📝 Fix comments on RLP encoding scheme (#301)

* ✍️ correct comment on RLP encoding scheme

* corrected comments

* adjust comment on max account nonce

* Update src/utils/LibRLP.sol

* Update src/utils/LibRLP.sol

* Update src/utils/LibRLP.sol

* Update src/utils/LibRLP.sol

---------

Co-authored-by: t11s <[email protected]>

src/utils/LibRLP.sol

@@ -10,21 +10,26 @@ library LibRLP {
 
     // prettier-ignore
     function computeAddress(address deployer, uint256 nonce) internal pure returns (address) {
+        // The theoretical allowed limit, based on EIP-2681, for an account nonce is 2**64-2: https://eips.ethereum.org/EIPS/eip-2681.
+        // However, we assume nobody can have a nonce large enough to require more than 4 bytes.
+        // Thus, no specific check is built-in to save deployment costs.
+
         // The integer zero is treated as an empty byte string, and as a result it only has a length prefix, 0x80, computed via 0x80 + 0.
-        // A one byte integer uses its own value as its length prefix, there is no additional "0x80 + length" prefix that comes before it.
         if (nonce == 0x00)             return keccak256(abi.encodePacked(bytes1(0xd6), bytes1(0x94), deployer, bytes1(0x80))).fromLast20Bytes();
+
+        // A one-byte integer in the [0x00, 0x7f] range uses its own value as a length prefix, there is no additional "0x80 + length" prefix that precedes it.
         if (nonce <= 0x7f)             return keccak256(abi.encodePacked(bytes1(0xd6), bytes1(0x94), deployer, uint8(nonce))).fromLast20Bytes();
 
-        // Nonces greater than 1 byte all follow a consistent encoding scheme, where each value is preceded by a prefix of 0x80 + length.
+        // In the case of nonce > 0x7f and nonce <= type(uint8).max, we have the following
+        // encoding scheme (the same calculation can be carried over for higher nonce bytes):
+        // 0xda = 0xc0 (short RLP prefix) + 0x1a (= the bytes length of: 0x94 + address + 0x84 + nonce, in hex),
+        // 0x94 = 0x80 + 0x14 (= the bytes length of an address, 20 bytes, in hex),
+        // 0x84 = 0x80 + 0x04 (= the bytes length of the nonce, 4 bytes, in hex).
         if (nonce <= type(uint8).max)  return keccak256(abi.encodePacked(bytes1(0xd7), bytes1(0x94), deployer, bytes1(0x81), uint8(nonce))).fromLast20Bytes();
         if (nonce <= type(uint16).max) return keccak256(abi.encodePacked(bytes1(0xd8), bytes1(0x94), deployer, bytes1(0x82), uint16(nonce))).fromLast20Bytes();
         if (nonce <= type(uint24).max) return keccak256(abi.encodePacked(bytes1(0xd9), bytes1(0x94), deployer, bytes1(0x83), uint24(nonce))).fromLast20Bytes();
 
-        // More details about RLP encoding can be found here: https://eth.wiki/fundamentals/rlp
-        // 0xda = 0xc0 (short RLP prefix) + 0x16 (length of: 0x94 ++ proxy ++ 0x84 ++ nonce)
-        // 0x94 = 0x80 + 0x14 (0x14 = the length of an address, 20 bytes, in hex)
-        // 0x84 = 0x80 + 0x04 (0x04 = the bytes length of the nonce, 4 bytes, in hex)
-        // We assume nobody can have a nonce large enough to require more than 32 bytes.
+        // Case for nonce > uint24 and nonce <= type(uint32).max.
         return keccak256(abi.encodePacked(bytes1(0xda), bytes1(0x94), deployer, bytes1(0x84), uint32(nonce))).fromLast20Bytes();
     }
 }