UnreadRunes implemented

reader.go

@@ -58,6 +58,22 @@ func (r *Reader) PeekRune() (rune, error) {
 	return rn, nil
 }
 
+// String returns the next len runes in r as a string.
+// If an error occurs, both the already read string and the error will be returned
+func (r *Reader) String(len int) (string, error) {
+	str := ""
+
+	for i := 0; i < len; i++ {
+		rn, err := r.Rune()
+		if err != nil {
+			return str, err
+		}
+		str += string(rn)
+	}
+
+	return str, nil
+}
+
 // UnreadRune unreads the last rune.
 // The next read will include the unread rune.
 // It returns ErrNothingToUnread if there wasn't any read yet
@@ -92,6 +108,17 @@ func (r *Reader) UnreadString(str string) error {
 	return r.UnreadRune()
 }
 
+// UnreadRunes calls UnreadRune n times
+func (r *Reader) UnreadRunes(n int) error {
+	for i := 0; i < n; i++ {
+		err := r.UnreadRune()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // StringWhile reads runes and calls f for each one.
 // It returns all runes as a string for which f returned true.
 // It stops when f returns false or an error occured.