object: add object_array initializer helper function

The object_array API has an OBJECT_ARRAY_INIT macro, but lacks a
function to initialize an object_array at a given location in memory.

Introduce `object_array_init()` to implement such a function.

Signed-off-by: Taylor Blau <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ttaylorr

object.c

@@ -356,6 +356,12 @@ void object_list_free(struct object_list **list)
  */
 static char object_array_slopbuf[1];
 
+void object_array_init(struct object_array *array)
+{
+	struct object_array blank = OBJECT_ARRAY_INIT;
+	memcpy(array, &blank, sizeof(*array));
+}
+
 void add_object_array_with_path(struct object *obj, const char *name,
 				struct object_array *array,
 				unsigned mode, const char *path)

object.h

@@ -57,6 +57,8 @@ struct object_array {
 
 #define OBJECT_ARRAY_INIT { 0 }
 
+void object_array_init(struct object_array *array);
+
 /*
  * object flag allocation:
  * revision.h:               0---------10         15             23------27