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60 lines
883 B
C++
60 lines
883 B
C++
// Copyright 2015-2020 modemm17 LLC.
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#pragma once
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#include "Filter.h"
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#include <array>
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#include <cstddef>
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namespace modemm17
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{
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template <size_t N>
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struct BaseFirFilter : FilterBase<float>
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{
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using array_t = std::array<float, N>;
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const array_t& taps_;
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array_t history_;
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size_t pos_ = 0;
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BaseFirFilter(const array_t& taps)
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: taps_(taps)
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{
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history_.fill(0.0);
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}
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float operator()(float input) override
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{
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history_[pos_++] = input;
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if (pos_ == N) pos_ = 0;
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float result = 0.0;
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size_t index = pos_;
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for (size_t i = 0; i != N; ++i)
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{
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index = (index != 0 ? index - 1 : N - 1);
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result += history_.at(index) * taps_.at(i);
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}
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return result;
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}
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void reset()
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{
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history_.fill(0.0);
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pos_ = 0;
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}
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};
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template <size_t N>
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BaseFirFilter<N> makeFirFilter(const std::array<float, N>& taps)
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{
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return std::move(BaseFirFilter<N>(taps));
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}
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} // modemm17
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