mirror of https://github.com/ShaYmez/xlxd.git
76 lines
2.3 KiB
C++
76 lines
2.3 KiB
C++
//
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// cfirfilter.cpp
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// ambed
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//
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// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
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// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
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//
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// ----------------------------------------------------------------------------
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// This file is part of ambed.
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//
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// xlxd 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 3 of the License, or
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// (at your option) any later version.
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//
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// xlxd 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 Foobar. If not, see <http://www.gnu.org/licenses/>.
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// ----------------------------------------------------------------------------
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// FIRFilter by Geoffrey Merck F4FXL / KC3FRA
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#include "cfirfilter.h"
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#include <string.h>
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CFIRFilter::CFIRFilter(const float* taps, int tapsLength)
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{
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m_taps = new float[tapsLength];
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m_buffer = new float[tapsLength];
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m_tapsLength = tapsLength;
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::memcpy(m_taps, taps, tapsLength * sizeof(float));
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::memset(m_buffer, 0, tapsLength * sizeof(float));
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m_currentBufferPosition = 0;
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}
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CFIRFilter::~CFIRFilter()
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{
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delete[] m_taps;
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delete[] m_buffer;
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}
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inline void CFIRFilter::ProcessSampleBlock(uint8* voice, int length)
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{
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for(int i = 0; i < length; i += 2)
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{
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float input = (float)(short)MAKEWORD(voice[i+1], voice[i]);
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float output = 0.0f;
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int iTaps = 0;
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// Buffer latest sample into delay line
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m_buffer[m_currentBufferPosition] = input;
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for(int i = m_currentBufferPosition; i >= 0; i--)
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{
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output += m_taps[iTaps++] * m_buffer[i];
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}
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for(int i = m_tapsLength - 1; i > m_currentBufferPosition; i--)
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{
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output += m_taps[iTaps++] * m_buffer[i];
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}
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m_currentBufferPosition = (m_currentBufferPosition + 1) % m_tapsLength;
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//write processed sample back
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voice[i] = HIBYTE((short)output);
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voice[i+1] = LOBYTE((short)output);
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}
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}
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