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https://github.com/eried/portapack-mayhem.git
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a558565886
Appropriating for use as a buffer accumulator that will save up enough audio samples to put into an audio DMA buffer.
101 lines
2.3 KiB
C++
101 lines
2.3 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 __BLOCK_DECIMATOR_H__
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#define __BLOCK_DECIMATOR_H__
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#include <cstdint>
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#include <cstddef>
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#include <array>
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#include "dsp_types.hpp"
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#include "complex.hpp"
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template<typename T, size_t N>
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class BlockDecimator {
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public:
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constexpr BlockDecimator(
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const size_t factor
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) : factor_ { factor }
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{
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}
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void set_input_sampling_rate(const uint32_t new_sampling_rate) {
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if( new_sampling_rate != input_sampling_rate() ) {
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input_sampling_rate_ = new_sampling_rate;
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reset_state();
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}
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}
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uint32_t input_sampling_rate() const {
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return input_sampling_rate_;
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}
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void set_factor(const size_t new_factor) {
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if( new_factor != factor() ) {
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factor_ = new_factor;
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reset_state();
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}
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}
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size_t factor() const {
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return factor_;
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}
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uint32_t output_sampling_rate() const {
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return input_sampling_rate() / factor();
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}
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template<typename BlockCallback>
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void feed(const buffer_t<T>& src, BlockCallback callback) {
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/* NOTE: Input block size must be >= factor */
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set_input_sampling_rate(src.sampling_rate);
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while( src_i < src.count ) {
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buffer[dst_i++] = src.p[src_i];
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if( dst_i == buffer.size() ) {
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callback({ buffer.data(), buffer.size(), output_sampling_rate() });
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reset_state();
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dst_i = 0;
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}
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src_i += factor();
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}
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src_i -= src.count;
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}
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private:
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std::array<T, N> buffer;
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uint32_t input_sampling_rate_ { 0 };
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size_t factor_ { 1 };
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size_t src_i { 0 };
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size_t dst_i { 0 };
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void reset_state() {
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src_i = 0;
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dst_i = 0;
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}
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};
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#endif/*__BLOCK_DECIMATOR_H__*/
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