New GC_iterate_free_hblks API function

Issue #460 (bdwgc).

* allchblk.c (GC_iterate_free_hblks): Implement (copy part of code
from GC_compute_large_free_bytes).
* allchblk.c [!NO_DEBUGGING || GC_ASSERTIONS] (add_hb_sz): New static
function.
* allchblk.c [!NO_DEBUGGING || GC_ASSERTIONS]
(GC_compute_large_free_bytes): Use GC_iterate_free_hblks(add_hb_sz).
* include/gc/gc_mark.h (GC_iterate_free_hblks): Declare public
function.

1 files changed, 6 insertions, 0 deletions

diff --git a/include/gc/gc_mark.h b/include/gc/gc_mark.h
index f825cac0..88557147 100644
--- a/include/gc/gc_mark.h
+++ b/include/gc/gc_mark.h
@@ -184,6 +184,12 @@ GC_API GC_ATTR_CONST size_t GC_CALL GC_get_hblk_size(void);
 typedef void (GC_CALLBACK *GC_walk_hblk_fn)(struct GC_hblk_s *,
                                             GC_word /* client_data */);
 
+/* Apply fn to each completely empty heap block.  It is the             */
+/* responsibility of the caller to avoid data race during the function  */
+/* execution (e.g. by holding the allocation lock).                     */
+GC_API void GC_CALL GC_iterate_free_hblks(GC_walk_hblk_fn,
+                                GC_word /* client_data */) GC_ATTR_NONNULL(1);
+
 /* Apply fn to each allocated heap block.  It is the responsibility     */
 /* of the caller to avoid data race during the function execution (e.g. */
 /* by holding the allocation lock).                                     */