70 lines
1.9 KiB
C++
70 lines
1.9 KiB
C++
/*
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* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __LINEAR_RESAMPLER_H__
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#define __LINEAR_RESAMPLER_H__
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namespace dsp {
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namespace interpolation {
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class LinearResampler {
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public:
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void configure(
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const float input_rate,
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const float output_rate
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) {
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phase_increment = calculate_increment(input_rate, output_rate);
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}
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template<typename InterpolatedSampleHandler>
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void operator()(
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const float sample,
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InterpolatedSampleHandler interpolated_sample_handler
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) {
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const float sample_delta = sample - last_sample;
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while( phase < 1.0f ) {
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const float interpolated_value = last_sample + phase * sample_delta;
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interpolated_sample_handler(interpolated_value);
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phase += phase_increment;
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}
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last_sample = sample;
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phase -= 1.0f;
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}
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void advance(const float fraction) {
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phase += (fraction * phase_increment);
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}
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private:
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float last_sample { 0.0f };
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float phase { 0.0f };
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float phase_increment { 0.0f };
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static constexpr float calculate_increment(const float input_rate, const float output_rate) {
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return input_rate / output_rate;
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}
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};
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} /* namespace interpolation */
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} /* namespace dsp */
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#endif/*__LINEAR_RESAMPLER_H__*/
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