snes9xgx/source/ngc/ngcunzip.cpp

/****************************************************************************
 * Snes9x 1.50 
 *
 * Nintendo Gamecube Unzip - borrowed from the GPP
 *
 * softdev July 2006
 ****************************************************************************/
#include <gccore.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <zlib.h>
#include "dvd.h"
#include "video.h"
#include "ftfont.h"
#include "ngcunzip.h"

/*
  * PKWare Zip Header - adopted into zip standard
  */
#define PKZIPID 0x504b0304
#define MAXROM 0x500000
#define ZIPCHUNK 2048

/*
 * Zip files are stored little endian
 * Support functions for short and int types
 */
u32
FLIP32 (u32 b)
{
  unsigned int c;

  c = (b & 0xff000000) >> 24;
  c |= (b & 0xff0000) >> 8;
  c |= (b & 0xff00) << 8;
  c |= (b & 0xff) << 24;

  return c;
}

u16
FLIP16 (u16 b)
{
  u16 c;

  c = (b & 0xff00) >> 8;
  c |= (b & 0xff) << 8;

  return c;
}

/****************************************************************************
 * IsZipFile
 *
 * Returns TRUE when PKZIPID is first four characters of buffer
 ****************************************************************************/
int
IsZipFile (char *buffer)
{
  unsigned int *check;

  check = (unsigned int *) buffer;

  if (check[0] == PKZIPID)
    return 1;

  return 0;
}

 /*****************************************************************************
 * unzip
 *
 * It should be noted that there is a limit of 5MB total size for any ROM
 ******************************************************************************/
int
UnZipBuffer (unsigned char *outbuffer, u64 discoffset, int length)
{
  PKZIPHEADER pkzip;
  int zipoffset = 0;
  int zipchunk = 0;
  char out[ZIPCHUNK];
  z_stream zs;
  int res;
  int bufferoffset = 0;
  int have = 0;
  char readbuffer[2048];
  char msg[128];

	/*** Read Zip Header ***/
  dvd_read (readbuffer, 2048, discoffset);

	/*** Copy PKZip header to local, used as info ***/
  memcpy (&pkzip, readbuffer, sizeof (PKZIPHEADER));

  sprintf (msg, "Unzipping %d bytes ... Wait",
	   FLIP32 (pkzip.uncompressedSize));
  ShowAction (msg);

	/*** Prepare the zip stream ***/
  memset (&zs, 0, sizeof (z_stream));
  zs.zalloc = Z_NULL;
  zs.zfree = Z_NULL;
  zs.opaque = Z_NULL;
  zs.avail_in = 0;
  zs.next_in = Z_NULL;
  res = inflateInit2 (&zs, -MAX_WBITS);

  if (res != Z_OK)
    return 0;

	/*** Set ZipChunk for first pass ***/
  zipoffset =
    (sizeof (PKZIPHEADER) + FLIP16 (pkzip.filenameLength) +
     FLIP16 (pkzip.extraDataLength));
  zipchunk = ZIPCHUNK - zipoffset;

	/*** Now do it! ***/
  do
    {
      zs.avail_in = zipchunk;
      zs.next_in = (Bytef *) & readbuffer[zipoffset];

		/*** Now inflate until input buffer is exhausted ***/
      do
	{
	  zs.avail_out = ZIPCHUNK;
	  zs.next_out = (Bytef *) & out;

	  res = inflate (&zs, Z_NO_FLUSH);

	  if (res == Z_MEM_ERROR)
	    {
	      inflateEnd (&zs);
	      return 0;
	    }

	  have = ZIPCHUNK - zs.avail_out;
	  if (have)
	    {
				/*** Copy to normal block buffer ***/
	      memcpy (&outbuffer[bufferoffset], &out, have);
	      bufferoffset += have;
	    }

	}
      while (zs.avail_out == 0);

		/*** Readup the next 2k block ***/
      zipoffset = 0;
      zipchunk = ZIPCHUNK;
      discoffset += 2048;

      dvd_read (readbuffer, 2048, discoffset);
    }
  while (res != Z_STREAM_END);

  inflateEnd (&zs);

  if (res == Z_STREAM_END)
    {
      if (FLIP32 (pkzip.uncompressedSize) == (u32) bufferoffset)
	return bufferoffset;
      else
	return FLIP32 (pkzip.uncompressedSize);
    }

  return 0;

}