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math/dct.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/>.
+ *
+ */
+
+// Based on eos' (I)RDFT code which is in turn
+// Based upon the (I)DCT code in FFmpeg
+// Copyright (c) 2009 Peter Ross <pross@xvid.org>
+// Copyright (c) 2010 Alex Converse <alex.converse@gmail.com>
+// Copyright (c) 2010 Vitor Sessak
+
+#ifndef MATH_DCT_H
+#define MATH_DCT_H
+
+#include "math/cosinetables.h"
+
+namespace Math {
+
+class RDFT;
+
+/**
+ * @defgroup math_dct Discrete Cosine Transforms
+ * @ingroup math
+ *
+ * @brief  Discrete Cosine Transforms.
+ *
+ * @{
+ */
+
+/**
+ * (Inverse) Discrete Cosine Transforms.
+ *
+ * Used in engines:
+ *  - Scumm
+ */
+class DCT {
+public:
+	enum TransformType {
+		DCT_II,
+		DCT_III,
+		DCT_I,
+		DST_I
+	};
+
+	DCT(int bits, TransformType trans);
+	~DCT();
+
+	void calc(float *data) const;
+
+private:
+	int _bits;
+	TransformType _trans;
+
+	CosineTable _cos;
+	const float *_tCos;
+
+	float *_csc2;
+
+	RDFT *_rdft;
+
+	void calcDCTI(float *data) const;
+	void calcDCTII(float *data) const;
+	void calcDCTIII(float *data) const;
+	void calcDSTI(float *data) const;
+};
+
+/** @} */
+
+} // End of namespace Math
+
+#endif // MATH_DCT_H