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| 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 (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 |
| 32 stream.next_in = (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 */ |
| 62 int ZEXPORT compress (dest, destLen, source, sourceLen) |
| 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 */ |
| 75 uLong ZEXPORT compressBound (sourceLen) |
| 76 uLong sourceLen; |
| 77 { |
| 78 return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + |
| 79 (sourceLen >> 25) + 13; |
| 80 } |
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