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engines/sci/resource/decompressor.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 SCI_RESOURCE_DECOMPRESSOR_H
+#define SCI_RESOURCE_DECOMPRESSOR_H
+
+#include "common/scummsys.h"
+
+namespace Common {
+class ReadStream;
+}
+
+namespace Sci {
+
+enum ResourceCompression {
+	kCompUnknown = -1,
+	kCompNone = 0,
+	kCompLZW,
+	kCompHuffman,
+	kCompLZW1,			// LZW-like compression used in SCI01 and SCI1
+	kCompLZW1View,		// Comp3 + view Post-processing
+	kCompLZW1Pic,		// Comp3 + pic Post-processing
+#ifdef ENABLE_SCI32
+	kCompSTACpack,	// ? Used in SCI32
+#endif
+	kCompDCL
+};
+
+/**
+ * Base class for decompressors.
+ * Simply copies nPacked bytes from src to dest.
+ */
+class Decompressor {
+public:
+	Decompressor() :
+		_dwBits(0),
+		_nBits(0),
+		_szPacked(0),
+		_szUnpacked(0),
+		_dwRead(0),
+		_dwWrote(0),
+		_src(nullptr),
+		_dest(nullptr)
+	{}
+
+	virtual ~Decompressor() {}
+
+
+	virtual int unpack(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked);
+
+protected:
+	/**
+	 * Initialize decompressor.
+	 * @param src		source stream to read from
+	 * @param dest		destination stream to write to
+	 * @param nPacked	size of packed data
+	 * @param nUnpacket	size of unpacked data
+	 * @return 0 on success, non-zero on error
+	 */
+	virtual void init(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked);
+
+	/**
+	 * Get a number of bits from _src stream, starting with the most
+	 * significant unread bit of the current four byte block.
+	 * @param n		number of bits to get
+	 * @return n-bits number
+	 */
+	uint32 getBitsMSB(int n);
+
+	/**
+	 * Get a number of bits from _src stream, starting with the least
+	 * significant unread bit of the current four byte block.
+	 * @param n		number of bits to get
+	 * @return n-bits number
+	 */
+	uint32 getBitsLSB(int n);
+
+	/**
+	 * Get one byte from _src stream.
+	 * @return byte
+	 */
+	byte getByteMSB();
+	byte getByteLSB();
+
+	void fetchBitsMSB();
+	void fetchBitsLSB();
+
+	/**
+	 * Write one byte into _dest stream
+	 * @param b byte to put
+	 */
+
+	virtual void putByte(byte b);
+
+	/**
+	 * Returns true if all expected data has been unpacked to _dest
+	 * and there is no more data in _src.
+	 */
+	bool isFinished() {
+		return (_dwWrote == _szUnpacked) && (_dwRead >= _szPacked);
+	}
+
+	uint32 _dwBits;		///< bits buffer
+	byte _nBits;		///< number of unread bits in _dwBits
+	uint32 _szPacked;	///< size of the compressed data
+	uint32 _szUnpacked;	///< size of the decompressed data
+	uint32 _dwRead;		///< number of bytes read from _src
+	uint32 _dwWrote;	///< number of bytes written to _dest
+	Common::ReadStream *_src;
+	byte *_dest;
+};
+
+/**
+ * Huffman decompressor
+ */
+class DecompressorHuffman : public Decompressor {
+public:
+	int unpack(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked) override;
+
+protected:
+	int16 getc2();
+
+	byte *_nodes;
+};
+
+/**
+ * LZW decompressor for SCI0/01/1
+ * TODO: Clean-up post-processing functions
+ */
+class DecompressorLZW : public Decompressor {
+public:
+	DecompressorLZW(ResourceCompression compression) : _compression(compression) {}
+	int unpack(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked) override;
+
+protected:
+	int unpackLZW(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked);
+
+	// functions to post-process view and pic resources
+	void reorderPic(byte *src, byte *dest, int dsize);
+	void reorderView(byte *src, byte *dest);
+	void decodeRLE(byte **rledata, byte **pixeldata, byte *outbuffer, int size);
+	int getRLEsize(byte *rledata, int dsize);
+	void buildCelHeaders(byte **seeker, byte **writer, int celindex, int *cc_lengths, int max);
+
+	ResourceCompression _compression;
+};
+
+/**
+ * DCL decompressor for SCI1.1
+ */
+class DecompressorDCL : public Decompressor {
+public:
+	int unpack(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked) override;
+};
+
+#ifdef ENABLE_SCI32
+/**
+ * STACpack decompressor for SCI32
+ */
+class DecompressorLZS : public Decompressor {
+public:
+	int unpack(Common::ReadStream *src, byte *dest, uint32 nPacked, uint32 nUnpacked) override;
+protected:
+	int unpackLZS();
+	uint32 getCompLen();
+	void copyComp(int offs, uint32 clen);
+};
+#endif
+
+} // End of namespace Sci
+
+#endif // SCI_RESOURCE_DECOMPRESSOR_H