libsidplayfp  1.0.3
SincResampler.h
00001 /*
00002  * This file is part of libsidplayfp, a SID player engine.
00003  *
00004  * Copyright 2011-2013 Leandro Nini <drfiemost@users.sourceforge.net>
00005  * Copyright 2007-2010 Antti Lankila
00006  * Copyright 2004 Dag Lem <resid@nimrod.no>
00007  *
00008  * This program is free software; you can redistribute it and/or modify
00009  * it under the terms of the GNU General Public License as published by
00010  * the Free Software Foundation; either version 2 of the License, or
00011  * (at your option) any later version.
00012  *
00013  * This program is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016  * GNU General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU General Public License
00019  * along with this program; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
00021  */
00022 
00023 #ifndef SINCRESAMPLER_H
00024 #define SINCRESAMPLER_H
00025 
00026 #include "Resampler.h"
00027 
00028 #include <string>
00029 #include <map>
00030 
00031 #include "../array.h"
00032 
00033 namespace reSIDfp
00034 {
00035 
00070 class SincResampler : public Resampler
00071 {
00072 private:
00073     static const int RINGSIZE = 2048;
00074 
00075     static const int BITS = 16;
00076 
00077     array<short>* firTable;
00078 
00079     int sampleIndex;
00080 
00081     int firRES, firN;
00082 
00083     const int cyclesPerSample;
00084 
00085     int sampleOffset;
00086 
00087     int outputValue;
00088 
00089     short sample[RINGSIZE * 2];
00090 
00094     static std::map<std::string, array<short> > FIR_CACHE;
00095 
00097     static const double I0E;
00098 
00107     static double I0(double x);
00108 
00117     static int convolve(const short* a, const short* b, int bLength);
00118 
00119     int fir(int subcycle);
00120 
00121 public:
00142     SincResampler(double clockFrequency, double samplingFrequency, double highestAccurateFrequency);
00143 
00144     bool input(int input);
00145 
00146     int output() const { return outputValue; }
00147 
00148     void reset();
00149 };
00150 
00151 } // namespace reSIDfp
00152 
00153 #endif