libkern/zlib/compress.c

   1 /*
   2  * Copyright (c) 2008-2016 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 */
  53 int ZEXPORT
  54 compress2(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen,
  55           int level)
  56 {
  57     z_stream stream;
  58     int err;
  59
  60     stream.next_in = (Bytef*)source;
  61     stream.avail_in = (uInt)sourceLen;
  62 #ifdef MAXSEG_64K
  63     /* Check for source > 64K on 16-bit machine: */
  64     if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
  65 #endif
  66     stream.next_out = dest;
  67     stream.avail_out = (uInt)*destLen;
  68     if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
  69
  70     stream.zalloc = (alloc_func)0;
  71     stream.zfree = (free_func)0;
  72     stream.opaque = (voidpf)0;
  73
  74     err = deflateInit(&stream, level);
  75     if (err != Z_OK) return err;
  76
  77     err = deflate(&stream, Z_FINISH);
  78     if (err != Z_STREAM_END) {
  79         deflateEnd(&stream);
  80         return err == Z_OK ? Z_BUF_ERROR : err;
  81     }
  82     *destLen = stream.total_out;
  83
  84     err = deflateEnd(&stream);
  85     return err;
  86 }
  87
  88 /* ===========================================================================
  89  */
  90 int ZEXPORT
  91 compress(Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen)
  92 {
  93     return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
  94 }
  95
  96 /* ===========================================================================
  97      If the default memLevel or windowBits for deflateInit() is changed, then
  98    this function needs to be updated.
  99  */
 100 uLong ZEXPORT
 101 compressBound(uLong sourceLen)
 102 {
 103     return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + 11;
 104 }