path: root/examples/precomp2.c

/* precomp2.c -- example program: how to generate pre-compressed data

   This file is part of the LZO real-time data compression library.

   Copyright (C) 1996-2017 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.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

   Markus F.X.J. Oberhumer
   <markus@oberhumer.com>
   http://www.oberhumer.com/opensource/lzo/
 */


/*************************************************************************
// This program shows how to generate pre-compressed data.
//
// Please study precomp.c first.
//
// We will be trying LZO1X-999 and LZO1Y-999, and we will be trying
// various parameters using the internal interface to squeeze out
// a little bit of extra compression.
//
// NOTE: this program can be quite slow for highly redundant files
**************************************************************************/

#include <lzo/lzoconf.h>
#include <lzo/lzo1x.h>
#include <lzo/lzo1y.h>

LZO_EXTERN(int)
lzo1x_999_compress_internal ( const lzo_bytep in , lzo_uint  in_len,
                                    lzo_bytep out, lzo_uintp out_len,
                                    lzo_voidp wrkmem,
                              const lzo_bytep dict, lzo_uint dict_len,
                                    lzo_callback_p cb,
                                    int try_lazy,
                                    lzo_uint good_length,
                                    lzo_uint max_lazy,
                                    lzo_uint nice_length,
                                    lzo_uint max_chain,
                                    lzo_uint32_t flags );

LZO_EXTERN(int)
lzo1y_999_compress_internal ( const lzo_bytep in , lzo_uint  in_len,
                                    lzo_bytep out, lzo_uintp out_len,
                                    lzo_voidp wrkmem,
                              const lzo_bytep dict, lzo_uint dict_len,
                                    lzo_callback_p cb,
                                    int try_lazy,
                                    lzo_uint good_length,
                                    lzo_uint max_lazy,
                                    lzo_uint nice_length,
                                    lzo_uint max_chain,
                                    lzo_uint32_t flags );

#define USE_LZO1X 1
#define USE_LZO1Y 1

#define PARANOID 1


/* portability layer */
static const char *progname = NULL;
#define WANT_LZO_MALLOC 1
#define WANT_LZO_FREAD 1
#define WANT_LZO_WILDARGV 1
#define WANT_XMALLOC 1
#include "examples/portab.h"


/*************************************************************************
//
**************************************************************************/

int __lzo_cdecl_main main(int argc, char *argv[])
{
    int r;
    int lazy;
    const int max_try_lazy = 5;
    const lzo_uint big = 65536L;    /* can result in very slow compression */
    const lzo_uint32_t flags = 0x1;

    lzo_bytep in;
    lzo_uint in_len;

    lzo_bytep out;
    lzo_uint out_bufsize;
    lzo_uint out_len = 0;

    lzo_voidp wrkmem;
    lzo_uint wrkmem_size;

    lzo_uint best_len;
    int best_compress = -1;
    int best_lazy = -1;

    lzo_uint orig_len;
    lzo_uint32_t uncompressed_checksum;
    lzo_uint32_t compressed_checksum;

    FILE *fp;
    const char *in_name = NULL;
    const char *out_name = NULL;
    long l;


    lzo_wildargv(&argc, &argv);

    printf("\nLZO real-time data compression library (v%s, %s).\n",
           lzo_version_string(), lzo_version_date());
    printf("Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer\nAll Rights Reserved.\n\n");

    progname = argv[0];
    if (argc < 2 || argc > 3)
    {
        printf("usage: %s file [output-file]\n", progname);
        exit(1);
    }
    in_name = argv[1];
    if (argc > 2) out_name = argv[2];

/*
 * Step 1: initialize the LZO library
 */
    if (lzo_init() != LZO_E_OK)
    {
        printf("internal error - lzo_init() failed !!!\n");
        printf("(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable '-DLZO_DEBUG' for diagnostics)\n");
        exit(1);
    }

/*
 * Step 2: allocate the work-memory
 */
    wrkmem_size = 1;
#ifdef USE_LZO1X
    wrkmem_size = (LZO1X_999_MEM_COMPRESS > wrkmem_size) ? LZO1X_999_MEM_COMPRESS : wrkmem_size;
#endif
#ifdef USE_LZO1Y
    wrkmem_size = (LZO1Y_999_MEM_COMPRESS > wrkmem_size) ? LZO1Y_999_MEM_COMPRESS : wrkmem_size;
#endif
    wrkmem = (lzo_voidp) xmalloc(wrkmem_size);
    if (wrkmem == NULL)
    {
        printf("%s: out of memory\n", progname);
        exit(1);
    }

