From 056035c540651bcb638f8b39be4faf9a6a2d77fa Mon Sep 17 00:00:00 2001
From: HalfInner <kajbrz@hotmail.com>
Date: Fri, 6 Oct 2023 12:20:30 +0200
Subject: [PATCH] patterns/zip: Add parsing local file header with minor
 adjustment (#172)

patterns/zip: add parsing local file header, and another adjustmenst

Add missing parsing for local file headers
Add compression method
Minor adjustments: removed black colors, marked magic ids
---
 patterns/zip.hexpat | 73 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 63 insertions(+), 10 deletions(-)

diff --git a/patterns/zip.hexpat b/patterns/zip.hexpat
index 7c06d65..c2dd8bf 100644
--- a/patterns/zip.hexpat
+++ b/patterns/zip.hexpat
@@ -1,4 +1,4 @@
-#pragma description End of Central Directory Header, Central Directory File Headers
+#pragma description End of Central Directory Header, Central Directory File Headers, Local File Header
 
 #pragma MIME application/zip
 
@@ -6,7 +6,7 @@
 #include <std/math.pat>
 
 struct EndOfCentralDirectory {
-    u32 headerSignature [[color("00000000")]];
+    u32 headerSignature [[comment("EoCD magic"), name("EoCD PK\\5\\6")]];
     u16 diskNum [[comment("Number of this disk "), name("Disk Number")]];
     u16 diskStart [[comment("Disk where central directory starts "), name("Central Directory Disk Number")]];
     u16 CDRCount [[comment("Number of central directory records on this disk"), name("Central Directory Entries")]];
@@ -36,24 +36,77 @@ fn find_eocd() {
 
 EndOfCentralDirectory fileInfo @ find_eocd() [[name("End of Central Directory Record")]];
 
+enum CompressionMethod : u16 {
+  None = 0,              // The file is stored (no compression)
+  Shrunk = 1,            // The file is Shrunk
+  Factor1 = 2,           // The file is Reduced with compression factor 1
+  Factor2 = 3,           // The file is Reduced with compression factor 2
+  Factor3 = 4,           // The file is Reduced with compression factor 3
+  Factor4 = 5,           // The file is Reduced with compression factor 4
+  Implode = 6,           // The file is Imploded
+  // ? =  7,             // Reserved for Tokenizing compression algorithm
+  Deflate  = 8,          // The file is Deflated
+  Deflate64 = 9,         // Enhanced Deflating using Deflate64(tm)
+  PKWARE = 10,           // PKWARE Data Compression Library Imploding (old IBM TERSE)
+  // ? =11,              // Reserved by PKWARE
+  BZIP2 = 12,            // File is compressed using BZIP2 algorithm
+  // ? = 13,             // Reserved by PKWARE
+  LZMA = 14,             // LZMA
+  // ? = 15,             // Reserved by PKWARE
+  CMPSC = 16,            // IBM z/OS CMPSC Compression
+  // ? = 17,             // Reserved by PKWARE
+  IBMTERSE = 18,         // File is compressed using IBM TERSE (new)
+  LZ77 = 19,             // IBM LZ77 z Architecture
+  _ZSTD = 20,            // deprecated (use method 93 for zstd)
+  ZSTD = 93,             // Zstandard (zstd) Compression
+  MP3 = 94,              // MP3 Compression
+  XZ = 95,               // XZ Compression
+  JPEG = 96,             // JPEG variant
+  WavPack = 97,          // WavPack compressed data
+  PPMd = 98,             // PPMd version I, Rev 1
+  AE_x = 99,             // AE-x encryption marker (see APPENDIX E)
+};
+
+struct LocalFileHeader {
+    u32 headerSignature [[name("LCF PK\\3\\4")]];
+    u16 version [[ comment("The minimum supported ZIP specification version needed to extract the file") ]];
+    u16 purposeBitflag  [[ comment("General purpose bit flag") ]];
+    CompressionMethod compressionMethod [[ comment("Compression method") ]];
+    u16 lastModifyTime [[ comment("File last modification time") ]];
+    u16 lastModifyDate [[ comment("File last modification date") ]];
+    u32 crc32 [[ comment("CRC-32") ]];
+    u32 compressedSize [[ comment("Compressed size") ]];
+    u32 uncompressedSize [[ comment("Uncompressed size") ]];
+    u16 fileNameLength [[ comment("File name length (n)") ]];
+    u16 extraFieldLength [[ comment("Extra field length (m)") ]];
+    char fileName[fileNameLength] [[ comment("File Name") ]];
+    char extraField[extraFieldLength] [[ comment("Extra Field") ]];
+    u8 data[compressedSize] [[name("File Data")]];
+};
+
+union File {
+    u32 fileOffset [[comment("Offset of local file header, relative to the start of the first disk on which the file occurs.")]];
+    LocalFileHeader *fileHeader : u32;
+};
+
 struct CentralDirectoryFileHeader {
-    u32 headerSignature [[color("00000000")]];
+    u32 headerSignature [[name("CDFH PK\\1\\2")]];
     u16 versionMade [[comment("Version file made by")]];
     u16 versionExtract [[comment("Minimum version needed to extract")]];
-    u16 generalFlag [[comment("General purpose bit flag"), color("00000000")]];
-    u16 compressionMethod;
+    u16 generalFlag [[comment("General purpose bit flag")]];
+    CompressionMethod compressionMethod;
     u16 fileLastModifyTime [[comment("File last modification time")]];
     u16 fileLastModifyDate [[comment("File last modification date")]];
-    u32 crc32 [[comment("CRC-32 of uncompressed data"), color("00000000")]];
+    u32 crc32 [[comment("CRC-32 of uncompressed data")]];
     u32 compressedSize;
     u32 uncompressedSize;
-    u16 fileNameLength [[color("00000000")]];
-    u16 extraFieldLength [[color("00000000")]];
-    u16 fileCommentLength [[color("00000000")]];
+    u16 fileNameLength;
+    u16 extraFieldLength;
+    u16 fileCommentLength;
     u16 diskNumber [[comment("Disk number where file starts")]];
     u16 internalFileAttributes;
     u32 externalFileAttributes;
-    u32 fileOffset [[comment("Offset of local file header, relative to the start of the first disk on which the file occurs.")]];
+    File file;
     char fileName[fileNameLength];
     u8 extraField[extraFieldLength];
     char comment[fileCommentLength];