Add mmelody_active_p

apps/squeak2/squeak2.c

@@ -100,8 +100,13 @@ static void button_task (__unused__ void *data)
     button_update ();
 
     if (button_push_event_p (BUTTON1))
+    {
+        if (mmelody_active_p (melody))
+            mmelody_play (melody, 0);            
+        else
             mmelody_play (melody, tune1);
     }
+}
 
 
 int main (void)

extra/mmelody.c

@@ -257,6 +257,8 @@ mmelody_play (mmelody_t mmelody, const char *str)
     mmelody->octave = MMELODY_OCTAVE_DEFAULT;
     /* Default to quarter notes.  */
     mmelody_note_fraction_set (mmelody, 4);
+    /* Stop what is currently sounding.  */
+    mmelody_note_play (mmelody, 0);
 }
 
 
@@ -277,6 +279,13 @@ mmelody_volume_set (mmelody_t mmelody, mmelody_volume_t volume)
 }
 
 
+bool
+mmelody_active_p (mmelody_t mmelody)
+{
+    return mmelody->cur != 0;
+}
+
+
 void
 mmelody_update (mmelody_t mmelody)
 {

extra/mmelody.h

@@ -68,4 +68,10 @@ mmelody_speed_set (mmelody_t mmelody, mmelody_speed_t speed);
 void 
 mmelody_volume_set (mmelody_t mmelody, mmelody_volume_t volume);
 
+
+/** Return non-zero if playing.  */
+bool
+mmelody_active_p (mmelody_t mmelody);
+
+
 #endif