1 // Copyright 2015 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 precis 6 7 import ( 8 "unicode/utf8" 9 ) 10 11 // TODO: Add contextual character rules from Appendix A of RFC5892. 12 13 // A class is a set of characters that match certain derived properties. The 14 // PRECIS framework defines two classes: The Freeform class and the Identifier 15 // class. The freeform class should be used for profiles where expressiveness is 16 // prioritized over safety such as nicknames or passwords. The identifier class 17 // should be used for profiles where safety is the first priority such as 18 // addressable network labels and usernames. 19 type class struct { 20 validFrom property 21 } 22 23 // Contains satisfies the runes.Set interface and returns whether the given rune 24 // is a member of the class. 25 func (c class) Contains(r rune) bool { 26 b := make([]byte, 4) 27 n := utf8.EncodeRune(b, r) 28 29 trieval, _ := dpTrie.lookup(b[:n]) 30 return c.validFrom <= property(trieval) 31 } 32 33 var ( 34 identifier = &class{validFrom: pValid} 35 freeform = &class{validFrom: idDisOrFreePVal} 36 ) 37