LXR linux/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        (16384)
  13#define LZ4HC_MEM_COMPRESS      (262144 + (2 * 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 */
  20static 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 */
  39int 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  */
  56int 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 */
  70int lz4_decompress(const unsigned char *src, size_t *src_len,
  71                unsigned char *dest, 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 */
  85int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
  86                unsigned char *dest, size_t *dest_len);
  87#endif
  88