portapack-mayhem/firmware/baseband/block_decimator.hpp
Jared Boone 6f2cbd1ac5 Partial refactor of channel filter frequency code.
Move channel filter frequency determination to baseband side, where the filtering is determined and performed.
Add useful accessor methods to BlockDecimator.
2015-07-18 16:49:40 -07:00

99 lines
2.3 KiB
C++

/*
* 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 "complex.hpp"
template<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_c16_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<complex16_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__*/