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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#ifndef COMMON_ZLIB_H
#define COMMON_ZLIB_H
#include "common/scummsys.h"
namespace Common {
class SeekableReadStream;
class WriteStream;
#if defined(USE_ZLIB)
/**
* Thin wrapper around zlib's uncompress() function. This wrapper makes
* it possible to uncompress data in engines without being forced to link
* them against zlib, thus simplifying the build system.
*
* Taken from the zlib manual:
* Decompresses the src buffer into the dst buffer.
* srcLen is the byte length of the source buffer. Upon entry, dstLen is the
* total size of the destination buffer, which must be large enough to hold
* the entire uncompressed data. Upon exit, dstLen is the actual size of the
* compressed buffer.
*
* @param dst the buffer to store into.
* @param dstLen a pointer to the size of the destination buffer.
* @param src the data to be decompressed.
* @param srcLen the size of the compressed data.
*
* @return true on success (i.e. Z_OK), false otherwise.
*/
bool uncompress(byte *dst, unsigned long *dstLen, const byte *src, unsigned long srcLen);
/**
* Wrapper around zlib's inflate functions. This function will call the
* necessary inflate functions to uncompress data compressed with deflate
* but *not* with the standard zlib header.
*
* Decompresses the src buffer into the dst buffer.
* srcLen is the byte length of the source buffer, dstLen is the byte
* length of the output buffer.
* It decompress as much data as possible, up to dstLen bytes.
* If a dictionary is provided through the dict buffer, uses it to initializes
* the internal decompression dictionary, before the decompression takes place.
*
* @param dst the buffer to store into.
* @param dstLen the size of the destination buffer.
* @param src the data to be decompressed.
* @param dstLen the size of the compressed data.
* @param dict (optional) a decompress dictionary.
* @param dictLen (optional) the size of the dictionary.
* Mandatory if dict is not 0.
*
* @return true on success (Z_OK or Z_STREAM_END), false otherwise.
*/
bool inflateZlibHeaderless(byte *dst, uint dstLen, const byte *src, uint srcLen, const byte *dict = 0, uint dictLen = 0);
#endif
/**
* Take an arbitrary SeekableReadStream and wrap it in a custom stream which
* provides transparent on-the-fly decompression. Assumes the data it
* retrieves from the wrapped stream to be either uncompressed or in gzip
* format. In the former case, the original stream is returned unmodified
* (and in particular, not wrapped).
*
* Certain GZip-formats don't supply an easily readable length, if you
* still need the length carried along with the stream, and you know
* the decompressed length at wrap-time, then it can be supplied as knownSize
* here. knownSize will be ignored if the GZip-stream DOES include a length.
*
* It is safe to call this with a NULL parameter (in this case, NULL is
* returned).
*
* @param toBeWrapped the stream to be wrapped (if it is in gzip-format)
* @param knownSize a supplied length of the compressed data (if not available directly)
*/
SeekableReadStream *wrapCompressedReadStream(SeekableReadStream *toBeWrapped, uint32 knownSize = 0);
/**
* Take an arbitrary WriteStream and wrap it in a custom stream which provides
* transparent on-the-fly compression. The compressed data is written in the
* gzip format, unless ZLIB support has been disabled, in which case the given
* stream is returned unmodified (and in particular, not wrapped).
*
* It is safe to call this with a NULL parameter (in this case, NULL is
* returned).
*/
WriteStream *wrapCompressedWriteStream(WriteStream *toBeWrapped);
} // End of namespace Common
#endif
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