1 | /* compress.c -- compress a memory buffer |
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2 | * Copyright (C) 1995-2002 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.cc,v 1.1 2005/05/12 21:04:53 duns Exp $ */ |
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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 (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen, int level) |
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23 | { |
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24 | z_stream stream; |
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25 | int err; |
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26 | |
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27 | stream.next_in = (Bytef*)source; |
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28 | stream.avail_in = (uInt)sourceLen; |
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29 | #ifdef MAXSEG_64K |
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30 | /* Check for source > 64K on 16-bit machine: */ |
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31 | if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR; |
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32 | #endif |
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33 | stream.next_out = dest; |
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34 | stream.avail_out = (uInt)*destLen; |
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35 | if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR; |
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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 | err = deflate(&stream, Z_FINISH); |
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45 | if (err != Z_STREAM_END) { |
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46 | deflateEnd(&stream); |
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47 | return err == Z_OK ? Z_BUF_ERROR : err; |
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48 | } |
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49 | *destLen = stream.total_out; |
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50 | |
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51 | err = deflateEnd(&stream); |
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52 | return err; |
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53 | } |
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54 | |
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55 | /* =========================================================================== |
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56 | */ |
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57 | int ZEXPORT compress (Bytef *dest, uLongf *destLen, const Bytef *source, uLong sourceLen) |
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58 | { |
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59 | return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION); |
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60 | } |
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61 | |
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62 | /* =========================================================================== |
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63 | If the default memLevel or windowBits for deflateInit() is changed, then |
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64 | this function needs to be updated. |
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65 | */ |
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66 | uLong ZEXPORT compressBound (uLong sourceLen) |
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67 | { |
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68 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + 11; |
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69 | } |
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