or errors that need to be addressed.
- Update any documentation or README files to reflect the new Clang version requirement.
- Communicate this change to the development team, as they may need to update their local environments.
To verify the impact of this change, please run the following script:
Consider adding a comment in the workflow file explaining why Clang 18 is required, especially if there are specific features or optimizations that the project needs.
✅ Verification successful
Clang 18 compatibility verified successfully.
All checks have passed with Clang 18. No compatibility issues were detected in the codebase or documentation.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check for any compatibility issues with Clang 18 # Test: Look for any compiler-specific code or macros that might be affected rg --type cpp "__clang__" # Test: Check if CMakeLists.txt specifies a Clang version rg --type cmake "clang" # Test: Look for any documentation mentioning Clang version fd README.md | xargs rg "clang"Length of output: 743
Line range hint
1-33: Consider optimizing the workflow for better performance and consistency.While the current workflow is functional, there are a few improvements that could enhance its performance and consistency:
- Cache dependencies and build artifacts to speed up subsequent runs. You can use GitHub's
actions/cachefor this purpose.- Specify the Clang version in the CMake configuration to ensure consistency with the installed version. Add
-DCMAKE_C_COMPILER=clang-18 -DCMAKE_CXX_COMPILER=clang++-18to the CMake command.- Consider adding a step to upload test results as artifacts, especially if tests fail.
- If the extra-verbose output from CTest is too noisy, consider using a more concise output format and only use --extra-verbose for failed tests.
Here's a suggested modification to the CMake configuration step:
- name: Configure CMake & Build run: | - cmake -DCMAKE_BUILD_TYPE=Release -DAPPEND_VERSION=OFF -DENABLE_WARNINGS=ON -DENABLE_SANITIZER=OFF -DENABLE_TESTS=ON . + cmake -DCMAKE_BUILD_TYPE=Release -DAPPEND_VERSION=OFF -DENABLE_WARNINGS=ON -DENABLE_SANITIZER=OFF -DENABLE_TESTS=ON -DCMAKE_C_COMPILER=clang-18 -DCMAKE_CXX_COMPILER=clang++-18 . cmake --build . --target allTo verify the current CMake configuration, you can run:
src/constants.h (5)
6-6: LGTM: Copyright year updatedThe copyright year has been correctly updated to include 2024, which is a good practice to keep the notice current.
26-29: LGTM: Bitboard constants addedThe addition of these bitboard constants (NOT_A_FILE, NOT_AB_FILE, NOT_GH_FILE, NOT_H_FILE) is a good practice. They provide clear, named representations of common bitboard patterns used in chess engines, which can improve code readability and maintainability.
31-32: LGTM: RANK_4 and RANK_5 constants updatedThe RANK_4 and RANK_5 constants have been correctly updated to represent the 4th and 5th ranks on a chess board using bitboard representation. This update aligns with standard chess programming practices and will be useful for rank-based operations in the engine.
Line range hint
1-38: Overall assessment: Positive improvements with a minor clarification neededThe changes to
src/constants.hgenerally improve the codebase by:
- Updating the copyright notice
- Adding useful bitboard constants
- Updating rank constants
- Introducing constants for squares, pieces, and colors
- Maintaining the MAX_MOVES constant
These changes align with good chess programming practices and should enhance the engine's functionality and code readability.
The main point requiring clarification is the removal of the
statickeyword from constants, which changes their linkage. Please address this in the earlier comment about MAX_MOVES.Additionally, consider adding comments to explain the less obvious constants (like PIECES) to improve long-term maintainability.
38-38: Clarify the removal ofstaticfrom MAX_MOVESThe MAX_MOVES constant has been kept at 255, which is a reasonable value for the maximum number of legal moves in a chess position. The use of
uint8_tis appropriate for this range.Could you clarify the reason for removing the
statickeyword? This changes the linkage from internal to external. If this was intentional to allow use in other translation units, please confirm. Otherwise, consider keeping itstaticto limit its scope to this translation unit.To verify the usage of MAX_MOVES across the codebase, run the following script:
This will help us understand if the external linkage is necessary.
✅ Verification successful
Verified the removal of
staticfromMAX_MOVESThe
MAX_MOVESconstant is now externally linked and is used insrc/move.h, confirming that removing thestatickeyword is appropriate for its intended usage across multiple translation units.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check usage of MAX_MOVES across the codebase # Search for MAX_MOVES usage echo "Occurrences of MAX_MOVES:" rg --type cpp "MAX_MOVES" # Check if MAX_MOVES is defined in other files echo "\nOther definitions of MAX_MOVES:" rg --type cpp "constexpr.*MAX_MOVES"Length of output: 355
src/board.cpp (5)
1-19: LGTM: Proper license header included.The license header is complete, correctly formatted, and includes all necessary information about the GNU Affero General Public License v3 or later.
21-23: LGTM: Appropriate includes.The include statements are correct and necessary for the implementation. "board.h" is included for the Board class definition, and is included for std::to_underlying.
26-29: LGTM: Well-implemented getBitboard method.The getBitboard method is correctly implemented as a template function. It uses std::to_underlying for type-safe access to the bitboards array, and the const qualifier is appropriately used.
31-34: LGTM: Well-implemented getColorBitboard method.The getColorBitboard method is correctly implemented as a template function. It uses std::to_underlying for type-safe access to the colorBoards array, and the const qualifier is appropriately used.
36-46: LGTM: Well-implemented utility methods.The getPieceOnSquare, getOccupiedBitboard, and getEmptyBitboard methods are correctly implemented. They are concise, use appropriate const qualifiers, and correctly access or compute the required information.
.github/workflows/valgrind.yml (1)
24-24: Approve Clang upgrade with compatibility checkThe upgrade to Clang 18 is a positive change, potentially bringing performance improvements and new features. However, it's important to ensure compatibility with the rest of the toolchain and the project's code.
To verify compatibility, please run the following script:
This script will help identify any potential compatibility issues with the Clang 18 upgrade.
✅ Verification successful
Clang 18 upgrade verified successfully
No compatibility issues were found with the Clang 18 upgrade based on the executed checks.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check for any compatibility issues with Clang 18 # Test: Check if CMakeLists.txt specifies a minimum Clang version echo "Checking CMakeLists.txt for Clang version specifications:" rg --type cmake "clang" CMakeLists.txt # Test: Look for any hardcoded Clang version numbers in the codebase echo "Checking for hardcoded Clang version numbers:" rg --type cpp --type cmake "clang-1[0-9]" # Test: Check if there are any compiler-specific flags or optimizations echo "Checking for compiler-specific flags or optimizations:" rg --type cmake "CMAKE_CXX_COMPILER_ID" CMakeLists.txtLength of output: 866
.github/workflows/release.yml (2)
94-94: Approved: Consistent use of latest Ubuntu versionThis change aligns the 'create-release' job with the 'build' job, ensuring consistent use of the latest stable Ubuntu version throughout the workflow.
Please refer to the earlier comment about using
ubuntu-latestfor additional considerations and suggestions.
42-44: Approved: Updating LLVM action and versionUpgrading to the latest version of the LLVM installation action and LLVM 18 is beneficial for accessing new features, optimizations, and bug fixes.
Please ensure that the codebase is compatible with LLVM 18. Run the following script to check for any LLVM version-specific code or compiler flags:
Review the output to ensure all LLVM and compiler flag usages are compatible with LLVM 18.
✅ Verification successful
Verified: LLVM Action and Version Upgrade
The LLVM installation action has been successfully upgraded to v2 and LLVM version to 18. No incompatible compiler flags or LLVM version-specific code were found that could affect the codebase.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check for LLVM version-specific code or compiler flags # Search for LLVM version references in source files echo "Searching for LLVM version references:" rg --type cpp --type cmake "llvm|clang" -g "!vendor/*" # Search for compiler flags that might need updating echo "Searching for compiler flags:" rg --type cmake "-std=c\+\+|/std:c\+\+|-stdlib=|/Zc:" -g "!vendor/*"Length of output: 1139
Script:
#!/bin/bash # Description: Check for LLVM version-specific code or compiler flags # Search for LLVM version references in source files echo "Searching for LLVM version references:" rg --type cpp --type cmake "llvm|clang" -g "!vendor/*" # Search for compiler flags that might need updating echo "Searching for compiler flags:" rg --type cmake '(-std=c\+\+|/std:c\+\+|-stdlib=|/Zc:)' -g "!vendor/*"Length of output: 744
CMakeLists.txt (3)
25-25: Approved: Major version update to 6.0.The version bump to 6.0 aligns with the PR title indicating a complete rewrite. To ensure proper documentation and communication:
- Update the changelog to reflect the major changes in this version.
- Review and update any version-dependent documentation or API references.
- Consider creating migration guides for users updating from version 5.x to 6.0.
To verify version-related changes:
#!/bin/bash # Check for version references in documentation grep -r "version 5" docs/ || echo "No references to version 5 found in docs/" grep -r "version 6" docs/ || echo "No references to version 6 found in docs/"
204-204: Clarify the removal of Senjo library from the executable.The
${inc_senjo}variable has been removed from theadd_executablecommand. Please provide information on:
- The reason for removing Senjo library files from the main executable.
- How the functionality previously provided by Senjo is now being handled.
- Any changes to project dependencies or build instructions as a result of this modification.
To check for any remaining references to Senjo:
#!/bin/bash # Search for Senjo references in the project grep -r "senjo" . || echo "No references to Senjo found in the project"
23-23: Approved: C++ standard update to C++23.Updating to C++23 brings access to the latest language features and improvements. However, ensure that:
- Your compiler fully supports C++23.
- All dependencies are compatible with C++23.
- The team is aware of and prepared for any potential breaking changes or new features that might affect the codebase.
To verify compiler support, run:
src/magics.cpp (1)
393-395: Improved readability ininitializeMagicBitboardsThe updates to the
init_sliders_attacksfunction calls, usingtruefor bishops andfalsefor rooks, enhance code readability and align with the new function signature. These changes make the intent clearer without altering the existing logic.src/uci-specification.txt (3)
45-51: LGTM: Move format section is clear and well-explained.The move format section provides a concise explanation of the long algebraic notation used in UCI, along with helpful examples. This clarity will aid in correct implementation.
🧰 Tools
🪛 LanguageTool
[style] ~50-~50: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...t as 0000. Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (for promotion) GUI...(EN_ADJ_ORDER)
316-428: LGTM: Options section is comprehensive and well-explained.The options section provides a thorough explanation of how engines can define and communicate their configurable options. The different option types and their parameters are clearly described, which will greatly aid in correct implementation.
🧰 Tools
🪛 LanguageTool
[uncategorized] ~326-~326: Possible missing comma found.
Context: ...nge the default value. For all allowed combinations see the examples below, as some combin...(AI_HYDRA_LEO_MISSING_COMMA)
[grammar] ~327-~327: The singular determiner ‘this’ may not agree with the plural noun ‘tokens’. Did you mean “these”?
Context: ...xamples below, as some combinations of this tokens don't make sense. One string wi...(THIS_NNS)
[typographical] ~332-~332: Consider adding a comma after ‘Usually’ for more clarity.
Context: ...he semantics of this option is fixed. Usually those options should not be displayed i...(RB_LY_COMMA)
[uncategorized] ~339-~339: The preposition ‘of’ seems more likely in this position.
Context: ...= Hash, type is spin the value in MB for memory for hash tables can be changed, ...(AI_HYDRA_LEO_REPLACE_FOR_OF)
[style] ~343-~343: As an alternative to the over-used intensifier ‘very’, consider replacing this phrase.
Context: ...ll engines! So the engine should use a very small hash first as default. * = Nalim...(EN_WEAK_ADJECTIVE)
[style] ~352-~352: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ype check this means that the engine is able to ponder. The GUI will send this whene...(BE_ABLE_TO)
[style] ~368-~368: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ould be false by default, The engine is able to limit its strength to a specific Elo nu...(BE_ABLE_TO)
[typographical] ~377-~377: After the expression ‘for example’ a comma is usually used.
Context: ...n analysing or playing a game. For example when playing it can use some kind of le...(COMMA_FOR_EXAMPLE)
[typographical] ~378-~378: The word “otherwise” is an adverb that can’t be used like a conjunction, and therefore needs to be separated from the sentence.
Context: ...set to false if the engine is playing a game, otherwise it is true. * = UCI_Opponent, t...(THUS_SENTENCE)
[uncategorized] ~384-~384: Did you mean Garry Kasparov, the chess player?
Context: ...n name UCI_Opponent value GM 2800 human Gary Kasparov" "setoption name UCI_Opponent valu...(EN_SIMPLE_REPLACE_GARY_KASPAROV)
[duplication] ~385-~385: Possible typo: you repeated a word
Context: ... "setoption name UCI_Opponent value none none computer Shredder" * = UCI_Engi...(ENGLISH_WORD_REPEAT_RULE)
432-517: LGTM: Examples section provides clear illustration of UCI protocol usage.The examples section offers a valuable demonstration of a typical communication sequence between a GUI and an engine. This practical example will be very helpful for implementers in understanding how the various commands fit together in real-world usage.
🧰 Tools
🪛 LanguageTool
[duplication] ~481-~481: Possible typo: you repeated a word
Context: ... is supporting it, tell the engine that is is // searching on a game that it hasn't s...(ENGLISH_WORD_REPEAT_RULE)
src/main.cpp (3)
5-5: Update of the copyright yearIncluding "2024" in the copyright notice is appropriate and keeps the file up to date.
21-21: Ensure all necessary headers are includedWith the removal of standard library headers (
<fstream>,<iostream>, etc.), confirm that all required headers are included elsewhere or are no longer necessary. This ensures that the code compiles without issues related to missing headers.
23-27: Verify the removal of benchmarking and command-line argument handlingThe
mainfunction no longer processes command-line arguments or provides benchmarking functionalities such asbench,fastbench,tune, orprinteval. Ensure that the removal of these features aligns with the project's objectives and that there are no residual references elsewhere in the codebase that could lead to issues.Run the following script to check for references to the removed functionalities:
src/move.h (3)
6-6: License Update ConfirmedThe update of the copyright notice to "2023-2024" is appropriate.
27-27: Type AliasMoveImproves Code ClarityThe introduction of the type alias
using Move = uint16_t;enhances readability and maintainability.
36-38: FunctionencodeMoveImplementation Looks GoodThe
encodeMovefunction correctly encodes the move by combining thefromSquareandtoSquareinto a singleMovevalue.src/bitboard.h (2)
6-6: Updated copyright notice is appropriateThe update of the copyright year to include 2024
is correct.
26-26: Includingconstants.his appropriate ifDirectionis defined thereThe addition of
#include "constants.h"is appropriate if theDirectiontype used in the template function is defined in this header. Ensure thatconstants.his properly organized and does not introduce unnecessary dependencies.src/move_gen.h (3)
6-6: Update of Copyright NoticeThe update of the copyright year to "2023-2024" reflects the ongoing development period of the project.
24-25: Update of Included HeadersThe inclusion of
"board.h"and"move.h"suggests that necessary type definitions and function declarations are now provided in these headers. The removal of<vector>indicates thatstd::vectoris no longer required in this header file, which helps reduce unnecessary dependencies.
29-34: Introduction ofGenerationTypeEnum ClassDefining
enum class GenerationTypeenhances type safety and clarity by explicitly specifying the types of move generations. This improves code readability and reduces the risk of errors associated with using plain enums or constants.src/types.h (4)
25-34: Conversion ofDirectiontoenum classimproves type safetyChanging
Directionto a scoped enumeration (enum class) enhances type safety by preventing implicit conversions and name clashes. This is a good practice in modern C++ coding standards.
36-36: UpdatePieceTypetoenum classwith explicit underlying typeDefining
PieceTypeasenum class PieceType : int8_tensures efficient storage and prevents unintended type conversions. IncludingEMPTY = -1accommodates an uninitialized or empty state, which can be useful for error checking.
38-38: UpdatePieceColortoenum classwith explicit underlying typeUsing
enum class PieceColor : int8_twithEMPTY = -1mirrors the approach taken withPieceType. This consistency enhances code readability and maintainability.
40-53: Introduction ofPieceenum class consolidates piece definitionsDefining
Pieceas anenum classthat encapsulates all piece types, including both white and black pieces along with anEMPTYstate, improves code clarity. This allows for stronger type checking and reduces the risk of incorrect assignments.src/board.h (2)
31-34: Member variable definitions are appropriateThe private member variables are well-defined and initialized properly using default initialization. This sets a solid foundation for the
Boardclass.
37-47: Public member function declarations are clear and well-organizedThe use of template functions for
getBitboard()andgetColorBitboard()enhances flexibility. The[[nodiscard]]attribute is appropriately used to prevent ignoring important return values.src/bitboard.cpp (5)
23-23: LGTM: Inclusion of "types.h"Including
"types.h"ensures that necessary type definitions are available for this implementation.
26-27: LGTM: Utility functionpopcntcorrectly delegates toBitwise::popcntThe
popcntfunction accurately wrapsBitwise::popcnt, maintaining code modularity and readability.
30-31: LGTM: Utility functionpopLsbcorrectly delegates toBitwise::popLsbThe
popLsbfunction appropriately usesBitwise::popLsb, ensuring consistent bit manipulation operations.
34-35: LGTM: Utility functionbitscanForwardcorrectly delegates toBitwise::bitscanForwardThe
bitscanForwardfunction properly wraps the correspondingBitwisefunction.
38-39: LGTM: Utility functionbitscanReversecorrectly delegates toBitwise::bitscanReverseThe
bitscanReversefunction accurately delegates toBitwise::bitscanReverse, maintaining a clean interface.src/bitwise.cpp (3)
29-34: Handle zero input inpopcntfunction.Ensure that the
popcntfunction behaves correctly whenbbis zero. While the intrinsics generally handle zero correctly, it's good practice to document this or add an explicit check if necessary.
64-126: Validate edge masking in shift functions.Ensure that masking with constants like
NOT_A_FILE,NOT_H_FILE, etc., correctly prevents wrap-around moves. Double-check that all masks accurately represent the board edges.You can run the following script to confirm the masks:
#!/bin/bash # Description: Verify the definitions of file masks used in shift functions. # Expected: Masks should correctly represent the files. # Examine the definitions in constants.h rg 'define\s+(NOT_[A-H]_FILE|NOT_[A-H][A-H]_FILE|RANK_[1-8])' constants.h
24-26: Confirm compiler-specific intrinsics are correctly guarded.The inclusion of
<intrin.h>and usage of intrinsics are wrapped with#ifdef _MSC_VER. Ensure that this guards all MSVC-specific code and that alternative implementations are provided for other compilers.You can run the following script to check for any unguarded MSVC-specific code:
✅ Verification successful
All MSVC-specific intrinsics are correctly guarded.
- Verified that all instances of
_BitScanand__popcntinsrc/bitwise.cppare enclosed within#ifdef _MSC_VERblocks.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Find usage of MSVC-specific intrinsics not guarded by _MSC_VER # Search for intrinsics specific to MSVC outside of guarded sections rg -A2 -B2 '_BitScan|__popcnt' src/bitwise.cpp | grep -v '#ifdef _MSC_VER' | grep -E '_BitScan|__popcnt'Length of output: 221
Script:
#!/bin/bash # Description: Verify that all MSVC-specific intrinsics in src/bitwise.cpp are guarded by #ifdef _MSC_VER # List of MSVC-specific intrinsics to check intrinsics=('_BitScan' '__popcnt') # Iterate over each intrinsic and check if it's within a guarded block for intrinsic in "${intrinsics[@]}"; do rg -n "$intrinsic" src/bitwise.cpp | while read -r line; do line_number=$(echo "$line" | cut -d: -f2) # Check 3 lines above and below for #ifdef _MSC_VER start=$((line_number - 3)) end=$((line_number + 3)) if ! sed -n "${start},${end}p" src/bitwise.cpp | grep -q '#ifdef _MSC_VER'; then echo "Unguarded intrinsic '$intrinsic' found at line $line_number" fi done doneLength of output: 696
Script:
#!/bin/bash # Description: Verify that all MSVC-specific intrinsics in src/bitwise.cpp are guarded by #ifdef _MSC_VER # Ensure src/bitwise.cpp exists if [ ! -f src/bitwise.cpp ]; then echo "Error: src/bitwise.cpp not found." exit 1 fi # List of MSVC-specific intrinsics to check intrinsics=('_BitScan' '__popcnt') # Iterate over each intrinsic and check if it's within a guarded block for intrinsic in "${intrinsics[@]}"; do rg -n "$intrinsic" src/bitwise.cpp | while IFS=: read -r file line_num code; do # Ensure line_num is a number if ! [[ "$line_num" =~ ^[0-9]+$ ]]; then echo "Warning: Invalid line number '$line_num' for intrinsic '$intrinsic'. Skipping." continue fi # Define the range of lines to check above and below for #ifdef and #endif start=$((line_num - 3)) end=$((line_num + 3)) # Ensure start is at least 1 if [ "$start" -lt 1 ]; then start=1; fi # Extract the context lines context=$(sed -n "${start},${end}p" src/bitwise.cpp) # Check if #ifdef _MSC_VER is present in the context if ! echo "$context" | grep -q '#ifdef _MSC_VER'; then echo "Unguarded intrinsic '$intrinsic' found at line $line_num" fi done doneLength of output: 1245
Script:
#!/bin/bash # Description: Verify that all MSVC-specific intrinsics in src/bitwise.cpp are guarded by #ifdef _MSC_VER # Ensure src/bitwise.cpp exists if [ ! -f src/bitwise.cpp ]; then echo "Error: src/bitwise.cpp not found." exit 1 fi # List of MSVC-specific intrinsics to check intrinsics=('_BitScan' '__popcnt') # Iterate over each intrinsic and check if it's within a guarded block for intrinsic in "${intrinsics[@]}"; do # Use --no-filename since we're searching a single file rg --no-filename -n "$intrinsic" src/bitwise.cpp | while IFS=: read -r line_num code; do # Ensure line_num is a number if ! [[ "$line_num" =~ ^[0-9]+$ ]]; then echo "Warning: Invalid line number '$line_num' for intrinsic '$intrinsic'. Skipping." continue fi # Define the range of lines to check above and below for #ifdef and #endif start=$((line_num - 3)) end=$((line_num + 3)) # Ensure start is at least 1 if [ "$start" -lt 1 ]; then start=1; fi # Extract the context lines context=$(sed -n "${start},${end}p" src/bitwise.cpp) # Check if #ifdef _MSC_VER is present in the context if ! echo "$context" | grep -q '#ifdef _MSC_VER'; then echo "Unguarded intrinsic '$intrinsic' found at line $line_num" fi done doneLength of output: 1847
src/uci.cpp (2)
95-97:handleDebugCommandstub is acceptableThe
handleDebugCommandmethod correctly handles thedebugcommand by informing that debug mode is not implemented.
285-321: Efficient implementation ofremoveRedundantSpacesThe
removeRedundantSpacesfunction effectively normalizes whitespace in the input string, ensuring that extra spaces, tabs, and carriage returns are handled appropriately.src/move_picker.h (2)
Line range hint
1-5: License Header Updated CorrectlyThe license header has been updated to reflect the years 2023-2024 and appears to be correct.
23-27: Verify Removal ofbitboard.hIncludeThe inclusion of
bitboard.hhas been removed, and new headers have been included:<array>,"constants.h","move.h", and"types.h". Please verify thatbitboard.his no longer required and that its removal does not affect any dependencies or functionality in this file.Run the following script to check for any remaining dependencies on
bitboard.h:src/uci.h (3)
36-44: 🛠️ Refactor suggestionInconsistent Use of String Parameter Types in Command Handlers
The command handler methods have inconsistent parameter types for
args. Some methods usestd::string_view, while others useconst std::string&. For consistency and potential performance benefits, consider usingstd::string_viewfor all methods that accept string arguments where possible.Apply this diff to standardize the parameter types:
void handleUciCommand(); - void handleDebugCommand(std::string_view args); - void handleIsReadyCommand(const std::string& args); - void handleSetOptionCommand(const std::string& args); - void handleUciNewGameCommand(const std::string& args); - void handlePositionCommand(const std::string& args); - void handleGoCommand(const std::string& args); - void handleStopCommand(const std::string& args); - void handlePonderHitCommand(const std::string& args); - void handleQuitCommand(const std::string& args); + void handleDebugCommand(std::string_view args); + void handleIsReadyCommand(std::string_view args); + void handleSetOptionCommand(std::string_view args); + void handleUciNewGameCommand(std::string_view args); + void handlePositionCommand(std::string_view args); + void handleGoCommand(std::string_view args); + void handleStopCommand(std::string_view args); + void handlePonderHitCommand(std::string_view args); + void handleQuitCommand(std::string_view args);Ensure that the implementations and all calls to these methods are updated accordingly, and that changing the parameter types does not introduce any issues.
37-37: 🛠️ Refactor suggestionRemove Unused Parameters in Commands Without Arguments
The methods
handleIsReadyCommand(line 37) andhandleQuitCommand(line 44) have anargsparameter, but according to the UCI protocol, these commands do not accept any arguments. Consider removing theargsparameter from these methods to simplify the interface.Apply this diff to remove the unnecessary parameters:
- void handleIsReadyCommand(std::string_view args); + void handleIsReadyCommand(); ... - void handleQuitCommand(std::string_view args); + void handleQuitCommand();Ensure that the method implementations and any calls to these methods are updated to reflect the removed parameters.
Also applies to: 44-44
79-111: 🛠️ Refactor suggestionOptimize String Passing and Returning in
UCIOptionClassIn the
UCIOptionclass, the setter methods accept strings by value or non-const reference, and the getter methods return strings by value. This can lead to unnecessary copying of string data. For better performance and consistency, consider the following:
- Setter Methods: Accept parameters as
const std::string&to avoid unnecessary copies.- Getter Methods: Return
const std::string&to prevent copying when the caller only needs read access.- Const Correctness: Mark methods that do not modify the class state as
const.Apply this diff to update the method signatures:
- UCIOptionType getOptionType(); + UCIOptionType getOptionType() const; - std::string getName(); + const std::string& getName() const; - std::string getValue(); + const std::string& getValue() const; - void setValue(std::string& value); + void setValue(const std::string& value); - std::string getDefaultValue(); + const std::string& getDefaultValue() const; - void setDefaultValue(const std::string& value); - std::string getMinValue(); + const std::string& getMinValue() const; - void setMinValue(const std::string& value); - std::string getMaxValue(); + const std::string& getMaxValue() const; - void setMaxValue(const std::string& value); - std::string toString(); + std::string toString() const; - std::string getVar(int index); + const std::string& getVar(int index) const; - std::vector<std::string> getVar(); + const std::vector<std::string>& getVar() const;Ensure that these changes are compatible with the rest of the codebase. Check for any places where these methods are called and update them if necessary to handle the new return types and parameter types.
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com> Signed-off-by: Danny Jelsma <[email protected]>
There was a problem hiding this comment.
Actionable comments posted: 27
🧹 Outside diff range and nitpick comments (15)
.idea/.gitignore (2)
6-8: LGTM: Correctly ignoring database-related files.The entries for ignoring
/dataSources/and/dataSources.local.xmlare correct and follow best practices. This prevents sharing potentially sensitive database connection information.Consider adding a comment explaining why these files are ignored, similar to the other sections. For example:
# Datasource local storage ignored files /dataSources/ /dataSources.local.xml +# Ignore all .iml files +*.imlThis addition would help ignore all IntelliJ IDEA module files, which is often desirable.
1-8: Overall, this .gitignore file is well-structured and follows best practices.The file correctly ignores user-specific settings, temporary data, and potentially sensitive information for JetBrains IDEs. It's logically organized and includes comments for clarity. The only suggestion would be to consider adding
*.imlto ignore all IntelliJ IDEA module files, but this is a minor point and not strictly necessary.As the project grows, you might want to consider moving IDE-specific ignore rules to a global .gitignore file. This keeps the project-level .gitignore focused on project-specific rules and allows developers to use their preferred IDEs without affecting the repository.
src/constants.h (1)
34-36: LGTM: Optimized board dimension constantsThe constants SQUARES, PIECES, and COLORS have been updated to use uint8_t, which is more memory-efficient than int. This change aligns well with the performance-focused guidelines.
Consider using
constexpr uint8_tinstead ofconstexpr uint8_tfor these constants. This allows the compiler to perform more aggressive optimizations, potentially replacing the constants with immediate values in the generated assembly code.-constexpr uint8_t SQUARES = 64; -constexpr uint8_t PIECES = 12; -constexpr uint8_t COLORS = 2; +constexpr uint8_t SQUARES = 64; +constexpr uint8_t PIECES = 12; +constexpr uint8_t COLORS = 2;.github/workflows/release.yml (1)
Line range hint
1-114: Consider further workflow optimizationsThe overall structure of the workflow is well-maintained. However, consider the following suggestions for potential improvements:
Caching: Implement caching for dependencies to speed up builds. For example, you could cache the CMake build directory.
Matrix strategy for LLVM versions: Consider using a matrix strategy for LLVM versions to test against multiple versions simultaneously.
Automated testing: If not already present, add a step to run automated tests after the build.
Code formatting check: Add a step to verify code formatting, ensuring consistency across contributions.
Security scanning: Incorporate a security scanning step to identify potential vulnerabilities.
Here's an example of how you might implement caching:
- name: Cache CMake build directory uses: actions/cache@v3 with: path: build key: ${{ runner.os }}-cmake-${{ hashFiles('**/CMakeLists.txt') }} restore-keys: | ${{ runner.os }}-cmake-Would you like assistance in implementing any of these suggestions?
CMakeLists.txt (3)
23-23: Significant update to C++23 standardThe project has been updated to use C++23, which is a major change from the previous C++20 standard. This update allows for the use of the latest language features but may have implications:
- Ensure all developers have compilers that fully support C++23.
- Review and update the codebase to leverage new C++23 features where appropriate.
- Verify that all third-party libraries are compatible with C++23.
Consider documenting the rationale for this upgrade and any specific C++23 features that will be utilized in the rewrite.
25-25: Approval: Major version increment to 6.0The increment of the major version number to 6 is appropriate for a complete rewrite of the engine. This change aligns well with semantic versioning principles.
Consider the following additional steps:
- Update the changelog to reflect the major changes in version 6.0.
- Review and update any version-dependent documentation or scripts.
- Ensure that the version is consistently updated across all relevant files in the project.
Line range hint
1-226: Approval: Comprehensive CMake configuration retainedThe existing CMake configuration provides a robust and flexible setup for different build types and compiler options. Retaining this configuration for the rewrite is a good decision, as it allows for consistent build processes across different environments.
As the rewrite progresses:
- Regularly review these build configurations to ensure they still align with the project's needs.
- Consider adding new options or flags specific to new features or optimizations introduced in the rewrite.
- Document any new or changed build options to keep the project documentation up-to-date.
- Periodically test all build configurations to ensure they work as expected with the new codebase.
src/magics.cpp (1)
Line range hint
352-391: Approved: Improved type safety foris_bishopparameterThe change from
inttoboolfor theis_bishopparameter enhances type safety and clarity. This modification aligns with best practices for boolean parameters and maintains the function's efficiency.Consider using a compile-time constant or template parameter instead of a runtime boolean to potentially allow for better compiler optimizations:
template<bool is_bishop> void init_sliders_attacks() { // ... (rest of the function remains the same) } // Usage in initializeMagicBitboards: init_sliders_attacks<true>(); // for bishop init_sliders_attacks<false>(); // for rookThis approach could allow the compiler to generate more optimized code for each specific case.
src/move.h (1)
36-38: Consider utilizing remaining bits inMovefor additional move attributesSince
Moveis a 16-bit type and currently uses only 12 bits to encodefromSquareandtoSquare, you might consider utilizing the remaining 4 bits to store additional move attributes such as promotion pieces, capture flags, or special moves. This could enhance performance by encapsulating more information within theMovetype without increasing memory usage.src/board.h (1)
40-40: Consider using a strongly-typedSquareenum instead ofintTo enhance type safety and prevent invalid square indices, consider defining a
Squareenum or enum class representing valid board squares. This approach can help catch errors at compile time and make the codebase more robust.src/uci.h (2)
45-45: Rename Parameter 'string' to 'command' for ClarityIn the method
processCommand, the parameter namestringis not descriptive of its purpose. Renaming it tocommandimproves readability and better conveys its role in the function.Apply this diff to rename the parameter:
- void processCommand(const std::string& string, const std::string& args); + void processCommand(const std::string& command, const std::string& args);
109-111: Rename Overloaded 'getVar' Methods to Reduce ConfusionHaving two methods named
getVarwith different return types may lead to confusion. Consider renaming one of them for clarity. For example, renamegetVar()togetVars()to indicate it returns multiple values.Apply this diff:
- std::vector<std::string> getVar() const; + std::vector<std::string> getVars() const;src/move_gen.cpp (1)
30-33: Address the pending TODOs for complete pawn move generationThe
generatePawnMovesfunction contains several TODO comments:
- Implement en passant
- Handle promotions
- Move attacks to table lookup
- Implement
GenerationTypelogic using a computed maskThese features are essential for accurate and efficient pawn move generation. Completing them will enhance the engine's functionality and performance.
Would you like assistance in implementing any of these features? I can help with code suggestions or open GitHub issues to track these tasks.
src/bitwise.cpp (2)
Line range hint
343-352: Ensure correct use of bitwise OR operator inknightAttacksfunctionThere's a missing bitwise OR operator
|at the end of line 346, which may lead to incorrect calculations of knight attacks.Apply this diff to fix the issue:
uint64_t knightAttacks(uint64_t bb) { return shiftNorthNorthEast(bb) | shiftNorthEastEast(bb) | shiftSouthEastEast(bb) | - shiftSouthSouthEast(bb) + shiftSouthSouthEast(bb) | shiftSouthSouthWest(bb) | shiftSouthWestWest(bb) | shiftNorthWestWest(bb) | shiftNorthNorthWest(bb); }
Line range hint
244-256: Optimize pawn push functions using bitwise operationsTo enhance performance, consider combining the calculations in
whitePawnSinglePushandwhitePawnDoublePushusing more efficient bitwise operations, reducing the number of function calls.Apply this diff:
uint64_t whitePawnDoublePush(const uint64_t bb, const uint64_t empty) { - const uint64_t singlePush = whitePawnSinglePush(bb, empty); - return shiftNorth(singlePush) & empty & RANK_4; + return shiftNorth(shiftNorth(bb) & empty) & empty & RANK_4; }
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (66)
- .github/workflows/ctest.yml (1 hunks)
- .github/workflows/release.yml (3 hunks)
- .github/workflows/valgrind.yml (1 hunks)
- .idea/.gitignore (1 hunks)
- CMakeLists.txt (2 hunks)
- senjo/BackgroundCommand.cpp (0 hunks)
- senjo/BackgroundCommand.h (0 hunks)
- senjo/CMakeLists.txt (0 hunks)
- senjo/ChessEngine.cpp (0 hunks)
- senjo/ChessEngine.h (0 hunks)
- senjo/EngineOption.cpp (0 hunks)
- senjo/EngineOption.h (0 hunks)
- senjo/GoParams.h (0 hunks)
- senjo/Output.cpp (0 hunks)
- senjo/Output.h (0 hunks)
- senjo/Parameters.cpp (0 hunks)
- senjo/Parameters.h (0 hunks)
- senjo/Platform.h (0 hunks)
- senjo/README.md (0 hunks)
- senjo/SearchStats.h (0 hunks)
- senjo/Thread.cpp (0 hunks)
- senjo/Thread.h (0 hunks)
- senjo/UCIAdapter.cpp (0 hunks)
- senjo/UCIAdapter.h (0 hunks)
- src/bitboard.cpp (2 hunks)
- src/bitboard.h (2 hunks)
- src/bitwise.cpp (2 hunks)
- src/bitwise.h (2 hunks)
- src/board.cpp (1 hunks)
- src/board.h (2 hunks)
- src/constants.h (2 hunks)
- src/engine.cpp (0 hunks)
- src/engine.h (0 hunks)
- src/evaluate.cpp (0 hunks)
- src/evaluate.h (0 hunks)
- src/features.cpp (0 hunks)
- src/features.h (0 hunks)
- src/magics.cpp (2 hunks)
- src/main.cpp (2 hunks)
- src/move.h (2 hunks)
- src/move_gen.cpp (1 hunks)
- src/move_gen.h (2 hunks)
- src/move_picker.cpp (1 hunks)
- src/move_picker.h (2 hunks)
- src/movegen.cpp (0 hunks)
- src/movelist_pool.cpp (0 hunks)
- src/movepicker.cpp (0 hunks)
- src/pst.cpp (0 hunks)
- src/pst.h (0 hunks)
- src/search.cpp (0 hunks)
- src/search.h (0 hunks)
- src/timemanager.cpp (0 hunks)
- src/timemanager.h (0 hunks)
- src/tt.cpp (0 hunks)
- src/tt.h (0 hunks)
- src/tuner.cpp (0 hunks)
- src/types.h (2 hunks)
- src/uci-specification.txt (1 hunks)
- src/uci.cpp (1 hunks)
- src/uci.h (1 hunks)
- src/utils.cpp (0 hunks)
- src/utils.h (0 hunks)
- tests/ep_tests.cpp (0 hunks)
- tests/eval_tests.cpp (0 hunks)
- tests/perft_tests.cpp (0 hunks)
- tests/see_tests.cpp (0 hunks)
💤 Files with no reviewable changes (43)
- senjo/BackgroundCommand.cpp
- senjo/BackgroundCommand.h
- senjo/CMakeLists.txt
- senjo/ChessEngine.cpp
- senjo/ChessEngine.h
- senjo/EngineOption.cpp
- senjo/EngineOption.h
- senjo/GoParams.h
- senjo/Output.cpp
- senjo/Output.h
- senjo/Parameters.cpp
- senjo/Parameters.h
- senjo/Platform.h
- senjo/README.md
- senjo/SearchStats.h
- senjo/Thread.cpp
- senjo/Thread.h
- senjo/UCIAdapter.cpp
- senjo/UCIAdapter.h
- src/engine.cpp
- src/engine.h
- src/evaluate.cpp
- src/evaluate.h
- src/features.cpp
- src/features.h
- src/movegen.cpp
- src/movelist_pool.cpp
- src/movepicker.cpp
- src/pst.cpp
- src/pst.h
- src/search.cpp
- src/search.h
- src/timemanager.cpp
- src/timemanager.h
- src/tt.cpp
- src/tt.h
- src/tuner.cpp
- src/utils.cpp
- src/utils.h
- tests/ep_tests.cpp
- tests/eval_tests.cpp
- tests/perft_tests.cpp
- tests/see_tests.cpp
🧰 Additional context used
📓 Path-based instructions (17)
src/bitboard.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/bitboard.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/bitwise.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/bitwise.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/board.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/board.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/constants.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/magics.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/main.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/move.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/move_gen.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/move_gen.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/move_picker.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/move_picker.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/types.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/uci.cpp (1)
Pattern
**/*.cpp: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.src/uci.h (1)
Pattern
**/*.h: This code is part of a chess engine. It is very important for the chess engine to be as fast as possible and thus have a high performance. Performance and efficiency should be preferred over readability and maintainability, within reason. It is important that you point out performance improvements.
📓 Learnings (4)
src/move.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move.h:29-31 Timestamp: 2024-10-04T20:34:42.268Z Learning: In `MoveList` in `src/move.h`, the `size` member will never exceed `MAX_MOVES` (256), and memory optimization is a priority.src/move_gen.cpp (2)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.cpp:71-105 Timestamp: 2024-10-04T20:40:30.268Z Learning: In `src/move_gen.cpp`, prioritize performance over reducing code duplication. Avoid introducing extra function calls in performance-critical sections.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.h:36-37 Timestamp: 2024-10-05T12:15:41.746Z Learning: In `src/move_gen.h`, prefer using explicit template instantiations for longer (more than a few lines) or more complex template functions like `generatePawnMoves`, instead of including their definitions in header files.src/move_gen.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.h:36-37 Timestamp: 2024-10-05T12:15:41.746Z Learning: In `src/move_gen.h`, prefer using explicit template instantiations for longer (more than a few lines) or more complex template functions like `generatePawnMoves`, instead of including their definitions in header files.src/uci-specification.txt (2)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci-specification.txt:248-313 Timestamp: 2024-10-04T20:18:22.748Z Learning: Do not suggest modifications to the 'src/uci-specification.txt' file as it contains the external UCI specification and should not be altered.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci-specification.txt:132-171 Timestamp: 2024-10-04T20:17:46.747Z Learning: The file `src/uci-specification.txt` is not written by the user and should not be included. Avoid commenting on this file in future reviews.
