1 files changed, 17 insertions, 0 deletions
diff --git a/string.c b/string.c
index 286c56a93..20ce81963 100644
--- a/string.c
+++ b/string.c
@@ -129,6 +129,23 @@ rb_enc_str_coderange(VALUE str)
     return cr;
 }
 
+int rb_enc_str_asciionly_p(VALUE str)
+{
+    rb_encoding *enc = rb_enc_get(str);
+
+    if (rb_enc_asciicompat(enc) &&
+        rb_enc_str_coderange(str) == ENC_CODERANGE_SINGLE) {
+        char *ptr = RSTRING_PTR(str);
+        long len = RSTRING_LEN(str);
+        long i;
+        for (i = 0; i < len; i++)
+            if (ptr[i] & 0x80)
+                return Qfalse;
+        return Qtrue;
+    }
+    return Qfalse;
+}
+
 static inline void
 str_mod_check(VALUE s, char *p, long len)
 {