AUD_DelayReader.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_DelayReader.h"

#include <cstring>

AUD_DelayReader::AUD_DelayReader(AUD_Reference<AUD_IReader> reader, float delay) :
        AUD_EffectReader(reader),
        m_delay(int(delay * reader->getSpecs().rate)),
        m_remdelay(int(delay * reader->getSpecs().rate))
{
}

void AUD_DelayReader::seek(int position)
{
    if(position < m_delay)
    {
        m_remdelay = m_delay - position;
        m_reader->seek(0);
    }
    else
    {
        m_remdelay = 0;
        m_reader->seek(position - m_delay);
    }
}

int AUD_DelayReader::getLength() const
{
    int len = m_reader->getLength();
    if(len < 0)
        return len;
    return len + m_delay;
}

int AUD_DelayReader::getPosition() const
{
    if(m_remdelay > 0)
        return m_delay - m_remdelay;
    return m_reader->getPosition() + m_delay;
}

void AUD_DelayReader::read(int& length, bool& eos, sample_t* buffer)
{
    if(m_remdelay > 0)
    {
        AUD_Specs specs = m_reader->getSpecs();
        int samplesize = AUD_SAMPLE_SIZE(specs);

        if(length > m_remdelay)
        {
            memset(buffer, 0, m_remdelay * samplesize);

            int len = length - m_remdelay;
            m_reader->read(len, eos, buffer + m_remdelay * specs.channels);

            length = m_remdelay + len;

            m_remdelay = 0;
        }
        else
        {
            memset(buffer, 0, length * samplesize);
            m_remdelay -= length;
        }
    }
    else
        m_reader->read(length, eos, buffer);
}