blob: d51ed2cd9f150f1c4722269fcc8e66107b668c43 [file] [log] [blame]
/****************************************************************************
* lzf -- an extremely fast/free compression/decompression-method
* http://liblzf.plan9.de/
*
* Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
* This algorithm is believed to be patent-free.
*
* Redistribution and use in source and binary forms, with or without modifica-
* tion, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __INCLUDE_LZF_H
#define __INCLUDE_LZF_H 1
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define LZF_VERSION 0x0105 /* 1.5, API version */
#define HLOG CONFIG_LIBC_LZF_HLOG
#define LZF_TYPE0_HDR 0
#define LZF_TYPE1_HDR 1
#define LZF_TYPE0_HDR_SIZE 5
#define LZF_TYPE1_HDR_SIZE 7
#define LZF_MAX_HDR_SIZE 7
#define LZF_MIN_HDR_SIZE 5
/****************************************************************************
* Public Types
****************************************************************************/
/* LZF headers */
struct lzf_header_s /* Common data header */
{
uint8_t lzf_magic[2]; /* [0]='Z', [1]='V' */
uint8_t lzf_type; /* LZF_TYPE0_HDR or LZF_TYPE1_HDR */
};
struct lzf_type0_header_s /* Uncompressed data header */
{
uint8_t lzf_magic[2]; /* [0]='Z', [1]='V' */
uint8_t lzf_type; /* LZF_TYPE0_HDR */
uint8_t lzf_len[2]; /* Data length (big-endian) */
};
struct lzf_type1_header_s /* Compressed data header */
{
uint8_t lzf_magic[2]; /* [0]='Z', [1]='V' */
uint8_t lzf_type; /* LZF_TYPE1_HDR */
uint8_t lzf_clen[2]; /* Compressed data length (big-endian) */
uint8_t lzf_ulen[2]; /* Uncompressed data length (big-endian) */
};
/* LZF hash table */
#if LZF_USE_OFFSETS
# define LZF_HSLOT_BIAS ((const uint8_t *)in_data)
typedef unsigned int lzf_hslot_t;
#else
# define LZF_HSLOT_BIAS 0
typedef const uint8_t *lzf_hslot_t;
#endif
typedef lzf_hslot_t lzf_state_t[1 << HLOG];
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: lzf_compress
*
* Description:
* Compress in_len bytes stored at the memory block starting at
* in_data and write the result to out_data, up to a maximum length
* of out_len bytes.
*
* If the output buffer is not large enough or any error occurs return 0,
* otherwise return the number of bytes used, which might be considerably
* more than in_len (but less than 104% of the original size), so it
* makes sense to always use out_len == in_len - 1), to ensure _some_
* compression, and store the data uncompressed otherwise (with a flag, of
* course.
*
* lzf_compress might use different algorithms on different systems and
* even different runs, thus might result in different compressed strings
* depending on the phase of the moon or similar factors. However, all
* these strings are architecture-independent and will result in the
* original data when decompressed using lzf_decompress.
*
* The buffers must not be overlapping.
*
* Compressed format:
*
* 000LLLLL <L+1> ; literal, L+1=1..33 octets
* LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset
* 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset
*
****************************************************************************/
size_t lzf_compress(FAR const void *const in_data,
unsigned int in_len, FAR void *out_data,
unsigned int out_len, lzf_state_t htab,
FAR struct lzf_header_s **reshdr);
/****************************************************************************
* Name: lzf_decompress
*
* Description:
* Decompress data compressed with some version of the lzf_compress
* function and stored at location in_data and length in_len. The result
* will be stored at out_data up to a maximum of out_len characters.
*
* If the output buffer is not large enough to hold the decompressed
* data, a 0 is returned and errno is set to E2BIG. Otherwise the number
* of decompressed bytes (i.e. the original length of the data) is
* returned.
*
* If an error in the compressed data is detected, a zero is returned and
* errno is set to EINVAL.
*
* This function is very fast, about as fast as a copying loop.
*
****************************************************************************/
unsigned int lzf_decompress(FAR const void *const in_data,
unsigned int in_len, FAR void *out_data,
unsigned int out_len);
#endif /* __INCLUDE_LZF_H */