zip.c

来自「psp上的GBA模拟器」· C语言 代码 · 共 146 行

/* gameplaySP
 *
 * Copyright (C) 2006 Exophase <[e-mail]>
 * Copyright (C) 2006 SiberianSTAR
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zlib.h>
#include "common.h"

#define ZIP_BUFFER_SIZE (128 * 1024)

struct SZIPFileDataDescriptor
{
  s32 CRC32;
  s32 CompressedSize;
  s32 UncompressedSize;
} __attribute__((packed));

struct SZIPFileHeader
{
  s32 Sig;
  s16 VersionToExtract;
  s16 GeneralBitFlag;
  s16 CompressionMethod;
  s16 LastModFileTime;
  s16 LastModFileDate;
  struct SZIPFileDataDescriptor DataDescriptor;
  s16 FilenameLength;
  s16 ExtraFieldLength;
}  __attribute__((packed));

u32 load_file_zip(char *filename)
{
  struct SZIPFileHeader data;
  u8 tmp[1024];
  s32 retval = -1;
  u8 *buffer = NULL;
  u8 *cbuffer;
  u8 *ext;

  file_open(fd, filename, read);

  if(!file_check_valid(fd))
    return -1;

  while(1)
  {
    file_read(fd, &data, sizeof(struct SZIPFileHeader));

    // zip file end
    if(data.Sig != 0x04034b50)
      break;

    file_read(fd, tmp, data.FilenameLength);
    tmp[data.FilenameLength] = 0; // end string

    if(data.ExtraFieldLength)
      file_seek(fd, data.ExtraFieldLength, SEEK_CUR);

    if(data.GeneralBitFlag & 0x0008)
    {
      file_read(fd, &data.DataDescriptor,
       sizeof(struct SZIPFileDataDescriptor));
    }

    ext = strrchr(tmp, '.') + 1;

    // file is too big
    if(data.DataDescriptor.UncompressedSize > gamepak_ram_buffer_size)
      goto outcode;

    if(!strcasecmp(ext, "bin") || !strcasecmp(ext, "gba"))
    {
      buffer = gamepak_rom;

      // ok, found
      switch(data.CompressionMethod)
      {
        case 0:
          retval = data.DataDescriptor.UncompressedSize;
          file_read(fd, buffer, retval);

          goto outcode;

        case 8:
        {
          z_stream stream;
          s32 err;

          cbuffer = malloc(ZIP_BUFFER_SIZE);

          stream.next_in = (Bytef*)cbuffer;
          stream.avail_in = (u32)ZIP_BUFFER_SIZE;

          stream.next_out = (Bytef*)buffer;
          retval = stream.avail_out = data.DataDescriptor.UncompressedSize;

          stream.zalloc = (alloc_func)0;
          stream.zfree = (free_func)0;

          err = inflateInit2(&stream, -MAX_WBITS);

          file_read(fd, cbuffer, ZIP_BUFFER_SIZE);

          if(err == Z_OK)
          {
            while(err != Z_STREAM_END)
            {
              err = inflate(&stream, Z_SYNC_FLUSH);
              if(err == Z_BUF_ERROR)
              {
                stream.avail_in = ZIP_BUFFER_SIZE;
                stream.next_in = (Bytef*)cbuffer;
                file_read(fd, cbuffer, ZIP_BUFFER_SIZE);
              }
            }
            err = Z_OK;
            inflateEnd(&stream);
          }
          free(cbuffer);
          goto outcode;
        }
      }
    }
  }

outcode:
  file_close(fd);

  return retval;
}