Merge "AudioMixer can be configured for fewer max tracks"

Author: gkasten

services/audioflinger/AudioMixer.cpp

@@ -42,12 +42,15 @@ namespace android {
 
 // ----------------------------------------------------------------------------
 
-AudioMixer::AudioMixer(size_t frameCount, uint32_t sampleRate)
-    :   mTrackNames(0), mSampleRate(sampleRate)
+AudioMixer::AudioMixer(size_t frameCount, uint32_t sampleRate, uint32_t maxNumTracks)
+    :   mTrackNames(0), mConfiguredNames((1 << maxNumTracks) - 1), mSampleRate(sampleRate)
 {
     // AudioMixer is not yet capable of multi-channel beyond stereo
     COMPILE_TIME_ASSERT_FUNCTION_SCOPE(2 == MAX_NUM_CHANNELS);
 
+    ALOG_ASSERT(maxNumTracks <= MAX_NUM_TRACKS, "maxNumTracks %u > MAX_NUM_TRACKS %u",
+            maxNumTracks, MAX_NUM_TRACKS);
+
     LocalClock lc;
 
     mState.enabledTracks= 0;
@@ -107,7 +110,7 @@ AudioMixer::~AudioMixer()
 
 int AudioMixer::getTrackName()
 {
-    uint32_t names = ~mTrackNames;
+    uint32_t names = (~mTrackNames) & mConfiguredNames;
     if (names != 0) {
         int n = __builtin_ctz(names);
         ALOGV("add track (%d)", n);

services/audioflinger/AudioMixer.h

@@ -31,7 +31,8 @@ namespace android {
 class AudioMixer
 {
 public:
-                            AudioMixer(size_t frameCount, uint32_t sampleRate);
+                            AudioMixer(size_t frameCount, uint32_t sampleRate,
+                                       uint32_t maxNumTracks = MAX_NUM_TRACKS);
 
     /*virtual*/             ~AudioMixer();  // non-virtual saves a v-table, restore if sub-classed
 
@@ -189,11 +190,17 @@ class AudioMixer
         int32_t         *outputTemp;
         int32_t         *resampleTemp;
         int32_t         reserved[2];
+        // FIXME allocate dynamically to save some memory when maxNumTracks < MAX_NUM_TRACKS
         track_t         tracks[MAX_NUM_TRACKS]; __attribute__((aligned(32)));
     };
 
     // bitmask of allocated track names, where bit 0 corresponds to TRACK0 etc.
     uint32_t        mTrackNames;
+
+    // bitmask of configured track names; ~0 if maxNumTracks == MAX_NUM_TRACKS,
+    // but will have fewer bits set if maxNumTracks < MAX_NUM_TRACKS
+    const uint32_t  mConfiguredNames;
+
     const uint32_t  mSampleRate;
 
     state_t         mState __attribute__((aligned(32)));