--- /dev/null
+// Copyright 2013 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.
+
+//go:generate go run gen.go gen_common.go -output tables.go
+//go:generate go run gen_index.go
+
+package language
+
+// TODO: Remove above NOTE after:
+// - verifying that tables are dropped correctly (most notably matcher tables).
+
+import (
+ "errors"
+ "fmt"
+ "strings"
+)
+
+const (
+ // maxCoreSize is the maximum size of a BCP 47 tag without variants and
+ // extensions. Equals max lang (3) + script (4) + max reg (3) + 2 dashes.
+ maxCoreSize = 12
+
+ // max99thPercentileSize is a somewhat arbitrary buffer size that presumably
+ // is large enough to hold at least 99% of the BCP 47 tags.
+ max99thPercentileSize = 32
+
+ // maxSimpleUExtensionSize is the maximum size of a -u extension with one
+ // key-type pair. Equals len("-u-") + key (2) + dash + max value (8).
+ maxSimpleUExtensionSize = 14
+)
+
+// Tag represents a BCP 47 language tag. It is used to specify an instance of a
+// specific language or locale. All language tag values are guaranteed to be
+// well-formed.
+type Tag struct {
+ lang langID
+ region regionID
+ // TODO: we will soon run out of positions for script. Idea: instead of
+ // storing lang, region, and script codes, store only the compact index and
+ // have a lookup table from this code to its expansion. This greatly speeds
+ // up table lookup, speed up common variant cases.
+ // This will also immediately free up 3 extra bytes. Also, the pVariant
+ // field can now be moved to the lookup table, as the compact index uniquely
+ // determines the offset of a possible variant.
+ script scriptID
+ pVariant byte // offset in str, includes preceding '-'
+ pExt uint16 // offset of first extension, includes preceding '-'
+
+ // str is the string representation of the Tag. It will only be used if the
+ // tag has variants or extensions.
+ str string
+}
+
+// Make is a convenience wrapper for Parse that omits the error.
+// In case of an error, a sensible default is returned.
+func Make(s string) Tag {
+ return Default.Make(s)
+}
+
+// Make is a convenience wrapper for c.Parse that omits the error.
+// In case of an error, a sensible default is returned.
+func (c CanonType) Make(s string) Tag {
+ t, _ := c.Parse(s)
+ return t
+}
+
+// Raw returns the raw base language, script and region, without making an
+// attempt to infer their values.
+func (t Tag) Raw() (b Base, s Script, r Region) {
+ return Base{t.lang}, Script{t.script}, Region{t.region}
+}
+
+// equalTags compares language, script and region subtags only.
+func (t Tag) equalTags(a Tag) bool {
+ return t.lang == a.lang && t.script == a.script && t.region == a.region
+}
+
+// IsRoot returns true if t is equal to language "und".
+func (t Tag) IsRoot() bool {
+ if int(t.pVariant) < len(t.str) {
+ return false
+ }
+ return t.equalTags(und)
+}
+
+// private reports whether the Tag consists solely of a private use tag.
+func (t Tag) private() bool {
+ return t.str != "" && t.pVariant == 0
+}
+
+// CanonType can be used to enable or disable various types of canonicalization.
+type CanonType int
+
+const (
+ // Replace deprecated base languages with their preferred replacements.
+ DeprecatedBase CanonType = 1 << iota
+ // Replace deprecated scripts with their preferred replacements.
+ DeprecatedScript
+ // Replace deprecated regions with their preferred replacements.
+ DeprecatedRegion
+ // Remove redundant scripts.
+ SuppressScript
+ // Normalize legacy encodings. This includes legacy languages defined in
+ // CLDR as well as bibliographic codes defined in ISO-639.
+ Legacy
+ // Map the dominant language of a macro language group to the macro language
+ // subtag. For example cmn -> zh.
+ Macro
+ // The CLDR flag should be used if full compatibility with CLDR is required.
+ // There are a few cases where language.Tag may differ from CLDR. To follow all
+ // of CLDR's suggestions, use All|CLDR.
+ CLDR
+
+ // Raw can be used to Compose or Parse without Canonicalization.
+ Raw CanonType = 0
+
+ // Replace all deprecated tags with their preferred replacements.
+ Deprecated = DeprecatedBase | DeprecatedScript | DeprecatedRegion
+
+ // All canonicalizations recommended by BCP 47.
+ BCP47 = Deprecated | SuppressScript
+
+ // All canonicalizations.
+ All = BCP47 | Legacy | Macro
+
+ // Default is the canonicalization used by Parse, Make and Compose. To
+ // preserve as much information as possible, canonicalizations that remove
+ // potentially valuable information are not included. The Matcher is
+ // designed to recognize similar tags that would be the same if
+ // they were canonicalized using All.
