1 files changed, 20 insertions, 0 deletions
diff --git a/string.c b/string.c
index 3ac56b56c..4b2706653 100644
--- a/string.c
+++ b/string.c
@@ -1116,6 +1116,26 @@ rb_str_cat2(VALUE str, const char *ptr)
     return rb_str_cat(str, ptr, strlen(ptr));
 }
 
+VALUE
+rb_str_buf_cat_ascii(VALUE str, const char *ptr)
+{
+    rb_encoding *enc = rb_enc_get(str);
+    if (rb_enc_asciicompat(enc)) {
+        return rb_str_buf_cat(str, ptr, strlen(ptr));
+    }
+    else {
+        char *buf = ALLOCA_N(char, rb_enc_mbmaxlen(enc));
+        while (*ptr) {
+            int c = (unsigned char)*ptr;
+            int len = rb_enc_codelen(c, enc);
+            rb_enc_mbcput(c, buf, enc);
+            rb_str_buf_cat(str, buf, len);
+            ptr++;
+        }
+        return str;
+    }
+}
+
 static VALUE
 rb_enc_cr_str_buf_cat(VALUE str, const char *ptr, long len,
     int ptr_encindex, int ptr_cr, int *ptr_cr_ret)