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compress.c
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1/* compress.c -- compress a memory buffer
2 * Copyright (C) 1995-2005, 2014, 2016 Jean-loup Gailly, Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6/* @(#) $Id$ */
7
8#define ZLIB_INTERNAL
9#include "zlib.h"
10
11/* ===========================================================================
12 Compresses the source buffer into the destination buffer. The level
13 parameter has the same meaning as in deflateInit. sourceLen is the byte
14 length of the source buffer. Upon entry, destLen is the total size of the
15 destination buffer, which must be at least 0.1% larger than sourceLen plus
16 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
17
18 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
19 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
20 Z_STREAM_ERROR if the level parameter is invalid.
21*/
22 int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
23 Bytef *dest;
24 uLongf *destLen;
25 const Bytef *source;
26 uLong sourceLen;
27 int level;
28{
29 z_stream stream;
30 int err;
31 const uInt max = (uInt)-1;
32 uLong left;
33
34 left = *destLen;
35 *destLen = 0;
36
37 stream.zalloc = (alloc_func)0;
38 stream.zfree = (free_func)0;
39 stream.opaque = (voidpf)0;
40
41 err = deflateInit(&stream, level);
42 if (err != Z_OK) return err;
43
44 stream.next_out = dest;
45 stream.avail_out = 0;
46 stream.next_in = (z_const Bytef *)source;
47 stream.avail_in = 0;
48
49 do {
50 if (stream.avail_out == 0) {
51 stream.avail_out = left > (uLong)max ? max : (uInt)left;
52 left -= stream.avail_out;
53 }
54 if (stream.avail_in == 0) {
55 stream.avail_in = sourceLen > (uLong)max ? max : (uInt)sourceLen;
56 sourceLen -= stream.avail_in;
57 }
58 err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH);
59 } while (err == Z_OK);
60
61 *destLen = stream.total_out;
62 deflateEnd(&stream);
63 return err == Z_STREAM_END ? Z_OK : err;
64}
65
66/* ===========================================================================
67 */
68 int ZEXPORT compress (dest, destLen, source, sourceLen)
69 Bytef *dest;
70 uLongf *destLen;
71 const Bytef *source;
72 uLong sourceLen;
73{
74 return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
75}
76
77/* ===========================================================================
78 If the default memLevel or windowBits for deflateInit() is changed, then
79 this function needs to be updated.
80 */
81 uLong ZEXPORT compressBound (sourceLen)
82 uLong sourceLen;
83{
84 return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
85 (sourceLen >> 25) + 13;
86}
compressBound
uLong ZEXPORT compressBound(uLong sourceLen)
Definition: compress.c:81
compress2
int ZEXPORT compress2(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level)
Definition: compress.c:22
compress
int ZEXPORT compress(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen)
Definition: compress.c:68
deflateEnd
int ZEXPORT deflateEnd(z_streamp strm)
Definition: deflate.c:1076
deflate
int ZEXPORT deflate(z_streamp strm, int flush)
Definition: deflate.c:763
z_stream_s
Definition: zlib.h:86
z_stream_s::avail_in
uInt avail_in
Definition: zlib.h:88
z_stream_s::zalloc
alloc_func zalloc
Definition: zlib.h:98
z_stream_s::avail_out
uInt avail_out
Definition: zlib.h:92
z_stream_s::next_in
z_const Bytef * next_in
Definition: zlib.h:87
z_stream_s::zfree
free_func zfree
Definition: zlib.h:99
z_stream_s::opaque
voidpf opaque
Definition: zlib.h:100
z_stream_s::total_out
uLong total_out
Definition: zlib.h:93
z_stream_s::next_out
Bytef * next_out
Definition: zlib.h:91
uLongf
uLong FAR uLongf
Definition: zconf.h:405
voidpf
Byte FAR * voidpf
Definition: zconf.h:413
ZEXPORT
#define ZEXPORT
Definition: zconf.h:380
uInt
unsigned int uInt
Definition: zconf.h:393
z_const
#define z_const
Definition: zconf.h:237
uLong
unsigned long uLong
Definition: zconf.h:394
Bytef
Byte FAR Bytef
Definition: zconf.h:400
zlib.h
Z_STREAM_END
#define Z_STREAM_END
Definition: zlib.h:178
Z_FINISH
#define Z_FINISH
Definition: zlib.h:172
Z_OK
#define Z_OK
Definition: zlib.h:177
Z_NO_FLUSH
#define Z_NO_FLUSH
Definition: zlib.h:168
deflateInit
#define deflateInit(strm, level)
Definition: zlib.h:1793
Z_DEFAULT_COMPRESSION
#define Z_DEFAULT_COMPRESSION
Definition: zlib.h:193