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1 /* compress.c -- compress a memory buffer
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2 * Copyright (C) 1995-2005 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 /* @(#) $Id$ */
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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
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32 stream.next_in = (Bytef*)source;
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33 stream.avail_in = (uInt)sourceLen;
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34 #ifdef MAXSEG_64K
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35 /* Check for source > 64K on 16-bit machine: */
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36 if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
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37 #endif
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38 stream.next_out = dest;
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39 stream.avail_out = (uInt)*destLen;
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40 if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
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41
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42 stream.zalloc = (alloc_func)0;
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43 stream.zfree = (free_func)0;
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44 stream.opaque = (voidpf)0;
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45
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46 err = deflateInit(&stream, level);
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47 if (err != Z_OK) return err;
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48
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49 err = deflate(&stream, Z_FINISH);
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50 if (err != Z_STREAM_END) {
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51 deflateEnd(&stream);
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52 return err == Z_OK ? Z_BUF_ERROR : err;
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53 }
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54 *destLen = stream.total_out;
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55
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56 err = deflateEnd(&stream);
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57 return err;
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58 }
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59
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60 /* ===========================================================================
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61 */
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62 int ZEXPORT compress (dest, destLen, source, sourceLen)
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63 Bytef *dest;
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64 uLongf *destLen;
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65 const Bytef *source;
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66 uLong sourceLen;
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67 {
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68 return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
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69 }
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70
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71 /* ===========================================================================
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72 If the default memLevel or windowBits for deflateInit() is changed, then
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73 this function needs to be updated.
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74 */
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75 uLong ZEXPORT compressBound (sourceLen)
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76 uLong sourceLen;
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77 {
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78 return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
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79 (sourceLen >> 25) + 13;
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80 }
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