/* precomp.c -- example program: how to generate pre-compressed data
This file is part of the LZO real-time data compression library.
Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
All Rights Reserved.
The LZO library 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.
The LZO library 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 the LZO library; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Markus F.X.J. Oberhumer
<markus@oberhumer.com>
*/
/*************************************************************************
// This program shows how to generate pre-compressed data.
//
// Please study LZO.FAQ and simple.c first.
//
// We will be trying both LZO1X-999 and LZO1Y-999 and choose
// the algorithm that achieves the best compression ratio.
**************************************************************************/
#include <lzoconf.h>
#if defined(LZO_999_UNSUPPORTED)
# error "compression level 999 not supported on this 16-bit system"
#endif
#include <lzo1x.h>
#include <lzo1y.h>
#define USE_LZO1X
#define USE_LZO1Y
#define PARANOID
/*************************************************************************
//
**************************************************************************/
#include "lutil.h"
#include <assert.h>
int main(int argc, char *argv[])
{
int r;
lzo_byte *in;
lzo_uint in_len;
lzo_byte *out;
lzo_uint out_len = 0;
lzo_byte *wrkmem;
lzo_uint wrk_len;
lzo_uint best_len;
int best_compress = -1;
lzo_uint orig_len;
lzo_uint32 uncompressed_checksum;
lzo_uint32 compressed_checksum;
FILE *f;
const char *progname = NULL;
const char *in_name = NULL;
const char *out_name = NULL;
long l;
#if defined(__EMX__)
_response(&argc,&argv);
_wildcard(&argc,&argv);
#endif
printf("\nLZO real-time data compression library (v%s, %s).\n",
lzo_version_string(), lzo_version_date());
printf("Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer\n\n");
progname = argv[0];
if (argc < 2 || argc > 3)
{
printf("usage: %s file [output-file]\n", progname);
exit(1);
}
in_name = argv[1];
out_name = (argc > 2) ? argv[2] : NULL;
/*
* Step 1: initialize the LZO library
*/
if (lzo_init() != LZO_E_OK)
{
printf("lzo_init() failed !!!\n");
exit(1);
}
/*
* Step 2: allocate the work-memory
*/
wrk_len = 1;
#ifdef USE_LZO1X
if (wrk_len < LZO1X_999_MEM_COMPRESS)
wrk_len = LZO1X_999_MEM_COMPRESS;
#endif
#ifdef USE_LZO1Y
if (wrk_len < LZO1Y_999_MEM_COMPRESS)
wrk_len = LZO1Y_999_MEM_COMPRESS;
#endif
wrkmem = (lzo_bytep) lzo_malloc(wrk_len);
if (wrkmem == NULL)
{
printf("%s: out of memory\n", progname);
exit(1);
}
/*
* Step 3: open the input file
*/
f = fopen(in_name,"rb");
if (f == NULL)
{
printf("%s: cannot open file %s\n", progname, in_name);
exit(1);
}
fseek(f,0,SEEK_END);
l = ftell(f);
fseek(f,0,SEEK_SET);
if (l <= 0)
{
printf("%s: %s: empty file\n", progname, in_name);
fclose(f);
exit(1);
}
in_len = (lzo_uint) l;
best_len = in_len;
/*
* Step 4: allocate compression buffers and read the file
*/
in = (lzo_bytep) lzo_malloc(in_len);
out = (lzo_bytep) lzo_malloc(in_len + in_len / 64 + 16 + 3);
if (in == NULL || out == NULL)
{
printf("%s: out of memory\n", progname);
exit(1);
}
in_len = lzo_fread(f,in,in_len);
printf("%s: loaded file %s: %ld bytes\n", progname, in_name, (long) in_len);
fclose(f);
/*
* Step 5: compute a checksum of the uncompressed data
*/
uncompressed_checksum = lzo_adler32(0,NULL,0);
uncompressed_checksum = lzo_adler32(uncompressed_checksum,in,in_len);