+ Default = Deprecated | Legacy
+
+ canonLang = DeprecatedBase | Legacy | Macro
+
+ // TODO: LikelyScript, LikelyRegion: suppress similar to ICU.
+)
+
+// canonicalize returns the canonicalized equivalent of the tag and
+// whether there was any change.
+func (t Tag) canonicalize(c CanonType) (Tag, bool) {
+ if c == Raw {
+ return t, false
+ }
+ changed := false
+ if c&SuppressScript != 0 {
+ if t.lang < langNoIndexOffset && uint8(t.script) == suppressScript[t.lang] {
+ t.script = 0
+ changed = true
+ }
+ }
+ if c&canonLang != 0 {
+ for {
+ if l, aliasType := normLang(t.lang); l != t.lang {
+ switch aliasType {
+ case langLegacy:
+ if c&Legacy != 0 {
+ if t.lang == _sh && t.script == 0 {
+ t.script = _Latn
+ }
+ t.lang = l
+ changed = true
+ }
+ case langMacro:
+ if c&Macro != 0 {
+ // We deviate here from CLDR. The mapping "nb" -> "no"
+ // qualifies as a typical Macro language mapping. However,
+ // for legacy reasons, CLDR maps "no", the macro language
+ // code for Norwegian, to the dominant variant "nb". This
+ // change is currently under consideration for CLDR as well.
+ // See http://unicode.org/cldr/trac/ticket/2698 and also
+ // http://unicode.org/cldr/trac/ticket/1790 for some of the
+ // practical implications. TODO: this check could be removed
+ // if CLDR adopts this change.
+ if c&CLDR == 0 || t.lang != _nb {
+ changed = true
+ t.lang = l
+ }
+ }
+ case langDeprecated:
+ if c&DeprecatedBase != 0 {
+ if t.lang == _mo && t.region == 0 {
+ t.region = _MD
+ }
+ t.lang = l
+ changed = true
+ // Other canonicalization types may still apply.
+ continue
+ }
+ }
+ } else if c&Legacy != 0 && t.lang == _no && c&CLDR != 0 {
+ t.lang = _nb
+ changed = true
+ }
+ break
+ }
+ }
+ if c&DeprecatedScript != 0 {
+ if t.script == _Qaai {
+ changed = true
+ t.script = _Zinh
+ }
+ }
+ if c&DeprecatedRegion != 0 {
+ if r := normRegion(t.region); r != 0 {
+ changed = true
+ t.region = r
+ }
+ }
+ return t, changed
+}
+
+// Canonicalize returns the canonicalized equivalent of the tag.
+func (c CanonType) Canonicalize(t Tag) (Tag, error) {
+ t, changed := t.canonicalize(c)
+ if changed {
+ t.remakeString()
+ }
+ return t, nil
+}
+
+// Confidence indicates the level of certainty for a given return value.
+// For example, Serbian may be written in Cyrillic or Latin script.
+// The confidence level indicates whether a value was explicitly specified,
+// whether it is typically the only possible value, or whether there is
+// an ambiguity.
+type Confidence int
+
+const (
+ No Confidence = iota // full confidence that there was no match
+ Low // most likely value picked out of a set of alternatives
+ High // value is generally assumed to be the correct match
+ Exact // exact match or explicitly specified value
+)
+
+var confName = []string{"No", "Low", "High", "Exact"}
+
+func (c Confidence) String() string {
+ return confName[c]
+}
+
+// remakeString is used to update t.str in case lang, script or region changed.
+// It is assumed that pExt and pVariant still point to the start of the
+// respective parts.
+func (t *Tag) remakeString() {
+ if t.str == "" {
+ return
+ }
+ extra := t.str[t.pVariant:]
+ if t.pVariant > 0 {
+ extra = extra[1:]
+ }
+ if t.equalTags(und) && strings.HasPrefix(extra, "x-") {
+ t.str = extra
+ t.pVariant = 0
+ t.pExt = 0
+ return
+ }
+ var buf [max99thPercentileSize]byte // avoid extra memory allocation in most cases.
+ b := buf[:t.genCoreBytes(buf[:])]
+ if extra != "" {
+ diff := len(b) - int(t.pVariant)
+ b = append(b, '-')
+ b = append(b, extra...)
+ t.pVariant = uint8(int(t.pVariant) + diff)
+ t.pExt = uint16(int(t.pExt) + diff)
+ } else {
+ t.pVariant = uint8(len(b))
+ t.pExt = uint16(len(b))
+ }
+ t.str = string(b)
+}
+
+// genCoreBytes writes a string for the base languages, script and region tags
+// to the given buffer and returns the number of bytes written. It will never
+// write more than maxCoreSize bytes.
