libsidplayfp  1.8.7
ZeroOrderResampler.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  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20  */
21 
22 #ifndef ZEROORDER_RESAMPLER_H
23 #define ZEROORDER_RESAMPLER_H
24 
25 #include "Resampler.h"
26 
27 namespace reSIDfp
28 {
29 
36 {
37 
38 private:
40  int cachedSample;
41 
43  const int cyclesPerSample;
44 
45  int sampleOffset;
46 
48  int outputValue;
49 
50 public:
51  ZeroOrderResampler(double clockFrequency, double samplingFrequency) :
52  cachedSample(0),
53  cyclesPerSample(static_cast<int>(clockFrequency / samplingFrequency * 1024.)),
54  sampleOffset(0),
55  outputValue(0) {}
56 
57  bool input(int sample)
58  {
59  bool ready = false;
60 
61  if (sampleOffset < 1024)
62  {
63  outputValue = cachedSample + (sampleOffset * (sample - cachedSample) >> 10);
64  ready = true;
65  sampleOffset += cyclesPerSample;
66  }
67 
68  sampleOffset -= 1024;
69 
70  cachedSample = sample;
71 
72  return ready;
73  }
74 
75  int output() const { return outputValue; }
76 
77  void reset()
78  {
79  sampleOffset = 0;
80  cachedSample = 0;
81  }
82 };
83 
84 } // namespace reSIDfp
85 
86 #endif
bool input(int sample)
Definition: ZeroOrderResampler.h:57
Definition: Dac.cpp:25
Definition: Resampler.h:32
Definition: ZeroOrderResampler.h:35