Simplify reading data from QSoundEffect

Just deliver as much data as being asked by the audio output.
There's no point in artificially limiting how much we write,
as the output should know best what it can handle.

Change-Id: I673f602f4989bb89f69f6db6d1936f0c921c79c6
Reviewed-by: Doris Verria <doris.verria@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 29 insertions, 70 deletions

diff --git a/src/multimedia/audio/qsoundeffect.cpp b/src/multimedia/audio/qsoundeffect.cpp
index 97be1e0a8..c3531d742 100644
--- a/src/multimedia/audio/qsoundeffect.cpp
+++ b/src/multimedia/audio/qsoundeffect.cpp
@@ -55,6 +55,12 @@ public:
 
     qint64 readData(char *data, qint64 len) override;
     qint64 writeData(const char *data, qint64 len) override;
+    qint64 size() const override {
+        return m_loopCount == QSoundEffect::Infinite ? 0 : m_loopCount * m_sample->data().size();
+    }
+    bool isSequential() const override {
+        return m_loopCount == QSoundEffect::Infinite;
+    }
 
     void setLoopsRemaining(int loopsRemaining);
     void setStatus(QSoundEffect::Status status);
@@ -133,84 +139,37 @@ void QSoundEffectPrivate::stateChanged(QAudio::State state)
 #ifdef QT_QAUDIO_DEBUG
     qDebug() << this << "stateChanged " << state;
 #endif
-    if ((state == QAudio::IdleState && m_runningCount == 0)
-         || (state == QAudio::StoppedState && m_audioOutput->error() != QAudio::NoError))
+    if ((state == QAudio::IdleState && m_runningCount == 0) || state == QAudio::StoppedState)
         emit q_ptr->stop();
 }
 
 qint64 QSoundEffectPrivate::readData(char *data, qint64 len)
 {
-    if ((m_runningCount > 0  || m_runningCount == QSoundEffect::Infinite) && m_playing) {
-
-        if (m_sample->state() != QSample::Ready)
-            return 0;
-
-        qint64 bytesWritten = 0;
-
-        const int   periodSize = m_audioOutput->periodSize();
-        const int   sampleSize = m_sample->data().size();
-        const char* sampleData = m_sample->data().constData();
-
-        // Some systems can have large buffers we only need a max of three
-        int    periodsFree = qMin(3, (int)(m_audioOutput->bytesFree()/periodSize));
-        int    dataOffset = 0;
-
-#ifdef QT_QAUDIO_DEBUG
-        qDebug() << "bytesFree=" << m_audioOutput->bytesFree() << ", can fit " << periodsFree << " periodSize() chunks";
-#endif
-
-        while ((periodsFree > 0) && (bytesWritten + periodSize
-                                     <= len)) {
-
-            if (sampleSize - m_offset >= periodSize) {
-                // We can fit a whole period of data
-                memcpy(data + dataOffset, sampleData + m_offset, periodSize);
-                m_offset += periodSize;
-                dataOffset += periodSize;
-                bytesWritten += periodSize;
-#ifdef QT_QAUDIO_DEBUG
-                qDebug() << "WHOLE PERIOD: bytesWritten=" << bytesWritten << ", offset=" << m_offset
-                         << ", filesize=" << sampleSize;
-#endif
-            } else {
-                // We are at end of sound, first write what is left of current sound
-                memcpy(data + dataOffset, sampleData + m_offset, sampleSize - m_offset);
-                bytesWritten += sampleSize - m_offset;
-                int wrapLen = periodSize - (sampleSize - m_offset);
-                if (wrapLen > sampleSize)
-                    wrapLen = sampleSize;
-#ifdef QT_QAUDIO_DEBUG
-                qDebug() << "END OF SOUND: bytesWritten=" << bytesWritten << ", offset=" << m_offset
-                         << ", part1=" << (sampleSize-m_offset);
-#endif
-                dataOffset += (sampleSize - m_offset);
-                m_offset = 0;
-
-                if (m_runningCount > 0 && m_runningCount != QSoundEffect::Infinite)
-                    setLoopsRemaining(m_runningCount-1);
-
-                if (m_runningCount > 0 || m_runningCount == QSoundEffect::Infinite) {
-                    // There are still more loops of this sound to play, append the start of sound to make up full period
-                    memcpy(data + dataOffset, sampleData + m_offset, wrapLen);
-                    m_offset += wrapLen;
-                    dataOffset += wrapLen;
-                    bytesWritten += wrapLen;
-#ifdef QT_QAUDIO_DEBUG
-                    qDebug() << "APPEND START FOR FULL PERIOD: bytesWritten=" << bytesWritten << ", offset=" << m_offset
-                             << ", part2=" << wrapLen;
-                    qDebug() << "part1 + part2 should be a period " << periodSize;
-#endif
-                }
-            }
-            if (m_runningCount == 0)
-                break;
-
-            periodsFree--;
+    if (m_sample->state() != QSample::Ready)
+        return 0;
+    if (m_runningCount == 0 || !m_playing)
+        return 0;
+
+    qint64 bytesWritten = 0;
+
+    const int   sampleSize = m_sample->data().size();
+    const char* sampleData = m_sample->data().constData();
+
+    while (len && m_runningCount) {
+        int toWrite = qMin(sampleSize - m_offset, len);
+        memcpy(data, sampleData + m_offset, toWrite);
+        bytesWritten += toWrite;
+        data += toWrite;
+        len -= toWrite;
+        m_offset += toWrite;
+        if (m_offset >= sampleSize) {
+            if (m_runningCount > 0 && m_runningCount != QSoundEffect::Infinite)
+                setLoopsRemaining(m_runningCount - 1);
+            m_offset = 0;
         }
-        return bytesWritten;
     }
 
-    return 0;
+    return bytesWritten;
 }
 
 qint64 QSoundEffectPrivate::writeData(const char *data, qint64 len)