FIFO: move threshold up to AudioStreamBuffered

Make FIFO cleaner.

3 files changed, 18 insertions, 17 deletions

diff --git a/src/fifo/FifoBuffer.cpp b/src/fifo/FifoBuffer.cpp
index 501fee69..1438941c 100644
--- a/src/fifo/FifoBuffer.cpp
+++ b/src/fifo/FifoBuffer.cpp
@@ -80,16 +80,17 @@ int32_t FifoBuffer::read(void *buffer, int32_t numFrames) {
     if (numFrames <= 0) {
         return 0;
     }
+    // safe because numFrames is guaranteed positive
     uint32_t framesToRead = static_cast<uint32_t>(numFrames);
     uint32_t framesAvailable = mFifo->getFullFramesAvailable();
     framesToRead = std::min(framesToRead, framesAvailable);
 
-    uint32_t readIndex = mFifo->getReadIndex();
+    uint32_t readIndex = mFifo->getReadIndex(); // ranges 0 to capacity
     uint8_t *destination = reinterpret_cast<uint8_t *>(buffer);
     uint8_t *source = &mStorage[convertFramesToBytes(readIndex)];
     if ((readIndex + framesToRead) > mFifo->getFrameCapacity()) {
         // read in two parts, first part here is at the end of the mStorage buffer
-        uint32_t frames1 = mFifo->getFrameCapacity() - readIndex;
+        int32_t frames1 = static_cast<int32_t>(mFifo->getFrameCapacity() - readIndex);
         int32_t numBytes = convertFramesToBytes(frames1);
         if (numBytes < 0) {
             return static_cast<int32_t>(Result::ErrorOutOfRange);
@@ -98,7 +99,7 @@ int32_t FifoBuffer::read(void *buffer, int32_t numFrames) {
         destination += numBytes;
         // read second part, which is at the beginning of mStorage
         source = &mStorage[0];
-        int frames2 = framesToRead - frames1;
+        int32_t frames2 = static_cast<uint32_t>(framesToRead - frames1);
         numBytes = convertFramesToBytes(frames2);
         if (numBytes < 0) {
             return static_cast<int32_t>(Result::ErrorOutOfRange);
@@ -121,6 +122,7 @@ int32_t FifoBuffer::write(const void *buffer, int32_t numFrames) {
     if (numFrames <= 0) {
         return 0;
     }
+    // Guaranteed positive.
     uint32_t framesToWrite = static_cast<uint32_t>(numFrames);
     uint32_t framesAvailable = mFifo->getEmptyFramesAvailable();
     framesToWrite = std::min(framesToWrite, framesAvailable);
@@ -131,7 +133,7 @@ int32_t FifoBuffer::write(const void *buffer, int32_t numFrames) {
     uint8_t *destination = &mStorage[byteIndex];
     if ((writeIndex + framesToWrite) > mFifo->getFrameCapacity()) {
         // write in two parts, first part here
-        int frames1 = mFifo->getFrameCapacity() - writeIndex;
+        int32_t frames1 = static_cast<uint32_t>(mFifo->getFrameCapacity() - writeIndex);
         int32_t numBytes = convertFramesToBytes(frames1);
         if (numBytes < 0) {
             return static_cast<int32_t>(Result::ErrorOutOfRange);
@@ -140,8 +142,8 @@ int32_t FifoBuffer::write(const void *buffer, int32_t numFrames) {
         // read second part
         source += convertFramesToBytes(frames1);
         destination = &mStorage[0];
-        int framesLeft = framesToWrite - frames1;
-        numBytes = convertFramesToBytes(framesLeft);
+        int frames2 = static_cast<uint32_t>(framesToWrite - frames1);
+        numBytes = convertFramesToBytes(frames2);
         if (numBytes < 0) {
             return static_cast<int32_t>(Result::ErrorOutOfRange);
         }
@@ -161,6 +163,9 @@ int32_t FifoBuffer::write(const void *buffer, int32_t numFrames) {
 
 int32_t FifoBuffer::readNow(void *buffer, int32_t numFrames) {
     int32_t framesRead = read(buffer, numFrames);
+    if (framesRead < 0) {
+        return framesRead;
+    }
     int32_t framesLeft = numFrames - framesRead;
     mFramesReadCount += framesRead;
     mFramesUnderrunCount += framesLeft;
diff --git a/src/opensles/AudioStreamBuffered.cpp b/src/opensles/AudioStreamBuffered.cpp
index 3972529b..7e48e4e6 100644
--- a/src/opensles/AudioStreamBuffered.cpp
+++ b/src/opensles/AudioStreamBuffered.cpp
@@ -131,7 +131,12 @@ ResultWithValue<int32_t> AudioStreamBuffered::transfer(void *buffer,
         if (getDirection() == Direction::Input) {
             result = mFifoBuffer->read(data, framesLeft);
         } else {
-            result = mFifoBuffer->write(data, framesLeft);
+            // between zero and capacity
+            uint32_t fullFrames = mFifoBuffer->getFifoControllerBase()->getFullFramesAvailable();
+            // Do not write above threshold size.
+            int32_t emptyFrames = getBufferSizeInFrames() - static_cast<int32_t>(fullFrames);
+            int32_t framesToWrite = std::max(0, std::min(framesLeft, emptyFrames));
+            result = mFifoBuffer->write(data, framesToWrite);
         }
         if (result > 0) {
             data += mFifoBuffer->convertFramesToBytes(result);
@@ -226,17 +231,10 @@ ResultWithValue<int32_t> AudioStreamBuffered::setBufferSizeInFrames(int32_t requ
     } else if (requestedFrames < getFramesPerBurst()) {
         requestedFrames = getFramesPerBurst();
     }
-    mFifoBuffer->setThresholdFrames(requestedFrames);
+    mBufferSizeInFrames = requestedFrames;
     return ResultWithValue<int32_t>(requestedFrames);
 }
 
-int32_t AudioStreamBuffered::getBufferSizeInFrames() {
-    if (mFifoBuffer) {
-        mBufferSizeInFrames = mFifoBuffer->getThresholdFrames();
-    }
-    return mBufferSizeInFrames;
-}
-
 int32_t AudioStreamBuffered::getBufferCapacityInFrames() const {
     if (mFifoBuffer) {
         return mFifoBuffer->getBufferCapacityInFrames();
diff --git a/src/opensles/AudioStreamBuffered.h b/src/opensles/AudioStreamBuffered.h
index 4ed23e9b..5923e8db 100644
--- a/src/opensles/AudioStreamBuffered.h
+++ b/src/opensles/AudioStreamBuffered.h
@@ -47,8 +47,6 @@ public:
 
     ResultWithValue<int32_t> setBufferSizeInFrames(int32_t requestedFrames) override;
 
-    int32_t getBufferSizeInFrames() override;
-
     int32_t getBufferCapacityInFrames() const override;
 
     ResultWithValue<int32_t> getXRunCount() const override {