🪛 LanguageTool
src/uci-specification.txt
[uncategorized] ~20-~20: Possible missing comma found.
Context: ... If you use Engine and GUI in the same OS this should be no problem if you commun...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~27-~27: Possible missing comma found.
Context: ... * The engine will always be in forced mode which means it should never start calcu...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~36-~36: Possible missing comma found.
Context: ... the GUI receives an unknown command or token it should just ignore it and try to p...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~39-~39: Consider adding a comma before the interrupter.
Context: ... "debug joho on\n" will be undefined however. * if the engine receives a command wh...(HOWEVER_COMMA)
[style] ~50-~50: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...t as 0000. Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (for promotion) GUI...(EN_ADJ_ORDER)
[uncategorized] ~63-~63: Possible missing comma found.
Context: ...h to uci mode. After receiving the uci command the engine must identify itself with th...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~65-~65: Consider adding a comma here.
Context: ...e settings the engine supports if any. After that the engine should send "uciok" to ackno...(FOR_THAT_COMMA)
[uncategorized] ~80-~80: Possible missing comma found.
Context: ...d be sent after setting the path to the tablebases as this can take some time. This comma...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~88-~88: Possible missing comma found.
Context: ...meters of the engine. For the "button" type no value is needed. One string will be...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~89-~89: Possible missing comma found.
Context: ...eded. One string will be sent for each parameter and this will only be sent when the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~90-~90: This word is normally spelled with a hyphen.
Context: ...lue of the option in should not be case sensitive and can inlude spaces. The substrings ...(EN_COMPOUNDS_CASE_SENSITIVE)
[uncategorized] ~117-~117: Possible missing comma found.
Context: ...uld play or a new game it should analyse but also the next position from a testsu...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~119-~119: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...sitions only. If the GUI hasn't sent a "ucinewgame" before the first "position...(EN_A_VS_AN)
[uncategorized] ~120-~120: Possible missing comma found.
Context: ...uldn't expect any further ucinewgame commands as the GUI is probably not supporting t...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~121-~121: Possible missing comma found.
Context: ... So the engine should not rely on this command even though all new GUIs should support...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~122-~122: Possible missing comma found.
Context: ... reaction to "ucinewgame" can take some time the GUI should always send "isready" ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~127-~127: This noun is normally spelled as one word.
Context: ...ard and play the moves on the internal chess board. if the game was played from the star...(BOARD_COMPOUNDS)
[uncategorized] ~128-~128: Possible missing comma found.
Context: ... if the game was played from the start position the string "startpos" will be sent Not...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~130-~130: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...to the engine, the GUI should have sent a "ucinewgame" inbetween. * go start ca...(EN_A_VS_AN)
[typographical] ~135-~135: It seems that a comma is missing.
Context: ...the same string. If one command is not sent its value should be interpreted as it w...(IF_COMMA)
[grammar] ~137-~137: The singular determiner ‘this’ may not agree with the plural noun ‘moves’. Did you mean “these”?
Context: ...ove1> .... restrict search to this moves only Example: After "position s...(THIS_NNS)
[duplication] ~143-~143: Possible typo: you repeated a word
Context: ...e! This means that the last move sent in in the position string is the ponder move....(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~173-~173: Possible typo: you repeated a word
Context: ...hout being told so in this mode! * stop stop calculating as soon as possible, don't...(ENGLISH_WORD_REPEAT_RULE)
[style] ~175-~175: For a more polite and respectful tone, consider rephrasing with ‘please’.
Context: ... stop calculating as soon as possible, don't forget the "bestmove" and possibly the "ponder...(DONT_FORGET)
[duplication] ~181-~181: Possible typo: you repeated a word
Context: ...tch from pondering to normal search. * quit quit the program as soon as possible Engin...(ENGLISH_WORD_REPEAT_RULE)
[typographical] ~212-~212: Consider adding a comma here.
Context: ...ve" command is needed! Directly before that the engine should send a final "info" c...(TO_THAT_COMMA)
[duplication] ~213-~213: Possible typo: you repeated a word
Context: ...and with the final search information, the the GUI has the complete statistics about t...(ENGLISH_WORD_REPEAT_RULE)
[typographical] ~218-~218: It seems that a comma is missing.
Context: ...yprotection checking". If the check is ok the engine should send "copyprotection ...(IF_COMMA)
[uncategorized] ~219-~219: Possible missing comma found.
Context: ..."copyprotection error". If there is an error the engine should not function properly...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~220-~220: Three successive sentences begin with the same word. Consider rewording the sentence or use a thesaurus to find a synonym.
Context: ...on properly but should not quit alone. If the engine reports "copyprotection erro...(ENGLISH_WORD_REPEAT_BEGINNING_RULE)
[uncategorized] ~232-~232: Possible missing comma found.
Context: ...atures. Analog to the "copyprotection" command the engine can send "registration check...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~234-~234: Possible missing comma found.
Context: ...istration ok" or "registration error". Also after every attempt to register the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~239-~239: Consider adding a comma after this introductory phrase.
Context: ...and might not use all its features. In addition the GUI should offer to open a dialog t...(IN_GENERAL_COMMA)
[uncategorized] ~240-~240: Possible missing comma found.
Context: ...on of the engine. To try to register an engine the GUI can send the "register" comman...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~253-~253: A comma may be missing after the conjunctive/linking adverb ‘Also’.
Context: ...nfo depth 12 nodes 123456 nps 100000". Also all infos belonging to the pv should be...(SENT_START_CONJUNCTIVE_LINKING_ADVERB_COMMA)
[typographical] ~262-~262: Consider adding a comma.
Context: ...in plies, if the engine sends seldepth there must also be a "depth" present in the s...(IF_THERE_COMMA)
[uncategorized] ~271-~271: Possible missing comma found.
Context: ... the multi pv mode. for the best move/pv add "multipv 1" in the string when you ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~272-~272: Possible missing comma found.
Context: ...tring when you send the pv. in k-best mode always send all k variants in k strings...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~282-~282: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ...bound. * upperbound the score is just an upper bound. * currmove cu...(REP_BE_JUST)
[grammar] ~299-~299: Possibly, a comma is missing after an introductory clause, the verb inflection is not correct, or a question mark is missing. Did you mean “string, command” or “string commands”?
Context: ...isplayed be the engine, if there is a string command the rest of the line will be interprete...(IF_DT_NN_VBZ)
[uncategorized] ~301-~301: Did you mean “I”?
Context: ...efuted by the line ... , i can be any number >= 1. Example: af...(I_LOWERCASE_PREMIUM)
[style] ~312-~312: This phrasing could be wordy, so try replacing it with something more concise.
Context: ... can be omitted. If is greater than 1, always send all k lines in k strings...(MORE_THAN_EXCEEDS)
[uncategorized] ~326-~326: Possible missing comma found.
Context: ...nge the default value. For all allowed combinations see the examples below, as some combin...(AI_HYDRA_LEO_MISSING_COMMA)
[grammar] ~327-~327: The singular determiner ‘this’ may not agree with the plural noun ‘tokens’. Did you mean “these”?
Context: ...xamples below, as some combinations of this tokens don't make sense. One string wi...(THIS_NNS)
[typographical] ~332-~332: Consider adding a comma after ‘Usually’ for more clarity.
Context: ...he semantics of this option is fixed. Usually those options should not be displayed i...(RB_LY_COMMA)
[uncategorized] ~339-~339: The preposition ‘of’ seems more likely in this position.
Context: ...= Hash, type is spin the value in MB for memory for hash tables can be changed, ...(AI_HYDRA_LEO_REPLACE_FOR_OF)
[style] ~343-~343: As an alternative to the over-used intensifier ‘very’, consider replacing this phrase.
Context: ...ll engines! So the engine should use a very small hash first as default. * = Nalim...(EN_WEAK_ADJECTIVE)
[style] ~352-~352: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ype check this means that the engine is able to ponder. The GUI will send this whene...(BE_ABLE_TO)
[style] ~368-~368: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ould be false by default, The engine is able to limit its strength to a specific Elo nu...(BE_ABLE_TO)
[typographical] ~377-~377: After the expression ‘for example’ a comma is usually used.
Context: ...n analysing or playing a game. For example when playing it can use some kind of le...(COMMA_FOR_EXAMPLE)
[typographical] ~378-~378: The word “otherwise” is an adverb that can’t be used like a conjunction, and therefore needs to be separated from the sentence.
Context: ...set to false if the engine is playing a game, otherwise it is true. * = UCI_Opponent, t...(THUS_SENTENCE)
[uncategorized] ~384-~384: Did you mean Garry Kasparov, the chess player?
Context: ...n name UCI_Opponent value GM 2800 human Gary Kasparov" "setoption name UCI_Opponent valu...(EN_SIMPLE_REPLACE_GARY_KASPAROV)
[duplication] ~385-~385: Possible typo: you repeated a word
Context: ... "setoption name UCI_Opponent value none none computer Shredder" * = UCI_Engi...(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~481-~481: Possible typo: you repeated a word
Context: ... is supporting it, tell the engine that is is // searching on a game that it hasn't s...(ENGLISH_WORD_REPEAT_RULE)
[uncategorized] ~526-~526: Possible missing comma found.
Context: ...l the GUI that it is capable of playing Chess960 and the GUI has to tell the engine that...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~526-~526: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ... of playing Chess960 and the GUI has to tell the engine that is should play accordin...(REP_TELL_X)
[grammar] ~527-~527: Do not use the modal verb ‘should’ after the verb ‘be’. Did you mean “should”?
Context: ...and the GUI has to tell the engine that is should play according to the Chess960 rules. T...(BE_MD)
[uncategorized] ~533-~533: Possible missing comma found.
Context: ...on to 'true'. Castling is different in Chess960 and the white king move when castling s...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~536-~536: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...es" his own rook. Example: e1h1 for the white short castle move in the normal chess start p...(EN_ADJ_ORDER)
🪛 cppcheck
src/uci.cpp
[performance] 343-343: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 351-351: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 359-359: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 406-406: Function parameter 'values' should be passed by const reference.
(passedByValue)
🔇 Additional comments (35)
.idea/.gitignore (2)
1-3: LGTM: Standard JetBrains IDE ignore entries.These entries are correct and follow best practices for JetBrains IDEs. Ignoring
/shelf/and/workspace.xmlprevents user-specific settings and temporary data from being tracked in version control.
4-5: LGTM: Correctly ignoring HTTP request files.Ignoring
/httpRequests/is a good practice. These files often contain user-specific or sensitive information that should not be tracked in version control..github/workflows/ctest.yml (1)
24-24: Approve the Clang version update, but verify compatibility and consistency.The update from Clang 17 to Clang 18 keeps the toolchain current with the latest features and bug fixes, which aligns well with the project's rewrite initiative. However, please ensure the following:
- Verify that Clang 18 is compatible with all project requirements and dependencies.
- Check other workflow files and build configurations to maintain consistency across the project.
- Be aware that Clang 18 is very recent and might have stability issues compared to Clang 17.
To ensure consistency across the project, run the following script:
This script will help identify any inconsistencies in Clang version references or C++ standard settings across the project.
✅ Verification successful
Clang version update to 18 is consistent across all workflows.
All workflow files (
ctest.yml,valgrind.yml,release.yml) have been updated to use Clang version 18, ensuring consistency throughout the project. Additionally, the C++ standard is correctly set to C++23 in the CMake configurations.No further actions are required.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check for Clang version references in other workflow files and CMake configurations # Test 1: Search for Clang version references in other workflow files echo "Checking other workflow files for Clang version references:" rg --type yaml "version: \"1[78]\"" .github/workflows # Test 2: Search for Clang-related configurations in CMake files echo "Checking CMake files for Clang-related configurations:" rg --type cmake "clang|llvm" . # Test 3: Check if C++23 standard is set in CMake files (as mentioned in the PR summary) echo "Checking for C++23 standard in CMake files:" rg --type cmake "set\\(CMAKE_CXX_STANDARD 23\\)" .Length of output: 1156
src/move_picker.cpp (1)
24-26: LGTM! Implementation follows best practices.The
getMoveList()function is correctly implemented as a const member function returning a const reference tomoveList. This follows the suggestion from the previous review and adheres to good C++ practices, preventing unintended modifications to the internal state ofMovePicker.Let's verify if there are any other members or methods in the
MovePickerclass that might need similar treatment:src/constants.h (5)
6-6: LGTM: Copyright year updatedThe copyright year has been correctly updated to include 2024, keeping the notice current.
26-29: LGTM: Efficient bitboard constantsThe file constants (NOT_A_FILE, NOT_AB_FILE, NOT_GH_FILE, NOT_H_FILE) are correctly defined using uint64_t and efficient bitwise representations. These will allow for fast bitwise operations in the chess engine, which aligns with the performance-focused guidelines.
31-32: LGTM: Efficient rank constants addedThe new RANK_4 and RANK_5 constants are correctly defined using uint64_t and efficient bitwise representations. These will be useful for rank-specific operations in the chess engine and contribute to maintaining high performance.
Line range hint
1-38: Overall assessment: Positive changes with minor suggestionsThe changes to
src/constants.hgenerally align well with the performance-focused guidelines for the chess engine. The use of more efficient types (uint64_t, uint8_t) and bitwise representations for constants should contribute to improved performance.Key points:
- Efficient bitboard and rank constants have been added or updated.
- Board dimension constants have been optimized.
- The MAX_MOVES constant has been type-optimized, but its linkage change needs clarification.
Consider the suggestions for further optimization, particularly the use of
constexprfor SQUARES, PIECES, and COLORS. Also, please clarify the intention behind the linkage change for MAX_MOVES.These changes should positively impact the engine's performance while maintaining clarity and correctness.
38-38: Type optimization approved, clarification needed on linkage changeThe update of MAX_MOVES to use uint8_t is a good optimization that aligns with the performance-focused guidelines. However, the removal of the
statickeyword changes the constant's linkage from internal to external.Could you clarify the intention behind removing the
statickeyword? This change affects how the constant can be used across different translation units. If external linkage is intended, it's fine as is. If not, consider adding thestatickeyword back.To verify the usage of MAX_MOVES across the project, please run the following script:
This will help us understand if the change in linkage could affect other parts of the project.
✅ Verification successful
Verification Successful: MAX_MOVES linkage change is appropriate
The removal of the
statickeyword fromMAX_MOVESdoes not introduce any linkage issues, as it is defined only once insrc/constants.hand used appropriately insrc/move.h.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check the usage of MAX_MOVES across the project # Search for MAX_MOVES usage echo "Occurrences of MAX_MOVES:" rg --type cpp "MAX_MOVES" # Check if MAX_MOVES is defined in other files echo "\nOther definitions of MAX_MOVES:" rg --type cpp "constexpr.*MAX_MOVES"Length of output: 355
.github/workflows/valgrind.yml (3)
Line range hint
52-56: Verify sanitizer build with new Clang versionWhile the Clang version update doesn't directly affect this part of the workflow, it's important to ensure that the sanitizer build still works as expected with Clang 18. Please verify that this step completes successfully and produces the desired results with the new Clang version.
After merging this change, please monitor the workflow runs to confirm that the sanitizer build step completes without issues. If you encounter any problems, you may need to adjust the sanitizer flags or options for compatibility with Clang 18.
Line range hint
1-60: Overall workflow update looks goodThe update to Clang 18 in this workflow is a positive change that keeps the project up-to-date with the latest tools. The rest of the workflow remains unchanged, which maintains consistency in the CI process.
Remember to:
- Test the entire workflow thoroughly after this change.
- Update any project documentation that might reference the Clang version.
- Consider adding a comment in the workflow file indicating the reason for using Clang 18, which can be helpful for future maintenance.
24-24: Clang version upgrade looks good, but verify compatibility.Upgrading to Clang 18 is a good practice for accessing the latest features and improvements. However, ensure that your project's code is compatible with this version and that it doesn't introduce any unexpected issues.
To ensure consistency across the project, please run the following script to check for other occurrences of Clang version references:
If any other occurrences are found, make sure to update them accordingly to maintain consistency with this change.
✅ Verification successful
Clang version upgrade verified.
No other references to Clang or LLVM versions 17 or 18 were found in the codebase. The upgrade to Clang 18 in the workflow file is isolated and does not affect other parts of the project.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check for Clang version references in the project # Search for Clang version references in all files echo "Searching for Clang version references:" rg --type-add 'cmake:*.cmake' --type-add 'cmake:CMakeLists.txt' -t cmake -t yaml -t cpp -t c "clang.*1[78]" . # Search for LLVM version references (as Clang is part of LLVM) echo "Searching for LLVM version references:" rg --type-add 'cmake:*.cmake' --type-add 'cmake:CMakeLists.txt' -t cmake -t yaml -t cpp -t c "llvm.*1[78]" .Length of output: 394
.github/workflows/release.yml (3)
15-15: Approved: Update to use latest Ubuntu versionUpdating to
ubuntu-latestis a good practice for maintaining the workflow with the latest stable Ubuntu version. This ensures you get the latest security updates and features.However, it's important to monitor for any potential breaking changes in future Ubuntu releases. To verify the current Ubuntu version being used, you can add this step to your workflow:
- name: Check Ubuntu version run: lsb_release -aThis will help you track which Ubuntu version is actually being used in your builds.
42-44: Approved: Update LLVM action and versionUpdating the
install-llvm-actionto v2 and LLVM to version 18 is good for leveraging the latest features and improvements.However, it's crucial to ensure that your project is compatible with LLVM 18. Consider adding a step to verify the LLVM version and its compatibility with your project:
- name: Verify LLVM version run: | clang --version # Add any additional compatibility checks hereAlso, you might want to run your test suite (if available) to ensure everything works correctly with the new LLVM version.
94-94: Approved: Consistent update to use latest Ubuntu versionUpdating the
create-releasejob to useubuntu-latestis consistent with the change in thebuildjob. This ensures that both the build and release processes use the same up-to-date environment.For consistency, consider adding the Ubuntu version check step here as well, similar to the suggestion for the
buildjob.CMakeLists.txt (1)
209-226: Acknowledge existing comment on test configurationI see that this issue has been addressed in a previous comment, and a GitHub issue (#83) has been created to track the task of re-enabling tests.
While the tests are disabled, consider the following to maintain code quality during the rewrite:
- Implement a phased approach to re-enable tests, starting with core components.
- Use feature flags to gradually introduce new functionality alongside existing tests.
- Establish clear criteria for when tests should be re-enabled for each module.
- Regularly update the GitHub issue with progress and any blockers encountered.
src/magics.cpp (2)
393-395: LGTM: Correct usage of boolean literalsThe updates to the
init_sliders_attacksfunction calls correctly use boolean literals (trueandfalse) instead of integers. This change improves readability and maintains consistency with the updated function signature.
Line range hint
1-448: Verify performance impact of changesThe changes to
init_sliders_attacksand its usage improve type safety and clarity without altering the core functionality of the magic bitboard generation. These modifications are positive and align with best practices for C++ programming.To ensure that these changes haven't inadvertently affected performance, it's recommended to run benchmarks comparing the old and new versions. Here's a script to help with the verification:
This script provides a framework for compiling both versions and running benchmarks. You'll need to replace the placeholder comments with actual commands specific to your build and benchmark system.
src/uci-specification.txt (1)
1-544: Acknowledging the UCI specification file.This file contains the Universal Chess Interface (UCI) specification, which is an external standard and not part of the codebase that should be modified. As per previous feedback, we will not be reviewing or suggesting changes to this file.
🧰 Tools
🪛 LanguageTool
[uncategorized] ~20-~20: Possible missing comma found.
Context: ... If you use Engine and GUI in the same OS this should be no problem if you commun...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~27-~27: Possible missing comma found.
Context: ... * The engine will always be in forced mode which means it should never start calcu...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~36-~36: Possible missing comma found.
Context: ... the GUI receives an unknown command or token it should just ignore it and try to p...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~39-~39: Consider adding a comma before the interrupter.
Context: ... "debug joho on\n" will be undefined however. * if the engine receives a command wh...(HOWEVER_COMMA)
[style] ~50-~50: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...t as 0000. Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (for promotion) GUI...(EN_ADJ_ORDER)
[uncategorized] ~63-~63: Possible missing comma found.
Context: ...h to uci mode. After receiving the uci command the engine must identify itself with th...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~65-~65: Consider adding a comma here.
Context: ...e settings the engine supports if any. After that the engine should send "uciok" to ackno...(FOR_THAT_COMMA)
[uncategorized] ~80-~80: Possible missing comma found.
Context: ...d be sent after setting the path to the tablebases as this can take some time. This comma...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~88-~88: Possible missing comma found.
Context: ...meters of the engine. For the "button" type no value is needed. One string will be...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~89-~89: Possible missing comma found.
Context: ...eded. One string will be sent for each parameter and this will only be sent when the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~90-~90: This word is normally spelled with a hyphen.
Context: ...lue of the option in should not be case sensitive and can inlude spaces. The substrings ...(EN_COMPOUNDS_CASE_SENSITIVE)
[uncategorized] ~117-~117: Possible missing comma found.
Context: ...uld play or a new game it should analyse but also the next position from a testsu...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~119-~119: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...sitions only. If the GUI hasn't sent a "ucinewgame" before the first "position...(EN_A_VS_AN)
[uncategorized] ~120-~120: Possible missing comma found.
Context: ...uldn't expect any further ucinewgame commands as the GUI is probably not supporting t...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~121-~121: Possible missing comma found.
Context: ... So the engine should not rely on this command even though all new GUIs should support...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~122-~122: Possible missing comma found.
Context: ... reaction to "ucinewgame" can take some time the GUI should always send "isready" ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~127-~127: This noun is normally spelled as one word.
Context: ...ard and play the moves on the internal chess board. if the game was played from the star...(BOARD_COMPOUNDS)
[uncategorized] ~128-~128: Possible missing comma found.
Context: ... if the game was played from the start position the string "startpos" will be sent Not...(AI_HYDRA_LEO_MISSING_COMMA)
[misspelling] ~130-~130: Use “an” instead of ‘a’ if the following word starts with a vowel sound, e.g. ‘an article’, ‘an hour’.
Context: ...to the engine, the GUI should have sent a "ucinewgame" inbetween. * go start ca...(EN_A_VS_AN)
[typographical] ~135-~135: It seems that a comma is missing.
Context: ...the same string. If one command is not sent its value should be interpreted as it w...(IF_COMMA)
[grammar] ~137-~137: The singular determiner ‘this’ may not agree with the plural noun ‘moves’. Did you mean “these”?
Context: ...ove1> .... restrict search to this moves only Example: After "position s...(THIS_NNS)
[duplication] ~143-~143: Possible typo: you repeated a word
Context: ...e! This means that the last move sent in in the position string is the ponder move....(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~173-~173: Possible typo: you repeated a word
Context: ...hout being told so in this mode! * stop stop calculating as soon as possible, don't...(ENGLISH_WORD_REPEAT_RULE)
[style] ~175-~175: For a more polite and respectful tone, consider rephrasing with ‘please’.
Context: ... stop calculating as soon as possible, don't forget the "bestmove" and possibly the "ponder...(DONT_FORGET)
[duplication] ~181-~181: Possible typo: you repeated a word
Context: ...tch from pondering to normal search. * quit quit the program as soon as possible Engin...(ENGLISH_WORD_REPEAT_RULE)
[typographical] ~212-~212: Consider adding a comma here.
Context: ...ve" command is needed! Directly before that the engine should send a final "info" c...(TO_THAT_COMMA)
[duplication] ~213-~213: Possible typo: you repeated a word
Context: ...and with the final search information, the the GUI has the complete statistics about t...(ENGLISH_WORD_REPEAT_RULE)
[typographical] ~218-~218: It seems that a comma is missing.
Context: ...yprotection checking". If the check is ok the engine should send "copyprotection ...(IF_COMMA)
[uncategorized] ~219-~219: Possible missing comma found.
Context: ..."copyprotection error". If there is an error the engine should not function properly...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~220-~220: Three successive sentences begin with the same word. Consider rewording the sentence or use a thesaurus to find a synonym.
Context: ...on properly but should not quit alone. If the engine reports "copyprotection erro...(ENGLISH_WORD_REPEAT_BEGINNING_RULE)
[uncategorized] ~232-~232: Possible missing comma found.
Context: ...atures. Analog to the "copyprotection" command the engine can send "registration check...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~234-~234: Possible missing comma found.
Context: ...istration ok" or "registration error". Also after every attempt to register the eng...(AI_HYDRA_LEO_MISSING_COMMA)
[typographical] ~239-~239: Consider adding a comma after this introductory phrase.
Context: ...and might not use all its features. In addition the GUI should offer to open a dialog t...(IN_GENERAL_COMMA)
[uncategorized] ~240-~240: Possible missing comma found.
Context: ...on of the engine. To try to register an engine the GUI can send the "register" comman...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~253-~253: A comma may be missing after the conjunctive/linking adverb ‘Also’.
Context: ...nfo depth 12 nodes 123456 nps 100000". Also all infos belonging to the pv should be...(SENT_START_CONJUNCTIVE_LINKING_ADVERB_COMMA)
[typographical] ~262-~262: Consider adding a comma.
Context: ...in plies, if the engine sends seldepth there must also be a "depth" present in the s...(IF_THERE_COMMA)
[uncategorized] ~271-~271: Possible missing comma found.
Context: ... the multi pv mode. for the best move/pv add "multipv 1" in the string when you ...(AI_HYDRA_LEO_MISSING_COMMA)
[uncategorized] ~272-~272: Possible missing comma found.
Context: ...tring when you send the pv. in k-best mode always send all k variants in k strings...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~282-~282: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ...bound. * upperbound the score is just an upper bound. * currmove cu...(REP_BE_JUST)
[grammar] ~299-~299: Possibly, a comma is missing after an introductory clause, the verb inflection is not correct, or a question mark is missing. Did you mean “string, command” or “string commands”?
Context: ...isplayed be the engine, if there is a string command the rest of the line will be interprete...(IF_DT_NN_VBZ)
[uncategorized] ~301-~301: Did you mean “I”?
Context: ...efuted by the line ... , i can be any number >= 1. Example: af...(I_LOWERCASE_PREMIUM)
[style] ~312-~312: This phrasing could be wordy, so try replacing it with something more concise.
Context: ... can be omitted. If is greater than 1, always send all k lines in k strings...(MORE_THAN_EXCEEDS)
[uncategorized] ~326-~326: Possible missing comma found.
Context: ...nge the default value. For all allowed combinations see the examples below, as some combin...(AI_HYDRA_LEO_MISSING_COMMA)
[grammar] ~327-~327: The singular determiner ‘this’ may not agree with the plural noun ‘tokens’. Did you mean “these”?
Context: ...xamples below, as some combinations of this tokens don't make sense. One string wi...(THIS_NNS)
[typographical] ~332-~332: Consider adding a comma after ‘Usually’ for more clarity.
Context: ...he semantics of this option is fixed. Usually those options should not be displayed i...(RB_LY_COMMA)
[uncategorized] ~339-~339: The preposition ‘of’ seems more likely in this position.
Context: ...= Hash, type is spin the value in MB for memory for hash tables can be changed, ...(AI_HYDRA_LEO_REPLACE_FOR_OF)
[style] ~343-~343: As an alternative to the over-used intensifier ‘very’, consider replacing this phrase.
Context: ...ll engines! So the engine should use a very small hash first as default. * = Nalim...(EN_WEAK_ADJECTIVE)
[style] ~352-~352: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ype check this means that the engine is able to ponder. The GUI will send this whene...(BE_ABLE_TO)
[style] ~368-~368: As a shorter alternative for ‘able to’, consider using “can”.
Context: ...ould be false by default, The engine is able to limit its strength to a specific Elo nu...(BE_ABLE_TO)
[typographical] ~377-~377: After the expression ‘for example’ a comma is usually used.
Context: ...n analysing or playing a game. For example when playing it can use some kind of le...(COMMA_FOR_EXAMPLE)
[typographical] ~378-~378: The word “otherwise” is an adverb that can’t be used like a conjunction, and therefore needs to be separated from the sentence.
Context: ...set to false if the engine is playing a game, otherwise it is true. * = UCI_Opponent, t...(THUS_SENTENCE)
[uncategorized] ~384-~384: Did you mean Garry Kasparov, the chess player?
Context: ...n name UCI_Opponent value GM 2800 human Gary Kasparov" "setoption name UCI_Opponent valu...(EN_SIMPLE_REPLACE_GARY_KASPAROV)
[duplication] ~385-~385: Possible typo: you repeated a word
Context: ... "setoption name UCI_Opponent value none none computer Shredder" * = UCI_Engi...(ENGLISH_WORD_REPEAT_RULE)
[duplication] ~481-~481: Possible typo: you repeated a word
Context: ... is supporting it, tell the engine that is is // searching on a game that it hasn't s...(ENGLISH_WORD_REPEAT_RULE)
[uncategorized] ~526-~526: Possible missing comma found.
Context: ...l the GUI that it is capable of playing Chess960 and the GUI has to tell the engine that...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~526-~526: You have already used this phrasing in nearby sentences. Consider replacing it to add variety to your writing.
Context: ... of playing Chess960 and the GUI has to tell the engine that is should play accordin...(REP_TELL_X)
[grammar] ~527-~527: Do not use the modal verb ‘should’ after the verb ‘be’. Did you mean “should”?
Context: ...and the GUI has to tell the engine that is should play according to the Chess960 rules. T...(BE_MD)
[uncategorized] ~533-~533: Possible missing comma found.
Context: ...on to 'true'. Castling is different in Chess960 and the white king move when castling s...(AI_HYDRA_LEO_MISSING_COMMA)
[style] ~536-~536: This is not the usual sequence for adjectives that have no special emphasis.
Context: ...es" his own rook. Example: e1h1 for the white short castle move in the normal chess start p...(EN_ADJ_ORDER)
src/main.cpp (3)
5-5: Updated Copyright NoticeThe update to the year range reflects the current time period and keeps the licensing information up to date.
21-21: Include UCI HeaderIncluding
"uci.h"is appropriate as it provides the necessary declarations for the UCI interface functionality.
23-27: SimplifiedmainFunctionThe
mainfunction has been streamlined to focus on initializing the engine and starting the UCI interface. This enhances clarity and reduces unnecessary complexity.src/move.h (1)
34-35: Comments accurately reflect bit assignmentsThe updated comments correctly describe the encoding of
fromSquareandtoSquare, matching the implementation inencodeMove.src/bitboard.h (1)
1-6: Update AcknowledgedThe update of the years to "2023-2024" in the file header accurately reflects the current development period.
src/types.h (4)
23-23: Verify the removal ofconstants.hincludeThe
#include "constants.h"has been replaced with#include <array>. Ensure that any constants previously defined inconstants.hare no longer needed or have been relocated appropriately. This change might lead to compilation issues if those constants are still in use elsewhere.
25-34: Good use of scoped enums forDirectionTransitioning
Directionto a scoped enum (enum class) enhances type safety by preventing implicit conversions and name clashes. This is a positive move towards modern C++ practices.
40-53: 🛠️ Refactor suggestionReview the size and alignment of
PieceenumWhile specifying
int8_treduces the size of thePieceenum, it's important to ensure that this doesn't introduce alignment issues on certain architectures. Misaligned accesses can degrade performance, negating the benefits of smaller type sizes. Verify that the use ofint8_tis actually providing a performance benefit and doesn't cause misalignment in structures or arrays.Consider using
uint8_tand adjusting theEMPTYvalue accordingly:-enum class Piece : int8_t { +enum class Piece : uint8_t { WHITE_PAWN, WHITE_KNIGHT, WHITE_BISHOP, WHITE_ROOK, WHITE_QUEEN, WHITE_KING, BLACK_PAWN, BLACK_KNIGHT, BLACK_BISHOP, BLACK_ROOK, BLACK_QUEEN, BLACK_KING, - EMPTY = -1 + EMPTY = 12 };This change ensures all values are non-negative and may improve performance on certain systems.
38-38: 🛠️ Refactor suggestion
⚠️ Potential issueAvoid negative enum values in
PieceColorSimilarly, using
int8_twithEMPTY = -1inPieceColorcan cause issues when interacting with unsigned integers or indexing. It's safer to useuint8_tand assignEMPTYa value that doesn't conflict with valid colors.Apply this diff to update the underlying type:
-enum class PieceColor : int8_t { WHITE, BLACK, EMPTY = -1 }; +enum class PieceColor : uint8_t { WHITE, BLACK, EMPTY = 2 };Alternatively, if only two colors are valid, you can use
boolor anenumwith explicit values for clarity.Likely invalid or redundant comment.
src/board.h (2)
37-38: Verify thatPieceis suitable as a non-type template parameterEnsure that
Pieceis an integral or enum type that can be used as a non-type template parameter. Using enums as non-type template parameters is valid in C++17 and onward, but it's important to verify thatPiecemeets the necessary criteria to prevent compilation issues.
42-43: Verify thatPieceColoris suitable as a non-type template parameterSimilar to
Piece, check thatPieceColoris an appropriate type for use as a non-type template parameter. This ensures that template instantiations work correctly without incurring any compilation errors.src/bitboard.cpp (1)
42-64: LGTM!The implementation of the
shiftfunction is appropriate and aligns with the design considerations. The use of aswitchstatement with theDirectionenum provides clarity, and the function effectively delegates to the correspondingBitwiseshift operations.src/bitwise.h (1)
27-100: Enhanced modularity with theBitwisenamespaceThe introduction of the
Zagreus::Bitwisenamespace improves code organization and encapsulation of bitwise operations. This change aligns with the performance goals of the engine and enhances maintainability.src/move_gen.cpp (2)
71-105: Efficient use of loops for pawn move generationYour implementation of separate while loops for each pawn move type (single pushes, double pushes, west attacks, east attacks) effectively maintains high performance by avoiding extra function calls. This aligns well with the performance priority outlined in the coding guidelines and past learnings.
108-127: Optimized knight move generationThe nested loops in the
generateKnightMovesfunction efficiently generate all possible knight moves without introducing unnecessary function calls or overhead. This approach prioritizes performance, which is crucial for the chess engine's efficiency.src/bitwise.cpp (1)
29-34: Efficient implementation ofpopcntfunctionThe use of compiler intrinsics for
popcntensures high-performance population count calculations across different platforms.
… parts of the codebase.
There was a problem hiding this comment.
Actionable comments posted: 5
🧹 Outside diff range and nitpick comments (9)
src/move_picker.h (1)
32-37: Approve changes with suggestions for further optimizationThe changes to the
MovePickerclass, particularly changingmoveListfrom a pointer to a direct instance, can improve performance by reducing indirection. The simplification of the class structure is also beneficial.However, consider the following improvements:
Make
getMoveList()return a const reference to maintain encapsulation:[[nodiscard]] const MoveList& getMoveList() const { return this->moveList; }Consider inlining the
getMoveList()method for better performance:[[nodiscard]] inline const MoveList& getMoveList() const { return this->moveList; }These changes would address concerns raised in previous reviews while maintaining the performance focus of the chess engine.
src/board.h (3)
39-47: LGTM: Well-implemented bitboard accessor functionsThe
getBitboardandgetColorBitboardtemplate functions are well-implemented, ensuring type safety and efficient access to bitboard data. The use of[[nodiscard]]is appropriate for these getter functions.Consider marking these functions as
constexprto enable potential compile-time optimizations:template <Piece piece> [[nodiscard]] constexpr uint64_t getBitboard() const { return bitboards[std::to_underlying(piece)]; } template <PieceColor color> [[nodiscard]] constexpr uint64_t getColorBitboard() const { return colorBoards[std::to_underlying(color)]; }This change allows the compiler to evaluate these functions at compile-time when possible, potentially improving performance.
49-52: LGTM: Efficient piece retrieval with bounds checkingThe
getPieceOnSquarefunction is well-implemented with appropriate bounds checking using an assertion. Consider marking this function asconstexprfor potential compile-time optimizations:[[nodiscard]] constexpr Piece getPieceOnSquare(const int square) const { assert(square >= 0 && square < 64); return board[square]; }This change allows the compiler to evaluate this function at compile-time when possible, potentially improving performance.
54-60: LGTM: Efficient bitboard accessorsThe
getOccupiedBitboardandgetEmptyBitboardfunctions are well-implemented and efficient. Consider marking these functions asconstexprfor potential compile-time optimizations:[[nodiscard]] constexpr uint64_t getOccupiedBitboard() const { return occupied; } [[nodiscard]] constexpr uint64_t getEmptyBitboard() const { return ~occupied; }This change allows the compiler to evaluate these functions at compile-time when possible, potentially improving performance.
src/uci.cpp (3)
21-21: Consider removing the ReSharper disable commentThe ReSharper disable comment
// ReSharper disable CppRedundantControlFlowJumpmight not be necessary in the final code. If it's addressing a specific issue, consider adding a brief explanation. Otherwise, it's best to remove it to keep the code clean.
38-38: Address the TODO comment for setupThe TODO comment indicates that additional setup steps are needed. It's important to implement these steps to ensure the engine is fully initialized.
Would you like assistance in identifying and implementing the necessary setup steps? I can help create a list of typical chess engine initialization tasks if needed.
262-262: Implement multi-threading for UCI input handlingThe TODO comment suggests implementing multi-threading to handle UCI input separately from the engine's thinking process. This is an important optimization that will allow the engine to remain responsive while calculating moves.
Consider creating a separate thread for handling UCI input, while the main thread (or another dedicated thread) handles the engine's thinking process. This will ensure that the engine can respond to commands like "stop" even when it's in the middle of a deep search.
Would you like assistance in designing a multi-threaded architecture for the UCI interface? I can provide a basic structure or pseudocode for this implementation if needed.
src/main.cpp (1)
30-30: Remove Redundant CommentThe comment
// Handle the exception or log the erroris unnecessary because the exception is being handled and logged in the subsequent lines.Apply this diff to remove the redundant comment:
- // Handle the exception or log the errorsrc/bitwise.h (1)
37-37: Addconstqualifier to the parameter inbitscanForwardfor consistencyThe parameter
bbinbitscanForwardis not modified within the function. Adding theconstqualifier enhances code safety and maintains consistency withbitscanReverse, which already uses aconstparameter.Apply this diff:
-inline int bitscanForward(uint64_t bb) { +inline int bitscanForward(const uint64_t bb) {
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (16)
- README.md (0 hunks)
- src/bitboard.cpp (0 hunks)
- src/bitboard.h (1 hunks)
- src/bitwise.cpp (0 hunks)
- src/bitwise.h (2 hunks)
- src/board.cpp (2 hunks)
- src/board.h (1 hunks)
- src/main.cpp (2 hunks)
- src/move.h (1 hunks)
- src/move_gen.cpp (1 hunks)
- src/move_gen.h (2 hunks)
- src/move_picker.cpp (1 hunks)
- src/move_picker.h (2 hunks)
- src/types.h (2 hunks)
- src/uci.cpp (1 hunks)
- src/uci.h (1 hunks)
💤 Files with no reviewable changes (3)
- README.md
- src/bitboard.cpp
- src/bitwise.cpp
🚧 Files skipped from review as they are similar to previous changes (2)
- src/move_gen.cpp
- src/uci.h
🧰 Additional context used
📓 Path-based instructions (11)
src/bitboard.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/bitwise.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/main.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_picker.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_picker.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/types.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/uci.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (2)
src/board.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/board.h:31-34 Timestamp: 2024-10-05T13:06:57.437Z Learning: In this codebase, `std::array` is preferred over C-style arrays, even in performance-critical sections, due to the extra features and safety it provides, and because the performance difference is negligible when compiled with optimizations.src/move_gen.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.h:36-37 Timestamp: 2024-10-05T12:15:41.746Z Learning: In `src/move_gen.h`, prefer using explicit template instantiations for longer (more than a few lines) or more complex template functions like `generatePawnMoves`, instead of including their definitions in header files.
🪛 cppcheck
src/uci.cpp
[performance] 361-361: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 369-369: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 418-418: Function parameter 'values' should be passed by const reference.
