Make `ary_replace()` to share entry buffers if possible.
MODIFY
src/array.c
src/array.c
@@ -349,12 +349,39 @@ mrb_ary_plus(mrb_state *mrb, mrb_value self)
return mrb_obj_value(a2);
}
+#define ARY_REPLACE_SHARED_MIN 20
+
static void
ary_replace(mrb_state *mrb, struct RArray *a, struct RArray *b)
{
mrb_int len = ARY_LEN(b);
- ary_modify(mrb, a);
+ ary_modify_check(mrb, a);
+ if (a == b) return;
+ if (ARY_SHARED_P(a)) {
+ mrb_ary_decref(mrb, a->as.heap.aux.shared);
+ a->as.heap.aux.capa = 0;
+ a->as.heap.len = 0;
+ a->as.heap.ptr = NULL;
+ ARY_UNSET_SHARED_FLAG(a);
+ }
+ if (ARY_SHARED_P(b)) {
+ shared_b:
+ if (ARY_EMBED_P(a)) {
+ ARY_UNSET_EMBED_FLAG(a);
+ }
+ a->as.heap.ptr = b->as.heap.ptr;
+ a->as.heap.len = len;
+ a->as.heap.aux.shared = b->as.heap.aux.shared;
+ a->as.heap.aux.shared->refcnt++;
+ ARY_SET_SHARED_FLAG(a);
+ mrb_write_barrier(mrb, (struct RBasic*)a);
+ return;
+ }
+ if (!MRB_FROZEN_P(b) && len > ARY_REPLACE_SHARED_MIN) {
+ ary_make_shared(mrb, b);
+ goto shared_b;
+ }
if (ARY_CAPA(a) < len)
ary_expand_capa(mrb, a, len);
array_copy(ARY_PTR(a), ARY_PTR(b), len);

Make `ary_replace()` to share entry buffers if possible.