AUD_BandPassReader.cpp

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * Copyright 2009-2011 Jörg Hermann Müller
 *
 * This file is part of AudaSpace.
 *
 * Audaspace 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 of the License, or
 * (at your option) any later version.
 *
 * AudaSpace 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 Audaspace; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include "AUD_BandPassReader.h"
#include "AUD_Buffer.h"

#include <cstring>
#include <stdio.h>

AUD_BandPassReader::AUD_BandPassReader(AUD_IReader* reader, float low,
                                       float high) :
        AUD_EffectReader(reader), m_low(low), m_high(high)
{
    m_buffer = new AUD_Buffer(); AUD_NEW("buffer")
    m_in = new AUD_Buffer(); AUD_NEW("buffer")
    m_out = new AUD_Buffer(); AUD_NEW("buffer")
    m_length = 0;
}

AUD_BandPassReader::~AUD_BandPassReader()
{
    if(m_length != 0)
    {
        fftw_destroy_plan(m_forward);
        fftw_destroy_plan(m_backward);
    }

    delete m_buffer; AUD_DELETE("buffer")
    delete m_in; AUD_DELETE("buffer")
    delete m_out; AUD_DELETE("buffer")
}

AUD_ReaderType AUD_BandPassReader::getType()
{
    return m_reader->getType();
}

void AUD_BandPassReader::read(int & length, sample_t* & buffer)
{
    AUD_Specs specs = m_reader->getSpecs();

    m_reader->read(length, buffer);

    if(length > 0)
    {
        m_buffer->assureSize(length * AUD_SAMPLE_SIZE(specs));

        if(length != m_length)
        {
            if(m_length != 0)
            {
                fftw_destroy_plan(m_forward);
                fftw_destroy_plan(m_backward);
            }

            m_length = length;

            if(m_length * sizeof(double) > m_in->getSize())
            {
                m_in->resize(m_length * sizeof(double));
                m_out->resize((m_length / 2 + 1) * sizeof(fftw_complex));
            }

            m_forward = fftw_plan_dft_r2c_1d(m_length,
                                             (double*)m_in->getBuffer(),
                                             (fftw_complex*)m_out->getBuffer(),
                                             FFTW_ESTIMATE);
            m_backward = fftw_plan_dft_c2r_1d(m_length,
                                              (fftw_complex*)m_out->getBuffer(),
                                              (double*)m_in->getBuffer(),
                                              FFTW_ESTIMATE);
        }

        double* target = (double*) m_in->getBuffer();
        sample_t* target2 = m_buffer->getBuffer();
        fftw_complex* complex = (fftw_complex*) m_out->getBuffer();
        float frequency;

        for(int channel = 0; channel < specs.channels; channel++)
        {
            for(int i = 0; i < m_length; i++)
                target[i] = buffer[i * specs.channels + channel];

            fftw_execute(m_forward);

            for(int i = 0; i < m_length / 2 + 1; i++)
            {
                frequency = i * specs.rate / (m_length / 2.0f + 1.0f);
                if((frequency < m_low) || (frequency > m_high))
                    complex[i][0] = complex[i][1] = 0.0;
            }

            fftw_execute(m_backward);

            for(int i = 0; i < m_length; i++)
                target2[i * specs.channels + channel] = target[i] / m_length;
        }
    }

    buffer = m_buffer->getBuffer();
}