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Simplifies AudioBuffer by consolidating logic into writes.

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This is kind of fiddling in the margins though; I'm having a lot of difficulty determining the semantically-correct way to get Qt not to funnel all activity through a single thread.
This commit is contained in:
Thomas Harte 2020-06-09 23:56:08 -04:00
parent d9f02aecdf
commit 5f13ee7c19
1 changed files with 6 additions and 17 deletions
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23
OSBindings/Qt/audiobuffer.h
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@ -38,22 +38,12 @@ struct AudioBuffer: public QIODevice {
if(readPointer == writePointer) return 0;
const size_t dataAvailable = std::min(writePointer - readPointer, size_t(maxlen));
size_t dataToCopy = dataAvailable;
// Push the read pointer such that only the most recent chunk is returned;
// nevertheless don't allow it to be pushed to a point where less than half
// a buffer is left, if avoidable. QAudioOutput doesn't make any guarantees
// about how much data it will read at a time so there's some second guessing here.
//
// TODO: can I be smarter than this?
// const size_t newReadPointer = std::min(writePointer - dataToCopy, writePointer - (buffer.size() >> 1));
// readPointer = std::max(readPointer, newReadPointer);
while(dataToCopy) {
const size_t nextLength = std::min(buffer.size() - (readPointer % buffer.size()), dataToCopy);
size_t bytesToCopy = dataAvailable;
while(bytesToCopy) {
const size_t nextLength = std::min(buffer.size() - (readPointer % buffer.size()), bytesToCopy);
memcpy(data, &buffer[readPointer % buffer.size()], nextLength);
dataToCopy -= nextLength;
bytesToCopy -= nextLength;
data += nextLength;
readPointer += nextLength;
}
@ -77,12 +67,9 @@ struct AudioBuffer: public QIODevice {
void write(const std::vector<int16_t> &source) {
std::lock_guard lock(mutex);
const size_t sourceSize = source.size() * sizeof(int16_t);
size_t endPoint = std::min(writePointer + sourceSize, readPointer + buffer.size());
writePointer = endPoint - sourceSize;
size_t bytesToCopy = sourceSize;
auto data = reinterpret_cast<const uint8_t *>(source.data());
while(bytesToCopy) {
size_t nextLength = std::min(buffer.size() - (writePointer % buffer.size()), bytesToCopy);
memcpy(&buffer[writePointer % buffer.size()], data, nextLength);
@ -91,6 +78,8 @@ struct AudioBuffer: public QIODevice {
data += nextLength;
writePointer += nextLength;
}
readPointer = std::max(readPointer, writePointer - buffer.size());
}
private: