//
// cfirfilter.cpp
// ambed
//
// Created by Jean-Luc Deltombe (LX3JL) on 26/04/2017.
// Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
//
// ----------------------------------------------------------------------------
// This file is part of ambed.
//
// xlxd 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 3 of the License, or
// (at your option) any later version.
//
// xlxd 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 Foobar. If not, see .
// ----------------------------------------------------------------------------
// FIRFilter by Geoffrey Merck F4FXL / KC3FRA
#include "cfirfilter.h"
#include
CFIRFilter::CFIRFilter(const float* taps, int tapsLength)
{
m_taps = new float[tapsLength];
m_buffer = new float[tapsLength];
m_tapsLength = tapsLength;
::memcpy(m_taps, taps, tapsLength * sizeof(float));
::memset(m_buffer, 0, tapsLength * sizeof(float));
m_currentBufferPostion = 0;
}
CFIRFilter::~CFIRFilter()
{
delete[] m_taps;
delete[] m_buffer;
}
inline float CFIRFilter::Process(float inputSample)
{
// Buffer latest sample
m_buffer[m_currentBufferPostion] = inputSample;
float outputSample = 0.0f;
for(int i = 0; i < m_tapsLength; i++)
{
outputSample += m_taps[i] * m_buffer[(m_currentBufferPostion + i) % m_tapsLength];
}
m_currentBufferPostion = (m_currentBufferPostion + 1) % m_tapsLength;
return outputSample;
}
void CFIRFilter::Process(uint8* voice, int length)
{
for(int i = 0; i < length; i++)
{
//Get the sample
float input = (float)(short)MAKEWORD(voice[i+1], voice[i]);
float output = Process(input);
//write processed sample back
voice[i] = HIBYTE((short)output);
voice[i+1] = LOBYTE((short)output);
}
}