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common/compression/deflate.h

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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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef COMMON_ZLIB_H
+#define COMMON_ZLIB_H
+
+#include "common/scummsys.h"
+#include "common/types.h"
+
+namespace Common {
+
+/**
+ * @defgroup common_deflate deflate
+ * @ingroup common
+ *
+ * @brief API for deflate based operations.
+ *
+ * @{
+ */
+
+class SeekableReadStream;
+class WriteStream;
+
+/**
+ * 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 inflateZlib(byte *dst, unsigned long *dstLen, const byte *src, unsigned long srcLen);
+static inline bool inflateZlib(byte *dst, unsigned long  dstLen, const byte *src, unsigned long srcLen) {
+	return inflateZlib(dst, &dstLen, src, 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 srcLen    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 = nullptr, uint dictLen = 0);
+static inline bool inflateZlibHeaderless(byte *dst, uint dstLen, const byte *src, uint srcLen, const byte *dict = nullptr, uint dictLen = 0) {
+	return inflateZlibHeaderless(dst, &dstLen, src, srcLen, dict, dictLen);
+}
+
+/**
+ * Wrapper around zlib's inflate functions. This function will call the
+ * modified inflate functions to uncompress data compressed for Clickteam
+ * Installer files.
+ *
+ * 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.
+ *
+ * @param dst       the buffer to store into.
+ * @param dstLen    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 (Z_OK or Z_STREAM_END), false otherwise.
+ */
+bool inflateClickteam(byte *dst, uint *dstLen, const byte *src, uint srcLen);
+static inline bool inflateClickteam(byte *dst, uint  dstLen, const byte *src, uint srcLen) {
+	return inflateClickteam(dst, &dstLen, src, srcLen);
+}
+
+/**
+ * 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). In the latter case the stream is
+ * returned wrapped, unless there is no ZLIB support, then NULL is returned
+ * and the old stream is destroyed.
+ *
+ * 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.
+ * The created stream also becomes responsible for freeing the passed stream.
+ *
+ * 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 uncompressed data (if not available directly)
+ */
+SeekableReadStream *wrapCompressedReadStream(SeekableReadStream *toBeWrapped,
+		DisposeAfterUse::Flag disposeParent = DisposeAfterUse::YES, uint64 knownSize = 0);
+
+/**
+ * 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 is compressed with deflate algorithm.
+ *
+ * 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 uncompressed data (if not available directly)
+ */
+SeekableReadStream *wrapDeflateReadStream(SeekableReadStream *toBeWrapped,
+		DisposeAfterUse::Flag disposeParent = DisposeAfterUse::YES, uint64 knownSize = 0,
+		const byte *dict = nullptr, uint dictLen = 0);
+
+/**
+ * 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 is compressed with the Clickteam deflate
+ * variant algorithm.
+ * The stream is returned wrapped, unless there is no ZLIB support,
+ * then NULL is returned and the old stream is destroyed.
+ *
+ * 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 *wrapClickteamReadStream(SeekableReadStream *toBeWrapped,
+		DisposeAfterUse::Flag disposeParent = DisposeAfterUse::YES, uint64 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).
+ * The created stream also becomes responsible for freeing the passed stream.
+ *
+ * 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