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