Ruby: ext/zlib/zlib-1.2.13/compress.c Source File

Ruby 3.0.5p211 (2022-11-24 revision ba5cf0f7c52d4d35cc6a173c89eda98ceffa2dcf)

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:1130
deflate
int ZEXPORT deflate(z_streamp strm, int flush)
Definition: deflate.c:815
max
int max
Definition: enough.c:225
stream
voidpf stream
Definition: ioapi.h:138
z_stream_s
Definition: zlib.h:86
err
int err
Definition: win32.c:142
uLongf
uLong FAR uLongf
Definition: zconf.h:411
uLong
unsigned long uLong
Definition: zconf.h:400
ZEXPORT
#define ZEXPORT
Definition: zconf.h:386
voidpf
void FAR * voidpf
Definition: zconf.h:415
uInt
unsigned int uInt
Definition: zconf.h:399
z_const
#define z_const
Definition: zconf.h:240
Bytef
Byte FAR Bytef
Definition: zconf.h:406
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:1810
Z_DEFAULT_COMPRESSION
#define Z_DEFAULT_COMPRESSION
Definition: zlib.h:193