1/*
2 * Copyright (c) 2008 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/* compress.c -- compress a memory buffer
29 * Copyright (C) 1995-2003 Jean-loup Gailly.
30 * For conditions of distribution and use, see copyright notice in zlib.h
31 */
32
33/* @(#) $Id$ */
34
35#define ZLIB_INTERNAL
36#if KERNEL
37    #include <libkern/zlib.h>
38#else
39    #include "zlib.h"
40#endif /* KERNEL */
41
42/* ===========================================================================
43     Compresses the source buffer into the destination buffer. The level
44   parameter has the same meaning as in deflateInit.  sourceLen is the byte
45   length of the source buffer. Upon entry, destLen is the total size of the
46   destination buffer, which must be at least 0.1% larger than sourceLen plus
47   12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
48
49     compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
50   memory, Z_BUF_ERROR if there was not enough room in the output buffer,
51   Z_STREAM_ERROR if the level parameter is invalid.
52*/
53int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
54    Bytef *dest;
55    uLongf *destLen;
56    const Bytef *source;
57    uLong sourceLen;
58    int level;
59{
60    z_stream stream;
61    int err;
62
63    stream.next_in = (Bytef*)source;
64    stream.avail_in = (uInt)sourceLen;
65#ifdef MAXSEG_64K
66    /* Check for source > 64K on 16-bit machine: */
67    if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
68#endif
69    stream.next_out = dest;
70    stream.avail_out = (uInt)*destLen;
71    if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
72
73    stream.zalloc = (alloc_func)0;
74    stream.zfree = (free_func)0;
75    stream.opaque = (voidpf)0;
76
77    err = deflateInit(&stream, level);
78    if (err != Z_OK) return err;
79
80    err = deflate(&stream, Z_FINISH);
81    if (err != Z_STREAM_END) {
82        deflateEnd(&stream);
83        return err == Z_OK ? Z_BUF_ERROR : err;
84    }
85    *destLen = stream.total_out;
86
87    err = deflateEnd(&stream);
88    return err;
89}
90
91/* ===========================================================================
92 */
93int ZEXPORT compress (dest, destLen, source, sourceLen)
94    Bytef *dest;
95    uLongf *destLen;
96    const Bytef *source;
97    uLong sourceLen;
98{
99    return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
100}
101
102/* ===========================================================================
103     If the default memLevel or windowBits for deflateInit() is changed, then
104   this function needs to be updated.
105 */
106uLong ZEXPORT compressBound (sourceLen)
107    uLong sourceLen;
108{
109    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + 11;
110}
111