(passedByValue)
🔇 Additional comments (35)
src/move_picker.cpp (1)
21-25: Approve the restructuring of the move_picker.cpp file.The changes to this file align well with the objectives of rewriting the Zagreus engine from scratch. The removal of the
mainfunction and initializations, coupled with the introduction of the Zagreus namespace, indicates a shift towards a more modular and maintainable structure. This approach is likely to improve the overall architecture of the chess engine.To ensure that the MovePicker implementation has been appropriately moved, let's verify the contents of the "move_picker.h" file:
This script will help us confirm that the MovePicker implementation has been moved to the header file as expected in the new structure.
✅ Verification successful
Verification of
move_picker.hSuccessfulThe contents of
move_picker.hhave been verified and confirm that the MovePicker implementation has been appropriately moved to the header file as expected.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify the contents of the move_picker.h file # Test: Check if move_picker.h exists and display its contents if [ -f "src/move_picker.h" ]; then echo "move_picker.h found. Contents:" cat src/move_picker.h else echo "move_picker.h not found in the src directory." # Search for move_picker.h in case it's located elsewhere fd -t f "move_picker.h" fiLength of output: 1147
src/board.cpp (3)
5-5: LGTM: Copyright year updatedThe copyright year has been correctly updated to reflect the ongoing development of the project.
21-23: Verify the changes in include directivesThe changes in include directives suggest a significant alteration in the file's dependencies:
- Removal of
#pragma onceis correct for a .cpp file.- Including "board.h" is appropriate if this file implements functions declared in that header.
- Replacing "bitboard.h" with indicates a major change in functionality.
Could you please clarify the reason for removing "bitboard.h"? Are the bitboard operations no longer needed in this file?
26-27: Clarify the relocation of move generation logicThe removal of the
GenerationTypeenum andgenerateMovesfunction, leaving theZagreusnamespace empty, indicates a significant refactoring of the chess engine's move generation logic. This aligns with the PR objective of rewriting the engine from scratch.Could you please provide information on:
- Where has the move generation logic been relocated?
- If it has been reimplemented, what approach is now being used?
- Are there any new files or classes that have taken over this functionality?
This information will help in understanding the new structure of the engine and ensure that no critical functionality has been inadvertently lost in the rewrite process.
src/move_picker.h (3)
5-5: LGTM: Copyright year updatedThe copyright year has been correctly updated to include 2024.
23-26: LGTM: Include directives optimized for performanceThe change from
<vector>to<array>is a good optimization for a chess engine, as it uses a fixed-size container which can be more performant. The addition of "constants.h" and "move.h" provides necessary functionality. These changes align well with the goal of prioritizing performance in the chess engine.
39-39: LGTM: Proper namespace closureThe
Zagreusnamespace is correctly closed, maintaining proper code structure.src/move_gen.h (5)
6-6: LGTM: Copyright year updatedThe copyright year has been correctly updated to include 2024, which is a good practice to keep the notice current.
24-25: LGTM: Updated header inclusionsThe addition of "board.h" and "move.h" headers and the removal of appear to be appropriate changes. This could potentially improve compilation times and reduce unnecessary dependencies.
29-34: LGTM: Well-defined GenerationType enumThe
GenerationTypeenum class is well-defined with an appropriate underlying type (uint8_t) for memory efficiency. The four types (All, Quiet, Capture, Evasions) cover the main categories of move generation needed in a chess engine.
36-40: LGTM: Well-designed move generation function templatesThe template functions
generatePawnMovesandgenerateKnightMovesare well-designed:
- They use compile-time specialization for
PieceColorandGenerationType, which can lead to better performance.- The function signatures are consistent and take appropriate parameters.
- The declarations without definitions align with the preference for explicit template instantiations for longer or more complex functions, as mentioned in the past feedback.
This approach should provide a good balance between performance and maintainability for the chess engine.
Line range hint
1-41: Overall: Excellent refactoring for move generationThe changes in this file represent a well-thought-out refactoring of the move generation system:
- The new
GenerationTypeenum provides a clear and efficient way to specify different types of move generation.- The template functions for pawn and knight moves are designed for high performance while maintaining flexibility.
- The removal of the
MoveListPoolclass (as noted in the AI summary) suggests a shift towards a different memory management strategy, which could potentially improve performance.These changes align well with the PR objective of rewriting the Zagreus engine from scratch, focusing on performance and maintainability. Great job on this part of the refactoring!
src/types.h (5)
25-34: LGTM: Improved type safety with enum class for DirectionThe transition to a scoped enum (enum class) for
Directionenhances type safety. The comprehensive set of directions is suitable for chess movements.
36-36: Excellent: Addressed previous concerns and improved efficiencyThe implementation of
PieceTypeas an enum class with uint8_t underlying type and EMPTY = 255 effectively addresses the previous concerns about potential issues with signed types and negative values. This change not only improves type safety but also enhances efficiency, which is crucial for a performance-oriented chess engine.
38-38: LGTM: Consistent and efficient implementation of PieceColorThe
PieceColorenum class is implemented consistently withPieceType, using uint8_t as the underlying type and setting EMPTY to 255. This approach maintains type safety and efficiency, which is crucial for the chess engine's performance.
40-53: Excellent addition: Efficient piece representationThe new
Pieceenum class efficiently combines piece types and colors into single values. This approach:
- Maintains consistency with other enums (uint8_t underlying type, EMPTY = 255).
- Potentially optimizes performance for bitboard operations and move generation.
- Reduces memory usage by representing a piece with a single byte.
This change aligns well with the performance-first approach of the chess engine.
23-53: Overall excellent improvements to the type systemThe changes in this file represent a significant enhancement to the chess engine's type system:
- Consistent use of scoped enums (enum class) improves type safety.
- Adoption of uint8_t as the underlying type for all enums potentially optimizes performance and memory usage.
- The new
Pieceenum efficiently combines piece type and color.- Consistent use of EMPTY = 255 across enums maintains a uniform approach.
These changes align perfectly with the performance-first approach while also improving type safety and code clarity. Great work on addressing previous concerns and optimizing the core types for the chess engine.
src/board.h (3)
1-29: LGTM: Well-structured file header and includesThe file header is comprehensive, including copyright information and license details. The use of
#pragma onceas a header guard is modern and efficient. The included headers seem appropriate for theBoardclass implementation.
30-37: LGTM: Efficient board representation using std::arrayThe
Boardclass definition and private members are well-structured. The use ofstd::arrayfor board representation aligns with the project's preference for combining safety and performance. The bitboard representation usinguint64_tis appropriate for efficient operations in a chess engine.
1-62: Overall: Well-implemented chess board representationThe
Boardclass provides an efficient and type-safe representation of a chess board, suitable for a high-performance chess engine. The use of modern C++ features, such asstd::array,[[nodiscard]], and template functions, contributes to both safety and performance.The suggested optimizations (marking functions as
constexpr) are minor and can be applied to potentially improve compile-time optimizations without affecting the overall design.Great job on implementing a solid foundation for the Zagreus chess engine!
src/bitboard.h (8)
30-44: LGTM: Efficient implementation of basic shift operationsThe implementation of
shiftNorth,shiftSouth,shiftEast, andshiftWestfunctions is correct and efficient. The use of inline functions is appropriate for these small, frequently used operations. The bit masksNOT_A_FILEandNOT_H_FILEcorrectly prevent unwanted wrapping on the edges of the board.
46-60: LGTM: Correct implementation of diagonal shift operationsThe diagonal shift operations (
shiftNorthEast,shiftNorthWest,shiftSouthEast,shiftSouthWest) are implemented correctly and efficiently. They consistently useNOT_A_FILEandNOT_H_FILEto prevent unwanted wrapping, which is crucial for maintaining the integrity of the bitboard representation. These functions build upon the basic shift operations, ensuring consistency in the codebase.
62-92: LGTM: Comprehensive implementation of knight move shift operationsThe knight move shift operations are implemented correctly and efficiently. Each function (
shiftNorthNorthEast,shiftNorthEastEast, etc.) uses appropriate bit shifts and masks to handle file wrapping. The use ofNOT_A_FILE,NOT_H_FILE,NOT_AB_FILE, andNOT_GH_FILEeffectively prevents unwanted wrapping, which is crucial for accurate knight move generation.These functions will be valuable for generating knight move bitboards efficiently.
94-117: LGTM: Efficient template-based shift function with C++23 featureThe template
shiftfunction provides a unified interface for all shift operations, which is both elegant and efficient. The use ofconstexprallows for potential compile-time evaluation, optimizing performance where possible. The default case, which returns the input bitboard unchanged, serves as a safe fallback for unexpected directions.Note the use of the C++23 feature
using enum Direction, which simplifies the switch statement syntax. Ensure that your build system and toolchain support C++23 features.
119-181: LGTM: Comprehensive and efficient pawn move and attack functionsThe pawn move and attack functions are implemented correctly and efficiently. Key points:
- Separate functions for white and black pawns appropriately handle their different move directions.
- Single pushes, double pushes, and attacks are all correctly implemented.
- Functions to determine pushable pawns are a useful addition for move generation.
- The use of previously defined shift functions promotes code reuse and consistency.
- Double push functions correctly check for empty squares and appropriate ranks (RANK_4 for white, RANK_5 for black).
This comprehensive set of pawn functions will be valuable for efficient move generation and evaluation in the chess engine.
183-187: LGTM: Efficient knight attack generationThe
knightAttacksfunction efficiently generates a bitboard representing all possible knight moves from a given position. It correctly uses the previously defined shift functions for knight moves, ensuring consistency and reducing the chance of errors. Combining all moves into a single bitboard using bitwise OR operations is an appropriate and efficient approach for knight attack generation.This function will be valuable for move generation and evaluation of knight positions in the chess engine.
1-187: Overall: Excellent implementation of bitboard operationsThis file provides a comprehensive and efficient set of bitboard operations crucial for a high-performance chess engine. Key strengths include:
- Correct and optimized implementations of various shift operations.
- Comprehensive coverage of pawn and knight move generation.
- Consistent use of bitwise operations and appropriate masking to prevent unwanted wrapping.
- Good use of inline functions for small, frequently used operations.
- A flexible template-based shift function that unifies different shift operations.
The code structure is clean, consistent, and well-organized. The prioritization of performance aligns well with the requirements of a chess engine.
Minor point to consider:
- Verify the impact of removed include directives as mentioned in the first comment.
Overall, this is a solid foundation for bitboard manipulations in the Zagreus chess engine.
1-26: Verify impact of removed include directivesThe copyright update is correct. However, the removal of certain include directives may have unintended consequences:
- Removal of
<x86intrin.h>might affect performance-critical intrinsics. Ensure that no x86 intrinsics are used in the codebase or that they are included elsewhere if needed.- Removal of
<cassert>could impact debug assertions. Verify that assertions are not used or are included in a different header.- Removal of
<string>might cause issues ifstd::stringis used. Confirm thatstd::stringis not used in this file or included elsewhere if needed.The addition of
"constants.h"is likely beneficial for consolidating constants used in bitboard operations.Run the following script to check for potential issues:
✅ Verification successful
Removal of include directives does not affect the codebase.
All removed includes (
<x86intrin.h>,<cassert>,<string>) were specific tosrc/bitboard.hand are not used elsewhere in that file. Other files that utilizestd::stringandassertinclude their own necessary headers, ensuring no unintended consequences from these removals.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Check for usage of intrinsics, assert, and std::string in the codebase rg --type cpp '(__builtin_|\bassert\b|\bstd::string\b)' src/Length of output: 4220
src/main.cpp (4)
5-5: Update License YearThe license year has been updated to include 2024, reflecting the current year.
23-23: Include Necessary Header for UCI FunctionalityIncluding
"uci.h"ensures that theZagreus::Engineclass and related UCI functionalities are properly referenced.
25-36: StreamlinedmainFunction for UCI InterfaceThe
mainfunction has been simplified to focus on initializing the engine and starting the UCI interface. This aligns with the project's shift towards a more modular and focused architecture.
27-31: Robust Exception Handling ImplementedWrapping
engine.startUci()in a try-catch block enhances the application's robustness by properly handling potential exceptions. Logging the error message provides valuable information for debugging.src/move.h (2)
27-28: Definition ofMoveType is AppropriateUsing
uint16_tfor theMovetype provides ample space for encoding move information while keeping memory usage efficient.
29-32: Initialization ofMoveListis EfficientThe
MoveListstructure is well-defined. Usinguint8_tforsizeoptimizes memory usage and is appropriate since the number of moves will not exceedMAX_MOVES(256).src/bitwise.h (1)
29-29:⚠️ Potential issueCorrect the namespace declaration to properly include
BitwiseCurrently, the namespace is declared as
namespace Zagreus {, but it closes with} // namespace Zagreus::Bitwiseat line 65. To define theBitwisenamespace withinZagreus, you need to explicitly open theBitwisenamespace.Apply this diff to fix the namespace declaration:
-namespace Zagreus { +namespace Zagreus::Bitwise {Alternatively, if you intend to nest
BitwiseinsideZagreus, modify the code as follows:namespace Zagreus { +namespace Bitwise { // ... functions ... +} } // namespace ZagreusLikely invalid or redundant comment.
There was a problem hiding this comment.
Actionable comments posted: 4
🧹 Outside diff range and nitpick comments (6)
src/move_gen.h (3)
36-37: LGTM: generatePawnMoves function declaration addedThe
generatePawnMovestemplate function declaration is well-designed:
- It uses template parameters for
PieceColorandGenerationType, allowing for compile-time optimizations.- The
const Board¶meter promotes efficiency.Remember the preference for explicit template instantiations for longer or more complex functions, as mentioned in a previous review. Consider implementing this function in a separate source file with explicit instantiations if it becomes complex.
39-43: LGTM: generateKnightMoves and generateBishopMoves functions addedThe
generateKnightMovesandgenerateBishopMovestemplate function declarations are consistent withgeneratePawnMoves:
- They use the same template parameters and function signatures, promoting a uniform API.
- This design allows for specialized move generation based on piece color and generation type.
Consider the following suggestions:
- As with
generatePawnMoves, remember the preference for explicit template instantiations for longer or more complex functions.- Given the similarity of these functions, you might want to consider creating a common base template function for all piece move generations, which could be specialized for different piece types. This could potentially reduce code duplication and improve maintainability.
Line range hint
1-44: Overall assessment: Significant improvements to move generation systemThe changes to
src/move_gen.hrepresent a substantial refactoring of the move generation system:
- Removal of the
MoveListPoolclass suggests a shift in memory management strategy.- Introduction of the
GenerationTypeenum provides a clear categorization of move types.- New template functions for generating moves offer flexibility and potential for compile-time optimizations.
These changes appear to be aimed at improving the efficiency and flexibility of the move generation system, which is crucial for a chess engine's performance. The new design seems more modular and potentially easier to extend for different piece types.
To ensure the success of this refactoring:
- Thoroughly test the new move generation functions to verify correctness and performance improvements.
- Update any code that previously used
MoveListPoolto work with the new system.- Consider benchmarking the new system against the old one to quantify any performance gains.
Great work on this significant update!
src/move_gen.cpp (2)
30-33: Create issues for TODO items to track future enhancementsThe TODO comments indicate important future enhancements:
- Implement en passant
- Handle promotions
- Move attacks to table lookup
- Implement GenerationType logic
Consider creating separate GitHub issues for each of these items to track their progress and ensure they're not overlooked in future development cycles.
Would you like me to create GitHub issues for these TODO items?
115-115: Create an issue for the TODO itemThe TODO comment suggests moving to table calculations for knight moves. This could potentially improve performance further.
Consider creating a GitHub issue to track this optimization task.
Would you like me to create a GitHub issue for this TODO item?
src/bitwise.h (1)
29-35: Ensure consistent use ofconstqualifier for function parametersThe functions
popcnt,bitscanForward, andbitscanReversehave inconsistent use of theconstqualifier for the parameterbb. Since these functions do not modifybb, consider addingconstto the parameter in all functions for consistency and potential optimizations.Apply this diff to update the function signatures:
-inline uint64_t popcnt(uint64_t bb) { +inline uint64_t popcnt(const uint64_t bb) { -inline int bitscanForward(uint64_t bb) { +inline int bitscanForward(const uint64_t bb) { -inline int bitscanReverse(const uint64_t bb) { +inline int bitscanReverse(const uint64_t bb) {Also applies to: 37-46, 48-57
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (6)
- .gitignore (1 hunks)
- src/bitboard.cpp (2 hunks)
- src/bitboard.h (1 hunks)
- src/bitwise.h (2 hunks)
- src/move_gen.cpp (1 hunks)
- src/move_gen.h (2 hunks)
✅ Files skipped from review due to trivial changes (1)
- .gitignore
🧰 Additional context used
📓 Path-based instructions (5)
src/bitboard.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/bitboard.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/bitwise.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (2)
src/move_gen.cpp (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.h:36-37 Timestamp: 2024-10-05T12:15:41.746Z Learning: In `src/move_gen.h`, prefer using explicit template instantiations for longer (more than a few lines) or more complex template functions like `generatePawnMoves`, instead of including their definitions in header files.src/move_gen.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.h:36-37 Timestamp: 2024-10-05T12:15:41.746Z Learning: In `src/move_gen.h`, prefer using explicit template instantiations for longer (more than a few lines) or more complex template functions like `generatePawnMoves`, instead of including their definitions in header files.
🔇 Additional comments (11)
src/move_gen.h (3)
6-6: LGTM: Copyright year updatedThe copyright year has been correctly updated to include 2024, reflecting the ongoing development of the project.
29-34: Excellent addition of GenerationType enumThe new
GenerationTypeenum class is a great addition:
- It provides a clear categorization of move generation types.
- Using
uint8_tas the underlying type optimizes memory usage, which is beneficial for a performance-critical chess engine.- The enum values cover all necessary move generation scenarios: All, Quiet, Capture, and Evasions.
This enum will likely improve code readability and type safety when dealing with move generation.
24-25: LGTM: Include statements updatedThe changes to the include statements appear to improve modularity by removing unnecessary dependencies and adding relevant ones. This aligns well with the functions declared in this header.
To ensure these changes don't negatively impact other parts of the codebase, please run the following script:
src/move_gen.cpp (6)
29-111: Efficient implementation of pawn move generationThe
generatePawnMovesfunction efficiently uses bitwise operations for move generation, which aligns well with the performance-first approach for this chess engine. The implementation correctly handles different pawn moves for both white and black pieces, including single pushes, double pushes, and attacks.The use of
constexprfor compile-time calculations and the clear separation of white and black pawn logic contribute to the overall efficiency.
76-110: Repeated code structure in move generation loopsThe move generation loops for single pushes, double pushes, and attacks have a similar structure. While this repetition could typically be refactored into a helper function, the current implementation is acceptable given the priority on performance over code duplication in this performance-critical section.
If profiling shows that this doesn't impact performance significantly, consider refactoring in the future to improve maintainability.
113-134: Efficient implementation of knight move generationThe
generateKnightMovesfunction efficiently uses bitwise operations for move generation, which aligns well with the performance-first approach for this chess engine. The implementation correctly handles knight moves for both white and black pieces.The use of
constexprfor compile-time calculations and the clear structure contribute to the overall efficiency.
122-133: Necessary nested loops in knight move generationThe nested loops in the knight move generation are necessary for efficient move generation, as previously discussed. This implementation aligns with the performance-first approach of the chess engine.
136-160: Efficient and consistent implementation of bishop move generationThe
generateBishopMovesfunction efficiently uses bitwise operations for move generation, aligning well with the performance-first approach of this chess engine. The implementation correctly handles bishop moves for both white and black pieces.Notable points:
- The use of
using enum Pieceimproves readability without sacrificing performance.- The structure is consistent with other move generation functions, which aids in maintainability.
- The use of
constexprfor compile-time calculations contributes to the overall efficiency.This implementation maintains the balance between performance and code clarity.
1-161: Overall high-quality implementation with room for future enhancementsThe
move_gen.cppfile demonstrates a high-quality implementation of move generation for pawns, knights, and bishops in the Zagreus chess engine. The code consistently prioritizes performance, making efficient use of bitwise operations and compile-time calculations.Key strengths:
- Efficient move generation using bitwise operations.
- Consistent structure across different piece move generations.
- Clear separation of logic for white and black pieces.
- Use of
constexprfor compile-time optimizations.To further improve the codebase:
- Create GitHub issues to track the TODO items mentioned in the
generatePawnMovesandgenerateKnightMovesfunctions.- Consider implementing the suggested optimizations (e.g., table lookups) in future iterations, ensuring to benchmark any changes to maintain the performance-first approach.
Overall, this implementation provides a solid foundation for the Zagreus chess engine's move generation system.
src/bitboard.cpp (1)
24-30: Efficient Implementation ofbishopAttacksFunctionThe
bishopAttacksfunction correctly computes bishop attack bitboards using magic bitboards. The use of bitwise operations and magic numbers aligns with the performance-focused coding guidelines for this project.src/bitwise.h (1)
29-65:⚠️ Potential issueFix namespace inconsistency between opening and closing declarations
The opening namespace is declared as
namespace Zagreus {at line 29, but the closing comment at line 65 indicates} // namespace Zagreus::Bitwise. This inconsistency can lead to confusion and potential linkage issues.To properly nest the
Bitwisenamespace withinZagreus, explicitly declare the nested namespace:namespace Zagreus { +namespace Bitwise { inline uint64_t popcnt(uint64_t bb) { // Function implementation } // ... Other function implementations ... +} // namespace Bitwise } // namespace ZagreusLikely invalid or redundant comment.
…t test 8 yet). Seem to be either ep or castling issues on other positions that need fixing.
There was a problem hiding this comment.
Actionable comments posted: 17
🧹 Outside diff range and nitpick comments (13)
src/types.h (1)
103-134: Remove redundant return statement in getCharacterForPieceTypeThe
getCharacterForPieceTypefunction is well-implemented, but there's a redundant return statement at the end of the function. Since the switch statement covers all possible cases, includingEMPTY, the final return statement is unreachable.Apply this diff to remove the redundant return statement:
constexpr char getCharacterForPieceType(const Piece piece) { switch (piece) { case WHITE_PAWN: return 'P'; case BLACK_PAWN: return 'p'; case WHITE_KNIGHT: return 'N'; case BLACK_KNIGHT: return 'n'; case WHITE_BISHOP: return 'B'; case BLACK_BISHOP: return 'b'; case WHITE_ROOK: return 'R'; case BLACK_ROOK: return 'r'; case WHITE_QUEEN: return 'Q'; case BLACK_QUEEN: return 'q'; case WHITE_KING: return 'K'; case BLACK_KING: return 'k'; case EMPTY: return ' '; } - - return ' '; }This change will make the function more concise and eliminate the unreachable code warning that some compilers might generate.
src/board.h (4)
37-42: LGTM: Well-structured BoardState struct.The
BoardStatestruct efficiently captures the essential elements of a chess position. For further optimization, consider using bit fields forenPassantSquareandcastlingRightsto reduce memory usage:struct BoardState { Move move = 0; Piece capturedPiece = EMPTY; uint8_t enPassantSquare : 6; // 6 bits are enough for 64 squares uint8_t castlingRights : 4; // 4 bits are enough for all castling rights };This change could potentially improve cache utilization in performance-critical sections.
56-109: LGTM: Well-implemented constructor and getter methods.The constructor and getter methods are efficiently implemented with appropriate use of
constexprand[[nodiscard]]. For further optimization, consider usingstd::fillinstead ofstd::ranges::fillin the constructor, as it might be more widely optimized across different compilers:Board() { std::fill(board.begin(), board.end(), EMPTY); std::fill(bitboards.begin(), bitboards.end(), 0); std::fill(colorBoards.begin(), colorBoards.end(), 0); std::fill(history.begin(), history.end(), BoardState{}); }This change might lead to slightly better performance, especially on older compiler versions.
111-166: LGTM: Efficient piece manipulation methods.The
setPieceandremovePiecemethods efficiently update all relevant board representations. The use of template versions allows for compile-time optimizations, which is excellent for performance.Consider extracting the common logic in
setPieceandremovePiecemethods to reduce code duplication:template <bool IsSet, typename PieceType> void updatePiece(PieceType piece, const uint8_t square) { const uint64_t squareBB = squareToBitboard(square); if constexpr (IsSet) { assert(piece != Piece::EMPTY); assert(board[square] == Piece::EMPTY); board[square] = piece; bitboards[piece] |= squareBB; occupied |= squareBB; colorBoards[getPieceColor(piece)] |= squareBB; } else { assert(piece != Piece::EMPTY); assert(board[square] == piece); board[square] = Piece::EMPTY; bitboards[piece] &= ~squareBB; occupied &= ~squareBB; colorBoards[getPieceColor(piece)] &= ~squareBB; } } template <Piece piece> void setPiece(const uint8_t square) { updatePiece<true>(piece, square); } void setPiece(const Piece piece, const uint8_t square) { updatePiece<true>(piece, square); } template <Piece piece> void removePiece(const uint8_t square) { updatePiece<false>(piece, square); } void removePiece(const Piece piece, const uint8_t square) { updatePiece<false>(piece, square); }This refactoring reduces code duplication while maintaining performance through template specialization.
168-191: LGTM: Comprehensive set of method declarations.The method declarations provide a robust set of functionalities essential for a chess engine. The use of templates and
[[nodiscard]]is appropriate for optimization and error prevention.Consider the following minor improvements:
Mark
isPositionLegalandgetSquareAttackersasconst:template <PieceColor movedColor> [[nodiscard]] bool isPositionLegal() const; [[nodiscard]] uint64_t getSquareAttackers(uint8_t square) const;Add
[[nodiscard]]attribute tosetFromFEN:[[nodiscard]] bool setFromFEN(std::string_view fen);Consider marking
resetandnoexcept:void reset() noexcept; void print() const noexcept;These changes can help catch potential errors and provide more information to the compiler for optimizations.
src/move_gen.cpp (1)
1-276: Overall excellent implementation with a few areas for improvementThe move generation code in
src/move_gen.cppis generally well-implemented, focusing on performance through efficient use of bitboard operations. Here's a summary of the main points:
- The use of bitboard operations and pre-computed attack tables ensures efficient move generation for all piece types.
- The TODO about implementing GenerationType logic in the main
generateMovesfunction should be addressed to fully utilize the type parameter.- Pawn promotions need to be implemented in the
generatePawnMovesfunction.- Consider refactoring the sliding piece move generation (bishops, rooks, queens) to reduce code duplication and improve maintainability.
- Verify the castling implementation in the
Boardclass to ensure all conditions are correctly checked.Overall, this is a solid foundation for a high-performance chess engine's move generation. Addressing the missing features and considering the suggested optimizations will further improve its completeness and maintainability.
Would you like assistance in implementing any of the suggested improvements?
src/board.cpp (3)
30-75: LGTM: Efficient implementation ofisPositionLegalThe
isPositionLegalmethod is well-implemented, efficiently using bitwise operations and handling special cases like castling. The code is correct and performant.Consider adding a brief comment explaining the purpose of the
castlingPathvariable for improved readability.
127-303: LGTM: Well-implemented core board operationsThe
reset,makeMove, andunmakeMovemethods are correctly implemented and cover all necessary cases for managing the chess board state. ThemakeMoveandunmakeMovemethods, in particular, handle various move types and state updates comprehensively.Consider adding more inline comments in the
makeMoveandunmakeMovemethods to explain the logic flow, especially for complex sections like handling different castling scenarios or en passant captures. This would improve maintainability and readability of the code.
1-456: Overall: Solid implementation with some areas for completionThe
src/board.cppfile demonstrates a strong foundation for a chess engine, with efficient implementations of core functionality. Most methods are well-implemented, using bitwise operations and other performance-oriented techniques.Key points:
- The
isPositionLegal,canCastle, andgetSquareAttackersmethods are particularly well-implemented and efficient.- The
makeMoveandunmakeMovemethods comprehensively handle various chess move scenarios.- The FEN parsing functionality is partially implemented, with some features still pending.
To complete this file:
- Implement the remaining FEN parsing features as noted in the previous comment.
- Add more inline comments to complex sections, particularly in
makeMoveandunmakeMove.- Consider implementing the Zobrist hash functionality, which is mentioned in TODO comments.
Overall, this is a strong implementation with clear attention to performance and correctness. Completing the noted items will further enhance its functionality.
src/uci.cpp (3)
98-100: Add TODO comment for future debug mode implementationWhile it's acceptable to have unimplemented features, it would be helpful to add a TODO comment for future implementation of the debug mode. This will serve as a reminder and provide context for other developers. Consider adding:
void Engine::handleDebugCommand(std::string_view args) { // TODO: Implement debug mode functionality sendMessage("Debug mode is currently not implemented."); }This change will help track the need for future implementation of this feature.
181-182: Add TODO comment for handleUciNewGameCommand implementationThe
handleUciNewGameCommandfunction is currently empty. While it's acceptable to have placeholder functions for future implementation, it would be helpful to add a TODO comment. This will serve as a reminder and provide context for other developers. Consider adding:void Engine::handleUciNewGameCommand(std::string_view args) { // TODO: Implement new game setup (e.g., reset board, clear transposition table) }This change will help track the need for future implementation of this feature.
239-250: Add TODO comments for unimplemented UCI command handlersThe following UCI command handlers are currently empty:
handleGoCommandhandleStopCommandhandlePonderHitCommandhandleQuitCommandWhile it's acceptable to have placeholder functions for future implementation, it would be helpful to add TODO comments. This will serve as a reminder and provide context for other developers. Consider adding:
void Engine::handleGoCommand(std::string_view args) { // TODO: Implement search logic based on go parameters } void Engine::handleStopCommand(std::string_view args) { // TODO: Implement logic to stop the current search } void Engine::handlePonderHitCommand(std::string_view args) { // TODO: Implement ponder hit logic } void Engine::handleQuitCommand(std::string_view args) { // TODO: Implement cleanup and exit logic }These changes will help track the need for future implementation of these features.
src/bitboard.h (1)
25-25: Redundant Include DirectiveThe
#include <utility>directive may be unnecessary if the code does not use any utilities from this header. Removing unused includes can slightly improve compilation times.
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (10)
- src/bitboard.h (1 hunks)
- src/board.cpp (1 hunks)
- src/board.h (1 hunks)
- src/constants.h (2 hunks)
- src/move.cpp (1 hunks)
- src/move.h (1 hunks)
- src/move_gen.cpp (1 hunks)
- src/types.h (2 hunks)
- src/uci.cpp (1 hunks)
- tests/types_tests.cpp (1 hunks)
🚧 Files skipped from review as they are similar to previous changes (3)
- src/move.cpp
- src/move.h
- tests/types_tests.cpp
🧰 Additional context used
📓 Path-based instructions (7)
src/bitboard.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/constants.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/types.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/uci.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (2)
src/bitboard.h (5)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:196-201 Timestamp: 2024-10-06T10:15:57.559Z Learning: In `src/bitboard.h`, the function `kingAttacks(uint64_t bb)` correctly includes diagonal moves for the king due to the line `bb |= attacks;`. This line updates `bb` to include east and west shifts before calculating additional attacks in the north and south directions, effectively accounting for all one-square king moves, including diagonals.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:196-201 Timestamp: 2024-10-09T11:49:41.012Z Learning: In `src/bitboard.h`, the function `kingAttacks(uint64_t bb)` correctly includes diagonal moves for the king due to the line `bb |= attacks;`. This line updates `bb` to include east and west shifts before calculating additional attacks in the north and south directions, effectively accounting for all one-square king moves, including diagonals.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:67-69 Timestamp: 2024-10-09T14:54:30.420Z Learning: In `src/bitboard.h`, the `shiftSouthWest` function correctly uses the `NOT_H_FILE` mask when shifting southwest.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:31-94 Timestamp: 2024-10-09T11:49:41.012Z Learning: In `src/bitboard.h`, do not suggest marking the shift functions as `constexpr` in future reviews, as it is not possible.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:31-94 Timestamp: 2024-10-05T15:48:09.435Z Learning: In `src/bitboard.h`, do not suggest marking the shift functions as `constexpr` in future reviews, as it is not possible.src/uci.cpp (3)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.cpp:394-430 Timestamp: 2024-10-11T16:04:05.283Z Learning: In `src/uci.cpp`, performance optimizations are unnecessary.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.h:77-77 Timestamp: 2024-10-05T13:12:32.035Z Learning: In UCI-related code (e.g., `src/uci.h` and `src/uci.cpp`), prioritize readability and maintainability over performance optimizations, as these functions are not performance-critical.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.h:77-77 Timestamp: 2024-10-09T11:49:41.012Z Learning: In UCI-related code (e.g., `src/uci.h` and `src/uci.cpp`), prioritize readability and maintainability over performance optimizations, as these functions are not performance-critical.
🪛 cppcheck
src/uci.cpp
[performance] 460-460: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 468-468: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 517-517: Function parameter 'values' should be passed by const reference.
(passedByValue)
🔇 Additional comments (44)
src/constants.h (7)
6-6: LGTM: Copyright year updated.The copyright year has been correctly updated to include 2024, reflecting ongoing development.
28-31: LGTM: Efficient bitboard constants added.The addition of these file mask constants (NOT_A_FILE, NOT_AB_FILE, NOT_GH_FILE, NOT_H_FILE) is a good practice. These predefined constants can improve performance in bitboard operations by avoiding runtime calculations.
33-40: LGTM: Improved rank constants representation.The update to RANK_1 through RANK_8 constants with full 64-bit representations is a good improvement. This change:
- Makes the constants more explicit.
- Reduces the risk of implicit type conversion issues.
- Ensures consistency across different platforms.
These changes align well with best practices for working with 64-bit integers in C++.
42-45: LGTM: Castling path constants added.The addition of castling path constants (WHITE_KINGSIDE_CASTLE_PATH, WHITE_QUEENSIDE_CASTLE_PATH, BLACK_KINGSIDE_CASTLE_PATH, BLACK_QUEENSIDE_CASTLE_PATH) is a good improvement. These constants:
- Enhance code readability in castling-related logic.
- Can improve performance by avoiding runtime calculations.
- Reduce the likelihood of errors in castling move generation and validation.
The values are correct for their intended purposes, representing the squares that must be empty for castling to be legal.
47-49: LGTM: Optimized type usage for chess-related constants.The change of SQUARES, PIECES, and COLORS constants to uint8_t type is a good optimization. This update:
- Improves space efficiency by using the smallest possible data type for these values.
- May lead to better cache utilization, potentially improving performance.
- More accurately represents the range of values needed for these constants.
This change aligns well with the principle of using the most appropriate data types in performance-critical code.
51-51: Type change approved, but linkage change needs clarification.The change of MAX_MOVES to uint8_t is appropriate and aligns with the actual maximum number of moves possible in a chess position.
However, the removal of the 'static' keyword changes the linkage from internal to external. While this might be intentional, it could have implications for how this constant is used across the codebase.
Could you clarify the intention behind removing the 'static' keyword? If this was unintentional, consider adding it back to maintain internal linkage.
51-51: Clarification needed on MVVLVA_TABLE removal.The MVVLVA_TABLE array, which is commonly used for move ordering in chess engines, has been removed from this file. This change could have significant implications for the engine's move ordering strategy and overall performance.
Could you please clarify:
- Was this table moved to another file?
- If not, what strategy is being used for move ordering in place of MVVLVA?
- How does this change impact the engine's performance and behavior?
This information will help ensure that the engine's move ordering capabilities haven't been unintentionally compromised.
src/types.h (4)
46-55: LGTM: Square enum is well-definedThe
Squareenum class is well-defined with appropriate use ofuint8_tas the underlying type. The inclusion of all chess board squares and theNONEvalue set to 255 is a good practice for handling edge cases.
68-81: LGTM: Piece enum is well-definedThe
Pieceenum class is well-structured, usinguint8_tas the underlying type and including all chess pieces for both colors. TheEMPTYvalue set to 255 is a good practice for handling empty squares.
93-101: LGTM: getPieceColor and getPieceType functions are well-implementedThe
getPieceColorandgetPieceTypefunctions are efficiently implemented using constexpr and appropriate assertions. The logic for determining color and type is correct and makes good use of the enum structure.
Line range hint
1-134: Overall assessment: Well-structured with minor improvements suggestedThe
types.hfile is well-structured and implements the necessary types and utility functions for a chess engine efficiently. The use of enum classes, constexpr functions, and appropriate underlying types demonstrates good C++ practices.The suggested improvements mainly focus on:
- Converting
DirectionandCastlingRightsto enum classes for consistency.- Improving error handling in the
operator!function forPieceColor.- Removing a redundant return statement in
getCharacterForPieceType.These changes will enhance consistency across the codebase and adhere more closely to modern C++ best practices. The core functionality and design of the types are solid and well-suited for a high-performance chess engine.
src/board.h (3)
1-35: LGTM: Appropriate license and includes.The license header and include statements are well-structured and appropriate for the chess engine implementation.
44-54: LGTM: Efficient and comprehensive board representation.The
Boardclass member variables provide a complete and efficient representation of the chess board state. The use ofstd::arrayanduint64_tfor bitboards is particularly well-suited for performance-critical chess engine operations.
1-193: Overall: Well-implemented Board class with room for minor optimizations.The
Boardclass insrc/board.his well-structured and efficiently implemented, suitable for a high-performance chess engine. It provides a comprehensive representation of the chess board state and includes all necessary methods for board manipulation and state querying.Key strengths:
- Efficient use of bitboards and std::array for board representation.
- Appropriate use of constexpr and [[nodiscard]] for optimization and error prevention.
- Template methods allowing for compile-time optimizations.
The suggested improvements, such as using bit fields in BoardState, extracting common logic in setPiece and removePiece methods, and adding const and noexcept qualifiers to some methods, can further enhance the code's performance and maintainability.
Great job on implementing a solid foundation for the Zagreus chess engine!
src/move_gen.cpp (3)
139-157: LGTM: Efficient knight move generationThe
generateKnightMovesfunction is well-implemented, using efficient bitboard operations and pre-computed attack tables. The code is clear and concise.
267-275: LGTM: Good use of explicit instantiationsThe explicit instantiations of
generateMovesfor different colors and generation types are a good practice. This can help reduce compile times and potentially reduce binary size.
219-265: Verify castling implementationThe
generateKingMovesfunction correctly generates normal king moves and includes castling logic. The implementation looks good overall.To ensure the castling logic is correct:
- Verify that the
canCastlemethod in theBoardclass checks for:
- The king and rook haven't moved
- No pieces between the king and rook
- The king is not in check
- The king doesn't pass through a checked square
- Consider adding a comment explaining the castling conditions for better maintainability.
src/board.cpp (4)
1-28: LGTM: Well-structured file header and includesThe file header contains appropriate copyright and license information, and the necessary headers are included. This section is well-organized and provides clear information about the file's purpose and licensing.
77-108: LGTM: Well-implementedcanCastlemethodThe
canCastlemethod is correctly implemented, efficiently using compile-time conditionals for different castling sides. It properly checks castling rights and path occupation, ensuring all necessary conditions are met before allowing castling.
110-125: LGTM: Efficient implementation ofgetSquareAttackersThe
getSquareAttackersmethod is well-implemented, efficiently using bitwise operations and pre-calculated attack patterns for each piece type. This approach ensures fast calculation of all attackers for a given square, which is crucial for chess engine performance.
305-348: LGTM: Clear implementation ofsetPieceFromFENCharThe
setPieceFromFENCharmethod is well-implemented, using a clear and concise switch statement to handle all piece types for both colors. This approach ensures correct piece placement based on FEN character representation.src/uci.cpp (6)
37-47: LGTM: Correct implementation of one-time setupThe
doSetupfunction correctly implements the one-time initialization of magic bitboards and attack lookup tables, adhering to UCI specifications. The use of thedidSetupflag ensures that this setup is performed only once, which is efficient and prevents unnecessary reinitialization.
85-96: LGTM: Correct implementation of UCI identificationThe
handleUciCommandfunction correctly implements the UCI protocol for engine identification. It sends the engine name, author, and available options, followed by the "uciok" message. This implementation ensures that the engine properly identifies itself to the UCI-compatible GUI.
102-108: LGTM: Correct implementation of isready commandThe
handleIsReadyCommandfunction correctly implements the UCI protocol for the "isready" command. It ensures that the engine setup is completed by callingdoSetup()if necessary, and then sends the "readyok" message. This implementation guarantees that the engine is ready for further commands.
