blob: 1b36935ef7be1945b8e75f5c74c95f88c7462b5d [file] [log] [blame]
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package compact defines a compact representation of language tags.
// Common language tags (at least all for which locale information is defined
// in CLDR) are assigned a unique index. Each Tag is associated with such an
// ID for selecting language-related resources (such as translations) as well
// as one for selecting regional defaults (currency, number formatting, etc.)
// It may want to export this functionality at some point, but at this point
// this is only available for use within x/text.
package compact // import ""
import (
// ID is an integer identifying a single tag.
type ID uint16
func getCoreIndex(t language.Tag) (id ID, ok bool) {
cci, ok := language.GetCompactCore(t)
if !ok {
return 0, false
i := sort.Search(len(coreTags), func(i int) bool {
return cci <= coreTags[i]
if i == len(coreTags) || coreTags[i] != cci {
return 0, false
return ID(i), true
// Parent returns the ID of the parent or the root ID if id is already the root.
func (id ID) Parent() ID {
return parents[id]
// Tag converts id to an internal language Tag.
func (id ID) Tag() language.Tag {
if int(id) >= len(coreTags) {
return specialTags[int(id)-len(coreTags)]
return coreTags[id].Tag()
var specialTags []language.Tag
func init() {
tags := strings.Split(specialTagsStr, " ")
specialTags = make([]language.Tag, len(tags))
for i, t := range tags {
specialTags[i] = language.MustParse(t)