memory: add method to check memory type

Add a method to check if a memory was allocated from an allocator of
a given type.

API: gst_memory_is_type()

docs/gst/gstreamer-sections.txt

@@ -1345,6 +1345,8 @@ GstMemoryIsSpanFunction
 
 gst_memory_init
 
+gst_memory_is_type
+
 gst_memory_ref
 gst_memory_unref
 

gst/gstmemory.c

@@ -138,6 +138,27 @@ gst_memory_init (GstMemory * mem, GstMemoryFlags flags,
       offset, size);
 }
 
+/**
+ * gst_memory_is_type:
+ * @mem: a #GstMemory
+ * @mem_type: a memory type
+ *
+ * Check if @mem if allocated with an allocator for @mem_type.
+ *
+ * Returns: %TRUE if @mem was allocated from an allocator for @mem_type.
+ *
+ * Since: 1.2
+ */
+gboolean
+gst_memory_is_type (GstMemory * mem, const gchar * mem_type)
+{
+  g_return_val_if_fail (mem != NULL, FALSE);
+  g_return_val_if_fail (mem->allocator != NULL, FALSE);
+  g_return_val_if_fail (mem_type != NULL, FALSE);
+
+  return (g_strcmp0 (mem->allocator->mem_type, mem_type) == 0);
+}
+
 /**
  * gst_memory_get_sizes:
  * @mem: a #GstMemory

gst/gstmemory.h

@@ -287,6 +287,9 @@ void           gst_memory_init         (GstMemory *mem, GstMemoryFlags flags,
                                         GstAllocator *allocator, GstMemory *parent,
                                         gsize maxsize, gsize align,
                                         gsize offset, gsize size);
+
+gboolean       gst_memory_is_type      (GstMemory *mem, const gchar *mem_type);
+
 /* refcounting */
 /**
  * gst_memory_ref: