AUD_DelayReader.cpp

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/*
 * $Id: AUD_DelayReader.cpp 35141 2011-02-25 10:21:56Z jesterking $
 *
 * ***** 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_IReader* reader, float delay) :
                AUD_EffectReader(reader),
                m_delay(int(delay * reader->getSpecs().rate)),
                m_remdelay(int(delay * reader->getSpecs().rate)),
                m_empty(true)
{
}

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, sample_t* & buffer)
{
        if(m_remdelay > 0)
        {
                AUD_Specs specs = m_reader->getSpecs();
                int samplesize = AUD_SAMPLE_SIZE(specs);

                if(m_buffer.getSize() < length * samplesize)
                {
                        m_buffer.resize(length * samplesize);
                        m_empty = false;
                }

                buffer = m_buffer.getBuffer();

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

                        int len = length - m_remdelay;
                        sample_t* buf;
                        m_reader->read(len, buf);

                        memcpy(buffer + m_remdelay * specs.channels,
                                   buf, len * samplesize);

                        if(len < length-m_remdelay)
                                length = m_remdelay + len;

                        m_remdelay = 0;
                        m_empty = false;
                }
                else
                {
                        if(!m_empty)
                        {
                                memset(buffer, 0, length * samplesize);
                                m_empty = true;
                        }
                        m_remdelay -= length;
                }
        }
        else
                m_reader->read(length, buffer);
}