472-487: LGTM: Correct implementation of getUciOptionTypeAsStringThe
getUciOptionTypeAsStringfunction correctly converts UCIOptionType to its string representation. It covers all known option types and includes a default case for unknown types, which is a good practice for enum conversions. This implementation ensures that all possible UCIOptionType values are handled appropriately.
513-535: LGTM: Correct implementations of UCIOption var methodsThe implementations of
addVar,setVar,removeVar,clearVar,getVar, and the vector-returninggetVarare correct and straightforward. These methods provide a complete set of operations for managing thevarvector of theUCIOptionclass, which is essential for handling combo-type UCI options.🧰 Tools
🪛 cppcheck
[performance] 517-517: Function parameter 'values' should be passed by const reference.
(passedByValue)
184-237:⚠️ Potential issueAdd error handling for invalid moves in
handlePositionCommandThe
handlePositionCommandmethod assumes that all moves parsed from the input are valid. If an invalid move notation is provided,fromMoveNotationmight return an invalidMove, and applying it withboard.makeMove(move)could lead to undefined behavior or crashes. To enhance robustness, consider adding error checking after parsing the move and before applying it to the board.Apply this diff to add error checking:
const Move move = fromMoveNotation(arg); + if (!isValidMove(move)) { + sendMessage("info string Error: Invalid move provided: " + arg); + return; + } board.makeMove(move);Note: Implement an
isValidMovefunction or include logic to validate the move before applying it.Would you like assistance in implementing the
isValidMovefunction?Likely invalid or redundant comment.
src/bitboard.h (17)
34-36: FunctionshiftNorthImplementation is CorrectThe
shiftNorthfunction correctly shifts the bitboard north by one rank usingbb << 8. This is efficient and aligns with the performance priorities for the chess engine.
42-44: Incorrect Mask inshiftEastFunctionThe
shiftEastfunction usesNOT_A_FILEas the mask. When shifting east (left), to prevent wrap-around from the H-file to the A-file,NOT_H_FILEshould be used.
46-48: Incorrect Mask inshiftWestFunction
50-52: Incorrect Mask inshiftNorthEastFunction
54-56: Incorrect Mask inshiftNorthWestFunction
58-60: Incorrect Mask inshiftSouthEastFunction
62-64: Acknowledged:shiftSouthWestFunction CorrectAs per previous discussions, the
shiftSouthWestfunction correctly usesNOT_H_FILEas the mask when shifting southwest. This prevents wrap-around and is implemented correctly.
66-68: Incorrect Mask inshiftNorthNorthEastFunction
70-72: Incorrect Mask inshiftNorthEastEastFunction
74-76: Incorrect Mask inshiftSouthEastEastFunction
78-80: Incorrect Mask inshiftSouthSouthEastFunction
82-84: Incorrect Mask inshiftNorthNorthWestFunction
86-88: Incorrect Mask inshiftNorthWestWestFunction
90-92: Incorrect Mask inshiftSouthWestWestFunction
94-96: Incorrect Mask inshiftSouthSouthWestFunction
99-133: TemplateshiftFunction Implementation is AppropriateThe
shifttemplate function uses aswitchstatement for direction-based shifting. Given thatDirectionis a template parameter, the compiler should optimize this at compile time. This approach aligns with the performance considerations for the chess engine.
218-223: FunctioncalculateKingAttacksCorrectly Computes King's MovesThe
calculateKingAttacksfunction properly calculates all possible king moves, including diagonals, by combining shifts in all directions. The implementation is efficient and aligns with the engine's performance goals.
There was a problem hiding this comment.
Actionable comments posted: 1
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (2)
- src/board.cpp (1 hunks)
- src/constants.h (2 hunks)
🚧 Files skipped from review as they are similar to previous changes (1)
- src/constants.h
🧰 Additional context used
📓 Path-based instructions (1)
src/board.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
🔇 Additional comments (8)
src/board.cpp (8)
1-29: LGTM: Comprehensive file header and necessary includes.The file header contains detailed copyright and licensing information, which is excellent for open-source projects. All necessary headers are included. The absence of
#pragma onceis noted, but this is acceptable if header guards are used in the corresponding header file.
30-75: LGTM: Well-implementedisPositionLegalmethod.The
isPositionLegalmethod is efficiently implemented as a template function. It correctly handles various scenarios, including special cases for castling moves. The use of bitwise operations and compile-time optimizations through templating is commendable.
78-108: LGTM: EfficientcanCastlemethod implementation.The
canCastlemethod is well-implemented as a template function. It efficiently checks castling possibilities for different sides using compile-time conditionals, which is an excellent optimization. The method correctly considers both castling rights and path occupancy.
110-125: LGTM: Comprehensive and efficientgetSquareAttackersimplementation.The
getSquareAttackersmethod is well-implemented, efficiently calculating all attackers on a specified square. It uses bitwise operations and modular helper functions for different piece types, resulting in a comprehensive and optimized implementation.
127-156: LGTM: Well-implementedresetandBoth the
resetandresetmethod efficiently initializes all necessary board state variables, while the
158-253: LGTM: ComprehensivemakeMoveimplementation.The
makeMovemethod is well-implemented, covering all aspects of making a move in chess. It correctly updates the board state, handles special cases like castling and en passant captures, and maintains game history. The code is structured logically and is easy to follow.
255-300: LGTM: Correct implementation ofunmakeMove.The
unmakeMovemethod is well-implemented, effectively reversing the last move and restoring the board to its previous state. It correctly handles special cases like castling and en passant captures, and uses the stored history to restore all necessary board state variables.
302-345: LGTM: Clear and correctsetPieceFromFENCharimplementation.The
setPieceFromFENCharmethod is well-implemented, correctly handling all possible FEN characters for chess pieces. The use of a switch statement makes the code clear and easy to maintain.
…correct now, tested on multiple positions
There was a problem hiding this comment.
Actionable comments posted: 4
🧹 Outside diff range and nitpick comments (7)
src/types.h (2)
61-67: LGTM! Consider improving operator! implementation.The updates to
PieceTypeandPieceColoras enum classes withuint8_tunderlying type are excellent, improving type safety and ensuring efficient memory usage.However, the
operator!implementation could be improved to handle all cases explicitly:constexpr PieceColor operator!(const PieceColor color) { - return color == WHITE ? BLACK : WHITE; + switch (color) { + case PieceColor::WHITE: return PieceColor::BLACK; + case PieceColor::BLACK: return PieceColor::WHITE; + } + __builtin_unreachable(); }This implementation uses a switch statement which may be more efficient for enum class types and makes the code more explicit about the possible cases.
104-135: LGTM! Consider minor optimization in getCharacterForPieceType.The
getCharacterForPieceTypefunction is well-implemented:
- It comprehensively handles all piece types.
- Using
constexprallows for compile-time evaluation when possible.Consider this minor optimization:
constexpr char getCharacterForPieceType(const Piece piece) { switch (piece) { // ... existing cases ... case EMPTY: return ' '; } - - return ' '; + __builtin_unreachable(); }This change removes the redundant default case, as all possible values of
Pieceare already covered in the switch statement. Using__builtin_unreachable()informs the compiler that this point should never be reached, potentially allowing for better optimizations.src/move.h (1)
54-64: Consider adding brief comments for function declarations.While the function names are descriptive, it would be beneficial to add brief comments explaining the purpose and expected input/output for each function. This will improve code readability and make it easier for other developers to understand and use these functions.
src/move_gen.cpp (1)
250-296: LGTM: King move generation looks good, with a minor suggestionThe
generateKingMovesfunction is well-implemented, efficiently generating both normal king moves and castling moves. The use of bitboard operations for normal moves is good for performance.Minor suggestion: Consider simplifying the castling logic by creating a helper function to reduce repetition:
template <CastlingSide side> void addCastlingMove(const Board& board, MoveList& moves, Square from, Square to) { if (board.getCastlingRights() & side && board.canCastle<side>()) { moves.moves[moves.size++] = encodeMove(from, to, CASTLING); } } // Usage in generateKingMoves: if constexpr (color == WHITE) { addCastlingMove<WHITE_KINGSIDE>(board, moves, E1, G1); addCastlingMove<WHITE_QUEENSIDE>(board, moves, E1, C1); } else { addCastlingMove<BLACK_KINGSIDE>(board, moves, E8, G8); addCastlingMove<BLACK_QUEENSIDE>(board, moves, E8, C8); }This change would make the castling logic more concise and easier to maintain.
src/board.cpp (3)
30-75: LGTM: Efficient implementation ofisPositionLegalThe
isPositionLegalmethod is well-implemented, efficiently using bitboards and handling special cases like castling. The code is clear and follows good practices.Consider adding a brief comment explaining the purpose of the
castlingPathvariable and its significance in the castling legality check.
110-156: LGTM: Well-implemented utility methodsThe
getSquareAttackers,reset, andgetSquareAttackersmethod makes good use of bitboards, and theresetmethod properly initializes all board components.In the
std::array<char, 2>instead ofstd::stringfor the piece characters to potentially improve performance, as it avoids dynamic memory allocation.
158-315: LGTM: Comprehensive implementation of move making and unmakingThe
makeMoveandunmakeMovemethods are well-implemented, handling all necessary cases including special moves like en passant and castling. They correctly update piece positions, castling rights, and en passant squares.Consider using a switch statement instead of if-else chains for handling different castling scenarios in both methods. This could potentially improve readability and performance, especially as the number of conditions grows.
Example for
makeMove:switch (toSquare) { case G1: removePiece(WHITE_ROOK, H1); setPiece(WHITE_ROOK, F1); break; case C1: removePiece(WHITE_ROOK, A1); setPiece(WHITE_ROOK, D1); break; // ... other cases ... }
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (5)
- src/board.cpp (1 hunks)
- src/move.cpp (1 hunks)
- src/move.h (1 hunks)
- src/move_gen.cpp (1 hunks)
- src/types.h (2 hunks)
🚧 Files skipped from review as they are similar to previous changes (1)
- src/move.cpp
🧰 Additional context used
📓 Path-based instructions (4)
src/board.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/types.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (1)
src/move.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move.h:34-37 Timestamp: 2024-10-09T11:50:14.518Z Learning: In `src/move.h`, the comments describing the bit assignment for move encoding are correct and should be followed. The `getFromSquare` and `getToSquare` methods have been fixed to match these comments.
🔇 Additional comments (20)
src/types.h (7)
47-56: LGTM! Improved Square enum definition.The updates to the
Squareenum are well-done:
- Using
uint8_tas the underlying type is appropriate for representing chess squares.- The compact definition improves readability.
- Adding
NONE = 255is a good choice as it's outside the valid square range.These changes enhance both the functionality and clarity of the
Squareenum.
69-82: LGTM! Well-designed Piece enum.The new
Pieceenum is well-designed:
- Using
enum classwithuint8_tunderlying type improves type safety and memory efficiency.- Combining color and type information in a single enum is an efficient representation.
- The alternating order of pieces (white, black) allows for easy color determination.
- Using 255 for
EMPTYis consistent with theSquareenum and allows for efficient checks.This design should contribute to the performance of the chess engine.
94-97: LGTM! Efficient getPieceColor implementation.The
getPieceColorfunction is well-implemented:
- Using
constexprallows for compile-time evaluation when possible.- The
asserthelps catch potential bugs early by ensuring the piece is notEMPTY.- The modulo operation efficiently determines the color, taking advantage of the alternating order in the
Pieceenum.This implementation contributes to the overall efficiency of the chess engine.
99-102: LGTM! Efficient getPieceType implementation.The
getPieceTypefunction is well-implemented:
- Using
constexprallows for compile-time evaluation when possible.- The
asserthelps catch potential bugs early by ensuring the piece is notEMPTY.- The integer division efficiently determines the piece type, taking advantage of the order in the
Pieceenum.This implementation aligns well with the performance-focused approach of the chess engine.
85-91: 🛠️ Refactor suggestionConsider converting CastlingRights to an enum class for consistency
The
CastlingRightsenum efficiently uses bit flags to represent different castling rights. However, for consistency with other enums in this file and to improve type safety, consider converting it to an enum class.Apply this diff to convert CastlingRights to an enum class:
-enum CastlingRights : uint8_t { +enum class CastlingRights : uint8_t { WHITE_KINGSIDE = 0b00000001, WHITE_QUEENSIDE = 0b00000010, BLACK_KINGSIDE = 0b00000100, BLACK_QUEENSIDE = 0b00001000, WHITE_CASTLING = 0b00000011, BLACK_CASTLING = 0b00001100, };Note that this change might require updating the usage of
CastlingRightsthroughout the codebase to use the scoped enum syntax and potentially defining bitwise operators for the enum class.Likely invalid or redundant comment.
27-43: 🛠️ Refactor suggestionConsider converting Direction to an enum class for consistency
While keeping
Directionas a regular enum might be intentional for performance reasons, converting it to an enum class would improve type safety and maintain consistency with other enums in this file. However, please weigh this against any performance implications for the chess engine.If you decide to convert, consider applying this change:
-enum Direction { +enum class Direction : int8_t { NORTH = 8, // ... other directions ... NORTH_NORTH_WEST = -15 };Note that this change might require updating the usage of
Directionthroughout the codebase to use the scoped enum syntax.Likely invalid or redundant comment.
23-24: LGTM! Verify constants usage.The addition of
<array>and<cassert>headers is appropriate for the use ofstd::arrayandassertin the code.Please confirm that the removal of
"constants.h"is intentional and that any necessary constants have been moved or are no longer needed.✅ Verification successful
Verified: Removal of
"constants.h"The removal of the
"constants.h"header fromsrc/types.hdoes not impact other parts of the codebase, as it remains included insrc/move_picker.h,src/move.h,src/bitboard.h, andsrc/board.h.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Verify the usage of constants from the removed header rg --type cpp '"constants\.h"'Length of output: 180
src/move.h (7)
1-22: Copyright and license information looks good.The copyright notice and license information are correctly included, providing clear terms for the use and distribution of the Zagreus chess engine.
22-32: Include statements and namespace declaration are appropriate.The use of
#pragma onceis a modern approach to prevent multiple inclusions. The necessary headers are included, and the code is correctly placed within the Zagreus namespace.
33-38: Move representation and MoveList structure are well-defined.The
Movetype alias andMoveListstructure are appropriately designed for efficient chess move representation. The use ofuint8_tfor thesizemember inMoveListis a good choice for memory optimization, as it will never exceedMAX_MOVES(256).
40-52: MoveType and PromotionPiece enumerations are well-defined.The
MoveTypeandPromotionPieceenumerations are correctly defined asuint8_twith appropriate bit representations. This design allows for efficient storage and manipulation of move types and promotion pieces.
99-113: getPieceFromPromotionPiece function is well-implemented.The
getPieceFromPromotionPiecefunction is correctly implemented, covering all promotion piece cases and considering the piece color. The use ofassert(false)in the default case is a good practice for catching unexpected inputs during development.
1-114: Overall, well-implemented move representation and manipulation.The
src/move.hfile provides a solid foundation for move handling in the Zagreus chess engine. The implementation is generally efficient and well-structured. Key points:
- Appropriate use of bit manipulation for compact move representation.
- Memory-efficient design of the
MoveListstructure.- Well-defined enumerations for move types and promotion pieces.
Main areas for improvement:
- Resolve the inconsistency in the basic
encodeMovefunction.- Add brief comments to function declarations for improved readability.
These changes will further enhance the quality and maintainability of the code.
66-73:⚠️ Potential issueInconsistency between comments and implementation in basic encodeMove function.
The comments describing the bit layout (lines 66-69) state that bits 0-5 represent the from square and bits 6-11 represent the to square. However, the implementation of the basic
encodeMovefunction (lines 70-73) doesn't match these comments. ThefromSquareshould be shifted left by 6 bits, andtoSquareshould not be shifted.To correct this, consider updating the function as follows:
inline Move encodeMove(const uint8_t fromSquare, const uint8_t toSquare) { // Assume normal move, so bits 12-13 are 00 and bits 14-15 are 00 - return static_cast<Move>(fromSquare | (toSquare << 6)); + return static_cast<Move>((fromSquare << 6) | toSquare); }This change will ensure that the implementation matches the described bit layout.
⛔ Skipped due to learnings
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move.h:34-37 Timestamp: 2024-10-09T11:50:14.518Z Learning: In `src/move.h`, the comments describing the bit assignment for move encoding are correct and should be followed. The `getFromSquare` and `getToSquare` methods have been fixed to match these comments.src/move_gen.cpp (3)
1-29: LGTM: File header and includes look good.The file header contains appropriate copyright and license information. The necessary includes are present for the move generation functionality.
170-188: LGTM: Knight move generation looks goodThe
generateKnightMovesfunction is efficiently implemented using bitboard operations. It's concise and easy to understand.
298-307: LGTM: Explicit instantiations are good for optimizationThe explicit instantiations of the
generateMovesfunction for various combinations of color and generation type are a good practice. This can help with compile-time optimization and potentially reduce binary size.src/board.cpp (3)
1-28: LGTM: Well-structured file header and includesThe file header contains appropriate copyright and license information, and the necessary headers are included. This section is well-organized and follows good practices.
78-108: LGTM: Efficient implementation ofcanCastleThe
canCastlemethod is well-implemented, using compile-time conditionals for efficiency and correctly checking both castling rights and path occupancy. The code is clear and follows good practices.
317-360: LGTM: Clear implementation ofsetPieceFromFENCharThe
setPieceFromFENCharmethod is well-implemented, using a clear switch statement to handle all piece types for both colors. The code is easy to read and maintain.
There was a problem hiding this comment.
Actionable comments posted: 11
🧹 Outside diff range and nitpick comments (9)
src/types.h (1)
104-135: Remove unreachable return statement in getCharacterForPieceTypeThe
getCharacterForPieceTypefunction is well-implemented and covers all possible piece types. However, the default return statement after the switch is unreachable and can be removed.Apply this diff to remove the unreachable return statement:
constexpr char getCharacterForPieceType(const Piece piece) { switch (piece) { case WHITE_PAWN: return 'P'; case BLACK_PAWN: return 'p'; case WHITE_KNIGHT: return 'N'; case BLACK_KNIGHT: return 'n'; case WHITE_BISHOP: return 'B'; case BLACK_BISHOP: return 'b'; case WHITE_ROOK: return 'R'; case BLACK_ROOK: return 'r'; case WHITE_QUEEN: return 'Q'; case BLACK_QUEEN: return 'q'; case WHITE_KING: return 'K'; case BLACK_KING: return 'k'; case EMPTY: return ' '; } - - return ' '; }This change removes the unreachable code and makes the function more concise.
src/move.h (2)
66-81: Suggestion: Update comments for clarity in move encodingThe move encoding functions are well-implemented and cover different scenarios. However, the comments describing the bit layout don't seem to match the implementation of the basic
encodeMovefunction. Since it has been confirmed that the implementation is correct, I suggest updating the comments to reflect the actual bit layout used in the encoding. This will prevent confusion for future maintainers.Consider updating the comments to match the actual implementation:
-// bits 0-5: from square (0-63) -// bits 6-11: to square (0-63) +// bits 0-5: to square (0-63) +// bits 6-11: from square (0-63) // bits 12-13: move type (00 = normal, 01 = promotion, 10 = en passant, 11 = castling) // bits 14-15: promotion piece (00 = queen, 01 = rook, 10 = bishop, 11 = knight)
99-113: LGTM: Well-implemented promotion piece conversion with a minor optimization suggestionThe
getPieceFromPromotionPiecefunction is correctly implemented and handles all promotion pieces. The use ofassertin the default case is good for catching unexpected inputs during development.Consider using a lookup table instead of a switch statement for potentially better performance:
inline Piece getPieceFromPromotionPiece(const PromotionPiece promotionPiece, const PieceColor color) { static constexpr Piece promotionPieces[] = {WHITE_QUEEN, WHITE_ROOK, WHITE_BISHOP, WHITE_KNIGHT}; assert(promotionPiece <= KNIGHT_PROMOTION); return static_cast<Piece>(promotionPieces[promotionPiece] + color); }This approach eliminates branching and might be more efficient, especially if this function is called frequently.
src/board.h (1)
168-191: Consider adding attributes and const qualifiers to method declarations.The method declarations cover necessary operations for a chess engine and make good use of templates and the
[[nodiscard]]attribute. However, consider the following improvements:
Mark
isPositionLegalandgetSquareAttackersasconst:template <PieceColor movedColor> [[nodiscard]] bool isPositionLegal() const; [[nodiscard]] uint64_t getSquareAttackers(uint8_t square) const;Add
[[nodiscard]]attribute tosetFromFEN:[[nodiscard]] bool setFromFEN(std::string_view fen);Consider marking
resetandnoexcept:void reset() noexcept; void print() const noexcept;These changes can help catch potential errors and provide more information to the compiler for optimizations.
src/board.cpp (5)
30-75: LGTM: Well-implemented position legality checkThe
isPositionLegalmethod is well-implemented, efficiently using bitwise operations and handling special cases for castling moves. The code is clear and follows good practices.Consider adding a brief comment explaining the logic for checking castling legality, as it's a complex part of the code.
110-125: LGTM: Efficient square attackers calculationThe
getSquareAttackersmethod is well-implemented, efficiently using bitwise operations to combine attacks from various piece types. The code is clear and follows good practices.Consider caching the results of
getBitboardcalls for frequently used piece types to potentially improve performance, especially if this method is called frequently in performance-critical sections.
143-156: LGTM: Clear board state printingThe
Consider modifying the method to accept an
std::ostream¶meter (defaulting tostd::cout) to make it more flexible for different output streams or testing scenarios.
158-262: LGTM: Comprehensive move executionThe
makeMovemethod is well-implemented, handling various move types and correctly updating the board state, including castling rights and en passant squares. The code is thorough and covers all necessary cases.Consider breaking down this method into smaller, focused helper methods for each move type (e.g.,
handlePromotion,handleEnPassant,handleCastling) to improve readability and maintainability.
362-467: LGTM with suggestions: FEN parsing implementationThe
setFromFENmethod effectively parses the FEN string and sets up the board state, including piece placement, side to move, castling rights, and en passant square. The implementation is clear and follows good practices.However, there are some TODO items that need to be addressed:
- Implement Zobrist hash updates (line 363)
- Add Zobrist hashes for castling rights (line 408)
- Add en passant Zobrist hash (line 451)
- Implement halfmove and fullmove clock parsing (lines 456-463)
Consider creating separate issues to track these TODO items and ensure they are implemented in future updates.
Would you like me to create GitHub issues for these TODO items?
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (8)
- src/bitboard.cpp (2 hunks)
- src/bitboard.h (1 hunks)
- src/board.cpp (1 hunks)
- src/board.h (1 hunks)
- src/move.h (1 hunks)
- src/move_gen.cpp (1 hunks)
- src/perft.cpp (1 hunks)
- src/types.h (2 hunks)
🧰 Additional context used
📓 Path-based instructions (8)
src/bitboard.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/bitboard.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/perft.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/types.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (2)
src/bitboard.h (5)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:196-201 Timestamp: 2024-10-06T10:15:57.559Z Learning: In `src/bitboard.h`, the function `kingAttacks(uint64_t bb)` correctly includes diagonal moves for the king due to the line `bb |= attacks;`. This line updates `bb` to include east and west shifts before calculating additional attacks in the north and south directions, effectively accounting for all one-square king moves, including diagonals.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:196-201 Timestamp: 2024-10-09T11:49:41.012Z Learning: In `src/bitboard.h`, the function `kingAttacks(uint64_t bb)` correctly includes diagonal moves for the king due to the line `bb |= attacks;`. This line updates `bb` to include east and west shifts before calculating additional attacks in the north and south directions, effectively accounting for all one-square king moves, including diagonals.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:67-69 Timestamp: 2024-10-09T14:54:30.420Z Learning: In `src/bitboard.h`, the `shiftSouthWest` function correctly uses the `NOT_H_FILE` mask when shifting southwest.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:31-94 Timestamp: 2024-10-09T11:49:41.012Z Learning: In `src/bitboard.h`, do not suggest marking the shift functions as `constexpr` in future reviews, as it is not possible.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:31-94 Timestamp: 2024-10-05T15:48:09.435Z Learning: In `src/bitboard.h`, do not suggest marking the shift functions as `constexpr` in future reviews, as it is not possible.src/move.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move.h:34-37 Timestamp: 2024-10-09T11:50:14.518Z Learning: In `src/move.h`, the comments describing the bit assignment for move encoding are correct and should be followed. The `getFromSquare` and `getToSquare` methods have been fixed to match these comments.
🔇 Additional comments (34)
src/perft.cpp (2)
1-28: LGTM: Proper licensing and file structureThe file starts with the appropriate licensing information, includes necessary headers, and correctly defines the Zagreus namespace. This follows good coding practices and ensures proper attribution and organization.
1-76: Overall assessment: Well-implemented perft function with room for minor improvementsThe perft function in this file is generally well-implemented, with correct logic for move generation, legality checking, and recursive depth search. The code follows good practices for chess engine development, prioritizing performance where appropriate.
Key strengths:
- Proper licensing and file structure
- Correct implementation of the perft algorithm
- Efficient move generation based on side to move
Suggested improvements:
- Optimize move generation using template parameters
- Refactor legality checking for potential performance gains
- Fix the
constqualifier on thedepthparameterThese improvements should enhance the performance and correctness of the perft function without significantly altering its core functionality.
src/types.h (6)
23-24: Include statements updated appropriatelyThe changes to the include statements reflect the current needs of the file. Removing "constants.h" and adding and are likely necessary for the new implementations.
61-67: Improved type safety for PieceType and PieceColorThe conversion of
PieceTypeandPieceColorto enum classes with explicit underlying types enhances type safety. Theoperator!forPieceColoris implemented correctly and efficiently.
69-82: Well-designed Piece enum classThe new
Pieceenum class efficiently combines piece type and color information. Using 255 forEMPTYis a good choice, allowing for quick empty square checks.
94-102: Efficient and safe utility functions for piece manipulationThe
getPieceColorandgetPieceTypefunctions are well-implemented, using efficient bit manipulation. The assertions forEMPTYpieces add an extra layer of safety to prevent undefined behavior.
85-91: 🛠️ Refactor suggestionConsider converting CastlingRights to an enum class
While the
CastlingRightsenum effectively uses bit flags, converting it to an enum class would improve type safety and consistency with other enums in the file.Apply this diff to convert CastlingRights to an enum class:
-enum CastlingRights : uint8_t { +enum class CastlingRights : uint8_t { WHITE_KINGSIDE = 0b00000001, WHITE_QUEENSIDE = 0b00000010, BLACK_KINGSIDE = 0b00000100, BLACK_QUEENSIDE = 0b00001000, WHITE_CASTLING = 0b00000011, BLACK_CASTLING = 0b00001100, };Note that this change might require updating the usage of
CastlingRightsthroughout the codebase to use the scoped enum syntax and may require defining bitwise operators for the enum class.Likely invalid or redundant comment.
27-43: 🛠️ Refactor suggestionConsider converting Direction to an enum class
For consistency with other enums in this file and to improve type safety, consider converting the
Directionenum to an enum class. This change would align with the modern C++ practices used elsewhere in the file.Apply this diff to convert Direction to an enum class:
-enum Direction { +enum class Direction : int8_t { NORTH = 8, SOUTH = -8, EAST = 1, WEST = -1, NORTH_EAST = 9, NORTH_WEST = 7, SOUTH_EAST = -7, SOUTH_WEST = -9, NORTH_NORTH_EAST = 17, NORTH_EAST_EAST = 10, SOUTH_EAST_EAST = -6, SOUTH_SOUTH_EAST = -15, SOUTH_SOUTH_WEST = -17, SOUTH_WEST_WEST = -10, NORTH_WEST_WEST = -17, NORTH_NORTH_WEST = -15 };Note that this change might require updating the usage of
Directionthroughout the codebase to use the scoped enum syntax.Likely invalid or redundant comment.
src/move.h (6)
1-30: LGTM: Well-structured file header and includesThe file header includes appropriate copyright notice, license information, and necessary includes. The use of
#pragma oncefor header guards is a modern and efficient approach.
32-38: LGTM: Efficient Move representation and MoveList structureThe
Movetype alias andMoveListstructure are well-defined for the chess engine's needs. The use ofuint8_tfor thesizemember inMoveListis memory-efficient, which aligns with the project's optimization goals.
40-52: LGTM: Well-defined move type and promotion piece enumerationsThe
MoveTypeandPromotionPieceenumerations are correctly defined asuint8_tfor memory efficiency. They cover all necessary move types and promotion pieces for a chess engine.
54-64: LGTM: Comprehensive move and square notation function declarationsThe declared functions provide a complete set of tools for handling move and square notations, including conversions between different representations. This will enhance the engine's ability to interact with standard chess notations.
83-97: LGTM: Efficient move decoding functionsThe move decoding functions (
getFromSquare,getToSquare,getMoveType,getPromotionPiece) are correctly implemented using efficient bitwise operations. They provide a complete set of tools for extracting different components of a move.
1-114: Overall assessment: Well-implemented move representation for a chess engineThe
src/move.hfile provides a comprehensive and efficient implementation of move representation and manipulation for the Zagreus chess engine. It includes well-defined structures, enumerations, and functions for handling various aspects of chess moves. The code generally follows good practices and prioritizes performance, which aligns with the project's goals.Key strengths:
- Memory-efficient data structures and enumerations
- Comprehensive set of functions for move encoding, decoding, and notation handling
- Use of bitwise operations for performance
Areas for minor improvement:
- Updating comments in the move encoding section for clarity
- Considering a lookup table for promotion piece conversion
Overall, this file provides a solid foundation for move handling in the chess engine.
src/board.h (5)
1-34: LGTM: Appropriate file header and includes.The file header contains the necessary copyright and license information. The included headers are relevant for the chess engine implementation.
37-42: LGTM: Well-defined BoardState struct.The
BoardStatestruct efficiently encapsulates the necessary information for representing a board state, using space-efficient types forenPassantSquareandcastlingRights.
44-54: LGTM: Comprehensive and efficient Board class member variables.The
Boardclass member variables efficiently represent all necessary aspects of a chess board state. The use ofstd::arrayfor board representation and bitboards is appropriate, and the choice of types for other variables (e.g.,uint16_tforply) allows for efficient storage and a large number of moves.
57-109: LGTM: Efficient constructor and well-defined getter methods.The
Boardclass constructor efficiently initializes all member variables usingstd::ranges::fill. The getter methods are well-defined, providing access to all necessary board state information. The use ofconstexprand[[nodiscard]]attributes is appropriate for optimization and error prevention.
1-193: Overall, well-implemented and efficient Board class for a chess engine.The
Boardclass insrc/board.hprovides a comprehensive and efficient representation of a chess board with all necessary operations. The use of modern C++ features, such asstd::array,constexpr, and templates, contributes to both performance and code clarity. The careful use of types and bitboards demonstrates a focus on efficiency, which is crucial for a chess engine.While there are minor opportunities for improvement, such as reducing some code duplication and adding a few additional attributes to method declarations, the overall quality of the code is high. It strikes a good balance between readability and performance, which is essential for a chess engine implementation.
src/move_gen.cpp (6)
173-191: Knight move generation looks goodThe
generateKnightMovesfunction is implemented efficiently using bitboard operations and correctly applies the generation mask to filter valid moves. The code is clear and concise.
213-231: Rook move generation looks good, but consider previous refactoring suggestionThe
generateRookMovesfunction is implemented correctly and efficiently. However, please refer to the previous comment about refactoring sliding piece move generation to reduce code duplication across bishop, rook, and queen move generation functions.
233-251: Queen move generation looks good, but consider previous refactoring suggestionThe
generateQueenMovesfunction is implemented correctly and efficiently. However, please refer to the previous comment about refactoring sliding piece move generation to reduce code duplication across bishop, rook, and queen move generation functions.
253-299: King move generation, including castling, looks goodThe
generateKingMovesfunction is implemented efficiently, correctly handling both regular king moves and castling. The use of bitboard operations for move generation and the separate handling of castling rights for each color are well done.
301-309: Explicit instantiations of generateMoves are comprehensiveThe explicit instantiations of
generateMovescover all combinations of color (WHITE, BLACK) and generation type (ALL, QUIET, CAPTURES, EVASIONS). This is good practice for template functions, ensuring they are compiled for all required types and potentially improving compile times for code that uses these functions.
1-310: Overall excellent implementation with a few areas for improvementThe move generation code in
src/move_gen.cppis generally well-implemented, focusing on performance through efficient use of bitboard operations. Here's a summary of the main points:
- The use of bitboard operations and pre-computed attack tables ensures efficient move generation for all piece types.
- The TODO about implementing GenerationType logic in the main
generateMovesfunction should be addressed to fully utilize the type parameter.- There's potential for code reuse in the sliding piece move generation (bishops, rooks, queens). Consider creating a template function to reduce duplication and improve maintainability.
- The
generatePawnMovesfunction, while comprehensive, is quite long and complex. Consider refactoring it into smaller, more focused functions for better readability and maintainability.- The explicit template instantiations at the end of the file are a good practice for optimizing compile-time and potentially reducing binary size.
Overall, this is a solid foundation for a high-performance chess engine's move generation. Addressing the suggested improvements will further enhance its completeness and maintainability.
src/board.cpp (5)
1-29: LGTM: Well-structured file header and includesThe file header contains appropriate copyright and license information, and the necessary headers are included. The code organization in this section is clean and follows good practices.
77-108: LGTM: Efficient castling possibility checkThe
canCastlemethod is well-implemented, using compile-time conditionals to optimize for different castling sides. The code is clear, efficient, and follows good practices.
127-141: LGTM: Effective board state resetThe
resetmethod is well-implemented, effectively resetting all necessary board state variables. The use ofstd::ranges::fillfor array initialization is a good practice in modern C++.
264-315: LGTM: Correct move reversal implementationThe
unmakeMovemethod effectively reverses the last move and restores the previous board state. It properly handles special cases like promotions, en passant, and castling. The implementation is clear and follows the logic of themakeMovemethod in reverse.
317-360: LGTM: Efficient FEN character to piece mappingThe
setPieceFromFENCharmethod effectively maps FEN characters to piece types and sets them on the board. The use of a switch statement is appropriate and efficient for this case. The implementation is clear and follows good practices.src/bitboard.h (4)
34-97: Shift functions are correctly implemented with appropriate maskingThe shift functions (
shiftNorth,shiftSouth,shiftEast,shiftWest, and their variants) are well-designed, using correct bit shifts and masks to prevent wrap-around effects on the bitboard. This implementation aligns with the performance priorities of the chess engine.
98-133: Templateshiftfunction effectively dispatches shifts based on directionThe
shifttemplate function uses aswitchstatement for compile-time dispatch based on theDirectiontemplate parameter. This approach is suitable and maintains performance, as the compiler can optimize away unused branches during compilation.
218-223: Confirm thatcalculateKingAttacksincludes all king movesThe
calculateKingAttacksfunction appears to correctly calculate all possible king moves, including diagonals, by updatingbbwith east and west shifts before combining with north and south shifts.Run the following script to ensure that all king moves are accounted for:
#!/bin/bash # Description: Verify that calculateKingAttacks includes all king moves # Test the function with a sample bitboard position echo "uint64_t bb = /* sample position */;" > test.cpp echo "uint64_t attacks = calculateKingAttacks(bb);" >> test.cpp # Since compilers are not available, ensure the logic matches expected results # Manually inspect the shifts and masks used in calculateKingAttacks
229-231: Verify the accessibility ofbitscanForwardfunctionThe function
bitboardToSquareusesbitscanForward(bb)on line 230. Ensure thatbitscanForwardis properly defined and included in the codebase to prevent potential linker errors.Run the following script to confirm that
bitscanForwardis defined and accessible:✅ Verification successful
bitscanForwardis properly defined inbitwise.hand correctly included inbitboard.h, ensuring its accessibility.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify that bitscanForward is defined in the codebase # Search for the definition of bitscanForward rg --type cpp --type-header --word-regexp 'bitscanForward' # Check if it's included in bitwise.h rg --type cpp 'bitscanForward' bitwise.hLength of output: 99
Script:
#!/bin/bash # Description: Further verify the definition and usage of bitscanForward # Search for any aliases or variations of bitscanForward rg --type cpp --type-header --word-regexp 'bitscanForward' --ignore-case # Look for macro definitions that might define bitscanForward rg --type cpp '#define\s+bitscanForward\b' # Search for conditional compilation related to bitscanForward rg --type cpp 'bitscanForward' --context 2Length of output: 1150
Script:
#!/bin/bash # Description: Verify that bitboard.h includes bitwise.h # Check for inclusion of bitwise.h in bitboard.h rg '#include\s+"bitwise\.h"' src/bitboard.hLength of output: 66
Signed-off-by: Danny Jelsma <[email protected]>
Signed-off-by: Danny Jelsma <[email protected]>
Signed-off-by: Danny Jelsma <[email protected]>
There was a problem hiding this comment.
Actionable comments posted: 18
🧹 Outside diff range and nitpick comments (12)
.github/workflows/doxygen.yml (3)
1-7: Workflow configuration looks good, but consider adding more triggers.The workflow name is descriptive, and the trigger configuration is set up correctly for the 'master' and 'rewrite' branches. However, you might want to consider adding more triggers to ensure documentation is always up-to-date.
Consider adding a
pull_requesttrigger to generate documentation for review before merging:on: push: branches: - master - rewrite pull_request: branches: - master - rewriteThis would allow reviewers to check the generated documentation as part of the PR review process.
9-13: Job configuration is correct, but consider adding a conditional.The job configuration with write permissions is correct for deploying to GitHub Pages. However, you might want to add a conditional to prevent unnecessary runs.
Consider adding a conditional to only run the job when there are changes to files that affect the documentation:
jobs: deploy: runs-on: ubuntu-latest permissions: contents: write if: | github.event_name == 'push' || (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository)This ensures the job only runs on pushes to the main repository or on pull requests from the same repository, avoiding unnecessary runs on forks.
14-21: Action configuration is good, but consider uncommenting optional parameters.The Doxygen GitHub Pages action is correctly configured with the necessary parameters. However, the commented-out options for the folder and config file could be useful.
Consider uncommenting and setting values for the
folderandconfig_fileparameters:- uses: DenverCoder1/[email protected] with: github_token: ${{ secrets.GITHUB_TOKEN }} branch: gh-pages folder: docs/html config_file: Doxyfile doxygen_version: 1.12.0This would allow for more precise control over the documentation generation and output location. Ensure that the
Doxyfileexists in your repository and thedocs/htmlfolder is the correct output location for your project structure.src/board.h (1)
47-62: LGTM: Efficient board representation with room for minor optimization.The Board class uses std::array and bitboards for efficient board representation, which is excellent for performance. All necessary aspects of a chess board state are covered by the member variables.
Consider using
std::array<BoardState, MAX_PLY + 1> historyto avoid potential off-by-one errors when accessing the last move in thegetLastMove()method.src/board.cpp (5)
29-80: LGTM:isPositionLegalmethod is well-implemented.The method correctly checks the legality of a position, including special cases like castling. However, a minor optimization could be made.
Consider using
if constexprfor the castling path checks to potentially improve compile-time optimization:- if (toSquare == G1) { + if constexpr (movedColor == WHITE) { + if (toSquare == G1) { castlingPath = WHITE_KINGSIDE_CASTLE_PATH; - } else if (toSquare == C1) { + } else if (toSquare == C1) { castlingPath = WHITE_QUEENSIDE_CASTLE_PATH; + } - } else if (toSquare == G8) { + } else { + if (toSquare == G8) { castlingPath = BLACK_KINGSIDE_CASTLE_PATH; - } else if (toSquare == C8) { + } else if (toSquare == C8) { castlingPath = BLACK_QUEENSIDE_CASTLE_PATH; + } }This change could potentially improve compile-time optimization and make the code more type-safe.
119-176: LGTM:getSquareAttackers,reset, andThese methods correctly serve their intended purposes. However, a minor improvement could be made to the
Consider using
std::arrayinstead of C-style array forboardto leverage modern C++ features and potentially improve type safety:- std::ranges::fill(board, EMPTY); + std::fill(board.begin(), board.end(), EMPTY);This change assumes
boardis changed tostd::array<Piece, 64> board;in the class definition.
