queuearray: Implement pop_tail_struct() for completeness

All other variants of {peek,pop}_{head,tail}_{,struct} were already
implemented.

https://bugzilla.gnome.org/show_bug.cgi?id=794035

docs/libs/gstreamer-libs-sections.txt

@@ -938,6 +938,7 @@ gst_queue_array_push_tail_struct
 gst_queue_array_peek_head_struct
 gst_queue_array_pop_head_struct
 gst_queue_array_peek_tail_struct
+gst_queue_array_pop_tail_struct
 gst_queue_array_drop_struct
 </SECTION>
 

libs/gst/base/gstqueuearray.c

@@ -401,6 +401,41 @@ gst_queue_array_pop_tail (GstQueueArray * array)
   return ret;
 }
 
+/**
+ * gst_queue_array_pop_tail_struct: (skip)
+ * @array: a #GstQueueArray object
+ *
+ * Returns the tail of the queue @array and removes
+ * it from the queue.
+ *
+ * Returns: The tail of the queue
+ *
+ * Since: 1.14
+ */
+gpointer
+gst_queue_array_pop_tail_struct (GstQueueArray * array)
+{
+  gpointer ret;
+  guint len, idx;
+
+  g_return_val_if_fail (array != NULL, NULL);
+
+  len = array->length;
+
+  /* empty array */
+  if (len == 0)
+    return NULL;
+
+  idx = (array->head + (len - 1)) % array->size;
+
+  ret = array->array + (array->elt_size * idx);
+
+  array->tail = idx;
+  array->length--;
+
+  return ret;
+}
+
 /**
  * gst_queue_array_is_empty: (skip)
  * @array: a #GstQueueArray object

libs/gst/base/gstqueuearray.h

@@ -84,6 +84,8 @@ gboolean        gst_queue_array_drop_struct      (GstQueueArray * array,
                                                   guint           idx,
                                                   gpointer        p_struct);
 GST_EXPORT
+gpointer        gst_queue_array_pop_tail_struct  (GstQueueArray * array);
+GST_EXPORT
 gpointer        gst_queue_array_peek_tail_struct (GstQueueArray * array);
 
 G_END_DECLS

win32/common/libgstbase.def

@@ -321,6 +321,7 @@ EXPORTS
 	gst_queue_array_pop_head
 	gst_queue_array_pop_head_struct
 	gst_queue_array_pop_tail
+	gst_queue_array_pop_tail_struct
 	gst_queue_array_push_tail
 	gst_queue_array_push_tail_struct
 	gst_type_find_helper