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/* compress.c -- compress a memory buffer
* Copyright (C) 1995-1996 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
/* $Id: compress.c,v 1.10 1996/05/23 16:51:12 me Exp $ */
#include "zlib.h"
/* ===========================================================================
Compresses the source buffer into the destination buffer. 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 8 bytes. Upon exit, destLen is the actual size of the
compressed buffer.
This function can be used to compress a whole file at once if the
input file is mmap'ed.
compress 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
int compress (dest, destLen, source, sourceLen)
Bytef *dest;
uLongf *destLen;
const Bytef *source;
uLong sourceLen;
z_stream stream;
int err;
stream.next_in = (Bytef*)source;
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;
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, Z_DEFAULT_COMPRESSION);
if (err != Z_OK) return err;
err = deflate(&stream, Z_FINISH);
if (err != Z_STREAM_END) {
return err == Z_OK ? Z_BUF_ERROR : err;
*destLen = stream.total_out;
err = deflateEnd(&stream);
return err;