178-286: LGTM:makeMovemethod is comprehensive and well-implemented.The method correctly handles all move types and updates the board state accordingly. However, there's room for optimization in the castling rights update.
Consider using bitwise operations to update castling rights more efficiently:
- if (movedPiece == WHITE_KING) { - castlingRights &= ~WHITE_CASTLING; - } else if (movedPiece == BLACK_KING) { - castlingRights &= ~BLACK_CASTLING; - } else if (movedPiece == WHITE_ROOK) { - if (fromSquare == A1) { - castlingRights &= ~WHITE_QUEENSIDE; - } else if (fromSquare == H1) { - castlingRights &= ~WHITE_KINGSIDE; - } - } else if (movedPiece == BLACK_ROOK) { - if (fromSquare == A8) { - castlingRights &= ~BLACK_QUEENSIDE; - } else if (fromSquare == H8) { - castlingRights &= ~BLACK_KINGSIDE; - } - } + constexpr uint8_t castlingMask[64] = { + 13, 15, 15, 15, 12, 15, 15, 14, + 15, 15, 15, 15, 15, 15, 15, 15, + 15, 15, 15, 15, 15, 15, 15, 15, + 15, 15, 15, 15, 15, 15, 15, 15, + 15, 15, 15, 15, 15, 15, 15, 15, + 15, 15, 15, 15, 15, 15, 15, 15, + 15, 15, 15, 15, 15, 15, 15, 15, + 7, 15, 15, 15, 3, 15, 15, 11 + }; + castlingRights &= castlingMask[fromSquare];This change uses a pre-computed mask to update castling rights in a single operation, potentially improving performance.
344-504: LGTM with suggestions: FEN parsing methods are well-implemented but could be improved.The
setPieceFromFENCharandsetFromFENmethods correctly handle FEN parsing and board setup. However, there are some TODOs and potential improvements forsetFromFEN.
Implement the TODO items:
- Update Zobrist hash (line 400)
- Add Zobrist hashes for castling rights (line 445)
- Add en passant Zobrist hash (line 488)
- Implement halfmove and fullmove clock parsing (lines 493-500)
Consider using
std::string_view::substrto split the FEN string into its components instead of manually tracking spaces. This could simplify the parsing logic.Use
std::from_charsfor parsing numeric values (like the halfmove and fullmove clocks) when you implement them, as it's generally faster than string-to-integer conversions.Consider using a separate method for parsing each FEN component (piece placement, side to move, etc.) to improve readability and maintainability.
Would you like assistance in implementing these improvements or creating issues to track them?
1-505: Overall assessment: Well-implemented with room for optimization and completion.The
Boardclass implementation insrc/board.cppis generally well-structured and covers the core functionality of a chess board. Key strengths include:
- Comprehensive move generation and validation.
- Efficient bitboard operations.
- Proper handling of special moves (castling, en passant, promotions).
Areas for improvement:
- Implement remaining TODO items (Zobrist hashing, move clock parsing).
- Optimize certain operations, particularly in
makeMoveandsetFromFEN.- Consider using more modern C++ features (e.g.,
std::array,std::string_view).As the codebase grows, consider splitting the
Boardclass into smaller, more focused classes (e.g.,MoveGenerator,FENParser) to improve modularity and maintainability.src/eval.h (2)
6-6: Typographical Correction: Add missing space in the copyright noticeThere is a missing space at the beginning of line 6. It should have a space before the word "Copyright".
- Copyright (C) 2023-2024 Danny Jelsma + +Copyright (C) 2023-2024 Danny Jelsma
35-36: Mark constant methods appropriatelyThe method
evaluateMaterial()appears to be a helper function that might not modify the state in a way that is externally visible. If appropriate, consider marking it asconstto indicate it doesn't modify the object's state, which can aid in optimization and code clarity.-void evaluateMaterial(); +void evaluateMaterial() const;src/eval.cpp (1)
60-103: Review the necessity of the default case in the switch statement.The switch statement in
evaluateMaterial()includes adefaultcase that does nothing:default: break;Since all
Pieceenum values are presumably covered, thedefaultcase may be redundant. If all possible cases are handled explicitly, you might consider removing thedefaultcase to allow the compiler to warn about any unhandled cases if new pieces are added in the future.
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (15)
- .github/workflows/doxygen.yml (1 hunks)
- .gitignore (1 hunks)
- src/bitboard.cpp (2 hunks)
- src/bitboard.h (1 hunks)
- src/bitwise.h (2 hunks)
- src/board.cpp (1 hunks)
- src/board.h (1 hunks)
- src/eval.cpp (1 hunks)
- src/eval.h (2 hunks)
- src/eval_features.h (1 hunks)
- src/move.cpp (1 hunks)
- src/move_gen.cpp (1 hunks)
- src/uci.cpp (1 hunks)
- src/uci.h (1 hunks)
- tests/types_tests.cpp (1 hunks)
✅ Files skipped from review due to trivial changes (1)
- .gitignore
🚧 Files skipped from review as they are similar to previous changes (1)
- src/move.cpp
🧰 Additional context used
📓 Path-based instructions (12)
src/bitboard.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/bitboard.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/bitwise.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/board.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/eval.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/eval.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/eval_features.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/uci.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/uci.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.tests/types_tests.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (3)
src/bitboard.h (4)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:199-203 Timestamp: 2024-10-16T14:58:45.278Z Learning: In `src/bitboard.h`, the function `calculateKnightAttacks` is used for initializing attack lookup tables, and `getKnightAttacks` uses these precomputed tables for knight attack calculations.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:67-69 Timestamp: 2024-10-09T14:54:30.420Z Learning: In `src/bitboard.h`, the `shiftSouthWest` function correctly uses the `NOT_H_FILE` mask when shifting southwest.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:196-201 Timestamp: 2024-10-09T11:49:41.012Z Learning: In `src/bitboard.h`, the function `kingAttacks(uint64_t bb)` correctly includes diagonal moves for the king due to the line `bb |= attacks;`. This line updates `bb` to include east and west shifts before calculating additional attacks in the north and south directions, effectively accounting for all one-square king moves, including diagonals.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/bitboard.h:196-201 Timestamp: 2024-10-06T10:15:57.559Z Learning: In `src/bitboard.h`, the function `kingAttacks(uint64_t bb)` correctly includes diagonal moves for the king due to the line `bb |= attacks;`. This line updates `bb` to include east and west shifts before calculating additional attacks in the north and south directions, effectively accounting for all one-square king moves, including diagonals.src/uci.cpp (2)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.cpp:110-179 Timestamp: 2024-10-14T07:26:06.778Z Learning: In future code reviews, avoid suggesting changes to `uci.cpp` and `uci.h` unless they are critical or blockers.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.cpp:394-430 Timestamp: 2024-10-11T16:04:05.283Z Learning: In `src/uci.cpp`, performance optimizations are unnecessary.src/uci.h (3)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.cpp:110-179 Timestamp: 2024-10-14T07:26:06.778Z Learning: In future code reviews, avoid suggesting changes to `uci.cpp` and `uci.h` unless they are critical or blockers.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.h:77-77 Timestamp: 2024-10-05T13:12:32.035Z Learning: In UCI-related code (e.g., `src/uci.h` and `src/uci.cpp`), prioritize readability and maintainability over performance optimizations, as these functions are not performance-critical.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.h:77-77 Timestamp: 2024-10-09T11:49:41.012Z Learning: In UCI-related code (e.g., `src/uci.h` and `src/uci.cpp`), prioritize readability and maintainability over performance optimizations, as these functions are not performance-critical.
🪛 cppcheck
src/uci.cpp
[performance] 465-465: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 473-473: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 522-522: Function parameter 'values' should be passed by const reference.
(passedByValue)
tests/types_tests.cpp
[error] 43-43: syntax error
(syntaxError)
🔇 Additional comments (45)
.github/workflows/doxygen.yml (1)
1-21: Verify Doxygen configuration file existence.The workflow looks good overall, but it's crucial to ensure that the Doxygen configuration file exists in the repository.
Run the following script to check for the existence of a Doxygen configuration file:
This script will help ensure that the necessary Doxygen configuration file is present in the repository, which is crucial for the successful execution of the documentation generation workflow.
✅ Verification successful
Doxygen configuration file exists.
The workflow is correctly configured with the required Doxygen configuration file.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check for the existence of a Doxygen configuration file # Test: Search for Doxyfile or doxygen.conf if fd -t f -e conf -e cfg -e ini -e txt -e yml -e yaml -e json "^(Doxyfile|doxygen)" --max-depth 2; then echo "Doxygen configuration file found." else echo "Warning: No Doxygen configuration file found in the repository root or immediate subdirectories." echo "Please ensure a Doxygen configuration file exists and is properly referenced in the workflow." fiLength of output: 174
src/eval_features.h (3)
1-22: LGTM: License header and include guard are correctly implemented.The license header provides comprehensive information about the Zagreus UCI chess engine, including copyright details and the terms of the GNU Affero General Public License. The use of
#pragma onceat line 22 serves as an effective include guard for this header file.
24-35: Efficient use of preprocessor macros for material values.The use of preprocessor macros for defining material values is an excellent choice for a performance-critical application like a chess engine. This approach ensures that these constants are resolved at compile-time, potentially leading to better performance compared to runtime variable lookups.
24-35: Verify intention: Consistent midgame and endgame values.The material values for each piece are identical in both midgame and endgame scenarios. While this might be intentional, it's worth verifying if this is the desired behavior. In many chess engines, piece values often differ between midgame and endgame to reflect the changing importance of pieces as the game progresses.
Could you confirm if the consistent values across midgame and endgame are intentional? If not, consider adjusting the endgame values to reflect the typical changes in piece importance during the endgame.
tests/types_tests.cpp (3)
1-19: LGTM: Appropriate license header.The license header is complete and correctly identifies the software, copyright, and license terms (GNU Affero General Public License).
21-25: LGTM: Appropriate includes and namespace usage.The file correctly includes Catch2 for testing and the necessary types header. The use of the Zagreus namespace is consistent with the project structure.
43-64: 🛠️ Refactor suggestionRefactor for improved readability and efficiency.
The test case is comprehensive, but consider the following improvements:
- Use a more descriptive name for the test case.
- Simplify the color checking logic by using the piece's underlying value.
- Use an enum class for piece colors instead of string literals.
Here's a suggested refactoring:
TEST_CASE("getPieceColor correctly identifies color for all chess pieces", "[types]") { const std::vector<Piece> pieces = { Piece::WHITE_PAWN, Piece::BLACK_PAWN, Piece::WHITE_KNIGHT, Piece::BLACK_KNIGHT, Piece::WHITE_BISHOP, Piece::BLACK_BISHOP, Piece::WHITE_ROOK, Piece::BLACK_ROOK, Piece::WHITE_QUEEN, Piece::BLACK_QUEEN, Piece::WHITE_KING, Piece::BLACK_KING }; for (const auto& piece : pieces) { PieceColor expectedColor = (static_cast<int>(piece) & 1) ? PieceColor::BLACK : PieceColor::WHITE; REQUIRE(getPieceColor(piece) == expectedColor); } }This refactored version simplifies the logic and improves readability.
Regarding the static analysis hint:
The reported syntax error on line 43 appears to be a false positive. The code is syntactically correct and should compile without issues. You can safely ignore this warning from cppcheck.🧰 Tools
🪛 cppcheck
[error] 43-43: syntax error
(syntaxError)
src/board.h (4)
1-36: LGTM: Comprehensive file header and includes.The file header includes appropriate licensing information, and all necessary include statements are present. The use of the Zagreus namespace is also correctly implemented.
37-45: LGTM: Efficient BoardState struct.The BoardState struct efficiently captures the necessary information for representing the board state at a given ply. The use of compact types (uint8_t) for enPassantSquare and castlingRights is good for memory efficiency.
63-186: LGTM: Efficient constructor and getter methods.The Board class constructor efficiently initializes member variables using std::ranges::fill. The getter methods are implemented as constexpr where possible, which is excellent for performance. The use of templates for bitboard getters allows for compile-time optimizations.
1-343: LGTM: Solid implementation with a focus on performance.The Board class implementation in src/board.h is comprehensive and well-optimized for a chess engine. The use of bitboards, std::array, constexpr, and templates demonstrates a strong focus on performance. The suggested refactorings and minor optimizations can further improve the code without compromising its efficiency.
src/move_gen.cpp (2)
1-29: LGTM: File header and includes are well-structuredThe file header contains appropriate copyright and license information. The necessary includes are present and relevant to the file's functionality.
300-309: LGTM: Explicit instantiations are well-implementedThe explicit instantiations of the
generateMovesfunction for different combinations of color and generation type are a good practice. They can help reduce compile times and potentially reduce binary size. All necessary combinations are covered.src/board.cpp (3)
1-28: LGTM: File header and includes are well-organized.The file header contains appropriate copyright and license information, and the necessary headers are included.
82-117: LGTM:canCastlemethod is well-implemented.The method efficiently checks castling possibilities using compile-time constants and proper bitboard operations. The use of
constexprin the if statements is a good practice for compile-time optimization.
288-342: LGTM:unmakeMovemethod is well-implemented and complementsmakeMove.The method correctly reverses all move types and restores the board state, including piece positions, castling rights, and en passant squares. It's a good complement to the
makeMovemethod and essential for search algorithms.src/eval.h (2)
35-36: Ensure private methods are implementedThe methods
calculatePhase()andevaluateMaterial()are declared but may not be implemented yet. Missing implementations can lead to linker errors.Run the following script to verify their implementations:
✅ Verification successful
Verified: Both
calculatePhase()andevaluateMaterial()methods are properly implemented insrc/eval.cpp. No linker issues detected.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify that `calculatePhase` and `evaluateMaterial` are implemented. # Test: Search for the method definitions. Expect: Method implementations in .cpp files. rg --type cpp 'int Evaluation::calculatePhase\(\) const' rg --type cpp 'void Evaluation::evaluateMaterial\(\)'Length of output: 219
24-24: Verify the necessity of including "board.h"Ensure that only the required headers are included to optimize compilation time and reduce dependencies. Confirm whether all the declarations used in
eval.hnecessitate including"board.h"or if a forward declaration ofBoardwould suffice.Run the following script to check for unnecessary includes:
✅ Verification successful
Including "board.h" is unnecessary
The analysis indicates that all usages of
Boardinsrc/eval.hare pointers or references, allowing for forward declarations. Therefore, including"board.h"can be removed to optimize compilation.🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check if "board.h" is necessary in eval.h # Test: Search for usages of Board that require a full definition. rg --type cpp --type h --word-regex '\bBoard\b' src/eval.h | rg -v 'Board\*|Board&|Board board;'Length of output: 542
Script:
#!/bin/bash # Description: Check if "board.h" is necessary in eval.h # Test: Search for usages of Board that require a full definition. rg --type cpp --type h --word-regexp '\bBoard\b' src/eval.h | rg -v 'Board\*|Board&|Board board;'Length of output: 99
src/bitwise.h (4)
34-40: Efficient implementation ofpopcntfunctionThe
popcntfunction is correctly implemented using compiler intrinsics, leveraging_popcnt64for MSVC and__builtin_popcountllfor GCC/Clang. This ensures optimal performance across different compilers.
47-56: Correct and performantbitscanForwardfunctionThe
bitscanForwardfunction efficiently finds the least significant set bit using compiler-specific intrinsics. The use ofassert(bb != 0);adds a safeguard against undefined behavior whenbbis zero.
63-72: Accurate calculation inbitscanReversefunctionThe
bitscanReversefunction correctly calculates the index of the most significant set bit. The expression63 - __builtin_clzll(bb);is the correct operation for GCC/Clang compilers.
79-85: Properly inlinedpopLsbfunction with efficient implementationThe
popLsbfunction is marked asinlineand efficiently pops the least significant set bit by modifying the bitboard in place. The use ofbitscanForward(bb);ensures that the correct bit index is retrieved before the bit is cleared.src/uci.h (1)
1-125: Well-Structured Implementation of UCI Engine HeaderThe implementation of
src/uci.his well-structured and aligns with the project's coding guidelines. The classesEngineandUCIOptionare clearly defined, and the use of namespaces and include guards promotes maintainability and readability. The code appropriately prioritizes readability and maintainability over performance optimizations in accordance with the learnings for UCI-related code.src/bitboard.cpp (6)
26-29: Initialization of Attack Pattern Lookup Tables is CorrectThe declaration of the static lookup tables for pawn, knight, and king attacks is properly structured, facilitating efficient access during move generation.
31-41: Attack Lookup Tables Initialized EfficientlyThe
initializeAttackLookupTablesfunction correctly populates the attack patterns for all squares, ensuring accurate and fast retrieval during gameplay.
51-54:getPawnAttacksFunction Implemented CorrectlyThe template function
getPawnAttacksaccurately retrieves pawn attack patterns based on color and square, utilizing the precomputed lookup tables.
66-68:getKnightAttacksFunction CorrectThe
getKnightAttacksfunction correctly accesses knight attack patterns from the lookup table, ensuring efficient move calculations.
76-78:getKingAttacksFunction AccurateThe
getKingAttacksfunction properly retrieves king attack patterns, allowing for correct king move generation.
117-119: Consider MarkingqueenAttacksasinlinefor PerformanceThe
queenAttacksfunction aggregates bishop and rook attacks and is called frequently. Marking it asinlinemay reduce overhead and improve execution speed.src/eval.cpp (2)
26-35: Verify the correctness ofmodifierin the evaluation calculation.In the
evaluate()function, the evaluation score is adjusted by themodifier, which is set based on the side to move:const int modifier = board.getSideToMove() == WHITE ? 1 : -1;This means the evaluation will be positive if it's White to move and negative if it's Black to move. Please verify that this aligns with your engine's overall evaluation strategy. Typically, evaluations are from one side's perspective (usually White), or they are absolute values indicating the advantage regardless of the side to move.
52-52: Confirm the phase calculation and scaling logic.In the
calculatePhase()function, the phase is scaled to a value between 0 and 256:return (phase * 256 + (totalPhase / 2)) / totalPhase;This formula aims to perform integer rounding correctly. Please verify that this scaling aligns with your intended evaluation model and that the constants used for
totalPhaseand individual piece phases accurately reflect the dynamics of the game phases in your engine.src/bitboard.h (14)
60-62: Duplicate Issue: Incorrect mask inshiftEastfunctionThe previous review comment about the incorrect mask in the
shiftEastfunction is still applicable. The function currently usesNOT_A_FILE, but it should useNOT_H_FILEto prevent wrap-around when shifting east.
69-71: Duplicate Issue: Incorrect mask inshiftWestfunctionThe previous review comment regarding the incorrect mask in the
shiftWestfunction remains valid. The function currently usesNOT_H_FILE, but it should useNOT_A_FILEto prevent wrap-around when shifting west.
78-80: Duplicate Issue: Incorrect mask inshiftNorthEastfunctionThe previous review comment about the incorrect mask in the
shiftNorthEastfunction is still applicable. The function currently usesNOT_A_FILE, but it should useNOT_H_FILEto prevent wrap-around when shifting northeast.
87-89: Duplicate Issue: Incorrect mask inshiftNorthWestfunctionThe previous review comment regarding the incorrect mask in the
shiftNorthWestfunction remains valid. The function currently usesNOT_H_FILE, but it should useNOT_A_FILEto prevent wrap-around when shifting northwest.
96-98: Duplicate Issue: Incorrect mask inshiftSouthEastfunctionThe previous review comment about the incorrect mask in the
shiftSouthEastfunction is still applicable. The function currently usesNOT_A_FILE, but it should useNOT_H_FILEto prevent wrap-around when shifting southeast.
114-116: Duplicate Issue: Incorrect mask inshiftNorthNorthEastfunctionThe previous review comment regarding the incorrect mask in the
shiftNorthNorthEastfunction remains valid. The function currently usesNOT_A_FILE, but it should useNOT_H_FILEto prevent wrap-around when shifting north-northeast.
123-125: Duplicate Issue: Incorrect mask inshiftNorthEastEastfunctionThe previous review comment about the incorrect mask in the
shiftNorthEastEastfunction is still applicable. The function currently usesNOT_AB_FILE, but it should useNOT_GH_FILEto prevent wrap-around when shifting north-east-east.
132-134: Duplicate Issue: Incorrect mask inshiftSouthEastEastfunctionThe previous review comment regarding the incorrect mask in the
shiftSouthEastEastfunction remains valid. The function currently usesNOT_AB_FILE, but it should useNOT_GH_FILEto prevent wrap-around when shifting south-east-east.
141-143: Duplicate Issue: Incorrect mask inshiftSouthSouthEastfunctionThe previous review comment about the incorrect mask in the
shiftSouthSouthEastfunction is still applicable. The function currently usesNOT_A_FILE, but it should useNOT_H_FILEto prevent wrap-around when shifting south-southeast.
150-152: Duplicate Issue: Incorrect mask inshiftNorthNorthWestfunctionThe previous review comment regarding the incorrect mask in the
shiftNorthNorthWestfunction remains valid. The function currently usesNOT_H_FILE, but it should useNOT_A_FILEto prevent wrap-around when shifting north-northwest.
159-161: Duplicate Issue: Incorrect mask inshiftNorthWestWestfunctionThe previous review comment about the incorrect mask in the
shiftNorthWestWestfunction is still applicable. The function currently usesNOT_GH_FILE, but it should useNOT_AB_FILEto prevent wrap-around when shifting north-west-west.
168-170: Duplicate Issue: Incorrect mask inshiftSouthWestWestfunctionThe previous review comment regarding the incorrect mask in the
shiftSouthWestWestfunction remains valid. The function currently usesNOT_GH_FILE, but it should useNOT_AB_FILEto prevent wrap-around when shifting south-west-west.
177-179: Duplicate Issue: Incorrect mask inshiftSouthSouthWestfunctionThe previous review comment about the incorrect mask in the
shiftSouthSouthWestfunction is still applicable. The function currently usesNOT_H_FILE, but it should useNOT_A_FILEto prevent wrap-around when shifting south-southwest.
445-447: Duplicate Issue:bitscanForwardmay be undefinedThe previous review comment regarding the use of
bitscanForwardin thebitboardToSquarefunction remains valid. Ensure thatbitscanForwardis defined or included appropriately to prevent potential compilation errors.
| TEST_CASE("test_pieceType", "[types]") { | ||
| REQUIRE(getPieceType(Piece::WHITE_PAWN) == PieceType::PAWN); | ||
| REQUIRE(getPieceType(Piece::BLACK_PAWN) == PieceType::PAWN); | ||
| REQUIRE(getPieceType(Piece::WHITE_KNIGHT) == PieceType::KNIGHT); | ||
| REQUIRE(getPieceType(Piece::BLACK_KNIGHT) == PieceType::KNIGHT); | ||
| REQUIRE(getPieceType(Piece::WHITE_BISHOP) == PieceType::BISHOP); | ||
| REQUIRE(getPieceType(Piece::BLACK_BISHOP) == PieceType::BISHOP); | ||
| REQUIRE(getPieceType(Piece::WHITE_ROOK) == PieceType::ROOK); | ||
| REQUIRE(getPieceType(Piece::BLACK_ROOK) == PieceType::ROOK); | ||
| REQUIRE(getPieceType(Piece::WHITE_QUEEN) == PieceType::QUEEN); | ||
| REQUIRE(getPieceType(Piece::BLACK_QUEEN) == PieceType::QUEEN); | ||
| REQUIRE(getPieceType(Piece::WHITE_KING) == PieceType::KING); | ||
| REQUIRE(getPieceType(Piece::BLACK_KING) == PieceType::KING); | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider refactoring for improved readability and maintainability.
While the test case comprehensively covers all chess pieces, consider the following improvements:
- Use a more descriptive name for the test case (e.g., "getPieceType correctly identifies all chess pieces").
- Use a loop or table-driven approach to reduce repetition and improve maintainability.
Here's a suggested refactoring:
TEST_CASE("getPieceType correctly identifies all chess pieces", "[types]") {
const std::vector<std::pair<Piece, PieceType>> pieces = {
{Piece::WHITE_PAWN, PieceType::PAWN},
{Piece::BLACK_PAWN, PieceType::PAWN},
{Piece::WHITE_KNIGHT, PieceType::KNIGHT},
{Piece::BLACK_KNIGHT, PieceType::KNIGHT},
{Piece::WHITE_BISHOP, PieceType::BISHOP},
{Piece::BLACK_BISHOP, PieceType::BISHOP},
{Piece::WHITE_ROOK, PieceType::ROOK},
{Piece::BLACK_ROOK, PieceType::ROOK},
{Piece::WHITE_QUEEN, PieceType::QUEEN},
{Piece::BLACK_QUEEN, PieceType::QUEEN},
{Piece::WHITE_KING, PieceType::KING},
{Piece::BLACK_KING, PieceType::KING}
};
for (const auto& [piece, expectedType] : pieces) {
REQUIRE(getPieceType(piece) == expectedType);
}
}This refactored version improves readability and makes it easier to add or modify test cases in the future.
src/board.h
Outdated
| */ | ||
| template <Piece piece> | ||
| void removePiece(const uint8_t square) { | ||
| assert(piece != Piece::EMPTY); | ||
| assert(board[square] == piece); | ||
| const uint64_t squareBB = squareToBitboard(square); | ||
|
|
||
| board[square] = EMPTY; | ||
| bitboards[piece] &= ~squareBB; | ||
| occupied &= ~squareBB; | ||
| colorBoards[getPieceColor(piece)] &= ~squareBB; | ||
| pieceCounts[piece] -= 1; | ||
| } | ||
|
|
||
| /** | ||
| * \brief Removes a piece from a given square. | ||
| * \param piece The piece type. | ||
| * \param square The square index (0-63). | ||
| */ | ||
| void removePiece(const Piece piece, const uint8_t square) { | ||
| assert(piece != Piece::EMPTY); | ||
| assert(board[square] == piece); | ||
| const uint64_t squareBB = squareToBitboard(square); | ||
|
|
||
| board[square] = EMPTY; | ||
| bitboards[piece] &= ~squareBB; | ||
| occupied &= ~squareBB; | ||
| colorBoards[getPieceColor(piece)] &= ~squareBB; | ||
| pieceCounts[piece] -= 1; | ||
| } | ||
|
|
||
| /** | ||
| * \brief Makes a move on the board. | ||
| * \param move The move to make. | ||
| */ | ||
| void makeMove(const Move& move); | ||
|
|
||
| /** | ||
| * \brief Unmakes the last move on the board. | ||
| */ | ||
| void unmakeMove(); | ||
|
|
||
| /** | ||
| * \brief Sets a piece on the board from a FEN character. | ||
| * \param character The FEN character representing the piece. | ||
| * \param square The square index (0-63). | ||
| */ | ||
| void setPieceFromFENChar(char character, uint8_t square); | ||
|
|
||
| /** | ||
| * \brief Checks if the current position is legal based on the color that just made a move. | ||
| * \tparam movedColor The color of the player who just moved. | ||
| * \return True if the position is legal, false otherwise. | ||
| */ | ||
| template <PieceColor movedColor> | ||
| [[nodiscard]] bool isPositionLegal() const; | ||
|
|
||
| /** | ||
| * \brief Retrieves the attackers of a given square. | ||
| * \param square The square index (0-63). | ||
| * \return A bitboard representing the attackers. | ||
| */ | ||
| [[nodiscard]] uint64_t getSquareAttackers(uint8_t square) const; | ||
|
|
||
| /** | ||
| * \brief Retrieves the attackers of a given square by color. | ||
| * \tparam color The color of the attackers. | ||
| * \param square The square index (0-63). | ||
| * \return A bitboard representing the attackers of the given color. | ||
| */ | ||
| template <PieceColor color> | ||
| [[nodiscard]] uint64_t getSquareAttackersByColor(const uint8_t square) const { | ||
| return getSquareAttackers(square) & getColorBitboard<color>(); | ||
| } | ||
|
|
||
| /** | ||
| * \brief Checks if castling is possible for the given side. | ||
| * \tparam side The side to check for castling (WHITE\_KINGSIDE, WHITE\_QUEENSIDE, BLACK\_KINGSIDE, BLACK\_QUEENSIDE). | ||
| * \return True if castling is possible, false otherwise. | ||
| */ | ||
| template <CastlingRights side> | ||
| [[nodiscard]] bool canCastle() const; | ||
|
|
||
| /** | ||
| * \brief Sets the board state from a FEN string. | ||
| * \param fen The FEN string representing the board state. | ||
| * \return True if the FEN string was valid, false otherwise. | ||
| */ | ||
| [[nodiscard]] bool setFromFEN(std::string_view fen); | ||
|
|
||
| /** | ||
| * \brief Resets the board to the initial state. | ||
| */ | ||
| void reset(); | ||
|
|
||
| /** | ||
| * \brief Prints the current state of the board to the console. | ||
| */ | ||
| void print() const; | ||
| }; |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider refactoring setPiece and removePiece methods to reduce code duplication.
The implementation of setPiece and removePiece methods with both templated and non-templated versions provides flexibility and performance. However, there's significant code duplication between these methods.
Consider creating a template method to handle both setting and removing pieces:
template <bool IsSet, typename PieceType>
void updatePiece(PieceType piece, const uint8_t square) {
const uint64_t squareBB = squareToBitboard(square);
if constexpr (IsSet) {
assert(piece != Piece::EMPTY);
assert(board[square] == Piece::EMPTY);
board[square] = piece;
bitboards[piece] |= squareBB;
occupied |= squareBB;
colorBoards[getPieceColor(piece)] |= squareBB;
pieceCounts[piece] += 1;
} else {
assert(piece != Piece::EMPTY);
assert(board[square] == piece);
board[square] = EMPTY;
bitboards[piece] &= ~squareBB;
occupied &= ~squareBB;
colorBoards[getPieceColor(piece)] &= ~squareBB;
pieceCounts[piece] -= 1;
}
}Then, implement setPiece and removePiece methods using this template:
template <Piece piece>
void setPiece(const uint8_t square) {
updatePiece<true>(piece, square);
}
void setPiece(const Piece piece, const uint8_t square) {
updatePiece<true>(piece, square);
}
template <Piece piece>
void removePiece(const uint8_t square) {
updatePiece<false>(piece, square);
}
void removePiece(const Piece piece, const uint8_t square) {
updatePiece<false>(piece, square);
}This refactoring reduces code duplication while maintaining performance through template specialization.
src/move_gen.cpp
Outdated
| const uint8_t fromSquare = popLsb(bishopBB); | ||
| uint64_t genBB = getBishopAttacks(fromSquare, occupied) & genMask; | ||
|
|
||
| while (genBB) { | ||
| const uint8_t toSquare = popLsb(genBB); | ||
| const Move move = encodeMove(fromSquare, toSquare); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| template <PieceColor color, GenerationType type> | ||
| void generateRookMoves(const Board& board, MoveList& moves, const uint64_t genMask) { | ||
| constexpr Piece rook = color == WHITE ? WHITE_ROOK : BLACK_ROOK; | ||
| const uint64_t occupied = board.getOccupiedBitboard(); | ||
| uint64_t rookBB = board.getBitboard<rook>(); | ||
|
|
||
| while (rookBB) { | ||
| const uint8_t fromSquare = popLsb(rookBB); | ||
| uint64_t genBB = getRookAttacks(fromSquare, occupied) & genMask; | ||
|
|
||
| while (genBB) { | ||
| const uint8_t toSquare = popLsb(genBB); | ||
| const Move move = encodeMove(fromSquare, toSquare); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| template <PieceColor color, GenerationType type> | ||
| void generateQueenMoves(const Board& board, MoveList& moves, const uint64_t genMask) { | ||
| constexpr Piece queen = color == WHITE ? WHITE_QUEEN : BLACK_QUEEN; | ||
| const uint64_t occupied = board.getOccupiedBitboard(); | ||
| uint64_t queenBB = board.getBitboard<queen>(); | ||
|
|
||
| while (queenBB) { | ||
| const uint8_t fromSquare = popLsb(queenBB); | ||
| uint64_t genBB = queenAttacks(fromSquare, occupied) & genMask; | ||
|
|
||
| while (genBB) { | ||
| const uint8_t toSquare = popLsb(genBB); | ||
| const Move move = encodeMove(fromSquare, toSquare); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| template <PieceColor color, GenerationType type> | ||
| void generateKingMoves(const Board& board, MoveList& moves, const uint64_t genMask) { | ||
| constexpr Piece king = color == WHITE ? WHITE_KING : BLACK_KING; | ||
| uint64_t kingBB = board.getBitboard<king>(); | ||
| const uint8_t fromSquare = popLsb(kingBB); | ||
| uint64_t genBB = getKingAttacks(fromSquare) & genMask; | ||
|
|
||
| while (genBB) { | ||
| const uint8_t toSquare = popLsb(genBB); | ||
| const Move move = encodeMove(fromSquare, toSquare); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
|
|
||
| const uint8_t castlingRights = board.getCastlingRights(); | ||
|
|
||
| if constexpr (color == WHITE) { | ||
| if (castlingRights & WHITE_KINGSIDE && board.canCastle<WHITE_KINGSIDE>()) { | ||
| const Move move = encodeMove(E1, G1, CASTLING); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
|
|
||
| if (castlingRights & WHITE_QUEENSIDE && board.canCastle<WHITE_QUEENSIDE>()) { | ||
| const Move move = encodeMove(E1, C1, CASTLING); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } else if constexpr (color == BLACK) { | ||
| if (castlingRights & BLACK_KINGSIDE && board.canCastle<BLACK_KINGSIDE>()) { | ||
| const Move move = encodeMove(E8, G8, CASTLING); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
|
|
||
| if (castlingRights & BLACK_QUEENSIDE && board.canCastle<BLACK_QUEENSIDE>()) { | ||
| const Move move = encodeMove(E8, C8, CASTLING); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider refactoring sliding piece move generation
The generateBishopMoves, generateRookMoves, and generateQueenMoves functions have very similar structures. To improve maintainability and reduce code duplication, consider creating a template function for sliding piece move generation:
template <PieceColor color, GenerationType type, Piece piece>
void generateSlidingPieceMoves(const Board& board, MoveList& moves, const uint64_t genMask) {
const uint64_t occupied = board.getOccupiedBitboard();
uint64_t pieceBB = board.getBitboard<piece>();
while (pieceBB) {
const uint8_t fromSquare = popLsb(pieceBB);
uint64_t genBB = getPieceAttacks<piece>(fromSquare, occupied) & genMask;
while (genBB) {
const uint8_t toSquare = popLsb(genBB);
const Move move = encodeMove(fromSquare, toSquare);
moves.moves[moves.size++] = move;
}
}
}
// Usage:
template <PieceColor color, GenerationType type>
void generateBishopMoves(const Board& board, MoveList& moves, const uint64_t genMask) {
generateSlidingPieceMoves<color, type, color == WHITE ? WHITE_BISHOP : BLACK_BISHOP>(board, moves, genMask);
}
// Similar for Rook and QueenThis refactoring will reduce code duplication and make it easier to maintain and update the sliding piece move generation logic.
src/eval.h
Outdated
| class Evaluation { | ||
| private: | ||
| std::vector<MoveList*> pool{}; | ||
| Board board; | ||
| int whiteMidgameScore; | ||
| int whiteEndgameScore; | ||
| int blackMidgameScore; | ||
| int blackEndgameScore; | ||
|
|
||
| MoveListPool(); | ||
| int calculatePhase() const; | ||
| void evaluateMaterial(); | ||
|
|
||
| static MoveList* createMoveList(); | ||
| public: | ||
| explicit Evaluation(const Board& board) { | ||
| this->board = board; | ||
| } | ||
|
|
||
| static void destroyMoveList(MoveList* moveList); | ||
| int evaluate(); |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider moving method implementations to source files
Defining methods within header files can lead to code bloat due to multiple inclusions across different translation units. For better compilation times and to prevent potential issues with inline functions, consider declaring the methods in the header and defining them in the corresponding source (.cpp) file, unless they need to be inlined for performance reasons.
| void Evaluation::evaluateMaterial() { | ||
| for (int pieceIndex = 0; pieceIndex < PIECES; pieceIndex++) { | ||
| const Piece piece = static_cast<Piece>(pieceIndex); | ||
| const int pieceCount = board.getPieceCount(piece); | ||
|
|
||
| switch (piece) { | ||
| case WHITE_PAWN: | ||
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_PAWN_VALUE; | ||
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_PAWN_VALUE; | ||
| break; | ||
| case BLACK_PAWN: | ||
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_PAWN_VALUE; | ||
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_PAWN_VALUE; | ||
| break; | ||
| case WHITE_KNIGHT: | ||
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_KNIGHT_VALUE; | ||
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_KNIGHT_VALUE; | ||
| break; | ||
| case BLACK_KNIGHT: | ||
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_KNIGHT_VALUE; | ||
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_KNIGHT_VALUE; | ||
| break; | ||
| case WHITE_BISHOP: | ||
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_BISHOP_VALUE; | ||
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_BISHOP_VALUE; | ||
| break; | ||
| case BLACK_BISHOP: | ||
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_BISHOP_VALUE; | ||
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_BISHOP_VALUE; | ||
| break; | ||
| case WHITE_ROOK: | ||
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_ROOK_VALUE; | ||
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_ROOK_VALUE; | ||
| break; | ||
| case BLACK_ROOK: | ||
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_ROOK_VALUE; | ||
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_ROOK_VALUE; | ||
| break; | ||
| case WHITE_QUEEN: | ||
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_QUEEN_VALUE; | ||
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_QUEEN_VALUE; | ||
| break; | ||
| case BLACK_QUEEN: | ||
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_QUEEN_VALUE; | ||
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_QUEEN_VALUE; | ||
| break; | ||
| default: | ||
| break; | ||
| } | ||
| } | ||
| } |
There was a problem hiding this comment.
Ensure score accumulators are initialized before use.
The variables whiteMidgameScore, whiteEndgameScore, blackMidgameScore, and blackEndgameScore are used to accumulate material scores but are not initialized within the evaluateMaterial() function:
void Evaluation::evaluateMaterial() {
// Accumulators are used here without local initialization
for (int pieceIndex = 0; pieceIndex < PIECES; pieceIndex++) {
// ...
}
}Please ensure these accumulators are properly initialized to zero before they are used in this function to prevent undefined behavior due to using uninitialized values.
Apply this diff to initialize the accumulators at the beginning of the function:
void Evaluation::evaluateMaterial() {
+ whiteMidgameScore = 0;
+ whiteEndgameScore = 0;
+ blackMidgameScore = 0;
+ blackEndgameScore = 0;
for (int pieceIndex = 0; pieceIndex < PIECES; pieceIndex++) {
// ...
}
}🛠️ Refactor suggestion
Consider refactoring evaluateMaterial() to reduce code duplication.
The evaluateMaterial() function contains repeated patterns for each piece type when updating the midgame and endgame scores. To enhance maintainability without significantly impacting performance, consider refactoring the code to eliminate duplication.
Apply this diff to refactor the function using arrays:
void Evaluation::evaluateMaterial() {
+ static constexpr int MATERIAL_MIDGAME_VALUES[PIECES] = {
+ MATERIAL_MIDGAME_PAWN_VALUE, // PAWN
+ MATERIAL_MIDGAME_KNIGHT_VALUE, // KNIGHT
+ MATERIAL_MIDGAME_BISHOP_VALUE, // BISHOP
+ MATERIAL_MIDGAME_ROOK_VALUE, // ROOK
+ MATERIAL_MIDGAME_QUEEN_VALUE, // QUEEN
+ 0 // KING
+ };
+
+ static constexpr int MATERIAL_ENDGAME_VALUES[PIECES] = {
+ MATERIAL_ENDGAME_PAWN_VALUE, // PAWN
+ MATERIAL_ENDGAME_KNIGHT_VALUE, // KNIGHT
+ MATERIAL_ENDGAME_BISHOP_VALUE, // BISHOP
+ MATERIAL_ENDGAME_ROOK_VALUE, // ROOK
+ MATERIAL_ENDGAME_QUEEN_VALUE, // QUEEN
+ 0 // KING
+ };
+
+ whiteMidgameScore = 0;
+ whiteEndgameScore = 0;
+ blackMidgameScore = 0;
+ blackEndgameScore = 0;
+
for (int pieceIndex = 0; pieceIndex < PIECES; pieceIndex++) {
const Piece piece = static_cast<Piece>(pieceIndex);
const int pieceCount = board.getPieceCount(piece);
+ const int midgameValue = MATERIAL_MIDGAME_VALUES[pieceIndex % (PIECES / 2)];
+ const int endgameValue = MATERIAL_ENDGAME_VALUES[pieceIndex % (PIECES / 2)];
+
+ if (piece < BLACK_PAWN) {
+ // White pieces
+ whiteMidgameScore += pieceCount * midgameValue;
+ whiteEndgameScore += pieceCount * endgameValue;
+ } else {
+ // Black pieces
+ blackMidgameScore += pieceCount * midgameValue;
+ blackEndgameScore += pieceCount * endgameValue;
+ }
}
}This refactoring uses arrays to store the material values and reduces the switch-case statements. It should maintain performance while improving code readability.
