src/lzf.h

   1 /*
   2  * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
   3  *
   4  * Redistribution and use in source and binary forms, with or without modifica-
   5  * tion, are permitted provided that the following conditions are met:
   6  *
   7  *   1.  Redistributions of source code must retain the above copyright notice,
   8  *       this list of conditions and the following disclaimer.
   9  *
  10  *   2.  Redistributions in binary form must reproduce the above copyright
  11  *       notice, this list of conditions and the following disclaimer in the
  12  *       documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  15  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
  16  * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
  17  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
  18  * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  20  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  21  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
  22  * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  23  * OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * the GNU General Public License ("GPL") version 2 or any later version,
  27  * in which case the provisions of the GPL are applicable instead of
  28  * the above. If you wish to allow the use of your version of this file
  29  * only under the terms of the GPL and not to allow others to use your
  30  * version of this file under the BSD license, indicate your decision
  31  * by deleting the provisions above and replace them with the notice
  32  * and other provisions required by the GPL. If you do not delete the
  33  * provisions above, a recipient may use your version of this file under
  34  * either the BSD or the GPL.
  35  */
  36
  37 #ifndef LZF_H
  38 #define LZF_H
  39
  40 /***********************************************************************
  41 **
  42 **      lzf -- an extremely fast/free compression/decompression-method
  43 **      http://liblzf.plan9.de/
  44 **
  45 **      This algorithm is believed to be patent-free.
  46 **
  47 ***********************************************************************/
  48
  49 #define LZF_VERSION 0x0105 /* 1.5, API version */
  50
  51 /*
  52  * Compress in_len bytes stored at the memory block starting at
  53  * in_data and write the result to out_data, up to a maximum length
  54  * of out_len bytes.
  55  *
  56  * If the output buffer is not large enough or any error occurs return 0,
  57  * otherwise return the number of bytes used, which might be considerably
  58  * more than in_len (but less than 104% of the original size), so it
  59  * makes sense to always use out_len == in_len - 1), to ensure _some_
  60  * compression, and store the data uncompressed otherwise (with a flag, of
  61  * course.
  62  *
  63  * lzf_compress might use different algorithms on different systems and
  64  * even different runs, thus might result in different compressed strings
  65  * depending on the phase of the moon or similar factors. However, all
  66  * these strings are architecture-independent and will result in the
  67  * original data when decompressed using lzf_decompress.
  68  *
  69  * The buffers must not be overlapping.
  70  *
  71  * If the option LZF_STATE_ARG is enabled, an extra argument must be
  72  * supplied which is not reflected in this header file. Refer to lzfP.h
  73  * and lzf_c.c.
  74  *
  75  */
  76 unsigned int
  77 lzf_compress (const void *const in_data,  unsigned int in_len,
  78               void             *out_data, unsigned int out_len);
  79
  80 /*
  81  * Decompress data compressed with some version of the lzf_compress
  82  * function and stored at location in_data and length in_len. The result
  83  * will be stored at out_data up to a maximum of out_len characters.
  84  *
  85  * If the output buffer is not large enough to hold the decompressed
  86  * data, a 0 is returned and errno is set to E2BIG. Otherwise the number
  87  * of decompressed bytes (i.e. the original length of the data) is
  88  * returned.
  89  *
  90  * If an error in the compressed data is detected, a zero is returned and
  91  * errno is set to EINVAL.
  92  *
  93  * This function is very fast, about as fast as a copying loop.
  94  */
  95 unsigned int
  96 lzf_decompress (const void *const in_data,  unsigned int in_len,
  97                 void             *out_data, unsigned int out_len);
  98
  99 #endif
 100