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/* $OpenBSD: compress.c,v 1.6 2005/07/20 15:56:41 millert Exp $ */ |
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/* compress.c -- compress a memory buffer |
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* Copyright (C) 1995-2003 Jean-loup Gailly. |
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* For conditions of distribution and use, see copyright notice in zlib.h |
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*/ |
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#define ZLIB_INTERNAL |
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#include "zlib.h" |
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/* =========================================================================== |
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Compresses the source buffer into the destination buffer. The level |
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parameter has the same meaning as in deflateInit. sourceLen is the byte |
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length of the source buffer. Upon entry, destLen is the total size of the |
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destination buffer, which must be at least 0.1% larger than sourceLen plus |
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12 bytes. Upon exit, destLen is the actual size of the compressed buffer. |
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compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
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Z_STREAM_ERROR if the level parameter is invalid. |
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*/ |
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int ZEXPORT compress2 (dest, destLen, source, sourceLen, level) |
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Bytef *dest; |
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uLongf *destLen; |
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const Bytef *source; |
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uLong sourceLen; |
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int level; |
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{ |
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z_stream stream; |
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int err; |
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stream.next_in = (Bytef*)source; |
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stream.avail_in = (uInt)sourceLen; |
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#ifdef MAXSEG_64K |
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/* Check for source > 64K on 16-bit machine: */ |
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if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR; |
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#endif |
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stream.next_out = dest; |
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stream.avail_out = (uInt)*destLen; |
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if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR; |
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stream.zalloc = (alloc_func)0; |
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stream.zfree = (free_func)0; |
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stream.opaque = (voidpf)0; |
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err = deflateInit(&stream, level); |
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if (err != Z_OK) return err; |
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err = deflate(&stream, Z_FINISH); |
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if (err != Z_STREAM_END) { |
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deflateEnd(&stream); |
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return err == Z_OK ? Z_BUF_ERROR : err; |
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} |
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*destLen = stream.total_out; |
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err = deflateEnd(&stream); |
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return err; |
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} |
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/* =========================================================================== |
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*/ |
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int ZEXPORT compress (dest, destLen, source, sourceLen) |
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Bytef *dest; |
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uLongf *destLen; |
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const Bytef *source; |
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uLong sourceLen; |
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{ |
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return compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION); |
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} |
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/* =========================================================================== |
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If the default memLevel or windowBits for deflateInit() is changed, then |
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this function needs to be updated. |
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*/ |
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uLong ZEXPORT compressBound (sourceLen) |
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uLong sourceLen; |
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{ |
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return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + 11; |
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} |