AUD_SRCResampleReader.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_SRCResampleReader.h"

#include <cmath>
#include <cstring>
#include <cstdio>

static long src_callback(void *cb_data, float **data)
{
    return ((AUD_SRCResampleReader*)cb_data)->doCallback(data);
}

static const char* state_error = "AUD_SRCResampleReader: SRC State couldn't be "
                                 "created.";

AUD_SRCResampleReader::AUD_SRCResampleReader(AUD_Reference<AUD_IReader> reader,
                                             AUD_Specs specs) :
        AUD_ResampleReader(reader, specs.rate),
        m_channels(reader->getSpecs().channels),
        m_position(0)
{
    int error;
    m_src = src_callback_new(src_callback,
                             SRC_SINC_MEDIUM_QUALITY,
                             m_channels,
                             &error,
                             this);

    if(!m_src)
    {
        // XXX printf("%s\n", src_strerror(error));
        AUD_THROW(AUD_ERROR_SRC, state_error);
    }
}

AUD_SRCResampleReader::~AUD_SRCResampleReader()
{
    src_delete(m_src);
}

long AUD_SRCResampleReader::doCallback(float** data)
{
    AUD_Specs specs;
    specs.channels = m_channels;
    specs.rate = m_rate;

    int length = m_buffer.getSize() / AUD_SAMPLE_SIZE(specs);

    *data = m_buffer.getBuffer();
    m_reader->read(length, m_eos, *data);

    return length;
}

void AUD_SRCResampleReader::seek(int position)
{
    AUD_Specs specs = m_reader->getSpecs();
    double factor = double(m_rate) / double(specs.rate);
    m_reader->seek(position / factor);
    src_reset(m_src);
    m_position = position;
}

int AUD_SRCResampleReader::getLength() const
{
    AUD_Specs specs = m_reader->getSpecs();
    double factor = double(m_rate) / double(specs.rate);
    return m_reader->getLength() * factor;
}

int AUD_SRCResampleReader::getPosition() const
{
    return m_position;
}

AUD_Specs AUD_SRCResampleReader::getSpecs() const
{
    AUD_Specs specs = m_reader->getSpecs();
    specs.rate = m_rate;
    return specs;
}

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

    double factor = double(m_rate) / double(specs.rate);

    specs.rate = m_rate;

    int size = length;

    m_buffer.assureSize(length * AUD_SAMPLE_SIZE(specs));

    if(specs.channels != m_channels)
    {
        src_delete(m_src);

        m_channels = specs.channels;

        int error;
        m_src = src_callback_new(src_callback,
                                 SRC_SINC_MEDIUM_QUALITY,
                                 m_channels,
                                 &error,
                                 this);

        if(!m_src)
        {
            // XXX printf("%s\n", src_strerror(error));
            AUD_THROW(AUD_ERROR_SRC, state_error);
        }
    }

    m_eos = false;

    length = src_callback_read(m_src, factor, length, buffer);

    m_position += length;

    eos = m_eos && (length < size);
}