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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 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