1 files changed, 10 insertions, 4 deletions
diff --git a/src/variable.c b/src/variable.c
index 0c94f412e..f05fcee90 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -4,7 +4,6 @@
 ** See Copyright Notice in mruby.h
 */
 
-#include <math.h>
 #include <mruby.h>
 #include <mruby/array.h>
 #include <mruby/class.h>
@@ -1132,9 +1131,16 @@ mrb_class_find_path(mrb_state *mrb, struct RClass *c)
 mrb_int
 mrb_obj_iv_tbl_memsize(mrb_state* mrb, mrb_value obj)
 {
-  return sizeof(iv_tbl) +
-    (sizeof(segment) * ceil(iv_size(mrb, mrb_obj_ptr(obj)->iv)/
-                            MRB_IV_SEGMENT_SIZE));
+  size_t nseg = 0;
+  segment *seg;
+
+  if (mrb_obj_ptr(obj)->iv == NULL) return 0;
+  seg = mrb_obj_ptr(obj)->iv->rootseg;
+  while (seg) {
+    nseg++;
+    seg = seg->next;
+  }
+  return sizeof(iv_tbl) + sizeof(segment)*nseg;
 }
 
 #define identchar(c) (ISALNUM(c) || (c) == '_' || !ISASCII(c))