include/linux/lz4.h

   1 #ifndef __LZ4_H__
   2 #define __LZ4_H__
   3 /*
   4  * LZ4 Kernel Interface
   5  *
   6  * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #define LZ4_MEM_COMPRESS        (4096 * sizeof(unsigned char *))
  13 #define LZ4HC_MEM_COMPRESS      (65538 * sizeof(unsigned char *))
  14
  15 /*
  16  * lz4_compressbound()
  17  * Provides the maximum size that LZ4 may output in a "worst case" scenario
  18  * (input data not compressible)
  19  */
  20 static inline size_t lz4_compressbound(size_t isize)
  21 {
  22         return isize + (isize / 255) + 16;
  23 }
  24
  25 /*
  26  * lz4_compress()
  27  *      src     : source address of the original data
  28  *      src_len : size of the original data
  29  *      dst     : output buffer address of the compressed data
  30  *              This requires 'dst' of size LZ4_COMPRESSBOUND.
  31  *      dst_len : is the output size, which is returned after compress done
  32  *      workmem : address of the working memory.
  33  *              This requires 'workmem' of size LZ4_MEM_COMPRESS.
  34  *      return  : Success if return 0
  35  *                Error if return (< 0)
  36  *      note :  Destination buffer and workmem must be already allocated with
  37  *              the defined size.
  38  */
  39 int lz4_compress(const unsigned char *src, size_t src_len,
  40                 unsigned char *dst, size_t *dst_len, void *wrkmem);
  41
  42  /*
  43   * lz4hc_compress()
  44   *      src     : source address of the original data
  45   *      src_len : size of the original data
  46   *      dst     : output buffer address of the compressed data
  47   *             This requires 'dst' of size LZ4_COMPRESSBOUND.
  48   *      dst_len : is the output size, which is returned after compress done
  49   *      workmem : address of the working memory.
  50   *             This requires 'workmem' of size LZ4HC_MEM_COMPRESS.
  51   *      return  : Success if return 0
  52   *                Error if return (< 0)
  53   *      note :  Destination buffer and workmem must be already allocated with
  54   *              the defined size.
  55   */
  56 int lz4hc_compress(const unsigned char *src, size_t src_len,
  57                 unsigned char *dst, size_t *dst_len, void *wrkmem);
  58
  59 /*
  60  * lz4_decompress()
  61  *      src     : source address of the compressed data
  62  *      src_len : is the input size, whcih is returned after decompress done
  63  *      dest    : output buffer address of the decompressed data
  64  *      actual_dest_len: is the size of uncompressed data, supposing it's known
  65  *      return  : Success if return 0
  66  *                Error if return (< 0)
  67  *      note :  Destination buffer must be already allocated.
  68  *              slightly faster than lz4_decompress_unknownoutputsize()
  69  */
  70 int lz4_decompress(const char *src, size_t *src_len, char *dest,
  71                 size_t actual_dest_len);
  72
  73 /*
  74  * lz4_decompress_unknownoutputsize()
  75  *      src     : source address of the compressed data
  76  *      src_len : is the input size, therefore the compressed size
  77  *      dest    : output buffer address of the decompressed data
  78  *      dest_len: is the max size of the destination buffer, which is
  79  *                      returned with actual size of decompressed data after
  80  *                      decompress done
  81  *      return  : Success if return 0
  82  *                Error if return (< 0)
  83  *      note :  Destination buffer must be already allocated.
  84  */
  85 int lz4_decompress_unknownoutputsize(const char *src, size_t src_len,
  86                 char *dest, size_t *dest_len);
  87 #endif