mirror of
https://github.com/rclone/rclone.git
synced 2024-11-23 17:04:01 +01:00
106 lines
3.4 KiB
Go
106 lines
3.4 KiB
Go
// Copyright 2015 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 colltab contains functionality related to collation tables.
|
|
// It is only to be used by the collate and search packages.
|
|
package colltab // import "golang.org/x/text/internal/colltab"
|
|
|
|
import (
|
|
"sort"
|
|
|
|
"golang.org/x/text/language"
|
|
)
|
|
|
|
// MatchLang finds the index of t in tags, using a matching algorithm used for
|
|
// collation and search. tags[0] must be language.Und, the remaining tags should
|
|
// be sorted alphabetically.
|
|
//
|
|
// Language matching for collation and search is different from the matching
|
|
// defined by language.Matcher: the (inferred) base language must be an exact
|
|
// match for the relevant fields. For example, "gsw" should not match "de".
|
|
// Also the parent relation is different, as a parent may have a different
|
|
// script. So usually the parent of zh-Hant is und, whereas for MatchLang it is
|
|
// zh.
|
|
func MatchLang(t language.Tag, tags []language.Tag) int {
|
|
// Canonicalize the values, including collapsing macro languages.
|
|
t, _ = language.All.Canonicalize(t)
|
|
|
|
base, conf := t.Base()
|
|
// Estimate the base language, but only use high-confidence values.
|
|
if conf < language.High {
|
|
// The root locale supports "search" and "standard". We assume that any
|
|
// implementation will only use one of both.
|
|
return 0
|
|
}
|
|
|
|
// Maximize base and script and normalize the tag.
|
|
if _, s, r := t.Raw(); (r != language.Region{}) {
|
|
p, _ := language.Raw.Compose(base, s, r)
|
|
// Taking the parent forces the script to be maximized.
|
|
p = p.Parent()
|
|
// Add back region and extensions.
|
|
t, _ = language.Raw.Compose(p, r, t.Extensions())
|
|
} else {
|
|
// Set the maximized base language.
|
|
t, _ = language.Raw.Compose(base, s, t.Extensions())
|
|
}
|
|
|
|
// Find start index of the language tag.
|
|
start := 1 + sort.Search(len(tags)-1, func(i int) bool {
|
|
b, _, _ := tags[i+1].Raw()
|
|
return base.String() <= b.String()
|
|
})
|
|
if start < len(tags) {
|
|
if b, _, _ := tags[start].Raw(); b != base {
|
|
return 0
|
|
}
|
|
}
|
|
|
|
// Besides the base language, script and region, only the collation type and
|
|
// the custom variant defined in the 'u' extension are used to distinguish a
|
|
// locale.
|
|
// Strip all variants and extensions and add back the custom variant.
|
|
tdef, _ := language.Raw.Compose(t.Raw())
|
|
tdef, _ = tdef.SetTypeForKey("va", t.TypeForKey("va"))
|
|
|
|
// First search for a specialized collation type, if present.
|
|
try := []language.Tag{tdef}
|
|
if co := t.TypeForKey("co"); co != "" {
|
|
tco, _ := tdef.SetTypeForKey("co", co)
|
|
try = []language.Tag{tco, tdef}
|
|
}
|
|
|
|
for _, tx := range try {
|
|
for ; tx != language.Und; tx = parent(tx) {
|
|
for i, t := range tags[start:] {
|
|
if b, _, _ := t.Raw(); b != base {
|
|
break
|
|
}
|
|
if tx == t {
|
|
return start + i
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return 0
|
|
}
|
|
|
|
// parent computes the structural parent. This means inheritance may change
|
|
// script. So, unlike the CLDR parent, parent(zh-Hant) == zh.
|
|
func parent(t language.Tag) language.Tag {
|
|
if t.TypeForKey("va") != "" {
|
|
t, _ = t.SetTypeForKey("va", "")
|
|
return t
|
|
}
|
|
result := language.Und
|
|
if b, s, r := t.Raw(); (r != language.Region{}) {
|
|
result, _ = language.Raw.Compose(b, s, t.Extensions())
|
|
} else if (s != language.Script{}) {
|
|
result, _ = language.Raw.Compose(b, t.Extensions())
|
|
} else if (b != language.Base{}) {
|
|
result, _ = language.Raw.Compose(t.Extensions())
|
|
}
|
|
return result
|
|
}
|