ao_coreaudio: simplify ch label to speaker id conversion

Previous code was using the values of the AudioChannelLabel enum directly to
create the channel bitmap. While this was quite smart it was pretty unreadable
and fragile (what if Apple changes the values of those enums?).

Change it to use a 'dumb' conversion table.

1 files changed, 37 insertions, 23 deletions

diff --git a/audio/out/ao_coreaudio_utils.c b/audio/out/ao_coreaudio_utils.c
index 2a3cd99028..9fa54c726c 100644
--- a/audio/out/ao_coreaudio_utils.c
+++ b/audio/out/ao_coreaudio_utils.c
@@ -336,31 +336,45 @@ bool ca_change_format(struct ao *ao, AudioStreamID stream,
     return format_set;
 }
 
+static const int speaker_map[][2] = {
+    { kAudioChannelLabel_Left,                 MP_SPEAKER_ID_FL   },
+    { kAudioChannelLabel_Right,                MP_SPEAKER_ID_FR   },
+    { kAudioChannelLabel_Center,               MP_SPEAKER_ID_FC   },
+    { kAudioChannelLabel_LFEScreen,            MP_SPEAKER_ID_LFE  },
+    { kAudioChannelLabel_LeftSurround,         MP_SPEAKER_ID_BL   },
+    { kAudioChannelLabel_RightSurround,        MP_SPEAKER_ID_BR   },
+    { kAudioChannelLabel_LeftCenter,           MP_SPEAKER_ID_FLC  },
+    { kAudioChannelLabel_RightCenter,          MP_SPEAKER_ID_FRC  },
+    { kAudioChannelLabel_CenterSurround,       MP_SPEAKER_ID_BC   },
+    { kAudioChannelLabel_LeftSurroundDirect,   MP_SPEAKER_ID_SL   },
+    { kAudioChannelLabel_RightSurroundDirect,  MP_SPEAKER_ID_SR   },
+    { kAudioChannelLabel_TopCenterSurround,    MP_SPEAKER_ID_TC   },
+    { kAudioChannelLabel_VerticalHeightLeft,   MP_SPEAKER_ID_TFL  },
+    { kAudioChannelLabel_VerticalHeightCenter, MP_SPEAKER_ID_TFC  },
+    { kAudioChannelLabel_VerticalHeightRight,  MP_SPEAKER_ID_TFR  },
+    { kAudioChannelLabel_TopBackLeft,          MP_SPEAKER_ID_TBL  },
+    { kAudioChannelLabel_TopBackCenter,        MP_SPEAKER_ID_TBC  },
+    { kAudioChannelLabel_TopBackRight,         MP_SPEAKER_ID_TBR  },
+
+    // unofficial extensions
+    { kAudioChannelLabel_RearSurroundLeft,     MP_SPEAKER_ID_SDL  },
+    { kAudioChannelLabel_RearSurroundRight,    MP_SPEAKER_ID_SDR  },
+    { kAudioChannelLabel_LeftWide,             MP_SPEAKER_ID_WL   },
+    { kAudioChannelLabel_RightWide,            MP_SPEAKER_ID_WR   },
+    { kAudioChannelLabel_LFE2,                 MP_SPEAKER_ID_LFE2 },
+
+    { kAudioChannelLabel_HeadphonesLeft,       MP_SPEAKER_ID_DL   },
+    { kAudioChannelLabel_HeadphonesRight,      MP_SPEAKER_ID_DR   },
+
+    { kAudioChannelLabel_Unknown,              -1 },
+};
+
 static int ca_label_to_mp_speaker_id(AudioChannelLabel label)
 {
-    if (label == kAudioChannelLabel_UseCoordinates ||
-        label == kAudioChannelLabel_Unknown ||
-        label > kAudioChannelLabel_LFE2)
-        return -1;
-
-    if (label <= kAudioChannelLabel_TopBackRight) {
-        return label - 1;
-    } else {
-        // Take care of extra labels after kAudioChannelLabel_TopBackRight
-        switch (label) {
-        case kAudioChannelLabel_RearSurroundLeft:
-            return MP_SPEAKER_ID_SDL;
-        case kAudioChannelLabel_RearSurroundRight:
-            return MP_SPEAKER_ID_SDR;
-        case kAudioChannelLabel_LeftWide:
-            return MP_SPEAKER_ID_WL;
-        case kAudioChannelLabel_RightWide:
-            return MP_SPEAKER_ID_WR;
-        case kAudioChannelLabel_LFE2:
-            return kAudioChannelLabel_LFE2;
-        }
-        return -1;
-    }
+    for (int i = 0; speaker_map[i][0] != kAudioChannelLabel_Unknown; i++)
+        if (speaker_map[i][0] == label)
+            return speaker_map[i][1];
+    return -1;
 }
 
 static bool ca_bitmap_from_ch_desc(struct ao *ao, AudioChannelLayout *layout,