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3
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1 /* compress.c -- compress a memory buffer
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2 * Copyright (C) 1995 Jean-loup Gailly.
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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: compress.c,v 1.1.1.1 1997/12/06 05:41:35 darius Exp $ */
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7
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8 #include "zlib.h"
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9
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10 /* ===========================================================================
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11 Compresses the source buffer into the destination buffer. sourceLen is
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12 the byte length of the source buffer. Upon entry, destLen is the total
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13 size of the destination buffer, which must be at least 0.1% larger than
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14 sourceLen plus 8 bytes. Upon exit, destLen is the actual size of the
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15 compressed buffer.
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16 This function can be used to compress a whole file at once if the
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17 input file is mmap'ed.
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18 compress returns Z_OK if success, Z_MEM_ERROR if there was not
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19 enough memory, Z_BUF_ERROR if there was not enough room in the output
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20 buffer.
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21 */
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22 int compress (dest, destLen, source, sourceLen)
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23 Byte *dest;
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24 uLong *destLen;
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25 Byte *source;
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26 uLong sourceLen;
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27 {
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28 z_stream stream;
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29 int err;
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30
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31 stream.next_in = source;
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32 stream.avail_in = (uInt)sourceLen;
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33 /* Check for source > 64K on 16-bit machine: */
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34 if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
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35
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36 stream.next_out = dest;
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37 stream.avail_out = (uInt)*destLen;
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38 if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
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39
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40 stream.zalloc = (alloc_func)0;
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41 stream.zfree = (free_func)0;
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42
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43 err = deflateInit(&stream, Z_DEFAULT_COMPRESSION);
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44 if (err != Z_OK) return err;
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45
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46 err = deflate(&stream, Z_FINISH);
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47 if (err != Z_STREAM_END) {
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48 deflateEnd(&stream);
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49 return err == Z_OK ? Z_BUF_ERROR : err;
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50 }
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51 *destLen = stream.total_out;
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52
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53 err = deflateEnd(&stream);
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54 return err;
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55 }
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