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*/
22int ZEXPORT compress2 (
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 = (z_const 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 */
62int ZEXPORT compress (
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 */
75uLong ZEXPORT compressBound (
76    uLong sourceLen)
77{
78    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
79           (sourceLen >> 25) + 13;
80}
81