volume: introduce pa_cvolume_{inc|dec}()

2 files changed, 42 insertions, 0 deletions

diff --git a/src/pulse/volume.c b/src/pulse/volume.c
index 3dcf3157..234c3f72 100644
--- a/src/pulse/volume.c
+++ b/src/pulse/volume.c
@@ -876,3 +876,37 @@ pa_cvolume* pa_cvolume_merge(pa_cvolume *dest, const pa_cvolume *a, const pa_cvo
 
     return dest;
 }
+
+pa_cvolume* pa_cvolume_inc(pa_cvolume *v, pa_volume_t inc) {
+    pa_volume_t m;
+
+    pa_assert(v);
+
+    pa_return_val_if_fail(pa_cvolume_valid(v), NULL);
+
+    m = pa_cvolume_max(v);
+
+    if (m >= PA_VOLUME_MAX - inc)
+        m = PA_VOLUME_MAX;
+    else
+        m += inc;
+
+    return pa_cvolume_scale(v, m);
+}
+
+pa_cvolume* pa_cvolume_dec(pa_cvolume *v, pa_volume_t dec) {
+    pa_volume_t m;
+
+    pa_assert(v);
+
+    pa_return_val_if_fail(pa_cvolume_valid(v), NULL);
+
+    m = pa_cvolume_max(v);
+
+    if (m <= PA_VOLUME_MUTED + dec)
+        m = PA_VOLUME_MUTED;
+    else
+        m -= dec;
+
+    return pa_cvolume_scale(v, m);
+}
diff --git a/src/pulse/volume.h b/src/pulse/volume.h
index 349ca49f..543b0af1 100644
--- a/src/pulse/volume.h
+++ b/src/pulse/volume.h
@@ -345,6 +345,14 @@ pa_volume_t pa_cvolume_get_position(pa_cvolume *cv, const pa_channel_map *map, p
  * and dest may point to the same structure. \since 0.9.16 */
 pa_cvolume* pa_cvolume_merge(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b);
 
+/** Increase the volume passed in by 'inc'. The proportions between
+ * the channels are kept. \since 0.9.16 */
+pa_cvolume* pa_cvolume_inc(pa_cvolume *v, pa_volume_t inc);
+
+/** Increase the volume passed in by 'inc'. The proportions between
+ * the channels are kept. \since 0.9.16 */
+pa_cvolume* pa_cvolume_dec(pa_cvolume *v, pa_volume_t dec);
+
 PA_C_DECL_END
 
 #endif