libsidplayfp  1.0.3
SincResampler.h
1 /*
2  * This file is part of libsidplayfp, a SID player engine.
3  *
4  * Copyright 2011-2013 Leandro Nini <drfiemost@users.sourceforge.net>
5  * Copyright 2007-2010 Antti Lankila
6  * Copyright 2004 Dag Lem <resid@nimrod.no>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
21  */
22 
23 #ifndef SINCRESAMPLER_H
24 #define SINCRESAMPLER_H
25 
26 #include "Resampler.h"
27 
28 #include <string>
29 #include <map>
30 
31 #include "../array.h"
32 
33 namespace reSIDfp
34 {
35 
70 class SincResampler : public Resampler
71 {
72 private:
73  static const int RINGSIZE = 2048;
74 
75  static const int BITS = 16;
76 
77  array<short>* firTable;
78 
79  int sampleIndex;
80 
81  int firRES, firN;
82 
83  const int cyclesPerSample;
84 
85  int sampleOffset;
86 
87  int outputValue;
88 
89  short sample[RINGSIZE * 2];
90 
94  static std::map<std::string, array<short> > FIR_CACHE;
95 
97  static const double I0E;
98 
107  static double I0(double x);
108 
117  static int convolve(const short* a, const short* b, int bLength);
118 
119  int fir(int subcycle);
120 
121 public:
142  SincResampler(double clockFrequency, double samplingFrequency, double highestAccurateFrequency);
143 
144  bool input(int input);
145 
146  int output() const { return outputValue; }
147 
148  void reset();
149 };
150 
151 } // namespace reSIDfp
152 
153 #endif