[388] | 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 | }
|
---|