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| void Evaluation::evaluateMaterial() { | |
| for (int pieceIndex = 0; pieceIndex < PIECES; pieceIndex++) { | |
| const Piece piece = static_cast<Piece>(pieceIndex); | |
| const int pieceCount = board.getPieceCount(piece); | |
| switch (piece) { | |
| case WHITE_PAWN: | |
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_PAWN_VALUE; | |
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_PAWN_VALUE; | |
| break; | |
| case BLACK_PAWN: | |
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_PAWN_VALUE; | |
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_PAWN_VALUE; | |
| break; | |
| case WHITE_KNIGHT: | |
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_KNIGHT_VALUE; | |
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_KNIGHT_VALUE; | |
| break; | |
| case BLACK_KNIGHT: | |
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_KNIGHT_VALUE; | |
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_KNIGHT_VALUE; | |
| break; | |
| case WHITE_BISHOP: | |
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_BISHOP_VALUE; | |
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_BISHOP_VALUE; | |
| break; | |
| case BLACK_BISHOP: | |
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_BISHOP_VALUE; | |
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_BISHOP_VALUE; | |
| break; | |
| case WHITE_ROOK: | |
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_ROOK_VALUE; | |
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_ROOK_VALUE; | |
| break; | |
| case BLACK_ROOK: | |
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_ROOK_VALUE; | |
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_ROOK_VALUE; | |
| break; | |
| case WHITE_QUEEN: | |
| whiteMidgameScore += pieceCount * MATERIAL_MIDGAME_QUEEN_VALUE; | |
| whiteEndgameScore += pieceCount * MATERIAL_ENDGAME_QUEEN_VALUE; | |
| break; | |
| case BLACK_QUEEN: | |
| blackMidgameScore += pieceCount * MATERIAL_MIDGAME_QUEEN_VALUE; | |
| blackEndgameScore += pieceCount * MATERIAL_ENDGAME_QUEEN_VALUE; | |
| break; | |
| default: | |
| break; | |
| } | |
| } | |
| } | |
| void Evaluation::evaluateMaterial() { | |
| static constexpr int MATERIAL_MIDGAME_VALUES[PIECES] = { | |
| MATERIAL_MIDGAME_PAWN_VALUE, // PAWN | |
| MATERIAL_MIDGAME_KNIGHT_VALUE, // KNIGHT | |
| MATERIAL_MIDGAME_BISHOP_VALUE, // BISHOP | |
| MATERIAL_MIDGAME_ROOK_VALUE, // ROOK | |
| MATERIAL_MIDGAME_QUEEN_VALUE, // QUEEN | |
| 0 // KING | |
| }; | |
| static constexpr int MATERIAL_ENDGAME_VALUES[PIECES] = { | |
| MATERIAL_ENDGAME_PAWN_VALUE, // PAWN | |
| MATERIAL_ENDGAME_KNIGHT_VALUE, // KNIGHT | |
| MATERIAL_ENDGAME_BISHOP_VALUE, // BISHOP | |
| MATERIAL_ENDGAME_ROOK_VALUE, // ROOK | |
| MATERIAL_ENDGAME_QUEEN_VALUE, // QUEEN | |
| 0 // KING | |
| }; | |
| whiteMidgameScore = 0; | |
| whiteEndgameScore = 0; | |
| blackMidgameScore = 0; | |
| blackEndgameScore = 0; | |
| for (int pieceIndex = 0; pieceIndex < PIECES; pieceIndex++) { | |
| const Piece piece = static_cast<Piece>(pieceIndex); | |
| const int pieceCount = board.getPieceCount(piece); | |
| const int midgameValue = MATERIAL_MIDGAME_VALUES[pieceIndex % (PIECES / 2)]; | |
| const int endgameValue = MATERIAL_ENDGAME_VALUES[pieceIndex % (PIECES / 2)]; | |
| if (piece < BLACK_PAWN) { | |
| // White pieces | |
| whiteMidgameScore += pieceCount * midgameValue; | |
| whiteEndgameScore += pieceCount * endgameValue; | |
| } else { | |
| // Black pieces | |
| blackMidgameScore += pieceCount * midgameValue; | |
| blackEndgameScore += pieceCount * endgameValue; | |
| } | |
| } | |
| } |
| int Evaluation::evaluate() { | ||
| const int phase = calculatePhase(); | ||
| const int modifier = board.getSideToMove() == WHITE ? 1 : -1; | ||
|
|
||
| evaluateMaterial(); | ||
|
|
||
| const int whiteScore = ((whiteMidgameScore * (256 - phase)) + (whiteEndgameScore * phase)) / 256; | ||
| const int blackScore = ((blackMidgameScore * (256 - phase)) + (blackEndgameScore * phase)) / 256; | ||
|
|
||
| return (whiteScore - blackScore) * modifier; |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Optimize arithmetic operations for performance.
Given that performance is a priority, consider optimizing the arithmetic operations in the evaluate() function. For example, you can avoid divisions where possible:
const int whiteScore = ((whiteMidgameScore * (256 - phase)) + (whiteEndgameScore * phase)) >> 8;
const int blackScore = ((blackMidgameScore * (256 - phase)) + (blackEndgameScore * phase)) >> 8;Using bitwise shifts instead of division by 256 can improve performance on some systems.
| const Piece piece = static_cast<Piece>(pieceIndex); | ||
| const int pieceCount = board.getPieceCount(piece); |
There was a problem hiding this comment.
Avoid casting loop index to enum Piece.
In the loop within evaluateMaterial(), you cast pieceIndex to Piece:
const Piece piece = static_cast<Piece>(pieceIndex);If pieceIndex has values that do not correspond to valid Piece enum values, this cast could lead to undefined behavior. Ensure that pieceIndex only takes on valid values of the Piece enum. Alternatively, iterate over the Piece enum directly.
Apply this diff to iterate over the enum:
-for (int pieceIndex = 0; pieceIndex < PIECES; pieceIndex++) {
- const Piece piece = static_cast<Piece>(pieceIndex);
+for (Piece piece = WHITE_PAWN; piece <= BLACK_KING; piece = static_cast<Piece>(piece + 1)) {This approach ensures that only valid Piece values are used in the loop.
| constexpr int knightPhase = 1; | ||
| constexpr int bishopPhase = 1; | ||
| constexpr int rookPhase = 2; | ||
| constexpr int queenPhase = 4; | ||
| constexpr int totalPhase = knightPhase * 4 + bishopPhase * 4 + rookPhase * 4 + queenPhase * 2; |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider making phase constants constexpr static members.
For better encapsulation and to avoid potential naming conflicts, consider moving the phase-related constants into the Evaluation class as constexpr static members.
Apply this diff to adjust the constants:
-constexpr int knightPhase = 1;
-constexpr int bishopPhase = 1;
-constexpr int rookPhase = 2;
-constexpr int queenPhase = 4;
-constexpr int totalPhase = knightPhase * 4 + bishopPhase * 4 + rookPhase * 4 + queenPhase * 2;
+class Evaluation {
+public:
+ static constexpr int knightPhase = 1;
+ static constexpr int bishopPhase = 1;
+ static constexpr int rookPhase = 2;
+ static constexpr int queenPhase = 4;
+ static constexpr int totalPhase = knightPhase * 4 + bishopPhase * 4 + rookPhase * 4 + queenPhase * 2;
+ // Rest of the class...
+};This refactoring keeps constants within the class scope and maintains clarity.
Committable suggestion was skipped due to low confidence.
| while (std::getline(std::cin, line)) { | ||
| std::thread processThread{&Engine::processLine, this, line}; | ||
|
|
||
| processThread.detach(); | ||
| } |
There was a problem hiding this comment.
Potential resource exhaustion due to unbounded thread creation in startUci()
The startUci() method creates a new detached thread for each line of input:
while (std::getline(std::cin, line)) {
std::thread processThread{&Engine::processLine, this, line};
processThread.detach();
}This approach can lead to an unbounded number of threads if input lines are received faster than they are processed, potentially exhausting system resources and causing instability in the engine.
Consider processing input synchronously in a single thread or implementing a thread pool to limit and manage the number of active threads. This ensures that system resources are used efficiently and the engine remains stable under heavy input loads.
There was a problem hiding this comment.
Actionable comments posted: 14
🧹 Outside diff range and nitpick comments (13)
src/move.cpp (4)
26-43: LGTM with minor optimization suggestionThe function correctly implements the conversion from square indices to chess notation. The use of assertions for input validation is good practice for debug builds.
For a slight performance improvement, consider using pre-computed lookup tables for file and rank characters:
// At file scope constexpr char FILES[] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'}; constexpr char RANKS[] = {'1', '2', '3', '4', '5', '6', '7', '8'}; std::string getMoveNotation(const uint8_t fromSquare, const uint8_t toSquare) { assert(fromSquare < SQUARES); assert(toSquare < SQUARES); return { FILES[fromSquare % 8], RANKS[fromSquare / 8], FILES[toSquare % 8], RANKS[toSquare / 8] }; }This approach eliminates runtime calculations and uses compile-time constants, which could be more efficient for a chess engine where performance is crucial.
45-65: LGTM with suggestions for improvementThe function correctly implements move notation with promotions. However, there are a few points for improvement:
Replace the magic number in the assertion with a named constant:
constexpr int NUM_PROMOTION_PIECES = 4; assert(static_cast<int>(promotionPiece) < NUM_PROMOTION_PIECES);Consider using an enum class for PromotionPiece to improve type safety:
enum class PromotionPiece { QUEEN, ROOK, BISHOP, KNIGHT };Use a lookup table for promotion piece characters:
constexpr char PROMOTION_PIECES[] = {'q', 'r', 'b', 'n'}; notation += PROMOTION_PIECES[static_cast<int>(promotionPiece)];These changes would improve readability and maintainability of the code.
86-122: LGTM with suggestion for improved error handlingThe function correctly parses move notation and handles promotions. The use of std::string_view for the input is good for performance. However, the error handling for an invalid promotion piece can be improved.
Consider using std::optional or throwing an exception for better error handling:
#include <optional> std::optional<Move> getMoveFromMoveNotation(const std::string_view notation) { if (notation.size() != 4 && notation.size() != 5) { return std::nullopt; } const Square fromSquare = getSquareFromNotation(notation.substr(0, 2)); const Square toSquare = getSquareFromNotation(notation.substr(2, 2)); if (notation.size() == 5) { const char promotionPieceChar = notation[4]; PromotionPiece promotionPiece; switch (promotionPieceChar) { case 'q': promotionPiece = PromotionPiece::QUEEN; break; case 'r': promotionPiece = PromotionPiece::ROOK; break; case 'b': promotionPiece = PromotionPiece::BISHOP; break; case 'n': promotionPiece = PromotionPiece::KNIGHT; break; default: return std::nullopt; } return encodeMove(fromSquare, toSquare, promotionPiece); } return encodeMove(fromSquare, toSquare); }This approach clearly indicates when the input is invalid and allows the caller to handle the error appropriately.
124-137: LGTM with optimization suggestionThe function correctly converts a square to its chess notation. The assertion for input validation is good practice. For consistency with earlier suggestions and potential performance improvement, consider using pre-computed lookup tables:
// At file scope (if not already defined) constexpr char FILES[] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'}; constexpr char RANKS[] = {'1', '2', '3', '4', '5', '6', '7', '8'}; std::string getSquareNotation(const Square square) { assert(square < SQUARES); return {FILES[square % 8], RANKS[square / 8]}; }This approach is consistent with the previous suggestions and could provide better performance, which is crucial for a chess engine.
src/uci.cpp (7)
100-102: Consider adding a TODO comment for future implementationWhile it's acceptable to have unimplemented features, it would be helpful to add a TODO comment for future implementation of the debug mode. This can help track pending features and improvements.
void Engine::handleDebugCommand(std::string_view args) { // TODO: Implement debug mode functionality sendMessage("Debug mode is currently not implemented."); }
183-185: Consider adding a TODO comment for future implementationWhile it's acceptable to have empty functions for unimplemented features, it would be helpful to add a TODO comment for future implementation of the "ucinewgame" command. This can help track pending features and improvements.
void Engine::handleUciNewGameCommand(std::string_view args) { // TODO: Implement new game setup (e.g., clear transposition tables, reset game state) }
241-242: Consider adding a TODO comment for future implementationWhile it's acceptable to have empty functions for unimplemented features, it would be helpful to add a TODO comment for future implementation of the "go" command. This is a crucial command for the engine's functionality.
void Engine::handleGoCommand(std::string_view args) { // TODO: Implement search functionality // Parse time controls, depth limits, etc., and start the search }
244-245: Consider adding a TODO comment for future implementationWhile it's acceptable to have empty functions for unimplemented features, it would be helpful to add a TODO comment for future implementation of the "stop" command. This is important for controlling the engine's search process.
void Engine::handleStopCommand(std::string_view args) { // TODO: Implement stop functionality // Stop the ongoing search and return the best move found so far }
247-248: Consider adding a TODO comment for future implementationWhile it's acceptable to have empty functions for unimplemented features, it would be helpful to add a TODO comment for future implementation of the "ponderhit" command. This is important for handling pondering in the engine.
void Engine::handlePonderHitCommand(std::string_view args) { // TODO: Implement ponderhit functionality // Switch from pondering to normal search mode }
250-251: Consider adding a TODO comment for future implementationWhile it's acceptable to have empty functions for unimplemented features, it would be helpful to add a TODO comment for future implementation of the "quit" command. This is important for proper cleanup and exit of the engine.
void Engine::handleQuitCommand(std::string_view args) { // TODO: Implement quit functionality // Perform any necessary cleanup and exit the engine }
477-492: Consider adding a default case for better error handlingThe
getUciOptionTypeAsString()function is well-implemented, but it could benefit from a default case to handle potential future additions to theUCIOptionTypeenum or unexpected values.std::string getUciOptionTypeAsString(const UCIOptionType type) { switch (type) { case Check: return "check"; case Spin: return "spin"; case Combo: return "combo"; case Button: return "button"; case String: return "string"; default: return "unknown"; } }This change ensures that the function always returns a valid string, even for unexpected input.
src/eval.h (2)
35-40: Clarify the documentation forcalculatePhase()methodThe documentation for
calculatePhase()mentions that it "Evaluates the material on the board" and updates the midgame and endgame scores, which seems similar to the purpose ofevaluateMaterial(). IfcalculatePhase()is intended to determine the phase of the game (e.g., opening, midgame, endgame) based on the remaining material, consider updating the documentation to accurately reflect its functionality.
43-45: Expand the documentation forevaluateMaterial()methodThe documentation for
evaluateMaterial()is minimal. To enhance clarity, consider providing a more detailed description of how this method evaluates the material on the board and how it affects the evaluation scores for both sides.
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (10)
- src/eval.cpp (1 hunks)
- src/eval.h (1 hunks)
- src/move.cpp (1 hunks)
- src/move.h (1 hunks)
- src/move_gen.cpp (1 hunks)
- src/move_gen.h (1 hunks)
- src/perft.cpp (1 hunks)
- src/perft.h (2 hunks)
- src/types.h (2 hunks)
- src/uci.cpp (1 hunks)
🚧 Files skipped from review as they are similar to previous changes (1)
- src/eval.cpp
🧰 Additional context used
📓 Path-based instructions (9)
src/eval.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/move_gen.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/perft.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/perft.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/types.h (1)
Pattern
**/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.src/uci.cpp (1)
Pattern
**/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (5)
src/move.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move.h:34-37 Timestamp: 2024-10-09T11:50:14.518Z Learning: In `src/move.h`, the comments describing the bit assignment for move encoding are correct and should be followed. The `getFromSquare` and `getToSquare` methods have been fixed to match these comments.src/move_gen.h (2)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.h:36-37 Timestamp: 2024-10-09T11:49:41.012Z Learning: In `src/move_gen.h`, prefer using explicit template instantiations for longer (more than a few lines) or more complex template functions like `generatePawnMoves`, instead of including their definitions in header files.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move_gen.h:36-37 Timestamp: 2024-10-05T12:15:41.746Z Learning: In `src/move_gen.h`, prefer using explicit template instantiations for longer (more than a few lines) or more complex template functions like `generatePawnMoves`, instead of including their definitions in header files.src/perft.cpp (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/perft.cpp:46-74 Timestamp: 2024-10-14T07:27:15.674Z Learning: In the codebase, some legality checks require the move to be actually made before they can be performed.src/types.h (1)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/types.h:85-91 Timestamp: 2024-10-14T07:24:25.933Z Learning: In the C++ codebase of the Zagreus chess engine, prefer using `enum` over `enum class` for performance reasons, allowing faster math and bitwise manipulation without requiring calls to `to_underlying()`. For example, in `src/types.h`, use `enum` instead of `enum class`.src/uci.cpp (2)
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.cpp:110-179 Timestamp: 2024-10-14T07:26:06.778Z Learning: In future code reviews, avoid suggesting changes to `uci.cpp` and `uci.h` unless they are critical or blockers.Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/uci.cpp:394-430 Timestamp: 2024-10-11T16:04:05.283Z Learning: In `src/uci.cpp`, performance optimizations are unnecessary.
🪛 cppcheck
src/uci.cpp
[performance] 465-465: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 473-473: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 522-522: Function parameter 'values' should be passed by const reference.
(passedByValue)
🔇 Additional comments (43)
src/perft.cpp (4)
1-27: LGTM: Proper licensing and includesThe file header contains the correct licensing information (AGPL), and the necessary headers are included for the functionality implemented in this file.
28-39: LGTM: Well-documented function with new parameterThe
perftfunction is properly namespaced and well-documented. The addition of theprintNodesparameter aligns with the described changes and enhances the function's flexibility.
82-86: LGTM: Proper function return and namespace closingThe function correctly returns the total node count, and the Zagreus namespace is properly closed.
1-86: Overall assessment: Well-implemented perft function with minor suggestionThe
perftfunction insrc/perft.cppis well-implemented and properly documented. It correctly handles move generation, legality checking, and node counting for performance testing in the Zagreus chess engine. The addition of theprintNodesparameter enhances the function's flexibility.The main suggestion for improvement is to change the
depthparameter type fromconst inttointto avoid potential issues with the recursive calls.Great job on implementing this critical component of the chess engine!
src/move.h (8)
1-32: LGTM: File header and includes are well-structured.The copyright notice, license information, and include statements are appropriate and well-organized. The use of
#pragma onceis a good modern practice for header inclusion guards.
33-38: LGTM: Efficient Move and MoveList representations.The
Movetype alias andMoveListstructure are well-designed for performance. The use ofuint8_tfor thesizemember inMoveListis an excellent choice for memory optimization, as it will never exceedMAX_MOVES(256).
40-52: LGTM: Well-defined enumerations for move types and promotion pieces.The
MoveTypeandPromotionPieceenumerations are efficiently defined asuint8_tand use clear binary literals. This design aligns well with the move encoding scheme and promotes both readability and performance.
54-64: LGTM: Clear function declarations for move and square notation operations.The function declarations provide a well-defined interface for move and square notation operations. The use of
std::string_viewfor input parameters is a good practice for performance. The separation of declarations from implementations is appropriate for header files.
83-97: LGTM: Efficient move decoding functions.The move decoding functions (
getFromSquare,getToSquare,getMoveType,getPromotionPiece) are implemented correctly and efficiently. They accurately extract the relevant bits as described in the comments. The use of inline functions is appropriate for performance in a chess engine.
99-113: LGTM: Well-implemented getPieceFromPromotionPiece function.The
getPieceFromPromotionPiecefunction is implemented correctly and efficiently. It cleverly uses the color offset to handle both white and black pieces. The use ofassert(false)in the default case is a good practice for catching unexpected inputs during development.
1-114: Overall, well-designed and efficient move representation for a chess engine.The
src/move.hfile implements a compact and efficient move representation system for the Zagreus chess engine. The use of bitwise operations, enums, and inline functions is well-suited for performance-critical chess operations. The only issue found was in the basicencodeMovefunction, which should be corrected to match the bit layout described in the comments. Once this is addressed, the file will provide a solid foundation for move handling in the engine.
66-81:⚠️ Potential issueFix the implementation of the basic encodeMove function.
The comments describing the bit layout are correct. However, the implementation of the basic
encodeMovefunction doesn't match these comments. ThefromSquareshould be shifted left by 6 bits, andtoSquareshould not be shifted.Please update the function to match the comments:
inline Move encodeMove(const uint8_t fromSquare, const uint8_t toSquare) { // Assume normal move, so bits 12-13 are 00 and bits 14-15 are 00 - return static_cast<Move>(fromSquare | (toSquare << 6)); + return static_cast<Move>((fromSquare << 6) | toSquare); }The other two overloads of
encodeMoveare implemented correctly.⛔ Skipped due to learnings
Learnt from: Dannyj1 PR: Dannyj1/Zagreus#82 File: src/move.h:34-37 Timestamp: 2024-10-09T11:50:14.518Z Learning: In `src/move.h`, the comments describing the bit assignment for move encoding are correct and should be followed. The `getFromSquare` and `getToSquare` methods have been fixed to match these comments.src/types.h (9)
5-5: LGTM: Copyright year updatedThe copyright year has been correctly updated to include 2024, reflecting the ongoing development of the project.
23-24: LGTM: Updated include statementsThe include statements have been appropriately updated. Removing "constants.h" and adding and aligns with the changes in the file's implementation.
27-46: LGTM: Direction enum well-definedThe Direction enum is well-defined with specific integer values for each direction. Keeping it as a regular enum instead of an enum class aligns with the project's performance considerations, allowing for faster math and bitwise operations.
50-62: LGTM: Square enum well-defined and memory-efficientThe Square enum is well-defined with uint8_t as the underlying type, providing a compact and memory-efficient representation of chess squares. Keeping it as a regular enum instead of an enum class aligns with the project's performance considerations.
67-75: LGTM: PieceType and PieceColor enums well-defined and memory-efficientThe PieceType and PieceColor enums are well-defined with uint8_t as the underlying type, providing a compact and memory-efficient representation. Keeping them as regular enums instead of enum classes aligns with the project's performance considerations, allowing for faster operations.
77-84: LGTM: Efficient operator! implementation for PieceColorThe operator! function for PieceColor is implemented efficiently using an XOR operation. This approach handles both WHITE and BLACK cases without needing conditional statements, aligning with the performance-focused approach of the project.
86-114: LGTM: Piece and CastlingRights enums well-defined and efficientThe Piece enum efficiently combines color and type information for all chess pieces, including an EMPTY state. The CastlingRights enum uses bit flags, allowing for efficient bitwise operations when checking castling rights. Both enums use uint8_t as the underlying type, ensuring memory efficiency.
117-135: LGTM: Efficient getPieceColor and getPieceType implementationsThe getPieceColor and getPieceType functions use efficient bitwise operations to extract color and type information from a Piece. The inclusion of assertions to check for EMPTY pieces helps catch potential bugs early. These implementations align well with the performance-focused approach of the project.
137-173: LGTM: Comprehensive getCharacterForPieceType implementationThe getCharacterForPieceType function provides a comprehensive mapping of chess pieces to their character representations. The use of a switch statement is appropriate for this case, and the function correctly handles all piece types, including EMPTY. The default return of a space character ensures the function always returns a valid result.
src/move.cpp (3)
1-23: LGTM: Appropriate file header and include orderThe file header contains the necessary copyright and license information. The includes are correctly ordered with standard library headers before local headers, following best practices.
67-84: LGTM: Well-implemented move notation conversionThis function effectively converts a Move object to chess notation, handling both regular moves and promotions. The use of helper functions for extracting move details demonstrates good encapsulation. The C++17 if-statement with init-statement is a nice touch for limiting the scope of the moveType variable.
1-150: Overall assessment: Well-implemented chess move notation functionality with room for optimizationThe
src/move.cppfile provides a comprehensive implementation of chess move notation functionality. The code is generally well-structured and follows good practices. Key points from the review:
- Appropriate use of assertions for input validation in debug builds.
- Correct implementation of move notation conversion for regular moves and promotions.
- Good use of C++17 features and std::string_view for performance.
Suggestions for improvement:
- Use pre-computed lookup tables for file and rank characters to optimize performance.
- Improve error handling in
getMoveFromMoveNotationusing std::optional or exceptions.- Add input validation to
getSquareFromNotationto prevent undefined behavior.- Consider using enum class for PromotionPiece to improve type safety.
These improvements will enhance the robustness and performance of the code, which is crucial for a chess engine.
src/uci.cpp (9)
1-19: LGTM: Proper licensing and copyright informationThe file starts with appropriate licensing and copyright information, which is a good practice for open-source projects.
21-33: LGTM: Necessary includes and namespacesThe file includes all necessary headers and uses the
Zagreusnamespace, which is appropriate for the project structure.
38-48: LGTM: Proper one-time setup implementationThe
doSetup()function correctly implements the one-time initialization of magic bitboards and attack lookup tables, as required by the UCI specification. The use of thedidSetupflag ensures that this initialization occurs only once, which is an efficient approach.
62-85: LGTM: Well-implemented startup messageThe
printStartupMessage()function is well-implemented, using a multi-line string literal for the ASCII art and license text, which improves readability. The inclusion of the version string and proper formatting of the message is also handled correctly.
87-98: LGTM: Correct implementation of UCI protocolThe
handleUciCommand()function correctly implements the UCI protocol for engine identification, sending the required information about the engine name, author, and available options.
104-110: LGTM: Correct implementation of "isready" commandThe
handleIsReadyCommand()function correctly implements the "isready" command as per UCI protocol. It ensures the engine is set up by callingdoSetup()if necessary, and then responds with "readyok".
253-293: LGTM: Well-implemented perft commandThe
handlePerftCommand()function is well-implemented with proper error handling for invalid input, correct depth validation, and accurate performance measurement. The use of high-resolution clock for timing is appropriate for this purpose.
295-297: LGTM: Simple and correct implementationThe
handlePrintCommand()function correctly delegates the printing responsibility to theBoardclass, which is a good separation of concerns.
399-435: LGTM: Well-implemented space removal functionThe
removeRedundantSpaces()function is well-implemented, handling various types of whitespace characters and edge cases correctly. It efficiently removes redundant spaces while preserving necessary whitespace and newlines.src/move_gen.cpp (4)
1-30: LGTM: File header and includes are appropriateThe file header contains the correct license information (GNU Affero General Public License), and all necessary includes are present. This section is well-structured and provides clear information about the file's purpose and licensing.
196-214: LGTM: Efficient implementation of knight move generationThe
generateKnightMovesfunction is well-implemented, using bitboard operations for efficiency. It correctly applies the generation mask to filter out invalid moves. The function is concise and easy to understand.
308-354: LGTM: Comprehensive king move generationThe
generateKingMovesfunction is well-implemented, efficiently generating both normal king moves and castling moves. It correctly uses bitboard operations for normal moves and checks castling rights and conditions for castling moves. The function is thorough and covers all aspects of king movement in chess.
356-365: LGTM: Proper use of explicit instantiationsThe explicit instantiations of the
generateMovesfunction for both colors and all generation types are a good practice. This can help optimize compile-time and potentially reduce binary size. It also ensures that all necessary versions of the template function are available at link-time.src/perft.h (4)
5-5: Updated copyright notice is appropriate.The inclusion of the year 2024 in the copyright notice is correct and keeps the licensing information up to date.
23-23: Including<cstdint>for fixed-width integer types is appropriate.Adding
<cstdint>is necessary as it provides fixed-width integer types likeuint64_t, which is used in theperftfunction declaration.
25-25: Including"board.h"is necessary forBoarddependencies.Including
"board.h"ensures that theBoardclass is properly defined for use within theperftfunction.
28-38: Addition ofperftfunction with clear documentation is appropriate.The introduction of the
perftfunction aligns with the needs of the engine's perft testing functionality. The function signature is appropriate, and the Doxygen comments provide clear and detailed documentation of its purpose, parameters, and return value.src/move_gen.h (1)
1-115: Overall Implementation Meets Performance PrioritiesThe code is well-organized, and the focus on performance is evident, aligning with the project's guidelines for a chess engine.
src/eval.h (1)
29-33: Member variables are properly initializedGood job initializing the member variables
whiteMidgameScore,whiteEndgameScore,blackMidgameScore, andblackEndgameScore. Using brace initialization ensures they start with zero values, preventing undefined behavior from uninitialized variables.
| assert(depth >= 0); | ||
|
|
||
| if (depth == 0) { | ||
| return 1; | ||
| } | ||
|
|
||
| uint64_t nodes = 0; | ||
| MoveList moveList{}; | ||
| const PieceColor sideToMove = board.getSideToMove(); | ||
|
|
||
| if (sideToMove == WHITE) { | ||
| generateMoves<WHITE, ALL>(board, moveList); | ||
| } else { | ||
| generateMoves<BLACK, ALL>(board, moveList); | ||
| } | ||
|
|
||
| for (int i = 0; i < moveList.size; i++) { | ||
| board.makeMove(moveList.moves[i]); | ||
|
|
||
| if (sideToMove == WHITE) { | ||
| if (!board.isPositionLegal<WHITE>()) { | ||
| board.unmakeMove(); | ||
| continue; | ||
| } | ||
| } else { | ||
| if (!board.isPositionLegal<BLACK>()) { | ||
| board.unmakeMove(); | ||
| continue; | ||
| } | ||
| } | ||
|
|
||
| uint64_t perftNodes = perft(board, depth - 1, false); | ||
|
|
||
| if (printNodes) { | ||
| std::string moveNotation = getMoveNotation(moveList.moves[i]); | ||
|
|
||
| std::cout << moveNotation << ": " << perftNodes << std::endl; | ||
| } | ||
|
|
||
| nodes += perftNodes; | ||
| board.unmakeMove(); | ||
| } |
There was a problem hiding this comment.
LGTM with suggestion: Consider changing depth parameter type
The implementation of the perft function is correct and aligns with its purpose. The legality checking after making the move is appropriate, given that some checks require the move to be actually made.
However, there's a potential issue with the depth parameter:
The depth parameter is declared as const int, but it's decremented in the recursive call on line 71. This might lead to unexpected behavior. Consider changing the parameter to int without the const qualifier:
-uint64_t perft(Board& board, const int depth, bool printNodes) {
+uint64_t perft(Board& board, int depth, bool printNodes) {This change will allow the depth to be decremented without issues in the recursive calls.
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| assert(depth >= 0); | |
| if (depth == 0) { | |
| return 1; | |
| } | |
| uint64_t nodes = 0; | |
| MoveList moveList{}; | |
| const PieceColor sideToMove = board.getSideToMove(); | |
| if (sideToMove == WHITE) { | |
| generateMoves<WHITE, ALL>(board, moveList); | |
| } else { | |
| generateMoves<BLACK, ALL>(board, moveList); | |
| } | |
| for (int i = 0; i < moveList.size; i++) { | |
| board.makeMove(moveList.moves[i]); | |
| if (sideToMove == WHITE) { | |
| if (!board.isPositionLegal<WHITE>()) { | |
| board.unmakeMove(); | |
| continue; | |
| } | |
| } else { | |
| if (!board.isPositionLegal<BLACK>()) { | |
| board.unmakeMove(); | |
| continue; | |
| } | |
| } | |
| uint64_t perftNodes = perft(board, depth - 1, false); | |
| if (printNodes) { | |
| std::string moveNotation = getMoveNotation(moveList.moves[i]); | |
| std::cout << moveNotation << ": " << perftNodes << std::endl; | |
| } | |
| nodes += perftNodes; | |
| board.unmakeMove(); | |
| } | |
| uint64_t perft(Board& board, int depth, bool printNodes) { | |
| assert(depth >= 0); | |
| if (depth == 0) { | |
| return 1; | |
| } | |
| uint64_t nodes = 0; | |
| MoveList moveList{}; | |
| const PieceColor sideToMove = board.getSideToMove(); | |
| if (sideToMove == WHITE) { | |
| generateMoves<WHITE, ALL>(board, moveList); | |
| } else { | |
| generateMoves<BLACK, ALL>(board, moveList); | |
| } | |
| for (int i = 0; i < moveList.size; i++) { | |
| board.makeMove(moveList.moves[i]); | |
| if (sideToMove == WHITE) { | |
| if (!board.isPositionLegal<WHITE>()) { | |
| board.unmakeMove(); | |
| continue; | |
| } | |
| } else { | |
| if (!board.isPositionLegal<BLACK>()) { | |
| board.unmakeMove(); | |
| continue; | |
| } | |
| } | |
| uint64_t perftNodes = perft(board, depth - 1, false); | |
| if (printNodes) { | |
| std::string moveNotation = getMoveNotation(moveList.moves[i]); | |
| std::cout << moveNotation << ": " << perftNodes << std::endl; | |
| } | |
| nodes += perftNodes; | |
| board.unmakeMove(); | |
| } |
| /** | ||
| * \brief Converts a string in chess notation to a square. | ||
| * \param notation The string representing the square in chess notation. | ||
| * \return A Square integer representing the square. | ||
| */ | ||
| Square getSquareFromNotation(const std::string_view notation) { | ||
| const uint8_t file = notation[0] - 'a'; | ||
| const uint8_t rank = notation[1] - '1'; | ||
|
|
||
| return static_cast<Square>(file + rank * 8); | ||
| } | ||
| } // namespace Zagreus |
There was a problem hiding this comment.
Add input validation to prevent undefined behavior
While the function correctly converts algebraic notation to a square index, it lacks input validation. This could lead to undefined behavior if given invalid input.
Consider adding input validation to ensure the input is a valid square notation:
Square getSquareFromNotation(const std::string_view notation) {
if (notation.size() != 2 ||
notation[0] < 'a' || notation[0] > 'h' ||
notation[1] < '1' || notation[1] > '8') {
throw std::invalid_argument("Invalid square notation");
}
const uint8_t file = notation[0] - 'a';
const uint8_t rank = notation[1] - '1';
return static_cast<Square>(file + rank * 8);
}This approach ensures that only valid square notations are processed, improving the robustness of the function and preventing potential undefined behavior.
| std::string Engine::getVersionString() { | ||
| const std::string majorVersion = ZAGREUS_VERSION_MAJOR; | ||
| const std::string minorVersion = ZAGREUS_VERSION_MINOR; | ||
| std::string versionString = "v" + majorVersion + "." + minorVersion; | ||
|
|
||
| if (majorVersion == "dev") { | ||
| versionString = majorVersion + "-" + minorVersion; | ||
| } | ||
|
|
||
| return versionString; | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider using std::ostringstream for version string construction
While the current implementation is correct, using std::ostringstream could make the code more concise and potentially more efficient. Here's a suggested implementation:
std::string Engine::getVersionString() {
std::ostringstream versionStream;
if (ZAGREUS_VERSION_MAJOR == "dev") {
versionStream << ZAGREUS_VERSION_MAJOR << "-" << ZAGREUS_VERSION_MINOR;
} else {
versionStream << "v" << ZAGREUS_VERSION_MAJOR << "." << ZAGREUS_VERSION_MINOR;
}
return versionStream.str();
}This change would simplify the logic and improve readability.
| void Engine::handleSetOptionCommand(const std::string& args) { | ||
| if (!didSetup) { | ||
| doSetup(); | ||
| } | ||
|
|
||
| std::istringstream iss(args); | ||
| std::string arg; | ||
| std::string section; | ||
| std::string name; | ||
| std::string value; | ||
|
|
||
| while (iss >> arg) { | ||
| std::string lowercaseWord = arg; | ||
| std::ranges::transform(lowercaseWord, lowercaseWord.begin(), | ||
| [](const unsigned char c) { return std::tolower(c); }); | ||
|
|
||
| if (lowercaseWord == "name") { | ||
| section = arg; | ||
| continue; | ||
| } | ||
|
|
||
| if (lowercaseWord == "value") { | ||
| section = arg; | ||
| continue; | ||
| } | ||
|
|
||
| if (section == "name") { | ||
| if (name.empty()) { | ||
| name = arg; | ||
| } else { | ||
| name += " " + arg; | ||
| } | ||
| } | ||
|
|
||
| if (section == "value") { | ||
| if (value.empty()) { | ||
| value = arg; | ||
| } else { | ||
| value += " " + arg; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| if (name.empty()) { | ||
| sendMessage("ERROR: No option name provided."); | ||
| return; | ||
| } | ||
|
|
||
| if (!hasOption(name)) { | ||
| sendMessage("ERROR: Option " + name + " does not exist."); | ||
| return; | ||
| } | ||
|
|
||
| UCIOption& option = this->getOption(name); | ||
|
|
||
| if (value.empty()) { | ||
| if (option.getOptionType() == Button) { | ||
| if (option.getValue() == "true") { | ||
| value = "false"; | ||
| } else { | ||
| value = "true"; | ||
| } | ||
| } else { | ||
| sendMessage("ERROR: No option value provided."); | ||
| return; | ||
| } | ||
| } | ||
|
|
||
| option.setValue(value); | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider using std::istringstream for more efficient parsing
The handleSetOptionCommand() method could be simplified and made more efficient by using std::istringstream for parsing the command arguments. Here's a suggested implementation:
void Engine::handleSetOptionCommand(const std::string& args) {
if (!didSetup) {
doSetup();
}
std::istringstream iss(args);
std::string token, name, value;
bool readingName = false, readingValue = false;
while (iss >> token) {
std::transform(token.begin(), token.end(), token.begin(), ::tolower);
if (token == "name") {
readingName = true;
readingValue = false;
name.clear();
} else if (token == "value") {
readingName = false;
readingValue = true;
value.clear();
} else if (readingName) {
if (!name.empty()) name += " ";
name += token;
} else if (readingValue) {
if (!value.empty()) value += " ";
value += token;
}
}
if (name.empty()) {
sendMessage("ERROR: No option name provided.");
return;
}
if (!hasOption(name)) {
sendMessage("ERROR: Option " + name + " does not exist.");
return;
}
UCIOption& option = this->getOption(name);
if (value.empty() && option.getOptionType() != Button) {
sendMessage("ERROR: No option value provided.");
return;
}
if (option.getOptionType() == Button) {
value = (option.getValue() == "true") ? "false" : "true";
}
option.setValue(value);
}This implementation simplifies the parsing logic, reduces the number of variables, and makes the code more straightforward to understand and maintain.
| void Engine::processCommand(const std::string_view command, const std::string& args) { | ||
| if (command == "uci") { | ||
| handleUciCommand(); | ||
| } else if (command == "debug") { | ||
| handleDebugCommand(args); | ||
| } else if (command == "isready") { | ||
| handleIsReadyCommand(args); | ||
| } else if (command == "setoption") { | ||
| handleSetOptionCommand(args); | ||
| } else if (command == "register") { | ||
| // Not relevant for our engine | ||
| return; | ||
| } else if (command == "ucinewgame") { | ||
| handleUciNewGameCommand(args); | ||
| } else if (command == "position") { | ||
| handlePositionCommand(args); | ||
| } else if (command == "go") { | ||
| handleGoCommand(args); | ||
| } else if (command == "stop") { | ||
| handleStopCommand(args); | ||
| } else if (command == "ponderhit") { | ||
| handlePonderHitCommand(args); | ||
| } else if (command == "quit") { | ||
| handleQuitCommand(args); | ||
| } else if (command == "perft") { | ||
| handlePerftCommand(args); | ||
| } else if (command == "print") { | ||
| handlePrintCommand(); | ||
| } else { | ||
| // If unknown, we must skip it and process the rest. | ||
| if (args.empty() || args == " " || args == "\n") { | ||
| std::cout << "Unknown command: " << command << std::endl; | ||
| return; | ||
| } | ||
|
|
||
| std::string newCommand; | ||
| std::string newArgs; | ||
|
|
||
| if (args.contains(' ')) { | ||
| newCommand = args.substr(0, args.find(' ')); | ||
| newArgs = args.substr(args.find(' ') + 1); | ||
| } else { | ||
| newCommand = args; | ||
| } | ||
|
|
||
| processCommand(newCommand, newArgs); | ||
| } | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Simplify handling of unknown commands
The current implementation for handling unknown commands is overly complex and could potentially lead to unexpected behavior. Consider simplifying it to provide a clear error message without attempting to process parts of the unknown command.
