1// Copyright 2010 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package mime
6
7import (
8	"strings"
9)
10
11// isTSpecial reports whether rune is in 'tspecials' as defined by RFC
12// 1521 and RFC 2045.
13func isTSpecial(r rune) bool {
14	return strings.ContainsRune(`()<>@,;:\"/[]?=`, r)
15}
16
17// isTokenChar reports whether rune is in 'token' as defined by RFC
18// 1521 and RFC 2045.
19func isTokenChar(r rune) bool {
20	// token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
21	//             or tspecials>
22	return r > 0x20 && r < 0x7f && !isTSpecial(r)
23}
24
25// isToken reports whether s is a 'token' as defined by RFC 1521
26// and RFC 2045.
27func isToken(s string) bool {
28	if s == "" {
29		return false
30	}
31	return strings.IndexFunc(s, isNotTokenChar) < 0
32}
33