AUD_LimiterReader.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_LimiterReader.h"
#include "AUD_Buffer.h"

AUD_LimiterReader::AUD_LimiterReader(AUD_Reference<AUD_IReader> reader,
                                     float start, float end) :
        AUD_EffectReader(reader),
        m_start(start),
        m_end(end)
{
    if(m_start > 0)
    {
        AUD_Specs specs = m_reader->getSpecs();
        AUD_Specs specs2;

        if(m_reader->isSeekable())
            m_reader->seek(m_start * specs.rate);
        else
        {
            // skip first m_start samples by reading them
            int length = AUD_DEFAULT_BUFFER_SIZE;
            AUD_Buffer buffer(AUD_DEFAULT_BUFFER_SIZE * AUD_SAMPLE_SIZE(specs));
            bool eos = false;
            for(int len = m_start * specs.rate;
                length > 0 && !eos;
                len -= length)
            {
                if(len < AUD_DEFAULT_BUFFER_SIZE)
                    length = len;

                m_reader->read(length, eos, buffer.getBuffer());

                specs2 = m_reader->getSpecs();
                if(specs2.rate != specs.rate)
                {
                    len = len * specs2.rate / specs.rate;
                    specs.rate = specs2.rate;
                }

                if(specs2.channels != specs.channels)
                {
                    specs = specs2;
                    buffer.assureSize(AUD_DEFAULT_BUFFER_SIZE * AUD_SAMPLE_SIZE(specs));
                }
            }
        }
    }
}

void AUD_LimiterReader::seek(int position)
{
    m_reader->seek(position + m_start * m_reader->getSpecs().rate);
}

int AUD_LimiterReader::getLength() const
{
    int len = m_reader->getLength();
    AUD_SampleRate rate = m_reader->getSpecs().rate;
    if(len < 0 || (len > m_end * rate && m_end >= 0))
        len = m_end * rate;
    return len - m_start * rate;
}

int AUD_LimiterReader::getPosition() const
{
    int pos = m_reader->getPosition();
    AUD_SampleRate rate = m_reader->getSpecs().rate;
    return AUD_MIN(pos, m_end * rate) - m_start * rate;
}

void AUD_LimiterReader::read(int& length, bool& eos, sample_t* buffer)
{
    eos = false;
    if(m_end >= 0)
    {
        int position = m_reader->getPosition();
        AUD_SampleRate rate = m_reader->getSpecs().rate;

        if(position + length > m_end * rate)
        {
            length = m_end * rate - position;
            eos = true;
        }

        if(position < m_start * rate)
        {
            int len2 = length;
            for(int len = m_start * rate - position;
                len2 == length && !eos;
                len -= length)
            {
                if(len < length)
                    len2 = len;

                m_reader->read(len2, eos, buffer);
                position += len2;
            }

            if(position < m_start * rate)
            {
                length = 0;
                return;
            }
        }

        if(length < 0)
        {
            length = 0;
            return;
        }
    }
    if(eos)
    {
        m_reader->read(length, eos, buffer);
        eos = true;
    }
    else
        m_reader->read(length, eos, buffer);
}