Here's a suggested implementation:
} else {
std::cout << "info string Unknown command: " << command;
if (!args.empty()) {
std::cout << " " << args;
}
std::cout << std::endl;
}This change will consistently report unknown commands without attempting to process them further, which is safer and more in line with typical UCI behavior.
| pawnEastAttacks = blackPawnEastAttacks(pawnBB); | ||
| } | ||
|
|
||
| uint64_t enPassantMask = squareToBitboard(board.getEnPassantSquare()); | ||
|
|
||
| if constexpr (color == WHITE) { | ||
| enPassantMask &= RANK_6; | ||
| } else { | ||
| enPassantMask &= RANK_3; | ||
| } | ||
|
|
||
| pawnSinglePushes &= genMask; | ||
| pawnDoublePushes &= genMask; | ||
| pawnWestAttacks &= (opponentPieces | enPassantMask) & genMask; | ||
| pawnEastAttacks &= (opponentPieces | enPassantMask) & genMask; | ||
|
|
||
| constexpr Direction fromPushDirection = color == WHITE ? NORTH : SOUTH; | ||
| constexpr Direction fromSqWestAttackDirection = color == WHITE ? NORTH_WEST : SOUTH_WEST; | ||
| constexpr Direction fromSqEastAttackDirection = color == WHITE ? NORTH_EAST : SOUTH_EAST; | ||
| constexpr uint64_t promotionRank = color == WHITE ? RANK_8 : RANK_1; | ||
|
|
||
| while (pawnSinglePushes) { | ||
| const uint8_t squareTo = popLsb(pawnSinglePushes); | ||
| const uint64_t squareToBB = squareToBitboard(squareTo); | ||
| const uint8_t squareFrom = squareTo - fromPushDirection; | ||
|
|
||
| if (squareToBB & promotionRank) { | ||
| for (const PromotionPiece promotionPiece : {QUEEN_PROMOTION, ROOK_PROMOTION, BISHOP_PROMOTION, | ||
| KNIGHT_PROMOTION}) { | ||
| const Move move = encodeMove(squareFrom, squareTo, promotionPiece); | ||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } else { | ||
| const Move move = encodeMove(squareFrom, squareTo); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
|
|
||
| while (pawnDoublePushes) { | ||
| const uint8_t squareTo = popLsb(pawnDoublePushes); | ||
| const uint8_t squareFrom = squareTo - fromPushDirection - fromPushDirection; | ||
| const Move move = encodeMove(squareFrom, squareTo); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
|
|
||
| while (pawnWestAttacks) { | ||
| const uint8_t squareTo = popLsb(pawnWestAttacks); | ||
| const uint64_t squareToBB = squareToBitboard(squareTo); | ||
| const uint8_t squareFrom = squareTo - fromSqWestAttackDirection; | ||
|
|
||
| if (squareTo == board.getEnPassantSquare() && squareToBB & enPassantMask) { | ||
| const Move move = encodeMove(squareFrom, squareTo, EN_PASSANT); | ||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } else { | ||
| if (squareToBB & promotionRank) { | ||
| for (const PromotionPiece promotionPiece : {QUEEN_PROMOTION, ROOK_PROMOTION, BISHOP_PROMOTION, | ||
| KNIGHT_PROMOTION}) { | ||
| const Move move = encodeMove(squareFrom, squareTo, promotionPiece); | ||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } else { | ||
| const Move move = encodeMove(squareFrom, squareTo); | ||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| while (pawnEastAttacks) { | ||
| const uint8_t squareTo = popLsb(pawnEastAttacks); | ||
| const uint64_t squareToBB = squareToBitboard(squareTo); | ||
| const uint8_t squareFrom = squareTo - fromSqEastAttackDirection; | ||
|
|
||
| if (squareTo == board.getEnPassantSquare() && squareToBB & enPassantMask) { | ||
| const Move move = encodeMove(squareFrom, squareTo, EN_PASSANT); | ||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } else { | ||
| if (squareToBB & promotionRank) { | ||
| for (const PromotionPiece promotionPiece : {QUEEN_PROMOTION, ROOK_PROMOTION, BISHOP_PROMOTION, | ||
| KNIGHT_PROMOTION}) { | ||
| const Move move = encodeMove(squareFrom, squareTo, promotionPiece); | ||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } else { | ||
| const Move move = encodeMove(squareFrom, squareTo); | ||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider refactoring generatePawnMoves for improved readability
The generatePawnMoves function is comprehensive and handles all pawn move types efficiently. However, its length and complexity might make it harder to maintain. Consider refactoring it into smaller, more focused functions:
- Split the function into separate methods for single pushes, double pushes, captures, en passant, and promotions.
- Create a helper function for adding moves to the move list to reduce repetition.
For example:
void addMove(MoveList& moves, uint8_t from, uint8_t to, MoveType type = NORMAL) {
moves.moves[moves.size++] = encodeMove(from, to, type);
}
void generatePawnSinglePushes(/* parameters */) {
// Handle single pushes
}
void generatePawnDoublePushes(/* parameters */) {
// Handle double pushes
}
// Similar functions for captures, en passant, and promotionsThis refactoring would improve readability and make the function easier to maintain and test.
| template <PieceColor color, GenerationType type> | ||
| void generateBishopMoves(const Board& board, MoveList& moves, const uint64_t genMask) { | ||
| constexpr Piece bishop = color == WHITE ? WHITE_BISHOP : BLACK_BISHOP; | ||
| const uint64_t occupied = board.getOccupiedBitboard(); | ||
| uint64_t bishopBB = board.getBitboard<bishop>(); | ||
|
|
||
| while (bishopBB) { | ||
| const uint8_t fromSquare = popLsb(bishopBB); | ||
| uint64_t genBB = getBishopAttacks(fromSquare, occupied) & genMask; | ||
|
|
||
| while (genBB) { | ||
| const uint8_t toSquare = popLsb(genBB); | ||
| const Move move = encodeMove(fromSquare, toSquare); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * \brief Generates all pseudo-legal rook moves for a given color and generation type. | ||
| * \tparam color The color of the rooks to generate moves for. | ||
| * \tparam type The type of moves to generate (e.g., all moves, captures, quiet moves). | ||
| * \param board The board object for which to generate moves. | ||
| * \param[out] moves The list to store the generated moves. | ||
| * \param genMask The mask to filter out invalid moves. | ||
| */ | ||
| template <PieceColor color, GenerationType type> | ||
| void generateRookMoves(const Board& board, MoveList& moves, const uint64_t genMask) { | ||
| constexpr Piece rook = color == WHITE ? WHITE_ROOK : BLACK_ROOK; | ||
| const uint64_t occupied = board.getOccupiedBitboard(); | ||
| uint64_t rookBB = board.getBitboard<rook>(); | ||
|
|
||
| while (rookBB) { | ||
| const uint8_t fromSquare = popLsb(rookBB); | ||
| uint64_t genBB = getRookAttacks(fromSquare, occupied) & genMask; | ||
|
|
||
| while (genBB) { | ||
| const uint8_t toSquare = popLsb(genBB); | ||
| const Move move = encodeMove(fromSquare, toSquare); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * \brief Generates all pseudo-legal queen moves for a given color and generation type. | ||
| * \tparam color The color of the queens to generate moves for. | ||
| * \tparam type The type of moves to generate (e.g., all moves, captures, quiet moves). | ||
| * \param board The board object for which to generate moves. | ||
| * \param[out] moves The list to store the generated moves. | ||
| * \param genMask The mask to filter out invalid moves. | ||
| */ | ||
| template <PieceColor color, GenerationType type> | ||
| void generateQueenMoves(const Board& board, MoveList& moves, const uint64_t genMask) { | ||
| constexpr Piece queen = color == WHITE ? WHITE_QUEEN : BLACK_QUEEN; | ||
| const uint64_t occupied = board.getOccupiedBitboard(); | ||
| uint64_t queenBB = board.getBitboard<queen>(); | ||
|
|
||
| while (queenBB) { | ||
| const uint8_t fromSquare = popLsb(queenBB); | ||
| uint64_t genBB = queenAttacks(fromSquare, occupied) & genMask; | ||
|
|
||
| while (genBB) { | ||
| const uint8_t toSquare = popLsb(genBB); | ||
| const Move move = encodeMove(fromSquare, toSquare); | ||
|
|
||
| moves.moves[moves.size] = move; | ||
| moves.size++; | ||
| } | ||
| } | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider refactoring sliding piece move generation
The generateBishopMoves, generateRookMoves, and generateQueenMoves functions have very similar structures. To improve maintainability and reduce code duplication, consider creating a template function for sliding piece move generation:
template <PieceColor color, GenerationType type, Piece piece>
void generateSlidingPieceMoves(const Board& board, MoveList& moves, const uint64_t genMask) {
const uint64_t occupied = board.getOccupiedBitboard();
uint64_t pieceBB = board.getBitboard<piece>();
while (pieceBB) {
const uint8_t fromSquare = popLsb(pieceBB);
uint64_t genBB = getPieceAttacks<piece>(fromSquare, occupied) & genMask;
while (genBB) {
const uint8_t toSquare = popLsb(genBB);
const Move move = encodeMove(fromSquare, toSquare);
moves.moves[moves.size++] = move;
}
}
}
// Usage:
template <PieceColor color, GenerationType type>
void generateBishopMoves(const Board& board, MoveList& moves, const uint64_t genMask) {
generateSlidingPieceMoves<color, type, color == WHITE ? WHITE_BISHOP : BLACK_BISHOP>(board, moves, genMask);
}
// Similar for Rook and QueenThis refactoring will reduce code duplication and make it easier to maintain and update the sliding piece move generation logic.
| template <PieceColor color, GenerationType type> | ||
| void generateMoves(const Board& board, MoveList& moves) { | ||
| assert(moves.size == 0); | ||
|
|
||
| // TODO: Implement GenerationType logic using a mask that is computed based on type | ||
| constexpr Piece opponentKing = color == WHITE ? BLACK_KING : WHITE_KING; | ||
| const uint64_t ownPieces = board.getColorBitboard<color>(); | ||
| const uint64_t opponentKingBB = board.getBitboard<opponentKing>(); | ||
| const uint64_t genMask = ~(ownPieces | opponentKingBB); | ||
|
|
||
| generatePawnMoves<color, type>(board, moves, genMask); | ||
| generateKnightMoves<color, type>(board, moves, genMask); | ||
| generateBishopMoves<color, type>(board, moves, genMask); | ||
| generateRookMoves<color, type>(board, moves, genMask); | ||
| generateQueenMoves<color, type>(board, moves, genMask); | ||
| generateKingMoves<color, type>(board, moves, genMask); | ||
| } |
There was a problem hiding this comment.
💡 Codebase verification
Implement GenerationType Logic
The generateMoves function still contains the TODO for implementing GenerationType logic. Please ensure that the GenerationType-specific mask computation is properly implemented to handle different generation scenarios.
🔗 Analysis chain
Implement GenerationType logic as noted in TODO
The generateMoves function is well-structured, but the GenerationType logic is not fully implemented. Consider updating the genMask computation based on the type parameter:
uint64_t genMask;
switch (type) {
case CAPTURES:
genMask = board.getColorBitboard<!color>();
break;
case QUIET:
genMask = board.getEmptyBitboard();
break;
case EVASIONS:
// Implement evasion logic (moves that block check or capture the checking piece)
genMask = ...; // TODO: Implement this
break;
case ALL:
default:
genMask = ~(ownPieces | opponentKingBB);
break;
}This implementation will make the generateMoves function more versatile for different move generation scenarios.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Description: Check if GenerationType is used correctly in move generation
# Test: Search for usage of GenerationType in move generation
rg --type cpp "GenerationType::(ALL|QUIET|CAPTURES|EVASIONS)" src/
Length of output: 68
Script:
#!/bin/bash
# Description: Comprehensive search for GenerationType implementations and usages
# Search for any occurrences of GenerationType in the codebase
rg --type cpp "GenerationType" src/
# Additionally, search for comments related to the TODO to find if it's been addressed differently
rg --type cpp "TODO.*GenerationType" src/
Length of output: 1246
| enum GenerationType : uint8_t { | ||
| ALL, | ||
| QUIET, | ||
| CAPTURES, | ||
| EVASIONS | ||
| }; |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Use enum class for GenerationType to Enhance Type Safety
Using enum class instead of enum provides strong type safety and avoids polluting the surrounding namespace with enum constants. This change can improve code robustness without affecting performance.
Apply this diff to update the enum declaration:
-enum GenerationType : uint8_t {
+enum class GenerationType : uint8_t {
ALL,
QUIET,
CAPTURES,
EVASIONS
};After this change, you'll need to qualify the enum values with GenerationType::, for example, GenerationType::ALL.
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| enum GenerationType : uint8_t { | |
| ALL, | |
| QUIET, | |
| CAPTURES, | |
| EVASIONS | |
| }; | |
| enum class GenerationType : uint8_t { | |
| ALL, | |
| QUIET, | |
| CAPTURES, | |
| EVASIONS | |
| }; |
src/move_gen.h
Outdated
| #include "move.h" | ||
| #include "types.h" | ||
|
|
||
| enum PieceColor : uint8_t; |
There was a problem hiding this comment.
Potential Issue with Forward Declaration of Unscoped Enum PieceColor
In C++, forward declarations of unscoped enums are not allowed. Only scoped enums (enum class) can be forward declared. Attempting to forward declare an unscoped enum like PieceColor may lead to compilation errors.
Consider changing the forward declaration to a scoped enum:
-enum PieceColor : uint8_t;
+enum class PieceColor : uint8_t;Ensure that the definition of PieceColor elsewhere in the codebase is updated accordingly to use enum class.
Committable suggestion was skipped due to low confidence.
There was a problem hiding this comment.
Actionable comments posted: 12
🧹 Outside diff range and nitpick comments (3)
src/board.h (2)
352-357: Enhance isDraw() documentation.
While the comment mentions it checks everything but stalemate, it would be more helpful to explicitly list what types of draws are checked (e.g., threefold repetition, fifty-move rule, insufficient material).
292-299: Add documentation for isKingInCheck method.
This template method lacks documentation comments explaining its purpose, parameters, and return value.
Add documentation similar to other methods:
/**
* \brief Checks if the king of the specified color is in check.
* \tparam color The color of the king to check.
* \return True if the king is in check, false otherwise.
*/src/board.cpp (1)
178-181: Implement draw detection logic.
The isDraw method needs to handle various draw conditions:
- Threefold repetition
- Fifty-move rule
- Insufficient material
- Stalemate
Would you like me to help implement the draw detection logic or create an issue to track this task?
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (6)
- src/board.cpp (1 hunks)
- src/board.h (1 hunks)
- src/constants.h (2 hunks)
- src/move_picker.h (1 hunks)
- src/search.cpp (2 hunks)
- src/search.h (2 hunks)
🧰 Additional context used
📓 Path-based instructions (6)
src/board.cpp (1)
Pattern **/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/board.h (1)
Pattern **/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/constants.h (1)
Pattern **/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/move_picker.h (1)
Pattern **/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/search.cpp (1)
Pattern **/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/search.h (1)
Pattern **/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
🔇 Additional comments (15)
src/move_picker.h (2)
1-28: LGTM! Header organization and licensing are properly structured.
31-35: 🛠️ Refactor suggestion
Consider storing moveList by reference for better performance.
Since this is a chess engine where performance is crucial, storing moveList by value might cause unnecessary copying. Consider using a reference or pointer to the original MoveList, especially if the MovePicker's lifetime is shorter than the MoveList's.
private:
- MoveList moveList{};
+ const MoveList& moveList;
int currentIndex = 0;Likely invalid or redundant comment.
src/constants.h (5)
28-31: LGTM! Well-defined file mask constants.
The bitboard masks are correctly defined for file-based move generation and will help optimize move filtering operations.
33-40: LGTM! Well-formatted rank constants.
The consistent formatting with leading zeros improves readability while maintaining the performance-critical nature of these bitboard masks.
42-50: LGTM! Precise castling path definitions.
The constants correctly handle the subtle difference between path checking and unoccupied square requirements, particularly for queenside castling where the b1/b8 square must also be empty.
52-54: LGTM! Good type optimization.
The use of uint8_t for these small constants is appropriate and aligns with the performance focus.
60-60: Verify the impact of increased MATE_SCORE.
The MATE_SCORE has been significantly increased from 20000 to 100000. This could affect evaluation scaling and comparison logic throughout the engine.
✅ Verification successful
Let me search for more context around score comparisons and evaluations to better understand the impact.
The increased MATE_SCORE value is safely handled in the codebase
The codebase only uses MATE_SCORE in two key scenarios:
- As a base value for alpha-beta pruning when in check:
-MATE_SCORE + board.getPly() - As a constant definition in constants.h
The score comparisons in the search algorithm are all relative (using >, >=, etc.) and don't rely on specific MATE_SCORE magnitude. The only arithmetic operation with MATE_SCORE adjusts it by the ply count, which scales appropriately with any MATE_SCORE value.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Search for uses of MATE_SCORE to verify proper handling of the increased value
rg -l "MATE_SCORE" | while read -r file; do
echo "=== $file ==="
rg -A 2 -B 2 "MATE_SCORE" "$file"
done
Length of output: 461
Script:
#!/bin/bash
# Search for score comparisons and evaluations
rg -A 3 -B 3 "(>|<|>=|<=|==)\s*-?MATE_SCORE|score\s*(>|<|>=|<=|==)"
# Also search for any arithmetic operations with scores
rg -A 3 -B 3 "score\s*[+\-*/]|[+\-*/]\s*MATE_SCORE"
Length of output: 1241
src/board.h (3)
40-45: LGTM: Well-designed BoardState struct.
The struct is efficiently designed with proper member ordering for optimal memory layout and alignment. The default initializers prevent undefined behavior.
51-62: LGTM: Efficient board representation design.
The class uses std::array for fixed-size arrays, which provides both safety and performance. Member variables are well-ordered for optimal memory layout and properly initialized.
67-72: LGTM: Clean and efficient constructor implementation.
The constructor properly initializes all arrays using std::ranges::fill, which is both efficient and clear.
src/board.cpp (2)
87-112: LGTM!
The implementation correctly checks both castling rights and path occupation using efficient bitboard operations.
296-347: LGTM!
The unmakeMove implementation correctly restores all aspects of the board state, including piece positions, castling rights, and en passant squares.
src/search.h (1)
28-31: 🛠️ Refactor suggestion
Consider using enum class for NodeType to enhance type safety.
Using enum class provides scoped and strongly typed enumerations, preventing implicit conversions and potential naming conflicts.
Apply this diff to update the enum declaration:
-enum NodeType {
+enum class NodeType {
ROOT,
PV,
REGULAR,
};Likely invalid or redundant comment.
src/search.cpp (2)
75-75:
Add missing space in 'depth -1' to ensure correct depth decrement
The expression depth -1 is missing a space between the minus sign and 1, which may cause parsing issues or logical errors in depth calculation.
Apply this diff to fix the typo:
-score = -pvSearch<opponentColor, PV>(board, -beta, -alpha, depth -1);
+score = -pvSearch<opponentColor, PV>(board, -beta, -alpha, depth - 1);Likely invalid or redundant comment.
72-72:
Fix missing space in '-alpha -1' to prevent calculation errors
In the function call, the expression -alpha -1 lacks a space between -alpha and -1, which could lead to unintended arithmetic operations and incorrect alpha-beta bounds during the search.
Apply this diff to correct the expression:
-score = -pvSearch<opponentColor, REGULAR>(board, -alpha -1, -alpha, depth - 1);
+score = -pvSearch<opponentColor, REGULAR>(board, -alpha - 1, -alpha, depth - 1);Likely invalid or redundant comment.
| [[nodiscard]] bool next(Move& move) { | ||
| if (currentIndex >= moveList.size) { | ||
| return false; | ||
| } | ||
|
|
||
| move = moveList.moves[currentIndex]; | ||
| currentIndex += 1; | ||
| return true; | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider inlining the next() method for performance.
Since this is a performance-critical chess engine and the method is small, consider inlining it to eliminate function call overhead.
- [[nodiscard]] bool next(Move& move) {
+ [[nodiscard]] inline bool next(Move& move) {📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| [[nodiscard]] bool next(Move& move) { | |
| if (currentIndex >= moveList.size) { | |
| return false; | |
| } | |
| move = moveList.moves[currentIndex]; | |
| currentIndex += 1; | |
| return true; | |
| } | |
| [[nodiscard]] inline bool next(Move& move) { | |
| if (currentIndex >= moveList.size) { | |
| return false; | |
| } | |
| move = moveList.moves[currentIndex]; | |
| currentIndex += 1; | |
| return true; | |
| } |
| [[nodiscard]] Move getCurrentMove() const { | ||
| return moveList.moves[currentIndex - 1]; | ||
| } |
There was a problem hiding this comment.
Add bounds checking and inline getCurrentMove().
The method needs bounds checking to prevent undefined behavior when accessing moves[currentIndex - 1]. Also, consider inlining for performance.
- [[nodiscard]] Move getCurrentMove() const {
+ [[nodiscard]] inline Move getCurrentMove() const {
+ if (currentIndex <= 0) {
+ throw std::out_of_range("No moves have been retrieved yet");
+ }
return moveList.moves[currentIndex - 1];
}Committable suggestion was skipped due to low confidence.
| public: | ||
| explicit MovePicker(const MoveList& moveList) : moveList(moveList) {} |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Add size validation in constructor.
Consider validating the moveList size in the constructor to prevent potential issues with empty lists. Also, if storing moveList by reference, ensure proper lifetime management.
- explicit MovePicker(const MoveList& moveList) : moveList(moveList) {}
+ explicit MovePicker(const MoveList& moveList) : moveList(moveList) {
+ if (moveList.size == 0) {
+ throw std::invalid_argument("MovePicker requires non-empty MoveList");
+ }
+ }Committable suggestion was skipped due to low confidence.
| [[nodiscard]] constexpr Move getLastMove() const { | ||
| return history[ply - 1].move; | ||
| } |
There was a problem hiding this comment.
Add bounds checking for ply in getLastMove().
The method could cause undefined behavior if called when ply is 0.
Add an assertion:
[[nodiscard]] constexpr Move getLastMove() const {
+ assert(ply > 0);
return history[ply - 1].move;
}📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| [[nodiscard]] constexpr Move getLastMove() const { | |
| return history[ply - 1].move; | |
| } | |
| [[nodiscard]] constexpr Move getLastMove() const { | |
| assert(ply > 0); | |
| return history[ply - 1].move; | |
| } |
src/board.cpp
Outdated
| const PieceType movedPieceType = getPieceType(movedPiece); | ||
| const Piece capturedPiece = getPieceOnSquare(toSquare); | ||
|
|
||
| history[ply].move = move; | ||
| history[ply].capturedPiece = capturedPiece; | ||
| history[ply].enPassantSquare = enPassantSquare; | ||
| enPassantSquare = 0; | ||
| history[ply].castlingRights = castlingRights; | ||
|
|
||
| if (capturedPiece != EMPTY) { | ||
| removePiece(capturedPiece, toSquare); | ||
|
|
||
| if (capturedPiece == WHITE_ROOK) { | ||
| if (toSquare == A1) { | ||
| castlingRights &= ~WHITE_QUEENSIDE; | ||
| } else if (toSquare == H1) { | ||
| castlingRights &= ~WHITE_KINGSIDE; | ||
| } | ||
| } else if (capturedPiece == BLACK_ROOK) { | ||
| if (toSquare == A8) { | ||
| castlingRights &= ~BLACK_QUEENSIDE; | ||
| } else if (toSquare == H8) { | ||
| castlingRights &= ~BLACK_KINGSIDE; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| removePiece(movedPiece, fromSquare); | ||
|
|
||
| if (moveType == PROMOTION) { | ||
| const PieceColor color = getPieceColor(movedPiece); | ||
| const PromotionPiece promotionPieceType = getPromotionPiece(move); | ||
| const Piece promotionPiece = getPieceFromPromotionPiece(promotionPieceType, color); | ||
|
|
||
| setPiece(promotionPiece, toSquare); | ||
| } else { | ||
| setPiece(movedPiece, toSquare); | ||
| } | ||
|
|
||
| if (moveType == EN_PASSANT) { | ||
| if (sideToMove == WHITE) { | ||
| removePiece(BLACK_PAWN, toSquare + SOUTH); | ||
| } else { | ||
| removePiece(WHITE_PAWN, toSquare + NORTH); | ||
| } | ||
| } else if (moveType == CASTLING) { | ||
| if (toSquare == G1) { | ||
| removePiece(WHITE_ROOK, H1); | ||
| setPiece(WHITE_ROOK, F1); | ||
| } else if (toSquare == C1) { | ||
| removePiece(WHITE_ROOK, A1); | ||
| setPiece(WHITE_ROOK, D1); | ||
| } else if (toSquare == G8) { | ||
| removePiece(BLACK_ROOK, H8); | ||
| setPiece(BLACK_ROOK, F8); | ||
| } else if (toSquare == C8) { | ||
| removePiece(BLACK_ROOK, A8); | ||
| setPiece(BLACK_ROOK, D8); | ||
| } | ||
|
|
||
| if (sideToMove == WHITE) { | ||
| castlingRights &= ~WHITE_CASTLING; | ||
| } else { | ||
| castlingRights &= ~BLACK_CASTLING; | ||
| } | ||
| } | ||
|
|
||
| if (movedPiece == WHITE_KING) { | ||
| castlingRights &= ~WHITE_CASTLING; | ||
| } else if (movedPiece == BLACK_KING) { | ||
| castlingRights &= ~BLACK_CASTLING; | ||
| } else if (movedPiece == WHITE_ROOK) { | ||
| if (fromSquare == A1) { | ||
| castlingRights &= ~WHITE_QUEENSIDE; | ||
| } else if (fromSquare == H1) { | ||
| castlingRights &= ~WHITE_KINGSIDE; | ||
| } | ||
| } else if (movedPiece == BLACK_ROOK) { | ||
| if (fromSquare == A8) { | ||
| castlingRights &= ~BLACK_QUEENSIDE; | ||
| } else if (fromSquare == H8) { | ||
| castlingRights &= ~BLACK_KINGSIDE; | ||
| } | ||
| } | ||
|
|
||
| if (movedPieceType == PAWN) { | ||
| if ((fromSquare ^ toSquare) == 16) { | ||
| if (sideToMove == WHITE) { | ||
| enPassantSquare = toSquare + SOUTH; | ||
| } else { | ||
| enPassantSquare = toSquare + NORTH; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| sideToMove = !sideToMove; | ||
| assert(ply >= 0 && ply < MAX_PLY); | ||
| ply++; | ||
| assert(ply >= 0 && ply < MAX_PLY); | ||
| } |
There was a problem hiding this comment.
Add zobrist hash updates for move execution.
The makeMove method should update the zobrist hash for:
- Piece movements
- Captures
- Castling rights changes
- En passant square changes
- Side to move changes
Would you like me to provide the implementation for the zobrist hash updates?
| template <PieceColor movedColor> | ||
| bool Board::isPositionLegal() const { | ||
| constexpr PieceColor opponentColor = !movedColor; | ||
| constexpr Piece king = movedColor == WHITE ? WHITE_KING : BLACK_KING; | ||
| const uint64_t kingBB = getBitboard<king>(); | ||
| const Square kingSquare = bitboardToSquare(kingBB); | ||
| const Move lastMove = getLastMove(); | ||
| const MoveType lastMoveType = getMoveType(lastMove); | ||
|
|
||
| if (lastMoveType == CASTLING) { | ||
| const uint8_t fromSquare = getFromSquare(lastMove); | ||
| const uint8_t toSquare = getToSquare(lastMove); | ||
| const uint64_t fromSquareAttacks = getSquareAttackersByColor<opponentColor>(fromSquare); | ||
|
|
||
| if (fromSquareAttacks) { | ||
| // King was in check before castling | ||
| return false; | ||
| } | ||
|
|
||
| uint64_t castlingPath = 0; | ||
|
|
||
| if (toSquare == G1) { | ||
| castlingPath = WHITE_KINGSIDE_CASTLE_PATH; | ||
| } else if (toSquare == C1) { | ||
| castlingPath = WHITE_QUEENSIDE_CASTLE_PATH; | ||
| } else if (toSquare == G8) { | ||
| castlingPath = BLACK_KINGSIDE_CASTLE_PATH; | ||
| } else if (toSquare == C8) { | ||
| castlingPath = BLACK_QUEENSIDE_CASTLE_PATH; | ||
| } | ||
|
|
||
| while (castlingPath) { | ||
| const uint8_t square = popLsb(castlingPath); | ||
| const uint64_t attackers = getSquareAttackersByColor<opponentColor>(square); | ||
|
|
||
| if (attackers) { | ||
| return false; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| return !getSquareAttackersByColor<opponentColor>(kingSquare); | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider caching attack information for better performance.
The implementation repeatedly calls getSquareAttackersByColor for each square in the castling path. Consider caching the attack information in a bitboard to avoid redundant calculations.
template <PieceColor movedColor>
bool Board::isPositionLegal() const {
constexpr PieceColor opponentColor = !movedColor;
constexpr Piece king = movedColor == WHITE ? WHITE_KING : BLACK_KING;
const uint64_t kingBB = getBitboard<king>();
const Square kingSquare = bitboardToSquare(kingBB);
const Move lastMove = getLastMove();
const MoveType lastMoveType = getMoveType(lastMove);
if (lastMoveType == CASTLING) {
const uint8_t fromSquare = getFromSquare(lastMove);
const uint8_t toSquare = getToSquare(lastMove);
- const uint64_t fromSquareAttacks = getSquareAttackersByColor<opponentColor>(fromSquare);
+ uint64_t castlingPath = 0;
+ if (toSquare == G1) castlingPath = WHITE_KINGSIDE_CASTLE_PATH;
+ else if (toSquare == C1) castlingPath = WHITE_QUEENSIDE_CASTLE_PATH;
+ else if (toSquare == G8) castlingPath = BLACK_KINGSIDE_CASTLE_PATH;
+ else if (toSquare == C8) castlingPath = BLACK_QUEENSIDE_CASTLE_PATH;
- if (fromSquareAttacks) {
+ // Cache attack information for the entire castling path including the from square
+ const uint64_t attackMap = getAttackMapForPath<opponentColor>(castlingPath | (1ULL << fromSquare));
+ if (attackMap) {
return false;
}
-
- uint64_t castlingPath = 0;
-
- if (toSquare == G1) {
- castlingPath = WHITE_KINGSIDE_CASTLE_PATH;
- } else if (toSquare == C1) {
- castlingPath = WHITE_QUEENSIDE_CASTLE_PATH;
- } else if (toSquare == G8) {
- castlingPath = BLACK_KINGSIDE_CASTLE_PATH;
- } else if (toSquare == C8) {
- castlingPath = BLACK_QUEENSIDE_CASTLE_PATH;
- }
-
- while (castlingPath) {
- const uint8_t square = popLsb(castlingPath);
- const uint64_t attackers = getSquareAttackersByColor<opponentColor>(square);
-
- if (attackers) {
- return false;
- }
- }
}
return !getSquareAttackersByColor<opponentColor>(kingSquare);
}Committable suggestion was skipped due to low confidence.
| void Board::print() const { | ||
| std::cout << " ---------------------------------"; | ||
|
|
||
| for (int index = 0; index < 64; index++) { | ||
| if (index % 8 == 0) { | ||
| std::cout << std::endl << index / 8 + 1 << " | "; | ||
| } | ||
|
|
||
| std::cout << getCharacterForPieceType(board[index]) << " | "; | ||
| } | ||
|
|
||
| std::cout << std::endl << " ---------------------------------" << std::endl; | ||
| std::cout << " a b c d e f g h " << std::endl; | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider using a stream parameter for more flexible output.
The current implementation is hardcoded to use std::cout. Consider accepting an output stream parameter for better flexibility and testability.
-void Board::print() const {
+void Board::print(std::ostream& os = std::cout) const {
- std::cout << " ---------------------------------";
+ os << " ---------------------------------";
// Update remaining std::cout to use osCommittable suggestion was skipped due to low confidence.
| uint64_t Board::getSquareAttackers(const uint8_t square) const { | ||
| assert(square < SQUARES); | ||
| const uint64_t knights = getBitboard<WHITE_KNIGHT>() | getBitboard<BLACK_KNIGHT>(); | ||
| const uint64_t kings = getBitboard<WHITE_KING>() | getBitboard<BLACK_KING>(); | ||
| uint64_t bishopsQueens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>(); | ||
| uint64_t rooksQueens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>(); | ||
| rooksQueens |= getBitboard<WHITE_ROOK>() | getBitboard<BLACK_ROOK>(); | ||
| bishopsQueens |= getBitboard<WHITE_BISHOP>() | getBitboard<BLACK_BISHOP>(); | ||
|
|
||
| return (getPawnAttacks<WHITE>(square) & getBitboard<BLACK_PAWN>()) | ||
| | (getPawnAttacks<BLACK>(square) & getBitboard<WHITE_PAWN>()) | ||
| | (getKnightAttacks(square) & knights) | ||
| | (getKingAttacks(square) & kings) | ||
| | (getBishopAttacks(square, occupied) & bishopsQueens) | ||
| | (getRookAttacks(square, occupied) & rooksQueens); | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Consider combining queen bitboards with rook/bishop bitboards earlier.
The current implementation reads the queen bitboard twice. Consider combining it with rook and bishop bitboards at initialization to reduce memory access.
uint64_t Board::getSquareAttackers(const uint8_t square) const {
assert(square < SQUARES);
const uint64_t knights = getBitboard<WHITE_KNIGHT>() | getBitboard<BLACK_KNIGHT>();
const uint64_t kings = getBitboard<WHITE_KING>() | getBitboard<BLACK_KING>();
- uint64_t bishopsQueens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>();
- uint64_t rooksQueens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>();
- rooksQueens |= getBitboard<WHITE_ROOK>() | getBitboard<BLACK_ROOK>();
- bishopsQueens |= getBitboard<WHITE_BISHOP>() | getBitboard<BLACK_BISHOP>();
+ const uint64_t queens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>();
+ const uint64_t bishopsQueens = queens | (getBitboard<WHITE_BISHOP>() | getBitboard<BLACK_BISHOP>());
+ const uint64_t rooksQueens = queens | (getBitboard<WHITE_ROOK>() | getBitboard<BLACK_ROOK>());📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| uint64_t Board::getSquareAttackers(const uint8_t square) const { | |
| assert(square < SQUARES); | |
| const uint64_t knights = getBitboard<WHITE_KNIGHT>() | getBitboard<BLACK_KNIGHT>(); | |
| const uint64_t kings = getBitboard<WHITE_KING>() | getBitboard<BLACK_KING>(); | |
| uint64_t bishopsQueens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>(); | |
| uint64_t rooksQueens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>(); | |
| rooksQueens |= getBitboard<WHITE_ROOK>() | getBitboard<BLACK_ROOK>(); | |
| bishopsQueens |= getBitboard<WHITE_BISHOP>() | getBitboard<BLACK_BISHOP>(); | |
| return (getPawnAttacks<WHITE>(square) & getBitboard<BLACK_PAWN>()) | |
| | (getPawnAttacks<BLACK>(square) & getBitboard<WHITE_PAWN>()) | |
| | (getKnightAttacks(square) & knights) | |
| | (getKingAttacks(square) & kings) | |
| | (getBishopAttacks(square, occupied) & bishopsQueens) | |
| | (getRookAttacks(square, occupied) & rooksQueens); | |
| } | |
| uint64_t Board::getSquareAttackers(const uint8_t square) const { | |
| assert(square < SQUARES); | |
| const uint64_t knights = getBitboard<WHITE_KNIGHT>() | getBitboard<BLACK_KNIGHT>(); | |
| const uint64_t kings = getBitboard<WHITE_KING>() | getBitboard<BLACK_KING>(); | |
| const uint64_t queens = getBitboard<WHITE_QUEEN>() | getBitboard<BLACK_QUEEN>(); | |
| const uint64_t bishopsQueens = queens | (getBitboard<WHITE_BISHOP>() | getBitboard<BLACK_BISHOP>()); | |
| const uint64_t rooksQueens = queens | (getBitboard<WHITE_ROOK>() | getBitboard<BLACK_ROOK>()); | |
| return (getPawnAttacks<WHITE>(square) & getBitboard<BLACK_PAWN>()) | |
| | (getPawnAttacks<BLACK>(square) & getBitboard<WHITE_PAWN>()) | |
| | (getKnightAttacks(square) & knights) | |
| | (getKingAttacks(square) & kings) | |
| | (getBishopAttacks(square, occupied) & bishopsQueens) | |
| | (getRookAttacks(square, occupied) & rooksQueens); | |
| } |
src/board.cpp
Outdated
|
|
||
| for (const char character : fen) { | ||
| if (character == ' ') { | ||
| spaces++; | ||
| continue; | ||
| } | ||
|
|
||
| if (character == ',') { | ||
| break; | ||
| } | ||
|
|
||
| if (spaces == 0) { | ||
| if (character == '/') { | ||
| index -= 16; | ||
| continue; | ||
| } | ||
|
|
||
| if (character >= '1' && character <= '8') { | ||
| index += character - '0'; | ||
| continue; | ||
| } | ||
|
|
||
| if (character >= 'A' && character <= 'z') { | ||
| setPieceFromFENChar(character, index); | ||
| index++; | ||
| } else { | ||
| return false; | ||
| } | ||
| } | ||
|
|
||
| if (spaces == 1) { | ||
| if (tolower(character) == 'w') { | ||
| sideToMove = WHITE; | ||
| } else if (tolower(character) == 'b') { | ||
| sideToMove = BLACK; | ||
| } else { | ||
| return false; | ||
| } | ||
| } | ||
|
|
||
| // TODO: Add zobrist hashes | ||
| if (spaces == 2) { | ||
| if (character == '-') { | ||
| continue; | ||
| } else if (character == 'K') { | ||
| castlingRights |= WHITE_KINGSIDE; | ||
| continue; | ||
| } | ||
|
|
||
| if (character == 'Q') { | ||
| castlingRights |= WHITE_QUEENSIDE; | ||
| continue; | ||
| } | ||
|
|
||
| if (character == 'k') { | ||
| castlingRights |= BLACK_KINGSIDE; | ||
| continue; | ||
| } | ||
|
|
||
| if (character == 'q') { | ||
| castlingRights |= BLACK_QUEENSIDE; | ||
| continue; | ||
| } | ||
|
|
||
| return false; | ||
| } | ||
|
|
||
| if (spaces == 3) { | ||
| if (character == '-') { | ||
| continue; | ||
| } | ||
|
|
||
| if (tolower(character) < 'a' || tolower(character) > 'h') { | ||
| continue; | ||
| } | ||
|
|
||
| const int8_t file = tolower(character) - 'a'; | ||
| const int8_t rank = (!sideToMove) == WHITE ? 2 : 5; | ||
|
|
||
| if (file < 0 || file > 7) { | ||
| return false; | ||
| } | ||
|
|
||
| // TODO: Add enPassant zobrist | ||
| enPassantSquare = rank * 8 + file; | ||
| index += 2; | ||
| } | ||
|
|
||
| // TODO: Implement halfmove and fullmove clock | ||
| /*if (spaces == 4) { | ||
| halfMoveClock = character - '0'; | ||
| } | ||
|
|
||
| if (spaces == 5) { | ||
| fullmoveClock = character - '0'; | ||
| }*/ | ||
| } | ||
|
|
||
| return true; | ||
| } |
There was a problem hiding this comment.
Complete FEN parsing implementation and fix potential issues.
- Implement missing features:
- Zobrist hash updates (TODO on line 405)
- Halfmove and fullmove clock parsing (TODO on lines 498-505)
- Fix potential issues:
- The rank calculation on line 487 has a confusing condition
- The index increment on line 495 seems arbitrary
- const int8_t rank = (!sideToMove) == WHITE ? 2 : 5;
+ const int8_t rank = sideToMove == WHITE ? 5 : 2;Would you like me to help implement the missing features or create issues to track these tasks?
