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compress.c
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1 /* compress.c -- compress a memory buffer
2 * Copyright (C) 1995-2005 Jean-loup Gailly.
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
32 stream.next_in = (Bytef*)source;
33 stream.avail_in = (uInt)sourceLen;
34 #ifdef MAXSEG_64K
35 /* Check for source > 64K on 16-bit machine: */
36 if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
37 #endif
38 stream.next_out = dest;
39 stream.avail_out = (uInt)*destLen;
40 if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
41
42 stream.zalloc = (alloc_func)0;
43 stream.zfree = (free_func)0;
44 stream.opaque = (voidpf)0;
45
46 err = deflateInit(&stream, level);
47 if (err != Z_OK) return err;
48
49 err = deflate(&stream, Z_FINISH);
50 if (err != Z_STREAM_END) {
51 deflateEnd(&stream);
52 return err == Z_OK ? Z_BUF_ERROR : err;
53 }
54 *destLen = stream.total_out;
55
56 err = deflateEnd(&stream);
57 return err;
58 }
59
60 /* ===========================================================================
61 */
62 int ZEXPORT compress (dest, destLen, source, sourceLen)
63 Bytef *dest;
64 uLongf *destLen;
65 const Bytef *source;
66 uLong sourceLen;
67 {
68 return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
69 }
70
71 /* ===========================================================================
72 If the default memLevel or windowBits for deflateInit() is changed, then
73 this function needs to be updated.
74 */
75 uLong ZEXPORT compressBound (sourceLen)
76 uLong sourceLen;
77 {
78 return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
79 (sourceLen >> 25) + 13;
80 }
compressBound
uLong ZEXPORT compressBound(uLong sourceLen)
Definition: compress.c:75
voidpf
Byte FAR * voidpf
Definition: zconf.h:355
z_stream_s::next_in
Bytef * next_in
Definition: zlib.h:86
z_stream_s::avail_in
uInt avail_in
Definition: zlib.h:87
uLong
unsigned long uLong
Definition: zconf.h:336
deflateEnd
int ZEXPORT deflateEnd(z_streamp strm)
Definition: deflate.c:895
Bytef
Byte FAR Bytef
Definition: zconf.h:342
z_stream_s::opaque
voidpf opaque
Definition: zlib.h:99
z_stream_s::zfree
free_func zfree
Definition: zlib.h:98
zlib.h
Z_FINISH
#define Z_FINISH
Definition: zlib.h:168
Z_STREAM_END
#define Z_STREAM_END
Definition: zlib.h:174
compress2
int ZEXPORT compress2(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level)
Definition: compress.c:22
z_stream_s::zalloc
alloc_func zalloc
Definition: zlib.h:97
z_stream_s::next_out
Bytef * next_out
Definition: zlib.h:90
deflate
int ZEXPORT deflate(z_streamp strm, int flush)
Definition: deflate.c:582
z_stream_s::total_out
uLong total_out
Definition: zlib.h:92
uLongf
uLong FAR uLongf
Definition: zconf.h:347
compress
int ZEXPORT compress(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen)
Definition: compress.c:62
Z_BUF_ERROR
#define Z_BUF_ERROR
Definition: zlib.h:180
deflateInit
#define deflateInit(strm, level)
Definition: zlib.h:1546
z_stream_s::avail_out
uInt avail_out
Definition: zlib.h:91
Z_OK
#define Z_OK
Definition: zlib.h:173
const
#define const
Definition: zconf.h:196
ZEXPORT
#define ZEXPORT
Definition: zconf.h:322
level
int level(0)
Z_DEFAULT_COMPRESSION
#define Z_DEFAULT_COMPRESSION
Definition: zlib.h:189
z_stream_s
Definition: zlib.h:85
uInt
unsigned int uInt
Definition: zconf.h:335