commit 5f82f49d4f31f0622b422e6254aa60d36f4a61fa
author jiabin <jiabin@google.com> Fri Apr 09 19:03:58 2021 +0000
committer jiabin <jiabin@google.com> Mon Apr 12 18:47:52 2021 +0000
tree 73e4a24bf9fb6fdf1c22d694b111b823d7e47e6e
parent 210e8ea1f6ca5a3e3d3829389c6ec7169d8a6ca5

Count channel mapping number from the back.

The channel mapping array may have leading UNUSED value. In that case,
count the channel mapping number from the back to avoid lost channel
mapping information.

Bug: 183558363
Test: repo steps in the bug
Test: atest android.hardware.audio@7.0-util_tests
Change-Id: Ic4238e520c16eb1daad7c9e92555e92637f8e7c9

audio/core/all-versions/default/util/CoreUtils.cpp

diff --git a/audio/core/all-versions/default/util/CoreUtils.cpp b/audio/core/all-versions/default/util/CoreUtils.cpp
index 14f76f3..773be21 100644
--- a/audio/core/all-versions/default/util/CoreUtils.cpp
+++ b/audio/core/all-versions/default/util/CoreUtils.cpp
@@ -66,13 +66,13 @@
     CONVERT_CHECKED(
             deviceAddressFromHal(halMicInfo.device, halMicInfo.address, &micInfo->deviceAddress),
             result);
-    size_t chCount;
-    for (chCount = 0; chCount < AUDIO_CHANNEL_COUNT_MAX; ++chCount) {
-        if (halMicInfo.channel_mapping[chCount] == AUDIO_MICROPHONE_CHANNEL_MAPPING_UNUSED) {
+    int chCount;
+    for (chCount = AUDIO_CHANNEL_COUNT_MAX - 1; chCount >= 0; --chCount) {
+        if (halMicInfo.channel_mapping[chCount] != AUDIO_MICROPHONE_CHANNEL_MAPPING_UNUSED) {
             break;
         }
     }
-    micInfo->channelMapping.resize(chCount);
+    micInfo->channelMapping.resize(chCount + 1);
     for (size_t ch = 0; ch < micInfo->channelMapping.size(); ch++) {
         micInfo->channelMapping[ch] = AudioMicrophoneChannelMapping(halMicInfo.channel_mapping[ch]);
     }