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7795edd6 JAS |
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 (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level) | |
23 | { | |
24 | z_stream stream; | |
25 | int err; | |
26 | ||
27 | stream.next_in = (Bytef *)source; | |
28 | stream.avail_in = (uInt)sourceLen; | |
29 | #ifdef MAXSEG_64K | |
30 | /* Check for source > 64K on 16-bit machine: */ | |
31 | if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR; | |
32 | #endif | |
33 | stream.next_out = dest; | |
34 | stream.avail_out = (uInt)*destLen; | |
35 | if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR; | |
36 | ||
37 | stream.zalloc = Z_NULL; | |
38 | stream.zfree = Z_NULL; | |
39 | stream.opaque = (voidpf)0; | |
40 | ||
41 | err = deflateInit(&stream, level); | |
42 | if (err != Z_OK) return err; | |
43 | ||
44 | err = deflate(&stream, Z_FINISH); | |
45 | if (err != Z_STREAM_END) { | |
46 | deflateEnd(&stream); | |
47 | return err == Z_OK ? Z_BUF_ERROR : err; | |
48 | } | |
49 | *destLen = stream.total_out; | |
50 | ||
51 | err = deflateEnd(&stream); | |
52 | return err; | |
53 | } | |
54 | ||
55 | /* =========================================================================== | |
56 | */ | |
57 | int ZEXPORT compress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen) | |
58 | { | |
59 | return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION); | |
60 | } | |
61 | ||
62 | /* =========================================================================== | |
63 | If the default memLevel or windowBits for deflateInit() is changed, then | |
64 | this function needs to be updated. | |
65 | */ | |
66 | uLong ZEXPORT compressBound (uLong sourceLen) | |
67 | { | |
68 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + | |
69 | (sourceLen >> 25) + 13; | |
70 | } |