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