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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 {
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 
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;
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  */
82  uLong sourceLen;
83 {
84  return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
85  (sourceLen >> 25) + 13;
86 }
GLint level
Definition: gl.h:1546
#define max(a, b)
Definition: svc.c:63
int ZEXPORT deflateEnd(z_streamp strm)
Definition: deflate.c:1079
#define deflateInit(strm, level)
Definition: zlib.h:1793
#define Z_STREAM_END
Definition: zlib.h:178
#define z_const
Definition: zconf.h:237
Byte FAR Bytef
Definition: zconf.h:400
int ZEXPORT compress2(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level)
Definition: compress.c:22
#define Z_OK
Definition: zlib.h:177
#define Z_DEFAULT_COMPRESSION
Definition: zlib.h:193
unsigned long uLong
Definition: zconf.h:394
uLong ZEXPORT compressBound(uLong sourceLen)
Definition: compress.c:81
int ZEXPORT compress(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen)
Definition: compress.c:68
GLint left
Definition: glext.h:7726
#define Z_NO_FLUSH
Definition: zlib.h:168
Definition: parse.h:22
GLuint GLuint stream
Definition: glext.h:7522
int ZEXPORT deflate(z_streamp strm, int flush)
Definition: deflate.c:766
#define err(...)
uLong FAR uLongf
Definition: zconf.h:405
Byte FAR * voidpf
Definition: zconf.h:413
#define Z_FINISH
Definition: zlib.h:172
GLsizei GLsizei GLchar * source
Definition: glext.h:6048
static char * dest
Definition: rtl.c:135
#define ZEXPORT
Definition: zconf.h:380
unsigned int uInt
Definition: zconf.h:393