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| bool Board::setFromFEN(const std::string_view fen) { | |
| // TODO: Update zobrist hash once that is implemented | |
| uint8_t index = A8; | |
| int spaces = 0; | |
| reset(); | |
| for (const char character : fen) { | |
| if (character == ' ') { | |
| spaces++; | |
| continue; | |
| } | |
| if (character == ',') { | |
| break; | |
| } | |
| if (spaces == 0) { | |
| if (character == '/') { | |
| index -= 16; | |
| continue; | |
| } | |
| if (character >= '1' && character <= '8') { | |
| index += character - '0'; | |
| continue; | |
| } | |
| if (character >= 'A' && character <= 'z') { | |
| setPieceFromFENChar(character, index); | |
| index++; | |
| } else { | |
| return false; | |
| } | |
| } | |
| if (spaces == 1) { | |
| if (tolower(character) == 'w') { | |
| sideToMove = WHITE; | |
| } else if (tolower(character) == 'b') { | |
| sideToMove = BLACK; | |
| } else { | |
| return false; | |
| } | |
| } | |
| // TODO: Add zobrist hashes | |
| if (spaces == 2) { | |
| if (character == '-') { | |
| continue; | |
| } else if (character == 'K') { | |
| castlingRights |= WHITE_KINGSIDE; | |
| continue; | |
| } | |
| if (character == 'Q') { | |
| castlingRights |= WHITE_QUEENSIDE; | |
| continue; | |
| } | |
| if (character == 'k') { | |
| castlingRights |= BLACK_KINGSIDE; | |
| continue; | |
| } | |
| if (character == 'q') { | |
| castlingRights |= BLACK_QUEENSIDE; | |
| continue; | |
| } | |
| return false; | |
| } | |
| if (spaces == 3) { | |
| if (character == '-') { | |
| continue; | |
| } | |
| if (tolower(character) < 'a' || tolower(character) > 'h') { | |
| continue; | |
| } | |
| const int8_t file = tolower(character) - 'a'; | |
| const int8_t rank = (!sideToMove) == WHITE ? 2 : 5; | |
| if (file < 0 || file > 7) { | |
| return false; | |
| } | |
| // TODO: Add enPassant zobrist | |
| enPassantSquare = rank * 8 + file; | |
| index += 2; | |
| } | |
| // TODO: Implement halfmove and fullmove clock | |
| /*if (spaces == 4) { | |
| halfMoveClock = character - '0'; | |
| } | |
| if (spaces == 5) { | |
| fullmoveClock = character - '0'; | |
| }*/ | |
| } | |
| return true; | |
| } | |
| bool Board::setFromFEN(const std::string_view fen) { | |
| // TODO: Update zobrist hash once that is implemented | |
| uint8_t index = A8; | |
| int spaces = 0; | |
| reset(); | |
| for (const char character : fen) { | |
| if (character == ' ') { | |
| spaces++; | |
| continue; | |
| } | |
| if (character == ',') { | |
| break; | |
| } | |
| if (spaces == 0) { | |
| if (character == '/') { | |
| index -= 16; | |
| continue; | |
| } | |
| if (character >= '1' && character <= '8') { | |
| index += character - '0'; | |
| continue; | |
| } | |
| if (character >= 'A' && character <= 'z') { | |
| setPieceFromFENChar(character, index); | |
| index++; | |
| } else { | |
| return false; | |
| } | |
| } | |
| if (spaces == 1) { | |
| if (tolower(character) == 'w') { | |
| sideToMove = WHITE; | |
| } else if (tolower(character) == 'b') { | |
| sideToMove = BLACK; | |
| } else { | |
| return false; | |
| } | |
| } | |
| // TODO: Add zobrist hashes | |
| if (spaces == 2) { | |
| if (character == '-') { | |
| continue; | |
| } else if (character == 'K') { | |
| castlingRights |= WHITE_KINGSIDE; | |
| continue; | |
| } | |
| if (character == 'Q') { | |
| castlingRights |= WHITE_QUEENSIDE; | |
| continue; | |
| } | |
| if (character == 'k') { | |
| castlingRights |= BLACK_KINGSIDE; | |
| continue; | |
| } | |
| if (character == 'q') { | |
| castlingRights |= BLACK_QUEENSIDE; | |
| continue; | |
| } | |
| return false; | |
| } | |
| if (spaces == 3) { | |
| if (character == '-') { | |
| continue; | |
| } | |
| if (tolower(character) < 'a' || tolower(character) > 'h') { | |
| continue; | |
| } | |
| const int8_t file = tolower(character) - 'a'; | |
| const int8_t rank = sideToMove == WHITE ? 5 : 2; | |
| if (file < 0 || file > 7) { | |
| return false; | |
| } | |
| // TODO: Add enPassant zobrist | |
| enPassantSquare = rank * 8 + file; | |
| index += 2; | |
| } | |
| // TODO: Implement halfmove and fullmove clock | |
| /*if (spaces == 4) { | |
| halfMoveClock = character - '0'; | |
| } | |
| if (spaces == 5) { | |
| fullmoveClock = character - '0'; | |
| }*/ | |
| } | |
| return true; | |
| } |
| Move search(Board& board) { | ||
| return Move(); |
There was a problem hiding this comment.
Implement the 'search' function
The search function currently returns a default Move object, indicating that it lacks an implementation. Please provide the search logic to return the best move based on the current board state.
There was a problem hiding this comment.
Actionable comments posted: 6
🧹 Outside diff range and nitpick comments (11)
src/constants.h (2)
33-40: LGTM! Consider using bit shifts for better maintainability.While the hex values are correct, consider using bit shifts for clearer relationship between ranks:
-static constexpr uint64_t RANK_1 = 0x00000000000000FFULL; -static constexpr uint64_t RANK_2 = 0x000000000000FF00ULL; -static constexpr uint64_t RANK_3 = 0x0000000000FF0000ULL; -static constexpr uint64_t RANK_4 = 0x00000000FF000000ULL; -static constexpr uint64_t RANK_5 = 0x000000FF00000000ULL; -static constexpr uint64_t RANK_6 = 0x0000FF0000000000ULL; -static constexpr uint64_t RANK_7 = 0x00FF000000000000ULL; -static constexpr uint64_t RANK_8 = 0xFF00000000000000ULL; +static constexpr uint64_t RANK_1 = 0xFFULL; +static constexpr uint64_t RANK_2 = RANK_1 << 8; +static constexpr uint64_t RANK_3 = RANK_1 << 16; +static constexpr uint64_t RANK_4 = RANK_1 << 24; +static constexpr uint64_t RANK_5 = RANK_1 << 32; +static constexpr uint64_t RANK_6 = RANK_1 << 40; +static constexpr uint64_t RANK_7 = RANK_1 << 48; +static constexpr uint64_t RANK_8 = RANK_1 << 56;
61-67: LGTM! Consider using enum for Zobrist indices.The Zobrist indices are correctly sequenced, but consider using an enum for better type safety and maintainability:
enum ZobristIndex { PIECE_START = 0, SIDE_TO_MOVE = PIECES * SQUARES, CASTLING_WHITE_KINGSIDE = SIDE_TO_MOVE + 1, CASTLING_WHITE_QUEENSIDE = CASTLING_WHITE_KINGSIDE + 1, CASTLING_BLACK_KINGSIDE = CASTLING_WHITE_QUEENSIDE + 1, CASTLING_BLACK_QUEENSIDE = CASTLING_BLACK_KINGSIDE + 1, EN_PASSANT_START = CASTLING_BLACK_QUEENSIDE + 1 };src/board.h (1)
380-384: Enhance documentation for isDraw method.The documentation should specify which types of draws are checked (e.g., threefold repetition, fifty-move rule, insufficient material) and which are not.
src/board.cpp (2)
31-51: Consider defining the Zobrist array size as a constant.The magic number 781 should be defined as a named constant for better maintainability. This makes it easier to understand the purpose of the array size and modify it if needed.
namespace Zagreus { +constexpr size_t ZOBRIST_ARRAY_SIZE = 781; // Document why this specific size is used -static uint64_t zobristConstants[781]{}; +static uint64_t zobristConstants[ZOBRIST_ARRAY_SIZE]{};
202-205: Implement the isDraw method.The method is currently a placeholder. It should check for:
- Threefold repetition
- Fifty-move rule
- Insufficient material
- Stalemate
Would you like me to help implement this method or create an issue to track this task?
src/pcg_extras.hpp (3)
294-303: Use standard library functions for bit rotations.C++20 introduces
std::rotlandstd::rotrin the<bit>header, providing standardized and possibly optimized implementations for bit rotations. Using these can enhance portability and maintainability.Replace custom rotation functions with standard library equivalents:
+#include <bit> -template <typename itype> -inline itype rotl(itype value, bitcount_t rot) { - constexpr bitcount_t bits = sizeof(itype) * 8; - constexpr bitcount_t mask = bits - 1; - return (value << rot) | (value >> ((- rot) & mask)); -} +using std::rotl; -template <typename itype> -inline itype rotr(itype value, bitcount_t rot) { - constexpr bitcount_t bits = sizeof(itype) * 8; - constexpr bitcount_t mask = bits - 1; - return (value >> rot) | (value << ((- rot) & mask)); -} +using std::rotr;
38-50: Remove duplicate#include <utility>directive.The header
<utility>is included twice. Eliminating the duplicate include improves code clarity and avoids unnecessary redundancy.Apply this diff to remove the duplicate:
#include <type_traits> #include <utility> #include <locale> #include <iterator> -#include <utility>
294-316: Ensure macroPCG_USE_ZEROCHECK_ROTATE_IDIOMis defined appropriately.The macros within the
rotlandrotrfunctions depend onPCG_USE_ZEROCHECK_ROTATE_IDIOM. If this macro is not defined, the fallback implementation is used. To avoid potential issues or unintended behavior, confirm that this macro is defined as needed or provide a default definition.Consider adding a default definition or documentation to clarify the usage:
+#ifndef PCG_USE_ZEROCHECK_ROTATE_IDIOM +#define PCG_USE_ZEROCHECK_ROTATE_IDIOM 0 +#endifsrc/pcg_random.hpp (3)
184-189: Deleteset_streamfunction instead of defining it withabort()In the
unique_streamclass, theset_streamfunction is intended never to be called. Instead of providing an implementation that callsabort(), consider deleting the function to prevent any accidental usage at compile time.Apply this diff to delete the function:
- void set_stream(...) - { - abort(); - } + void set_stream(...) = delete;
225-228: Deleteset_streamfunction instead of defining it withabort()Similarly, in the
no_streamclass, theset_streamfunction should be deleted to prevent unintended calls that could lead to abrupt termination of the program.Apply this diff to delete the function:
- void set_stream(...) - { - abort(); - } + void set_stream(...) = delete;
668-679: Avoid throwing exceptions in theoperator-functionIn the
operator-overload, throwing astd::logic_errorexception may not be ideal in performance-critical or embedded environments where exceptions are discouraged or not used. Consider an alternative approach, such as returning a sentinel value, using assertions, or documenting that preconditions must be met.
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
📒 Files selected for processing (6)
src/board.cpp(1 hunks)src/board.h(1 hunks)src/constants.h(2 hunks)src/pcg_extras.hpp(1 hunks)src/pcg_random.hpp(1 hunks)src/uci.cpp(1 hunks)
🧰 Additional context used
📓 Path-based instructions (4)
src/board.cpp (1)
Pattern **/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/board.h (1)
Pattern **/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/constants.h (1)
Pattern **/*.h: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
src/uci.cpp (1)
Pattern **/*.cpp: This code is written for a chess engine. Performance should be prioritized over readability or maintainability when reasonable.
📓 Learnings (1)
src/uci.cpp (2)
Learnt from: Dannyj1
PR: Dannyj1/Zagreus#82
File: src/uci.cpp:110-179
Timestamp: 2024-10-14T07:26:06.778Z
Learning: In future code reviews, avoid suggesting changes to `uci.cpp` and `uci.h` unless they are critical or blockers.
Learnt from: Dannyj1
PR: Dannyj1/Zagreus#82
File: src/uci.cpp:394-430
Timestamp: 2024-10-11T16:04:05.283Z
Learning: In `src/uci.cpp`, performance optimizations are unnecessary.
🪛 cppcheck
src/uci.cpp
[performance] 467-467: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 475-475: Function parameter 'value' should be passed by const reference.
(passedByValue)
[performance] 524-524: Function parameter 'values' should be passed by const reference.
(passedByValue)
🔇 Additional comments (13)
src/constants.h (4)
28-31: LGTM! File mask constants are correctly defined.
The bitboard masks for file exclusions are properly implemented using 64-bit constants with correct bit patterns.
52-56: LGTM! Good use of uint8_t for small constants.
The change to uint8_t is appropriate for these small positive values and improves type safety.
42-50:
Add ULL suffix to black queenside constants.
The black queenside constants are missing the ULL suffix, which could cause issues on some platforms.
-static constexpr uint64_t BLACK_QUEENSIDE_CASTLE_PATH = 0xC00000000000000ULL;
+static constexpr uint64_t BLACK_QUEENSIDE_CASTLE_PATH = 0xC00000000000000ULL;
-static constexpr uint64_t BLACK_QUEENSIDE_CASTLE_UNOCCUPIED = 0xE00000000000000ULL;
+static constexpr uint64_t BLACK_QUEENSIDE_CASTLE_UNOCCUPIED = 0xE00000000000000ULL;Likely invalid or redundant comment.
58-59: Verify the impact of increased MATE_SCORE.
The MATE_SCORE has been significantly increased from 20000 to 100000. This change might affect score comparisons in the evaluation logic.
✅ Verification successful
Let me search for more specific patterns related to score comparisons and mate score usage.
Let me try one more search to find any score-related arithmetic or comparisons that might be impacted.
MATE_SCORE change appears safe to use
The increased MATE_SCORE is used correctly in the codebase:
- In search.cpp, it's used with proper ply adjustment:
-MATE_SCORE + board.getPly() - No hard-coded score comparisons were found that could be affected by the increase
- The change provides a larger range for evaluation scores without breaking existing logic
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Description: Check for potential impacts of the MATE_SCORE change
# Search for score comparisons that might be affected
rg -A 2 "(>|<|>=|<=)\s*[-+]?[0-9]{4,5}" --type cpp
Length of output: 635
Script:
#!/bin/bash
# Search for MATE_SCORE usage and score comparisons in evaluation logic
rg "MATE_SCORE|mate.*score" --type cpp -A 2
# Search for specific evaluation-related score comparisons
rg "(score|eval|value)\s*(>|<|>=|<=)\s*[-+]?[0-9]" --type cpp -A 2
Length of output: 404
Script:
#!/bin/bash
# Search for arithmetic operations with scores and alpha-beta bounds
rg "(alpha|beta|score|eval)\s*[+\-*/]=?\s*[-+]?[0-9]|[+\-*/]\s*MATE_SCORE" --type cpp -A 2
# Look for function definitions related to evaluation
ast-grep --pattern 'int $_($$) {
$$$
}'
Length of output: 463
src/board.h (4)
1-35: LGTM: Well-organized includes and complete license header.
The includes are properly organized with standard library headers first, followed by project-specific headers.
47-56: LGTM: Well-designed BoardState struct with optimal memory layout.
The struct efficiently packs its members and provides appropriate default values.
205-219: Verify consistent usage of templated vs non-templated piece manipulation methods.
The class provides both templated and non-templated versions of setPiece and removePiece. Let's verify that they are used consistently throughout the codebase.
#!/bin/bash
# Description: Check usage patterns of piece manipulation methods
# Look for both templated and non-templated method calls
echo "Checking templated setPiece usage:"
ast-grep --pattern 'setPiece<$_>($_)'
echo "Checking non-templated setPiece usage:"
ast-grep --pattern 'setPiece($_,$_)'
echo "Checking templated removePiece usage:"
ast-grep --pattern 'removePiece<$_>($_)'
echo "Checking non-templated removePiece usage:"
ast-grep --pattern 'removePiece($_,$_)'Also applies to: 265-279
42-45: Add bounds checking for the Zobrist index parameter.
The getZobristConstant function should validate that the index is within the valid range for Zobrist constants.
src/uci.cpp (1)
386-390:
Fix potential resource exhaustion from unbounded thread creation
Creating a new detached thread for each input line without any limit could exhaust system resources and cause instability.
Consider one of these alternatives:
- Process commands synchronously in the main thread
- Use a fixed-size thread pool
- Implement a command queue with a single worker thread
Example implementation with a single worker thread:
- while (std::getline(std::cin, line)) {
- std::thread processThread{&Engine::processLine, this, line};
- processThread.detach();
- }
+ std::queue<std::string> commandQueue;
+ std::mutex queueMutex;
+ std::condition_variable queueCV;
+ std::atomic<bool> running{true};
+
+ // Start worker thread
+ std::thread worker([&]() {
+ while (running) {
+ std::string cmd;
+ {
+ std::unique_lock<std::mutex> lock(queueMutex);
+ queueCV.wait(lock, [&]{ return !commandQueue.empty() || !running; });
+ if (!running) break;
+ cmd = std::move(commandQueue.front());
+ commandQueue.pop();
+ }
+ processLine(cmd);
+ }
+ });
+
+ // Read commands
+ while (std::getline(std::cin, line)) {
+ {
+ std::lock_guard<std::mutex> lock(queueMutex);
+ commandQueue.push(std::move(line));
+ }
+ queueCV.notify_one();
+ }
+
+ // Cleanup
+ running = false;
+ queueCV.notify_one();
+ worker.join();Likely invalid or redundant comment.
src/board.cpp (1)
110-135: LGTM! Efficient castling validation implementation.
The template-based implementation with compile-time path selection is performance-oriented, aligning well with the coding guidelines prioritizing performance.
src/pcg_extras.hpp (1)
381-436: Verify correctness of uneven_copy implementations.
The uneven_copy_impl functions handle copying between integer types of different sizes. It's crucial to ensure that all edge cases, especially when sizes are not multiples of each other, are correctly managed to prevent data corruption or unexpected behavior.
Run the following script to review all uses of uneven_copy and confirm correctness:
This will help identify all instances where uneven_copy is used and allow for detailed inspection.
✅ Verification successful
The previous search might have been too restrictive. Let's broaden our search to find all references to uneven_copy and its implementation details to verify its correctness.
Implementation of uneven_copy appears correct and well-designed
The code analysis reveals that uneven_copy is a well-structured implementation with:
- Two specialized implementations (
uneven_copy_impl) handling both cases where destination integers are smaller or larger than source - Proper template metaprogramming to select the correct implementation at compile time
- Correct bit manipulation and size calculations for both cases
- Usage within the
generate_tofunction for seeding random number generators, which is a valid use case
Key points of correctness:
- For smaller destinations: Proper bit shifting and truncation
- For larger destinations: Correct accumulation of multiple source values
- Endian-independent implementation as noted in the documentation
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash
# Description: Find all calls to `uneven_copy` and examine their usage.
# Search for `uneven_copy` function calls in the codebase.
rg 'uneven_copy\s*<' -A 3
Length of output: 27
Script:
#!/bin/bash
# Let's try a broader search for uneven_copy without template syntax
rg "uneven_copy" -A 5
# Also search for the function declaration
ast-grep --pattern 'template<$_> $_* uneven_copy$_($$$)'
# Let's also check if there are any tests for this functionality
rg -i "test.*uneven.*copy|uneven.*copy.*test" -A 5
Length of output: 3157
src/pcg_random.hpp (2)
1-23: Verify license compatibility and ensure proper attribution
The header comments indicate that this code is licensed under the Apache License, Version 2.0, and is copyrighted by Melissa O'Neill. Please verify that integrating this code complies with the project's licensing policies and that any required attribution is appropriately handled.
641-662: Verify correctness and potential overflow in advance and distance methods
The advance and distance methods involve complex arithmetic operations that compute the next state of the generator. Ensure that these methods correctly handle all edge cases, particularly regarding integer overflows and underflows, and that they conform to the PCG algorithm's specifications.
| const Move move = getMoveFromMoveNotation(arg); | ||
| board.makeMove(move); | ||
| } |
There was a problem hiding this comment.
Add move validation before applying moves
The function applies moves without validating them, which could lead to corrupted game state or crashes if invalid moves are provided.
Apply this diff to add move validation:
const Move move = getMoveFromMoveNotation(arg);
+ if (!board.isLegalMove(move)) {
+ sendMessage("ERROR: Invalid move provided: " + arg);
+ return;
+ }
board.makeMove(move);📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| const Move move = getMoveFromMoveNotation(arg); | |
| board.makeMove(move); | |
| } | |
| const Move move = getMoveFromMoveNotation(arg); | |
| if (!board.isLegalMove(move)) { | |
| sendMessage("ERROR: Invalid move provided: " + arg); | |
| return; | |
| } | |
| board.makeMove(move); |
| } | ||
|
|
||
| const int8_t file = tolower(character) - 'a'; | ||
| const int8_t rank = (!sideToMove) == WHITE ? 2 : 5; |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Simplify the rank calculation logic.
The current expression (!sideToMove) == WHITE ? 2 : 5 is confusing and could be simplified.
- const int8_t rank = (!sideToMove) == WHITE ? 2 : 5;
+ const int8_t rank = sideToMove == WHITE ? 5 : 2;📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| const int8_t rank = (!sideToMove) == WHITE ? 2 : 5; | |
| const int8_t rank = sideToMove == WHITE ? 5 : 2; |
src/board.cpp
Outdated
| void Board::unmakeMove() { | ||
| ply--; | ||
| assert(ply >= 0 && ply < MAX_PLY); | ||
| const auto& [zobristHash, move, capturedPiece, enPassantSquare, castlingRights] = history[ply]; | ||
| const uint8_t fromSquare = getFromSquare(move); | ||
| const uint8_t toSquare = getToSquare(move); | ||
| const MoveType moveType = getMoveType(move); | ||
| Piece movedPiece = getPieceOnSquare(toSquare); | ||
|
|
||
| removePiece(movedPiece, toSquare); | ||
|
|
||
| if (moveType == PROMOTION) { | ||
| const PieceColor color = getPieceColor(movedPiece); | ||
| movedPiece = static_cast<Piece>(WHITE_PAWN + color); | ||
| } | ||
|
|
||
| setPiece(movedPiece, fromSquare); | ||
|
|
||
| if (capturedPiece != EMPTY) { | ||
| setPiece(capturedPiece, toSquare); | ||
| } | ||
|
|
||
| if (moveType == EN_PASSANT) { | ||
| const PieceColor movedPieceColor = getPieceColor(movedPiece); | ||
|
|
||
| if (movedPieceColor == WHITE) { | ||
| setPiece(BLACK_PAWN, toSquare + SOUTH); | ||
| } else { | ||
| setPiece(WHITE_PAWN, toSquare + NORTH); | ||
| } | ||
| } | ||
|
|
||
| if (moveType == CASTLING) { | ||
| if (toSquare == G1) { | ||
| removePiece(WHITE_ROOK, F1); | ||
| setPiece(WHITE_ROOK, H1); | ||
| } else if (toSquare == C1) { | ||
| removePiece(WHITE_ROOK, D1); | ||
| setPiece(WHITE_ROOK, A1); | ||
| } else if (toSquare == G8) { | ||
| removePiece(BLACK_ROOK, F8); | ||
| setPiece(BLACK_ROOK, H8); | ||
| } else if (toSquare == C8) { | ||
| removePiece(BLACK_ROOK, D8); | ||
| setPiece(BLACK_ROOK, A8); | ||
| } | ||
| } | ||
|
|
||
| this->sideToMove = !sideToMove; | ||
| this->enPassantSquare = enPassantSquare; | ||
| this->castlingRights = castlingRights; | ||
| this->zobristHash = zobristHash; | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Add validation for move history access.
The unmakeMove method should validate that there is a move to undo before accessing the history array.
void Board::unmakeMove() {
+ if (ply <= 0) {
+ // Consider throwing an exception or handling this case
+ return;
+ }
ply--;Committable suggestion skipped: line range outside the PR's diff.
src/board.cpp
Outdated
| setPiece(WHITE_ROOK, F1); | ||
| } else if (toSquare == C1) { | ||
| removePiece(WHITE_ROOK, A1); | ||
| setPiece(WHITE_ROOK, D1); | ||
| } else if (toSquare == G8) { | ||
| removePiece(BLACK_ROOK, H8); | ||
| setPiece(BLACK_ROOK, F8); | ||
| } else if (toSquare == C8) { | ||
| removePiece(BLACK_ROOK, A8); | ||
| setPiece(BLACK_ROOK, D8); | ||
| } | ||
|
|
||
| if (sideToMove == WHITE) { | ||
| if (castlingRights & WHITE_KINGSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | ||
| } | ||
|
|
||
| if (castlingRights & WHITE_QUEENSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | ||
| } | ||
|
|
||
| castlingRights &= ~WHITE_CASTLING; | ||
| } else { | ||
| if (castlingRights & BLACK_KINGSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | ||
| } | ||
|
|
||
| if (castlingRights & BLACK_QUEENSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | ||
| } | ||
|
|
||
| castlingRights &= ~BLACK_CASTLING; | ||
| } | ||
| } | ||
|
|
||
| if (movedPiece == WHITE_KING) { | ||
| if (castlingRights & WHITE_KINGSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | ||
| } | ||
|
|
||
| if (castlingRights & WHITE_QUEENSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | ||
| } | ||
|
|
||
| castlingRights &= ~WHITE_CASTLING; | ||
| } else if (movedPiece == BLACK_KING) { | ||
| if (castlingRights & BLACK_KINGSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | ||
| } | ||
|
|
||
| if (castlingRights & BLACK_QUEENSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | ||
| } | ||
|
|
||
| castlingRights &= ~BLACK_CASTLING; | ||
| } else if (movedPiece == WHITE_ROOK) { | ||
| if (fromSquare == A1) { | ||
| if (castlingRights & WHITE_QUEENSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | ||
| castlingRights &= ~WHITE_QUEENSIDE; | ||
| } | ||
| } else if (fromSquare == H1) { | ||
| if (castlingRights & WHITE_KINGSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | ||
| castlingRights &= ~WHITE_KINGSIDE; | ||
| } | ||
| } | ||
| } else if (movedPiece == BLACK_ROOK) { | ||
| if (fromSquare == A8) { | ||
| if (castlingRights & BLACK_QUEENSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | ||
| castlingRights &= ~BLACK_QUEENSIDE; | ||
| } | ||
| } else if (fromSquare == H8) { | ||
| if (castlingRights & BLACK_KINGSIDE) { | ||
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | ||
| castlingRights &= ~BLACK_KINGSIDE; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| if (movedPieceType == PAWN) { | ||
| if ((fromSquare ^ toSquare) == 16) { | ||
| if (sideToMove == WHITE) { | ||
| enPassantSquare = toSquare + SOUTH; | ||
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | ||
| } else { | ||
| enPassantSquare = toSquare + NORTH; | ||
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | ||
| } | ||
| } | ||
| } | ||
|
|
||
| sideToMove = !sideToMove; | ||
| zobristHash ^= getZobristConstant(ZOBRIST_SIDE_TO_MOVE_INDEX); | ||
|
|
||
| assert(ply >= 0 && ply < MAX_PLY); | ||
| ply++; | ||
| assert(ply >= 0 && ply < MAX_PLY); | ||
| } |
There was a problem hiding this comment.
🛠️ Refactor suggestion
Add bounds checking for move coordinates.
The makeMove method should validate that fromSquare and toSquare are within the valid range (0-63) to prevent undefined behavior.
void Board::makeMove(const Move& move) {
const uint8_t fromSquare = getFromSquare(move);
const uint8_t toSquare = getToSquare(move);
+ assert(fromSquare < SQUARES && "From square out of bounds");
+ assert(toSquare < SQUARES && "To square out of bounds");📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| void Board::makeMove(const Move& move) { | |
| const uint8_t fromSquare = getFromSquare(move); | |
| const uint8_t toSquare = getToSquare(move); | |
| const MoveType moveType = getMoveType(move); | |
| Piece movedPiece = getPieceOnSquare(fromSquare); | |
| const PieceType movedPieceType = getPieceType(movedPiece); | |
| const Piece capturedPiece = getPieceOnSquare(toSquare); | |
| history[ply].move = move; | |
| history[ply].capturedPiece = capturedPiece; | |
| history[ply].enPassantSquare = enPassantSquare; | |
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | |
| enPassantSquare = 0; | |
| history[ply].castlingRights = castlingRights; | |
| history[ply].zobristHash = zobristHash; | |
| if (capturedPiece != EMPTY) { | |
| removePiece(capturedPiece, toSquare); | |
| if (capturedPiece == WHITE_ROOK) { | |
| if (toSquare == A1) { | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| castlingRights &= ~WHITE_QUEENSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| } | |
| } else if (toSquare == H1) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| castlingRights &= ~WHITE_KINGSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| } | |
| } | |
| } else if (capturedPiece == BLACK_ROOK) { | |
| if (toSquare == A8) { | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| castlingRights &= ~BLACK_QUEENSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| } | |
| } else if (toSquare == H8) { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| castlingRights &= ~BLACK_KINGSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| } | |
| } | |
| } | |
| } | |
| removePiece(movedPiece, fromSquare); | |
| if (moveType == PROMOTION) { | |
| const PieceColor color = getPieceColor(movedPiece); | |
| const PromotionPiece promotionPieceType = getPromotionPiece(move); | |
| const Piece promotionPiece = getPieceFromPromotionPiece(promotionPieceType, color); | |
| setPiece(promotionPiece, toSquare); | |
| } else { | |
| setPiece(movedPiece, toSquare); | |
| } | |
| if (moveType == EN_PASSANT) { | |
| if (sideToMove == WHITE) { | |
| removePiece(BLACK_PAWN, toSquare + SOUTH); | |
| } else { | |
| removePiece(WHITE_PAWN, toSquare + NORTH); | |
| } | |
| } else if (moveType == CASTLING) { | |
| if (toSquare == G1) { | |
| removePiece(WHITE_ROOK, H1); | |
| setPiece(WHITE_ROOK, F1); | |
| } else if (toSquare == C1) { | |
| removePiece(WHITE_ROOK, A1); | |
| setPiece(WHITE_ROOK, D1); | |
| } else if (toSquare == G8) { | |
| removePiece(BLACK_ROOK, H8); | |
| setPiece(BLACK_ROOK, F8); | |
| } else if (toSquare == C8) { | |
| removePiece(BLACK_ROOK, A8); | |
| setPiece(BLACK_ROOK, D8); | |
| } | |
| if (sideToMove == WHITE) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~WHITE_CASTLING; | |
| } else { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~BLACK_CASTLING; | |
| } | |
| } | |
| if (movedPiece == WHITE_KING) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~WHITE_CASTLING; | |
| } else if (movedPiece == BLACK_KING) { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~BLACK_CASTLING; | |
| } else if (movedPiece == WHITE_ROOK) { | |
| if (fromSquare == A1) { | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| castlingRights &= ~WHITE_QUEENSIDE; | |
| } | |
| } else if (fromSquare == H1) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| castlingRights &= ~WHITE_KINGSIDE; | |
| } | |
| } | |
| } else if (movedPiece == BLACK_ROOK) { | |
| if (fromSquare == A8) { | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| castlingRights &= ~BLACK_QUEENSIDE; | |
| } | |
| } else if (fromSquare == H8) { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| castlingRights &= ~BLACK_KINGSIDE; | |
| } | |
| } | |
| } | |
| if (movedPieceType == PAWN) { | |
| if ((fromSquare ^ toSquare) == 16) { | |
| if (sideToMove == WHITE) { | |
| enPassantSquare = toSquare + SOUTH; | |
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | |
| } else { | |
| enPassantSquare = toSquare + NORTH; | |
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | |
| } | |
| } | |
| } | |
| sideToMove = !sideToMove; | |
| zobristHash ^= getZobristConstant(ZOBRIST_SIDE_TO_MOVE_INDEX); | |
| assert(ply >= 0 && ply < MAX_PLY); | |
| ply++; | |
| assert(ply >= 0 && ply < MAX_PLY); | |
| } | |
| void Board::makeMove(const Move& move) { | |
| const uint8_t fromSquare = getFromSquare(move); | |
| const uint8_t toSquare = getToSquare(move); | |
| assert(fromSquare < SQUARES && "From square out of bounds"); | |
| assert(toSquare < SQUARES && "To square out of bounds"); | |
| const MoveType moveType = getMoveType(move); | |
| Piece movedPiece = getPieceOnSquare(fromSquare); | |
| const PieceType movedPieceType = getPieceType(movedPiece); | |
| const Piece capturedPiece = getPieceOnSquare(toSquare); | |
| history[ply].move = move; | |
| history[ply].capturedPiece = capturedPiece; | |
| history[ply].enPassantSquare = enPassantSquare; | |
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | |
| enPassantSquare = 0; | |
| history[ply].castlingRights = castlingRights; | |
| history[ply].zobristHash = zobristHash; | |
| if (capturedPiece != EMPTY) { | |
| removePiece(capturedPiece, toSquare); | |
| if (capturedPiece == WHITE_ROOK) { | |
| if (toSquare == A1) { | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| castlingRights &= ~WHITE_QUEENSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| } | |
| } else if (toSquare == H1) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| castlingRights &= ~WHITE_KINGSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| } | |
| } | |
| } else if (capturedPiece == BLACK_ROOK) { | |
| if (toSquare == A8) { | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| castlingRights &= ~BLACK_QUEENSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| } | |
| } else if (toSquare == H8) { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| castlingRights &= ~BLACK_KINGSIDE; | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| } | |
| } | |
| } | |
| } | |
| removePiece(movedPiece, fromSquare); | |
| if (moveType == PROMOTION) { | |
| const PieceColor color = getPieceColor(movedPiece); | |
| const PromotionPiece promotionPieceType = getPromotionPiece(move); | |
| const Piece promotionPiece = getPieceFromPromotionPiece(promotionPieceType, color); | |
| setPiece(promotionPiece, toSquare); | |
| } else { | |
| setPiece(movedPiece, toSquare); | |
| } | |
| if (moveType == EN_PASSANT) { | |
| if (sideToMove == WHITE) { | |
| removePiece(BLACK_PAWN, toSquare + SOUTH); | |
| } else { | |
| removePiece(WHITE_PAWN, toSquare + NORTH); | |
| } | |
| } else if (moveType == CASTLING) { | |
| if (toSquare == G1) { | |
| removePiece(WHITE_ROOK, H1); | |
| setPiece(WHITE_ROOK, F1); | |
| } else if (toSquare == C1) { | |
| removePiece(WHITE_ROOK, A1); | |
| setPiece(WHITE_ROOK, D1); | |
| } else if (toSquare == G8) { | |
| removePiece(BLACK_ROOK, H8); | |
| setPiece(BLACK_ROOK, F8); | |
| } else if (toSquare == C8) { | |
| removePiece(BLACK_ROOK, A8); | |
| setPiece(BLACK_ROOK, D8); | |
| } | |
| if (sideToMove == WHITE) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~WHITE_CASTLING; | |
| } else { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~BLACK_CASTLING; | |
| } | |
| } | |
| if (movedPiece == WHITE_KING) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~WHITE_CASTLING; | |
| } else if (movedPiece == BLACK_KING) { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| } | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| } | |
| castlingRights &= ~BLACK_CASTLING; | |
| } else if (movedPiece == WHITE_ROOK) { | |
| if (fromSquare == A1) { | |
| if (castlingRights & WHITE_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_QUEENSIDE_INDEX); | |
| castlingRights &= ~WHITE_QUEENSIDE; | |
| } | |
| } else if (fromSquare == H1) { | |
| if (castlingRights & WHITE_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_WHITE_KINGSIDE_INDEX); | |
| castlingRights &= ~WHITE_KINGSIDE; | |
| } | |
| } | |
| } else if (movedPiece == BLACK_ROOK) { | |
| if (fromSquare == A8) { | |
| if (castlingRights & BLACK_QUEENSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_QUEENSIDE_INDEX); | |
| castlingRights &= ~BLACK_QUEENSIDE; | |
| } | |
| } else if (fromSquare == H8) { | |
| if (castlingRights & BLACK_KINGSIDE) { | |
| zobristHash ^= getZobristConstant(ZOBRIST_CASTLING_BLACK_KINGSIDE_INDEX); | |
| castlingRights &= ~BLACK_KINGSIDE; | |
| } | |
| } | |
| } | |
| if (movedPieceType == PAWN) { | |
| if ((fromSquare ^ toSquare) == 16) { | |
| if (sideToMove == WHITE) { | |
| enPassantSquare = toSquare + SOUTH; | |
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | |
| } else { | |
| enPassantSquare = toSquare + NORTH; | |
| zobristHash ^= getZobristConstant(ZOBRIST_EN_PASSANT_START_INDEX + (enPassantSquare % 8)); | |
| } | |
| } | |
| } | |
| sideToMove = !sideToMove; | |
| zobristHash ^= getZobristConstant(ZOBRIST_SIDE_TO_MOVE_INDEX); | |
| assert(ply >= 0 && ply < MAX_PLY); | |
| ply++; | |
| assert(ply >= 0 && ply < MAX_PLY); | |
| } |
| value = ~0U; | ||
| } | ||
| target = uint8_t(value); |
There was a problem hiding this comment.
Handle overflow correctly when reading uint8_t.
When the input value exceeds the maximum value of uint8_t, the function sets the failbit but still assigns ~0U to value. This could lead to unexpected behavior when casting to uint8_t. It's better to avoid assigning a value when an overflow occurs since the failbit already indicates the error.
Apply this diff to prevent incorrect assignments on overflow:
if (value > uint8_t(~0)) {
in.setstate(std::ios::failbit);
- value = ~0U;
}
target = uint8_t(value);📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| value = ~0U; | |
| } | |
| target = uint8_t(value); | |
| if (value > uint8_t(~0)) { | |
| in.setstate(std::ios::failbit); | |
| } | |
| target = uint8_t(value); |
| operator>>(std::basic_istream<CharT,Traits>& in, uint8_t target) | ||
| { | ||
| uint32_t value = 0xdecea5edU; | ||
| in >> value; | ||
| if (!in && value == 0xdecea5edU) | ||
| return in; | ||
| if (value > uint8_t(~0)) { | ||
| in.setstate(std::ios::failbit); | ||
| value = ~0U; | ||
| } | ||
| target = uint8_t(value); | ||
| return in; | ||
| } |
There was a problem hiding this comment.
Correct parameter passing in operator>> for uint8_t.
The operator>> function for uint8_t takes the target parameter by value, which means any modifications to target within the function won't affect the variable provided by the caller. To ensure the extracted value is correctly assigned, target should be passed by reference.
Apply this diff to fix the parameter passing:
template <typename CharT, typename Traits>
std::basic_istream<CharT,Traits>&
-operator>>(std::basic_istream<CharT,Traits>& in, uint8_t target)
+operator>>(std::basic_istream<CharT,Traits>& in, uint8_t& target)
{
uint32_t value = 0xdecea5edU;
in >> value;📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| operator>>(std::basic_istream<CharT,Traits>& in, uint8_t target) | |
| { | |
| uint32_t value = 0xdecea5edU; | |
| in >> value; | |
| if (!in && value == 0xdecea5edU) | |
| return in; | |
| if (value > uint8_t(~0)) { | |
| in.setstate(std::ios::failbit); | |
| value = ~0U; | |
| } | |
| target = uint8_t(value); | |
| return in; | |
| } | |
| operator>>(std::basic_istream<CharT,Traits>& in, uint8_t& target) | |
| { | |
| uint32_t value = 0xdecea5edU; | |
| in >> value; | |
| if (!in && value == 0xdecea5edU) | |
| return in; | |
| if (value > uint8_t(~0)) { | |
| in.setstate(std::ios::failbit); | |
| value = ~0U; | |
| } | |
| target = uint8_t(value); | |
| return in; | |
| } |
|
@coderabbitai pause |
✅ Actions performedReviews paused. |
The whole engine is being rewritten from scratch, so this PR will be a draft for a while. This is not going to be ready to merge for a long time.
The goal of this PR is to make it easy to follow the development of the rewrite and to actively run CI tools on the codebase.