release/src/router/lzo/examples/simple.c

   1 /* simple.c -- the annotated simple example program for the LZO library
   2
   3    This file is part of the LZO real-time data compression library.
   4
   5    Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer
   6    Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer
   7    Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer
   8    Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
   9    Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
  10    Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
  11    Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
  12    Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
  13    Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
  14    Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
  15    Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
  16    Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
  17    Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
  18    Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
  19    Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
  20    Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
  21    All Rights Reserved.
  22
  23    The LZO library is free software; you can redistribute it and/or
  24    modify it under the terms of the GNU General Public License as
  25    published by the Free Software Foundation; either version 2 of
  26    the License, or (at your option) any later version.
  27
  28    The LZO library is distributed in the hope that it will be useful,
  29    but WITHOUT ANY WARRANTY; without even the implied warranty of
  30    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  31    GNU General Public License for more details.
  32
  33    You should have received a copy of the GNU General Public License
  34    along with the LZO library; see the file COPYING.
  35    If not, write to the Free Software Foundation, Inc.,
  36    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  37
  38    Markus F.X.J. Oberhumer
  39    <markus@oberhumer.com>
  40    http://www.oberhumer.com/opensource/lzo/
  41  */
  42
  43
  44 /*************************************************************************
  45 // This program shows the basic usage of the LZO library.
  46 // We will compress a block of data and decompress again.
  47 //
  48 // See also LZO.FAQ
  49 **************************************************************************/
  50
  51 /* We will be using the LZO1X-1 algorithm, so we have
  52  * to include <lzo1x.h>
  53  */
  54
  55 #include "lzo/lzoconf.h"
  56 #include "lzo/lzo1x.h"
  57
  58 /* portability layer */
  59 static const char *progname = NULL;
  60 #define WANT_LZO_MALLOC 1
  61 #define WANT_XMALLOC 1
  62 #include "examples/portab.h"
  63
  64
  65 /* We want to compress the data block at 'in' with length 'IN_LEN' to
  66  * the block at 'out'. Because the input block may be incompressible,
  67  * we must provide a little more output space in case that compression
  68  * is not possible.
  69  */
  70
  71 #ifndef IN_LEN
  72 #define IN_LEN      (128*1024L)
  73 #endif
  74 #define OUT_LEN     (IN_LEN + IN_LEN / 16 + 64 + 3)
  75
  76
  77 /*************************************************************************
  78 //
  79 **************************************************************************/
  80
  81 int __lzo_cdecl_main main(int argc, char *argv[])
  82 {
  83     int r;
  84     lzo_bytep in;
  85     lzo_bytep out;
  86     lzo_voidp wrkmem;
  87     lzo_uint in_len;
  88     lzo_uint out_len;
  89     lzo_uint new_len;
  90
  91     if (argc < 0 && argv == NULL)   /* avoid warning about unused args */
  92         return 0;
  93
  94     printf("\nLZO real-time data compression library (v%s, %s).\n",
  95            lzo_version_string(), lzo_version_date());
  96     printf("Copyright (C) 1996-2011 Markus Franz Xaver Johannes Oberhumer\nAll Rights Reserved.\n\n");
  97
  98 /*
  99  * Step 1: initialize the LZO library
 100  */
 101     if (lzo_init() != LZO_E_OK)
 102     {
 103         printf("internal error - lzo_init() failed !!!\n");
 104         printf("(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable '-DLZO_DEBUG' for diagnostics)\n");
 105         return 4;
 106     }
 107
 108 /*
 109  * Step 2: allocate blocks and the work-memory
 110  */
 111     in = (lzo_bytep) xmalloc(IN_LEN);
 112     out = (lzo_bytep) xmalloc(OUT_LEN);
 113     wrkmem = (lzo_voidp) xmalloc(LZO1X_1_MEM_COMPRESS);
 114     if (in == NULL || out == NULL || wrkmem == NULL)
 115     {
 116         printf("out of memory\n");
 117         return 3;
 118     }
 119
 120 /*
 121  * Step 3: prepare the input block that will get compressed.
 122  *         We just fill it with zeros in this example program,
 123  *         but you would use your real-world data here.
 124  */
 125     in_len = IN_LEN;
 126     lzo_memset(in,0,in_len);
 127
 128 /*
 129  * Step 4: compress from 'in' to 'out' with LZO1X-1
 130  */
 131     r = lzo1x_1_compress(in,in_len,out,&out_len,wrkmem);
 132     if (r == LZO_E_OK)
 133         printf("compressed %lu bytes into %lu bytes\n",
 134             (unsigned long) in_len, (unsigned long) out_len);
 135     else
 136     {
 137         /* this should NEVER happen */
 138         printf("internal error - compression failed: %d\n", r);
 139         return 2;
 140     }
 141     /* check for an incompressible block */
 142     if (out_len >= in_len)
 143     {
 144         printf("This block contains incompressible data.\n");
 145         return 0;
 146     }
 147
 148 /*
 149  * Step 5: decompress again, now going from 'out' to 'in'
 150  */
 151     new_len = in_len;
 152     r = lzo1x_decompress(out,out_len,in,&new_len,NULL);
 153     if (r == LZO_E_OK && new_len == in_len)
 154         printf("decompressed %lu bytes back into %lu bytes\n",
 155             (unsigned long) out_len, (unsigned long) in_len);
 156     else
 157     {
 158         /* this should NEVER happen */
 159         printf("internal error - decompression failed: %d\n", r);
 160         return 1;
 161     }
 162
 163     lzo_free(wrkmem);
 164     lzo_free(out);
 165     lzo_free(in);
 166     printf("Simple compression test passed.\n");
 167     return 0;
 168 }
 169
 170 /*
 171 vi:ts=4:et
 172 */
 173