liblzf/lzf.h

/*
 * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
 *
 * 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.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#ifndef LZF_H
#define LZF_H

/***********************************************************************
**
**      lzf -- an extremely fast/free compression/decompression-method
**      http://liblzf.plan9.de/
**
**      This algorithm is believed to be patent-free.
**
***********************************************************************/

/* API version (major * 256 + minor)
 * major API version gets bumped on incompatible changes.
 * minor API version gets bumped on compatible changes.
 * 1.5 => 1.6: add LZF_MAX_COMPRESSED_SIZE
 */
#define LZF_VERSION 0x0106

/*
 * 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 1 + 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.
 *
 * If the option LZF_STATE_ARG is enabled, an extra argument must be
 * supplied which is not reflected in this header file. Refer to lzfP.h
 * and lzf_c.c.
 *
 */
unsigned int
lzf_compress (const void *const in_data,  unsigned int in_len,
              void             *out_data, unsigned int out_len);

/*
 * The maximum out_len that needs to be allocated to make sure
 * any input data can be compressed without overflowing the output
 * buffer, i.e. maximum out_len = LZF_MAX_COMPRESSED_SIZE (in_len).
 * This is useful if you don't want to bother with the case of
 * incompressible data and just want to provide a buffer that is
 * guaranteeed to be big enough.
 * This macro can be used at preprocessing time.
 */
#define LZF_MAX_COMPRESSED_SIZE(n) ((((n) * 33) >> 5 ) + 1)

/*
 * 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 (const void *const in_data,  unsigned int in_len,
                void             *out_data, unsigned int out_len);

#endif

Revision:	1.18
Committed:	Mon Dec 10 21:34:33 2012 UTC (11 years, 4 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.17:	+1 -1 lines
Log Message:	* empty log message *
#	Content
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	/* API version (major * 256 + minor)
50	* major API version gets bumped on incompatible changes.
51	* minor API version gets bumped on compatible changes.
52	* 1.5 => 1.6: add LZF_MAX_COMPRESSED_SIZE
53	*/
54	#define LZF_VERSION 0x0106
55
56	/*
57	* Compress in_len bytes stored at the memory block starting at
58	* in_data and write the result to out_data, up to a maximum length
59	* of out_len bytes.
60	*
61	* If the output buffer is not large enough or any error occurs return 0,
62	* otherwise return the number of bytes used, which might be considerably
63	* more than in_len (but less than 1 + 104% of the original size), so it
64	* makes sense to always use out_len == in_len - 1), to ensure _some_
65	* compression, and store the data uncompressed otherwise (with a flag, of
66	* course.
67	*
68	* lzf_compress might use different algorithms on different systems and
69	* even different runs, thus might result in different compressed strings
70	* depending on the phase of the moon or similar factors. However, all
71	* these strings are architecture-independent and will result in the
72	* original data when decompressed using lzf_decompress.
73	*
74	* The buffers must not be overlapping.
75	*
76	* If the option LZF_STATE_ARG is enabled, an extra argument must be
77	* supplied which is not reflected in this header file. Refer to lzfP.h
78	* and lzf_c.c.
79	*
80	*/
81	unsigned int
82	lzf_compress (const void *const in_data, unsigned int in_len,
83	void *out_data, unsigned int out_len);
84
85	/*
86	* The maximum out_len that needs to be allocated to make sure
87	* any input data can be compressed without overflowing the output
88	* buffer, i.e. maximum out_len = LZF_MAX_COMPRESSED_SIZE (in_len).
89	* This is useful if you don't want to bother with the case of
90	* incompressible data and just want to provide a buffer that is
91	* guaranteeed to be big enough.
92	* This macro can be used at preprocessing time.
93	*/
94	#define LZF_MAX_COMPRESSED_SIZE(n) ((((n) * 33) >> 5 ) + 1)
95
96	/*
97	* Decompress data compressed with some version of the lzf_compress
98	* function and stored at location in_data and length in_len. The result
99	* will be stored at out_data up to a maximum of out_len characters.
100	*
101	* If the output buffer is not large enough to hold the decompressed
102	* data, a 0 is returned and errno is set to E2BIG. Otherwise the number
103	* of decompressed bytes (i.e. the original length of the data) is
104	* returned.
105	*
106	* If an error in the compressed data is detected, a zero is returned and
107	* errno is set to EINVAL.
108	*
109	* This function is very fast, about as fast as a copying loop.
110	*/
111	unsigned int
112	lzf_decompress (const void *const in_data, unsigned int in_len,
113	void *out_data, unsigned int out_len);
114
115	#endif
116