diff --git a/lib/rb/ext/macros.h b/lib/rb/ext/macros.h
index 6dbb7ad..8e1f343 100644
--- a/lib/rb/ext/macros.h
+++ b/lib/rb/ext/macros.h
@@ -26,4 +26,16 @@
 
 #ifndef RFLOAT_VALUE
 #  define RFLOAT_VALUE(v) RFLOAT(rb_Float(v))->value
+#endif
+
+#ifndef RSTRING_LEN
+#  define RSTRING_LEN(v) RSTRING(rb_String(v))->len
+#endif
+
+#ifndef RSTRING_PTR
+#  define RSTRING_PTR(v) RSTRING(rb_String(v))->ptr
+#endif
+
+#ifndef RARRAY_LEN
+#  define RARRAY_LEN(v) RARRAY(rb_Array(v))->len
 #endif
\ No newline at end of file