| 1 | /* compress.c -- compress a memory buffer
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| 2 | * Copyright (C) 1995-2005, 2014, 2016 Jean-loup Gailly, Mark Adler
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| 3 | * For conditions of distribution and use, see copyright notice in zlib.h
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| 4 | */
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| 5 |
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| 6 | /* @(#) $Id$ */
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| 7 |
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| 8 | #define ZLIB_INTERNAL
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| 9 | #include "zlib.h"
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| 10 |
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| 11 | /* ===========================================================================
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| 12 | Compresses the source buffer into the destination buffer. The level
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| 13 | parameter has the same meaning as in deflateInit. sourceLen is the byte
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| 14 | length of the source buffer. Upon entry, destLen is the total size of the
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| 15 | destination buffer, which must be at least 0.1% larger than sourceLen plus
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| 16 | 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
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| 17 |
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| 18 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
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| 19 | memory, Z_BUF_ERROR if there was not enough room in the output buffer,
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| 20 | Z_STREAM_ERROR if the level parameter is invalid.
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| 21 | */
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| 22 | int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
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| 23 | Bytef *dest;
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| 24 | uLongf *destLen;
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| 25 | const Bytef *source;
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| 26 | uLong sourceLen;
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| 27 | int level;
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| 28 | {
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| 29 | z_stream stream;
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| 30 | int err;
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| 31 | const uInt max = (uInt)-1;
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| 32 | uLong left;
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| 33 |
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| 34 | left = *destLen;
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| 35 | *destLen = 0;
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| 36 |
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| 37 | stream.zalloc = (alloc_func)0;
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| 38 | stream.zfree = (free_func)0;
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| 39 | stream.opaque = (voidpf)0;
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| 40 |
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| 41 | err = deflateInit(&stream, level);
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| 42 | if (err != Z_OK) return err;
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| 43 |
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| 44 | stream.next_out = dest;
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| 45 | stream.avail_out = 0;
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| 46 | stream.next_in = (z_const Bytef *)source;
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| 47 | stream.avail_in = 0;
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| 48 |
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| 49 | do {
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| 50 | if (stream.avail_out == 0) {
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| 51 | stream.avail_out = left > (uLong)max ? max : (uInt)left;
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| 52 | left -= stream.avail_out;
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| 53 | }
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| 54 | if (stream.avail_in == 0) {
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| 55 | stream.avail_in = sourceLen > (uLong)max ? max : (uInt)sourceLen;
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| 56 | sourceLen -= stream.avail_in;
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| 57 | }
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| 58 | err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH);
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| 59 | } while (err == Z_OK);
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| 60 |
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| 61 | *destLen = stream.total_out;
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| 62 | deflateEnd(&stream);
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| 63 | return err == Z_STREAM_END ? Z_OK : err;
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| 64 | }
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| 65 |
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| 66 | /* ===========================================================================
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| 67 | */
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| 68 | int ZEXPORT compress (dest, destLen, source, sourceLen)
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| 69 | Bytef *dest;
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| 70 | uLongf *destLen;
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| 71 | const Bytef *source;
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| 72 | uLong sourceLen;
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| 73 | {
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| 74 | return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
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| 75 | }
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| 76 |
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| 77 | /* ===========================================================================
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| 78 | If the default memLevel or windowBits for deflateInit() is changed, then
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| 79 | this function needs to be updated.
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| 80 | */
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| 81 | uLong ZEXPORT compressBound (sourceLen)
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| 82 | uLong sourceLen;
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| 83 | {
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| 84 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
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| 85 | (sourceLen >> 25) + 13;
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| 86 | }
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