libsidplayfp 1.0.3
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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 * 00007 * This program is free software; you can redistribute it and/or modify 00008 * it under the terms of the GNU General Public License as published by 00009 * the Free Software Foundation; either version 2 of the License, or 00010 * (at your option) any later version. 00011 * 00012 * This program is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 * GNU General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU General Public License 00018 * along with this program; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 00020 */ 00021 00022 #ifndef ZEROORDER_RESAMPLER_H 00023 #define ZEROORDER_RESAMPLER_H 00024 00025 #include "Resampler.h" 00026 00027 namespace reSIDfp 00028 { 00029 00035 class ZeroOrderResampler : public Resampler 00036 { 00037 00038 private: 00039 int cachedSample; 00040 00041 const int cyclesPerSample; 00042 int sampleOffset; 00043 int outputValue; 00044 00045 public: 00046 ZeroOrderResampler(double clockFrequency, double samplingFrequency) : 00047 cachedSample(0), 00048 cyclesPerSample((int)(clockFrequency / samplingFrequency * 1024.)), 00049 sampleOffset(0), 00050 outputValue(0) {} 00051 00052 bool input(int sample) 00053 { 00054 bool ready = false; 00055 00056 if (sampleOffset < 1024) 00057 { 00058 outputValue = cachedSample + (sampleOffset * (sample - cachedSample) >> 10); 00059 ready = true; 00060 sampleOffset += cyclesPerSample; 00061 } 00062 00063 sampleOffset -= 1024; 00064 00065 cachedSample = sample; 00066 00067 return ready; 00068 } 00069 00070 int output() const { return outputValue; } 00071 00072 void reset() 00073 { 00074 sampleOffset = 0; 00075 cachedSample = 0; 00076 } 00077 }; 00078 00079 } // namespace reSIDfp 00080 00081 #endif