/* * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc. * * This file is part of PortaPack. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; see the file COPYING. If not, write to * the Free Software Foundation, Inc., 51 Franklin Street, * Boston, MA 02110-1301, USA. */ #ifndef __BLOCK_DECIMATOR_H__ #define __BLOCK_DECIMATOR_H__ #include <cstdint> #include <cstddef> #include <array> #include "dsp_types.hpp" #include "complex.hpp" template<typename T, size_t N> class BlockDecimator { public: constexpr BlockDecimator( const size_t factor ) : factor_ { factor } { } void set_input_sampling_rate(const uint32_t new_sampling_rate) { if( new_sampling_rate != input_sampling_rate() ) { input_sampling_rate_ = new_sampling_rate; reset_state(); } } uint32_t input_sampling_rate() const { return input_sampling_rate_; } void set_factor(const size_t new_factor) { if( new_factor != factor() ) { factor_ = new_factor; reset_state(); } } size_t factor() const { return factor_; } uint32_t output_sampling_rate() const { return input_sampling_rate() / factor(); } template<typename BlockCallback> void feed(const buffer_t<T>& src, BlockCallback callback) { /* NOTE: Input block size must be >= factor */ set_input_sampling_rate(src.sampling_rate); while( src_i < src.count ) { buffer[dst_i++] = src.p[src_i]; if( dst_i == buffer.size() ) { callback({ buffer.data(), buffer.size(), output_sampling_rate() }); reset_state(); dst_i = 0; } src_i += factor(); } src_i -= src.count; } private: std::array<T, N> buffer { }; uint32_t input_sampling_rate_ { 0 }; size_t factor_ { 1 }; size_t src_i { 0 }; size_t dst_i { 0 }; void reset_state() { src_i = 0; dst_i = 0; } }; #endif/*__BLOCK_DECIMATOR_H__*/