/*
 * Step 3: open the input file
 */
    fp = fopen(in_name,"rb");
    if (fp == NULL)
    {
        printf("%s: cannot open file %s\n", progname, in_name);
        exit(1);
    }
    fseek(fp, 0, SEEK_END);
    l = ftell(fp);
    fseek(fp, 0, SEEK_SET);
    if (l <= 0)
    {
        printf("%s: %s: empty file\n", progname, in_name);
        fclose(fp); fp = NULL;
        exit(1);
    }
    in_len = (lzo_uint) l;
    out_bufsize = in_len + in_len / 16 + 64 + 3;
    best_len = in_len;

/*
 * Step 4: allocate compression buffers and read the file
 */
    in = (lzo_bytep) xmalloc(in_len);
    out = (lzo_bytep) xmalloc(out_bufsize);
    if (in == NULL || out == NULL)
    {
        printf("%s: out of memory\n", progname);
        exit(1);
    }
    in_len = (lzo_uint) lzo_fread(fp, in, in_len);
    printf("%s: loaded file %s: %ld bytes\n", progname, in_name, (long) in_len);
    fclose(fp); fp = NULL;

/*
 * 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
    for (lazy = 0; lazy <= max_try_lazy; lazy++)
    {
        out_len = out_bufsize;
        r = lzo1x_999_compress_internal(in,in_len,out,&out_len,wrkmem,
                                        NULL, 0, 0,
                                        lazy, big, big, big, big, flags);
        if (r != LZO_E_OK)
        {
            /* this should NEVER happen */
            printf("internal error - compression failed: %d\n", r);
            exit(1);
        }
        printf("LZO1X-999: lazy =%2d: %8lu -> %8lu\n",
                lazy, (unsigned long) in_len, (unsigned long) out_len);
        if (out_len < best_len)
        {
            best_len = out_len;
            best_lazy = lazy;
            best_compress = 1;      /* LZO1X-999 */
        }
    }
#endif /* USE_LZO1X */

/*
 * Step 6b: compress from 'in' to 'out' with LZO1Y-999
 */
#ifdef USE_LZO1Y
    for (lazy = 0; lazy <= max_try_lazy; lazy++)
    {
        out_len = out_bufsize;
        r = lzo1y_999_compress_internal(in,in_len,out,&out_len,wrkmem,
                                        NULL, 0, 0,
                                        lazy, big, big, big, big, flags);
        if (r != LZO_E_OK)
        {
            /* this should NEVER happen */
            printf("internal error - compression failed: %d\n", r);
            exit(1);
        }
        printf("LZO1Y-999: lazy =%2d: %8lu -> %8lu\n",
                lazy, (unsigned long) in_len, (unsigned long) out_len);
        if (out_len < best_len)
        {
            best_len = out_len;
            best_lazy = lazy;
            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
 */
    out_len = out_bufsize;
    if (best_compress == 1)
        r = lzo1x_999_compress_internal(in,in_len,out,&out_len,wrkmem,
                                        NULL, 0, 0,
                                        best_lazy, big, big, big, big, flags);
    else if (best_compress == 2)
        r = lzo1y_999_compress_internal(in,in_len,out,&out_len,wrkmem,
                                        NULL, 0, 0,
                                        best_lazy, big, big, big, big, flags);
    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;
    r = -100;
#ifdef USE_LZO1X
    if (best_compress == 1)
        r = lzo1x_optimize(out,out_len,in,&orig_len,NULL);
#endif
#ifdef USE_LZO1Y
    if (best_compress == 2)
        r = lzo1y_optimize(out,out_len,in,&orig_len,NULL);
#endif
    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);
        fp = fopen(out_name,"wb");
        if (fp == NULL)
        {
            printf("%s: cannot open output file %s\n", progname, out_name);
            exit(1);
        }
        if (lzo_fwrite(fp, out, out_len) != out_len || fclose(fp) != 0)
        {
            printf("%s: write error !!\n", progname);
            exit(1);
        }
    }

/*
 * Step 12: verify decompression
 */
#ifdef PARANOID
    lzo_memset(in,0,in_len);    /* paranoia - clear output buffer */
    orig_len = in_len;
    r = -100;
#ifdef USE_LZO1X
    if (best_compress == 1)
        r = lzo1x_decompress_safe(out,out_len,in,&orig_len,NULL);
#endif
#ifdef USE_LZO1Y
    if (best_compress == 2)
        r = lzo1y_decompress_safe(out,out_len,in,&orig_len,NULL);
#endif
    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;
}


/* vim:set ts=4 sw=4 et: */