Mercurial > repos > blastem
comparison zlib/compress.c @ 1530:00d788dac91a
Added support for reading gzipped ROMs
author | Michael Pavone <pavone@retrodev.com> |
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date | Fri, 23 Mar 2018 22:30:02 -0700 |
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1529:f7fe240a7da6 | 1530:00d788dac91a |
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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 } |