57 lines
1.8 KiB
C
57 lines
1.8 KiB
C
/* compress.c -- compress a memory buffer
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* Copyright (C) 1995 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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/* $Id: compress.c,v 1.6 1995/05/03 17:27:08 jloup Exp $ */
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#include "zlib.h"
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/* ===========================================================================
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Compresses the source buffer into the destination buffer. sourceLen is
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the byte length of the source buffer. Upon entry, destLen is the total
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size of the destination buffer, which must be at least 0.1% larger than
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sourceLen plus 8 bytes. Upon exit, destLen is the actual size of the
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compressed buffer.
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This function can be used to compress a whole file at once if the
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input file is mmap'ed.
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compress returns Z_OK if success, Z_MEM_ERROR if there was not
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enough memory, Z_BUF_ERROR if there was not enough room in the output
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buffer.
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*/
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int compress (dest, destLen, source, sourceLen)
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Bytef *dest;
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uLongf *destLen;
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Bytef *source;
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uLong sourceLen;
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{
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z_stream stream;
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int err;
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stream.next_in = source;
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stream.avail_in = (uInt)sourceLen;
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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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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, Z_DEFAULT_COMPRESSION);
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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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