/* 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.
 *
 */

// Based on eos' (I)RDFT code which is in turn
// Based upon the (I)RDFT code in FFmpeg
// Copyright (c) 2009 Alex Converse <alex dot converse at gmail dot com>

#ifndef COMMON_RDFT_H
#define COMMON_RDFT_H

#include "common/scummsys.h"
#include "common/math.h"
#include "common/fft.h"

namespace Common {

/**
 * (Inverse) Real Discrete Fourier Transform.
 *
 * Used in audio:
 *  - QDM2
 *
 * Used in engines:
 *  - scumm
 */

class RDFT {
public:
	enum TransformType {
		DFT_R2C,
		IDFT_C2R,
		IDFT_R2C,
		DFT_C2R
	};

	RDFT(int bits, TransformType trans);
	~RDFT();

	void calc(float *data);

private:
	int _bits;
	int _inverse;
	int _signConvention;

	const float *_tSin;
	const float *_tCos;

	FFT *_fft;
};

} // End of namespace Common

#endif // COMMON_RDFT_H