commit 62cd0f4a5aa2be7d870108630f4ac9447af95d9d
author Phil Burk <philburk@google.com> Fri Apr 20 17:24:38 2018 -0700
committer JP Sugarbroad <jpsugar@google.com> Mon Jan 14 14:56:23 2019 -0800
tree 792602639ca2bd715c0e946ae97bf043c5ee5fbc
parent 8cd9380c57b4924b41ba32cdebdf8e009d1addb0

RESTRICT AUTOMERGE: aaudio: fix FIFO wrapround frame counts

The number of frames in the second part was incorrect
when it wrapped past the end of the FIFO.

Bug: 78139448
Bug: 120789744
Test: adb shell aaudio_loopback -c2 -C2 -tm -m2 -Pl -pn
Change-Id: Ib6a22f30f0ee5321444c6d6137d9488943c34f3d
(cherry picked from commit 685607be811e6d5fffc407d71a2703de9c351969)

media/libaaudio/src/fifo/FifoBuffer.cpp

diff --git a/media/libaaudio/src/fifo/FifoBuffer.cpp b/media/libaaudio/src/fifo/FifoBuffer.cpp
index a869886..c8ec15079f 100644
--- a/media/libaaudio/src/fifo/FifoBuffer.cpp
+++ b/media/libaaudio/src/fifo/FifoBuffer.cpp
@@ -22,6 +22,8 @@
 //#define LOG_NDEBUG 0
 #include <utils/Log.h>
 
+#include <algorithm>
+
 #include "FifoControllerBase.h"
 #include "FifoController.h"
 #include "FifoControllerIndirect.h"
@@ -85,15 +87,14 @@
     wrappingBuffer->data[1] = nullptr;
     wrappingBuffer->numFrames[1] = 0;
     if (framesAvailable > 0) {
-
         uint8_t *source = &mStorage[convertFramesToBytes(startIndex)];
         // Does the available data cross the end of the FIFO?
         if ((startIndex + framesAvailable) > mFrameCapacity) {
             wrappingBuffer->data[0] = source;
-            wrappingBuffer->numFrames[0] = mFrameCapacity - startIndex;
+            fifo_frames_t firstFrames = mFrameCapacity - startIndex;
+            wrappingBuffer->numFrames[0] = firstFrames;
             wrappingBuffer->data[1] = &mStorage[0];
-            wrappingBuffer->numFrames[1] = mFrameCapacity - startIndex;
-
+            wrappingBuffer->numFrames[1] = framesAvailable - firstFrames;
         } else {
             wrappingBuffer->data[0] = source;
             wrappingBuffer->numFrames[0] = framesAvailable;
@@ -102,18 +103,19 @@
         wrappingBuffer->data[0] = nullptr;
         wrappingBuffer->numFrames[0] = 0;
     }
-
 }
 
 fifo_frames_t FifoBuffer::getFullDataAvailable(WrappingBuffer *wrappingBuffer) {
-    fifo_frames_t framesAvailable = mFifo->getFullFramesAvailable();
+    // The FIFO might be overfull so clip to capacity.
+    fifo_frames_t framesAvailable = std::min(mFifo->getFullFramesAvailable(), mFrameCapacity);
     fifo_frames_t startIndex = mFifo->getReadIndex();
     fillWrappingBuffer(wrappingBuffer, framesAvailable, startIndex);
     return framesAvailable;
 }
 
 fifo_frames_t FifoBuffer::getEmptyRoomAvailable(WrappingBuffer *wrappingBuffer) {
-    fifo_frames_t framesAvailable = mFifo->getEmptyFramesAvailable();
+    // The FIFO might have underrun so clip to capacity.
+    fifo_frames_t framesAvailable = std::min(mFifo->getEmptyFramesAvailable(), mFrameCapacity);
     fifo_frames_t startIndex = mFifo->getWriteIndex();
     fillWrappingBuffer(wrappingBuffer, framesAvailable, startIndex);
     return framesAvailable;