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    16 ** GNU Lesser General Public License Usage

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    40 ****************************************************************************/

    41 

    42 #include "wavedecoder_p.h"

    43 

    44 #include <QtCore/qtimer.h>

    45 #include <QtCore/qendian.h>

    46 

    47 QT_BEGIN_NAMESPACE

    48 

    49 WaveDecoder::WaveDecoder(QIODevice *s, QObject *parent):

    50     QIODevice(parent),

    51     haveFormat(false),

    52     dataSize(0),

    53     remaining(0),

    54     source(s)

    55 {

    56     open(QIODevice::ReadOnly | QIODevice::Unbuffered);

    57 

    58     if (source->bytesAvailable() >= qint64(sizeof(CombinedHeader) + sizeof(DATAHeader) + sizeof(quint16)))

    59         QTimer::singleShot(0, this, SLOT(handleData()));

    60     else

    61         connect(source, SIGNAL(readyRead()), SLOT(handleData()));

    62 }

    63 

    64 WaveDecoder::~WaveDecoder()

    65 {

    66 }

    67 

    68 QAudioFormat WaveDecoder::audioFormat() const

    69 {

    70     return format;

    71 }

    72 

    73 int WaveDecoder::duration() const

    74 {

    75     return size() * 1000 / (format.sampleSize() / 8) / format.channels() / format.frequency();

    76 }

    77 

    78 qint64 WaveDecoder::size() const

    79 {

    80     return haveFormat ? dataSize : 0;

    81 }

    82 

    83 bool WaveDecoder::isSequential() const

    84 {

    85     return source->isSequential();

    86 }

    87 

    88 qint64 WaveDecoder::bytesAvailable() const

    89 {

    90     return haveFormat ? source->bytesAvailable() : 0;

    91 }

    92 

    93 qint64 WaveDecoder::readData(char *data, qint64 maxlen)

    94 {

    95     return haveFormat ? source->read(data, maxlen) : 0;

    96 }

    97 

    98 qint64 WaveDecoder::writeData(const char *data, qint64 len)

    99 {

   100     Q_UNUSED(data);

   101     Q_UNUSED(len);

   102 

   103     return -1;

   104 }

   105 

   106 void WaveDecoder::handleData()

   107 {

   108     if (source->bytesAvailable() < qint64(sizeof(CombinedHeader) + sizeof(DATAHeader) + sizeof(quint16)))

   109         return;

   110 

   111     source->disconnect(SIGNAL(readyRead()), this, SLOT(handleData()));

   112     source->read((char*)&header, sizeof(CombinedHeader));

   113 

   114     if (qstrncmp(header.riff.descriptor.id, "RIFF", 4) != 0 ||

   115         qstrncmp(header.riff.type, "WAVE", 4) != 0 ||

   116         qstrncmp(header.wave.descriptor.id, "fmt ", 4) != 0 ||

   117         (header.wave.audioFormat != 0 && header.wave.audioFormat != 1)) {

   118 

   119         emit invalidFormat();

   120     }

   121     else {

   122         DATAHeader dataHeader;

   123 

   124         if (qFromLittleEndian<quint32>(header.wave.descriptor.size) > sizeof(WAVEHeader)) {

   125             // Extended data available

   126             quint16 extraFormatBytes;

   127             source->peek((char*)&extraFormatBytes, sizeof(quint16));

   128             extraFormatBytes = qFromLittleEndian<quint16>(extraFormatBytes);

   129             source->read(sizeof(quint16) + extraFormatBytes);   // dump it all

   130         }

   131 

   132         source->read((char*)&dataHeader, sizeof(DATAHeader));

   133 

   134         int bps = qFromLittleEndian<quint16>(header.wave.bitsPerSample);

   135 

   136         format.setCodec(QLatin1String("audio/pcm"));

   137         format.setSampleType(bps == 8 ? QAudioFormat::UnSignedInt : QAudioFormat::SignedInt);

   138         format.setByteOrder(QAudioFormat::LittleEndian);

   139         format.setFrequency(qFromLittleEndian<quint32>(header.wave.sampleRate));

   140         format.setSampleSize(bps);

   141         format.setChannels(qFromLittleEndian<quint16>(header.wave.numChannels));

   142 

   143         dataSize = qFromLittleEndian<quint32>(dataHeader.descriptor.size);

   144 

   145         haveFormat = true;

   146         connect(source, SIGNAL(readyRead()), SIGNAL(readyRead()));

   147         emit formatKnown();

   148     }

   149 }

   150 

   151 QT_END_NAMESPACE