Add initial support for deflate64 zip files

guzba · Aug 6, 2024 · 05d584f · 05d584f
1 parent 687f03f
commit 05d584f
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Showing 4 changed files with 34 additions and 7 deletions.
diff --git a/src/zippy/internal.nim b/src/zippy/internal.nim
@@ -9,7 +9,7 @@ const allowSimd* =
 const
   maxCodeLength* = 15
   maxLitLenCodes* = 286
-  maxDistanceCodes* = 30
+  maxDistanceCodes* = 32
   maxFixedLitLenCodes* = 288
   maxWindowSize* = 32768
   maxUncompressedBlockSize* = 65535
@@ -86,7 +86,8 @@ const
     2049, 3073, # 22-23
     4097, 6145, # 24-25
     8193, 12289, # 26-27
-    16385, 24577 # 28-29
+    16385, 24577, # 28-29
+    32769, 49153, # 30-31
   ]
 
   baseDistanceExtraBits* = [
@@ -103,7 +104,8 @@ const
     10, 10, # 22-23
     11, 11, # 24-25
     12, 12, # 26-27
-    13, 13 # 28-29
+    13, 13, # 28-29
+    14, 14, # 30-31
   ]
 
   clclOrder* = [

diff --git a/src/zippy/ziparchives.nim b/src/zippy/ziparchives.nim
@@ -11,6 +11,9 @@ const
   zip64EndOfCentralDirectorySignature = 0x06064b50.uint32
   zip64EndOfCentralDirectoryLocatorSignature = 0x07064b50.uint32
   zip64ExtraFieldId = 1.uint16
+  NoneCompression = 0.uint16
+  DeflateCompression = 8.uint16
+  Deflate64Compression = 9.uint16
 
 type
   ZipArchiveRecordKind = enum
@@ -78,11 +81,11 @@ proc extractFile*(
 
   case record.kind:
   of FileRecord:
-    if compressionMethod == 0: # No compression
+    if compressionMethod == NoneCompression: # No compression
       if record.compressedSize > 0:
         result.setLen(record.compressedSize)
         copyMem(result[0].addr, src[pos].addr, record.compressedSize)
-    elif compressionMethod == 8: # Deflate
+    elif compressionMethod in [DeflateCompression, Deflate64Compression]:
       result = uncompress(src[pos].addr, record.compressedSize, dfDeflate)
     else:
       raise newException(ZippyError, "Unsupported archive, compression method")
@@ -293,7 +296,7 @@ proc openZipArchive*(
         # internalFileAttr = read16(src, pos + 36)
         externalFileAttr = read32(src, pos + 38)
 
-      if compressionMethod notin [0.uint16, 8]:
+      if compressionMethod notin [NoneCompression, DeflateCompression, Deflate64Compression]:
         raise newException(ZippyError, "Unsupported archive, compression method")
 
       if fileDiskNumber != 0:

diff --git a/tests/data/ziparchives/deflate64test.zip b/tests/data/ziparchives/deflate64test.zip
diff --git a/tests/test_ziparchives_read.nim b/tests/test_ziparchives_read.nim
@@ -1,4 +1,4 @@
-import std/os, zippy/ziparchives, std/tables
+import std/os, zippy/ziparchives, std/tables, std/strutils, std/strformat
 
 const testDir = getTempDir() # "tmp/zip"
 
@@ -61,3 +61,25 @@ block:
   except:
     let e = getCurrentException()
     doAssert e.msg == "Error adding file tests/data/ziparchives/ to archive, appears to be a directory?"
+
+block: # Test deflate64
+  # test file obtained from https://github.com/brianhelba/zipfile-deflate64/tree/beec33184da6da4697a1994c0ac4c64cef8cff50/tests/data
+  let
+    archive = openZipArchive("tests/data/ziparchives/deflate64test.zip")
+    entries = {
+      "100_lines.txt": (101, 1890),
+      "100k_lines.txt": (100_001, 2188890),
+      "10_lines.txt": (11, 180),
+      "10k_lines.txt": (10_001, 208890),
+    }.toTable()
+  var numEntries: int
+  for entry in archive.walkFiles:
+    let
+      contents = archive.extractFile(entry)
+      actual_lines = contents.splitLines.len
+      actual_size = contents.len
+      (lines, size) = entries[entry]
+    doAssert actual_lines == lines, &"Expected {entry} to have {lines} not {actual_lines}"
+    doAssert actual_size == size, &"Expected {entry} to be {size} bytes not {actual_size}"
+    inc numEntries
+  doAssert numEntries == entries.len