libgo/go/mime/grammar.go

   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
   5 package mime
   6
   7 import (
   8         "strings"
   9 )
  10
  11 // isTSpecial returns true if rune is in 'tspecials' as defined by RFC
  12 // 1531 and RFC 2045.
  13 func isTSpecial(rune int) bool {
  14         return strings.IndexRune(`()<>@,;:\"/[]?=`, rune) != -1
  15 }
  16
  17 // IsTokenChar returns true if rune is in 'token' as defined by RFC
  18 // 1531 and RFC 2045.
  19 func IsTokenChar(rune int) bool {
  20         // token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
  21         //             or tspecials>
  22         return rune > 0x20 && rune < 0x7f && !isTSpecial(rune)
  23 }
  24
  25 // IsQText returns true if rune is in 'qtext' as defined by RFC 822.
  26 func IsQText(rune int) bool {
  27         // CHAR        =  <any ASCII character>        ; (  0-177,  0.-127.)
  28         // qtext       =  <any CHAR excepting <">,     ; => may be folded
  29         //                "\" & CR, and including
  30         //                linear-white-space>
  31         switch rune {
  32         case '"', '\\', '\r':
  33                 return false
  34         }
  35         return rune < 0x80
  36 }