src/unzip.cpp

   1 //
   2 // ZIP file support
   3 // This is here to simplify interfacing to zlib, as zlib does NO zip file handling
   4 //
   5 // by James Hammons
   6 // (C) 2012 Underground Software
   7 //
   8 // JLH = James Hammons <jlhamm@acm.org>
   9 //
  10 // Who  When        What
  11 // ---  ----------  -------------------------------------------------------------
  12 // JLH  01/16/2010  Created this log ;-)
  13 // JLH  02/28/2010  Removed unnecessary cruft
  14 // JLH  05/31/2012  Rewrote everything and removed all MAME code
  15 //
  16
  17 #include "unzip.h"
  18
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <zlib.h>
  22 #include "log.h"
  23
  24
  25 uint32_t GetLong(FILE * fp)
  26 {
  27         uint32_t n = ((uint32_t)fgetc(fp));
  28         n |= ((uint32_t)fgetc(fp)) << 8;
  29         n |= ((uint32_t)fgetc(fp)) << 16;
  30         n |= ((uint32_t)fgetc(fp)) << 24;
  31
  32         return n;
  33 }
  34
  35
  36 uint16_t GetWord(FILE * fp)
  37 {
  38         uint16_t n = ((uint16_t)fgetc(fp));
  39         n |= ((uint16_t)fgetc(fp)) << 8;
  40
  41         return n;
  42 }
  43
  44
  45 bool GetZIPHeader(FILE * fp, ZipFileEntry & ze)
  46 {
  47         ze.signature = GetLong(fp);
  48         ze.version = GetWord(fp);
  49         ze.flags = GetWord(fp);
  50         ze.method = GetWord(fp);
  51         ze.modifiedTime = GetWord(fp);
  52         ze.modifiedDate = GetWord(fp);
  53         ze.crc32 = GetLong(fp);
  54         ze.compressedSize = GetLong(fp);
  55         ze.uncompressedSize = GetLong(fp);
  56         ze.filenameLength = GetWord(fp);
  57         ze.extraLength = GetWord(fp);
  58
  59         // This handling is really ungraceful; but if someone is going to feed us
  60         // shit, then why eat it? :-)
  61         if (ze.filenameLength < 512)
  62         {
  63                 fread(ze.filename, 1, ze.filenameLength, fp);
  64                 ze.filename[ze.filenameLength] = 0;
  65         }
  66         else
  67         {
  68                 fseek(fp, ze.filenameLength, SEEK_CUR);
  69                 ze.filename[0] = 0;
  70         }
  71
  72         // Skip the "extra" header
  73         fseek(fp, ze.extraLength, SEEK_CUR);
  74
  75         return (ze.signature == 0x04034B50 ? true : false);
  76 }
  77
  78
  79 //
  80 // Uncompress a file from a ZIP file filestream
  81 // NOTE: The passed in buffer *must* be fully allocated before calling this!
  82 //
  83 #define CHUNKSIZE 16384
  84 int UncompressFileFromZIP(FILE * fp, ZipFileEntry ze, uint8_t * buffer)
  85 {
  86         z_stream zip;
  87         unsigned char inBuffer[CHUNKSIZE];
  88         uint32_t remaining = ze.compressedSize;
  89
  90         // Set up z_stream for inflating
  91         zip.zalloc = Z_NULL;
  92         zip.zfree = Z_NULL;
  93         zip.opaque = Z_NULL;
  94         zip.avail_in = 0;
  95         zip.next_in = Z_NULL;
  96
  97         int ret = inflateInit2(&zip, -MAX_WBITS);       // -MAX_WBITS tells it there's no header
  98
  99         // Bail if can't initialize the z_stream...
 100         if (ret != Z_OK)
 101                 return ret;
 102
 103         zip.avail_out = ze.uncompressedSize;
 104         zip.next_out = buffer;
 105
 106         // Decompress until deflate stream ends or we hit end of file
 107         do
 108         {
 109                 zip.avail_in = fread(inBuffer, 1, (remaining < CHUNKSIZE ? remaining : CHUNKSIZE), fp);
 110                 zip.next_in = inBuffer;
 111                 remaining -= CHUNKSIZE;
 112
 113                 if (ferror(fp))
 114                 {
 115                         inflateEnd(&zip);
 116                         return Z_ERRNO;
 117                 }
 118
 119                 if (zip.avail_in == 0)
 120                         break;
 121
 122                 ret = inflate(&zip, Z_NO_FLUSH);
 123
 124                 if ((ret == Z_NEED_DICT) || (ret == Z_DATA_ERROR) || (ret == Z_MEM_ERROR))
 125                 {
 126                         inflateEnd(&zip);
 127                         return ret;
 128                 }
 129
 130         }
 131         while (ret != Z_STREAM_END);
 132
 133         inflateEnd(&zip);
 134
 135         return (ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR);
 136 }