implement pa_channel_map_can_fade

3 files changed, 58 insertions, 5 deletions

diff --git a/src/map-file b/src/map-file
index e076a435..3aa1d7a8 100644
--- a/src/map-file
+++ b/src/map-file
@@ -10,6 +10,7 @@ pa_bytes_per_second;
 pa_bytes_snprint;
 pa_bytes_to_usec;
 pa_channel_map_can_balance;
+pa_channel_map_can_fade;
 pa_channel_map_compatible;
 pa_channel_map_equal;
 pa_channel_map_init;
diff --git a/src/pulse/channelmap.c b/src/pulse/channelmap.c
index 455bda1b..6ff30c26 100644
--- a/src/pulse/channelmap.c
+++ b/src/pulse/channelmap.c
@@ -647,30 +647,77 @@ int pa_channel_map_superset(const pa_channel_map *a, const pa_channel_map *b) {
 
 int pa_channel_map_can_balance(const pa_channel_map *map) {
     unsigned c;
+    pa_bool_t left = FALSE, right = FALSE;
 
     pa_assert(map);
 
-    for (c = 0; c < map->channels; c++)
+    for (c = 0; c < map->channels; c++) {
 
         switch (map->map[c]) {
             case PA_CHANNEL_POSITION_LEFT:
-            case PA_CHANNEL_POSITION_RIGHT:
             case PA_CHANNEL_POSITION_REAR_LEFT:
-            case PA_CHANNEL_POSITION_REAR_RIGHT:
             case PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER:
-            case PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER:
             case PA_CHANNEL_POSITION_SIDE_LEFT:
+            case PA_CHANNEL_POSITION_TOP_FRONT_LEFT:
+            case PA_CHANNEL_POSITION_TOP_REAR_LEFT:
+                left = TRUE;
+                break;
+
+            case PA_CHANNEL_POSITION_RIGHT:
+            case PA_CHANNEL_POSITION_REAR_RIGHT:
+            case PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER:
             case PA_CHANNEL_POSITION_SIDE_RIGHT:
+            case PA_CHANNEL_POSITION_TOP_FRONT_RIGHT:
+            case PA_CHANNEL_POSITION_TOP_REAR_RIGHT:
+                right = TRUE;
+                break;
+
+            default:
+                ;
+        }
+
+        if (left && right)
+            return 1;
+    }
+
+    return 0;
+}
+
+int pa_channel_map_can_fade(const pa_channel_map *map) {
+    unsigned c;
+    pa_bool_t front = FALSE, rear = FALSE;
+
+    for (c = 0; c < map->channels; c++) {
+
+        switch (map->map[c]) {
+            case PA_CHANNEL_POSITION_FRONT_LEFT:
+            case PA_CHANNEL_POSITION_FRONT_RIGHT:
+            case PA_CHANNEL_POSITION_FRONT_CENTER:
+            case PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER:
+            case PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER:
             case PA_CHANNEL_POSITION_TOP_FRONT_LEFT:
             case PA_CHANNEL_POSITION_TOP_FRONT_RIGHT:
+            case PA_CHANNEL_POSITION_TOP_FRONT_CENTER:
+                front = TRUE;
+                break;
+
+            case PA_CHANNEL_POSITION_REAR_LEFT:
+            case PA_CHANNEL_POSITION_REAR_RIGHT:
+            case PA_CHANNEL_POSITION_REAR_CENTER:
             case PA_CHANNEL_POSITION_TOP_REAR_LEFT:
             case PA_CHANNEL_POSITION_TOP_REAR_RIGHT:
-                return 1;
+            case PA_CHANNEL_POSITION_TOP_REAR_CENTER:
+                rear = TRUE;
+                break;
 
             default:
                 ;
         }
 
+        if (front && rear)
+            return 1;
+    }
+
     return 0;
 }
 
diff --git a/src/pulse/channelmap.h b/src/pulse/channelmap.h
index de2d712a..f9124b2e 100644
--- a/src/pulse/channelmap.h
+++ b/src/pulse/channelmap.h
@@ -239,6 +239,11 @@ int pa_channel_map_superset(const pa_channel_map *a, const pa_channel_map *b) PA
  * available. \since 0.9.15 */
 int pa_channel_map_can_balance(const pa_channel_map *map) PA_GCC_PURE;
 
+/** Returns non-zero if it makes sense to apply a volume 'fade'
+ * (i.e. 'balance' between front and rear) with this mapping, i.e. if
+ * there are front/rear channels available. \since 0.9.15 */
+int pa_channel_map_can_fade(const pa_channel_map *map) PA_GCC_PURE;
+
 /** Tries to find a well-known channel mapping name for this channel
  * mapping. I.e. "stereo", "surround-71" and so on. If the channel
  * mapping is unknown NULL will be returned. This name can be parsed