/*
* Step 6a: compress from `in' to `out' with LZO1X-999
*/
#ifdef USE_LZO1X
r = lzo1x_999_compress(in,in_len,out,&out_len,wrkmem);
if (r != LZO_E_OK)
{
/* this should NEVER happen */
printf("internal error - compression failed: %d\n", r);
exit(1);
}
printf("LZO1X-999: %8lu -> %8lu\n", (long) in_len, (long) out_len);
if (out_len < best_len)
{
best_len = out_len;
best_compress = 1; /* LZO1X-999 */
}
#endif /* USE_LZO1X */
/*
* Step 6b: compress from `in' to `out' with LZO1Y-999
*/
#ifdef USE_LZO1Y
r = lzo1y_999_compress(in,in_len,out,&out_len,wrkmem);
if (r != LZO_E_OK)
{
/* this should NEVER happen */
printf("internal error - compression failed: %d\n", r);
exit(1);
}
printf("LZO1Y-999: %8lu -> %8lu\n", (long) in_len, (long) out_len);
if (out_len < best_len)
{
best_len = out_len;
best_compress = 2; /* LZO1Y-999 */
}
#endif /* USE_LZO1Y */
/*
* Step 7: check if compressible
*/
if (best_len >= in_len)
{
printf("This file contains incompressible data.\n");
return 0;
}
/*
* Step 8: compress data again using the best compressor found
*/
if (best_compress == 1)
r = lzo1x_999_compress(in,in_len,out,&out_len,wrkmem);
else if (best_compress == 2)
r = lzo1y_999_compress(in,in_len,out,&out_len,wrkmem);
else
r = -100;
assert(r == LZO_E_OK);
assert(out_len == best_len);
/*
* Step 9: optimize compressed data (compressed data is in `out' buffer)
*/
#if 1
/* Optimization does not require any data in the buffer that will
* hold the uncompressed data. To prove this, we clear the buffer.
*/
lzo_memset(in,0,in_len);
#endif
orig_len = in_len;
if (best_compress == 1)
r = lzo1x_optimize(out,out_len,in,&orig_len,NULL);
else if (best_compress == 2)
r = lzo1y_optimize(out,out_len,in,&orig_len,NULL);
else
r = -100;
if (r != LZO_E_OK || orig_len != in_len)
{
/* this should NEVER happen */
printf("internal error - optimization failed: %d\n", r);
exit(1);
}
/*
* Step 10: compute a checksum of the compressed data
*/
compressed_checksum = lzo_adler32(0,NULL,0);
compressed_checksum = lzo_adler32(compressed_checksum,out,out_len);
/*
* Step 11: write compressed data to a file
*/
printf("%s: %s: %ld -> %ld, checksum 0x%08lx 0x%08lx\n",
progname, in_name, (long) in_len, (long) out_len,
(long) uncompressed_checksum, (long) compressed_checksum);
if (out_name && out_name[0])
{
printf("%s: writing to file %s\n", progname, out_name);
f = fopen(out_name,"wb");
if (f == NULL)
{
printf("%s: cannot open output file %s\n", progname, out_name);
exit(1);
}
if (lzo_fwrite(f,out,out_len) != out_len || fclose(f) != 0)
{
printf("%s: write error !!\n", progname);
exit(1);
}
}
/*
* Step 12: verify decompression
*/
#ifdef PARANOID
orig_len = in_len;
if (best_compress == 1)
r = lzo1x_decompress(out,out_len,in,&orig_len,NULL);
else if (best_compress == 2)
r = lzo1y_decompress(out,out_len,in,&orig_len,NULL);
else
r = -100;
if (r != LZO_E_OK || orig_len != in_len)
{
/* this should NEVER happen */
printf("internal error - decompression failed: %d\n", r);
exit(1);
}
if (uncompressed_checksum != lzo_adler32(lzo_adler32(0,NULL,0),in,in_len))
{
/* this should NEVER happen */
printf("internal error - decompression data error\n");
exit(1);
}
/* Now you could also verify decompression under similar conditions as in
* your application, e.g. overlapping assembler decompression etc.
*/
#endif
lzo_free(in);
lzo_free(out);
lzo_free(wrkmem);
return 0;
}
/*
vi:ts=4
*/