1// Copyright 2018 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 compact defines a compact representation of language tags.
6//
7// Common language tags (at least all for which locale information is defined
8// in CLDR) are assigned a unique index. Each Tag is associated with such an
9// ID for selecting language-related resources (such as translations) as well
10// as one for selecting regional defaults (currency, number formatting, etc.)
11//
12// It may want to export this functionality at some point, but at this point
13// this is only available for use within x/text.
14package compact // import "golang.org/x/text/internal/language/compact"
15
16import (
17	"sort"
18	"strings"
19
20	"golang.org/x/text/internal/language"
21)
22
23// ID is an integer identifying a single tag.
24type ID uint16
25
26func getCoreIndex(t language.Tag) (id ID, ok bool) {
27	cci, ok := language.GetCompactCore(t)
28	if !ok {
29		return 0, false
30	}
31	i := sort.Search(len(coreTags), func(i int) bool {
32		return cci <= coreTags[i]
33	})
34	if i == len(coreTags) || coreTags[i] != cci {
35		return 0, false
36	}
37	return ID(i), true
38}
39
40// Parent returns the ID of the parent or the root ID if id is already the root.
41func (id ID) Parent() ID {
42	return parents[id]
43}
44
45// Tag converts id to an internal language Tag.
46func (id ID) Tag() language.Tag {
47	if int(id) >= len(coreTags) {
48		return specialTags[int(id)-len(coreTags)]
49	}
50	return coreTags[id].Tag()
51}
52
53var specialTags []language.Tag
54
55func init() {
56	tags := strings.Split(specialTagsStr, " ")
57	specialTags = make([]language.Tag, len(tags))
58	for i, t := range tags {
59		specialTags[i] = language.MustParse(t)
60	}
61}
62