--- ferret-0.11.8.4/ext/r_analysis.c.ruby22hash	2015-01-18 02:41:02.096371434 +0900
+++ ferret-0.11.8.4/ext/r_analysis.c	2015-01-18 02:46:51.435722105 +0900
@@ -65,7 +65,11 @@
 frb_rb_hash_size(VALUE hash)
 {
 #ifdef FRT_RUBY_VERSION_1_9
+#ifdef RHASH_SIZE
+    return RHASH_SIZE(hash);
+#else
     return RHASH(hash)->ntbl->num_entries;
+#endif
 #else
     return RHASH(hash)->tbl->num_entries;
 #endif