1 files changed, 133 insertions, 0 deletions
diff --git a/graphics/decoders/jpeg.h b/graphics/decoders/jpeg.h
new file mode 100644
index 0000000000..c566d5ad21
--- /dev/null
+++ b/graphics/decoders/jpeg.h
@@ -0,0 +1,133 @@
+/* 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 GRAPHICS_JPEG_H
+#define GRAPHICS_JPEG_H
+
+#include "graphics/surface.h"
+#include "graphics/decoders/image_decoder.h"
+
+namespace Common {
+class SeekableReadStream;
+}
+
+namespace Graphics {
+
+struct PixelFormat;
+
+#define JPEG_MAX_QUANT_TABLES 4
+#define JPEG_MAX_HUFF_TABLES 2
+
+class JPEGDecoder : public ImageDecoder {
+public:
+	JPEGDecoder();
+	~JPEGDecoder();
+
+	// ImageDecoder API
+	void destroy();
+	bool loadStream(Common::SeekableReadStream &str);
+	const Surface *getSurface() const;
+
+	bool isLoaded() const { return _numComp && _w && _h; }
+	uint16 getWidth() const { return _w; }
+	uint16 getHeight() const { return _h; }
+	const Surface *getComponent(uint c) const;
+
+private:
+	Common::SeekableReadStream *_stream;
+	uint16 _w, _h;
+	uint16 _restartInterval;
+
+	// mutable so that we can convert to RGB only during
+	// a getSurface() call while still upholding the
+	// const requirement in other ImageDecoders
+	mutable Graphics::Surface *_rgbSurface;
+
+	// Image components
+	uint8 _numComp;
+	struct Component {
+		// Global values
+		uint8 id;
+		uint8 factorH;
+		uint8 factorV;
+		uint8 quantTableSelector;
+
+		// Scan specific values
+		uint8 DCentropyTableSelector;
+		uint8 ACentropyTableSelector;
+		int16 DCpredictor;
+
+		// Result image for this component
+		Surface surface;
+	};
+
+	Component *_components;
+
+	// Scan components
+	uint8 _numScanComp;
+	Component **_scanComp;
+	Component *_currentComp;
+
+	// Maximum sampling factors, used to calculate the interleaving of the MCU
+	uint8 _maxFactorV;
+	uint8 _maxFactorH;
+
+	// Quantization tables
+	uint16 *_quant[JPEG_MAX_QUANT_TABLES];
+
+	// Huffman tables
+	struct HuffmanTable {
+		uint8 count;
+		uint8 *values;
+		uint8 *sizes;
+		uint16 *codes;
+	} _huff[2 * JPEG_MAX_HUFF_TABLES];
+
+	// Marker read functions
+	bool readJFIF();
+	bool readSOF0();
+	bool readDHT();
+	bool readSOS();
+	bool readDQT();
+	bool readDRI();
+
+	// Helper functions
+	bool readMCU(uint16 xMCU, uint16 yMCU);
+	bool readDataUnit(uint16 x, uint16 y);
+	int16 readDC();
+	void readAC(int16 *out);
+	int16 readSignedBits(uint8 numBits);
+
+	// Huffman decoding
+	uint8 readHuff(uint8 table);
+	uint8 readBit();
+	uint8 _bitsData;
+	uint8 _bitsNumber;
+
+	// Inverse Discrete Cosine Transformation
+	static void idct1D8x8(int32 src[8], int32 dest[64], int32 ps, int32 half);
+	static void idct2D8x8(int32 block[64]);
+};
+
+} // End of Graphics namespace
+
+#endif // GRAPHICS_JPEG_H