+func (t *Tag) genCoreBytes(buf []byte) int {
+ n := t.lang.stringToBuf(buf[:])
+ if t.script != 0 {
+ n += copy(buf[n:], "-")
+ n += copy(buf[n:], t.script.String())
+ }
+ if t.region != 0 {
+ n += copy(buf[n:], "-")
+ n += copy(buf[n:], t.region.String())
+ }
+ return n
+}
+
+// String returns the canonical string representation of the language tag.
+func (t Tag) String() string {
+ if t.str != "" {
+ return t.str
+ }
+ if t.script == 0 && t.region == 0 {
+ return t.lang.String()
+ }
+ buf := [maxCoreSize]byte{}
+ return string(buf[:t.genCoreBytes(buf[:])])
+}
+
+// Base returns the base language of the language tag. If the base language is
+// unspecified, an attempt will be made to infer it from the context.
+// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change.
+func (t Tag) Base() (Base, Confidence) {
+ if t.lang != 0 {
+ return Base{t.lang}, Exact
+ }
+ c := High
+ if t.script == 0 && !(Region{t.region}).IsCountry() {
+ c = Low
+ }
+ if tag, err := addTags(t); err == nil && tag.lang != 0 {
+ return Base{tag.lang}, c
+ }
+ return Base{0}, No
+}
+
+// Script infers the script for the language tag. If it was not explicitly given, it will infer
+// a most likely candidate.
+// If more than one script is commonly used for a language, the most likely one
+// is returned with a low confidence indication. For example, it returns (Cyrl, Low)
+// for Serbian.
+// If a script cannot be inferred (Zzzz, No) is returned. We do not use Zyyy (undetermined)
+// as one would suspect from the IANA registry for BCP 47. In a Unicode context Zyyy marks
+// common characters (like 1, 2, 3, '.', etc.) and is therefore more like multiple scripts.
+// See http://www.unicode.org/reports/tr24/#Values for more details. Zzzz is also used for
+// unknown value in CLDR. (Zzzz, Exact) is returned if Zzzz was explicitly specified.
+// Note that an inferred script is never guaranteed to be the correct one. Latin is
+// almost exclusively used for Afrikaans, but Arabic has been used for some texts
+// in the past. Also, the script that is commonly used may change over time.
+// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change.
+func (t Tag) Script() (Script, Confidence) {
+ if t.script != 0 {
+ return Script{t.script}, Exact
+ }
+ sc, c := scriptID(_Zzzz), No
+ if t.lang < langNoIndexOffset {
+ if scr := scriptID(suppressScript[t.lang]); scr != 0 {
+ // Note: it is not always the case that a language with a suppress
+ // script value is only written in one script (e.g. kk, ms, pa).
+ if t.region == 0 {
+ return Script{scriptID(scr)}, High
+ }
+ sc, c = scr, High
+ }
+ }
+ if tag, err := addTags(t); err == nil {
+ if tag.script != sc {
+ sc, c = tag.script, Low
+ }
+ } else {
+ t, _ = (Deprecated | Macro).Canonicalize(t)
+ if tag, err := addTags(t); err == nil && tag.script != sc {
+ sc, c = tag.script, Low
+ }
+ }
+ return Script{sc}, c
+}
+
+// Region returns the region for the language tag. If it was not explicitly given, it will
+// infer a most likely candidate from the context.
+// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change.
+func (t Tag) Region() (Region, Confidence) {
+ if t.region != 0 {
+ return Region{t.region}, Exact
+ }
+ if t, err := addTags(t); err == nil {
+ return Region{t.region}, Low // TODO: differentiate between high and low.
+ }
+ t, _ = (Deprecated | Macro).Canonicalize(t)
+ if tag, err := addTags(t); err == nil {
+ return Region{tag.region}, Low
+ }
+ return Region{_ZZ}, No // TODO: return world instead of undetermined?
+}
+
+// Variant returns the variants specified explicitly for this language tag.
+// or nil if no variant was specified.
+func (t Tag) Variants() []Variant {
+ v := []Variant{}
+ if int(t.pVariant) < int(t.pExt) {
+ for x, str := "", t.str[t.pVariant:t.pExt]; str != ""; {
+ x, str = nextToken(str)
+ v = append(v, Variant{x})
+ }
+ }
+ return v
+}
+
+// Parent returns the CLDR parent of t. In CLDR, missing fields in data for a
+// specific language are substituted with fields from the parent language.
+// The parent for a language may change for newer versions of CLDR.
+func (t Tag) Parent() Tag {
+ if t.str != "" {
+ // Strip the variants and extensions.
+ t, _ = Raw.Compose(t.Raw())
+ if t.region == 0 && t.script != 0 && t.lang != 0 {
+ base, _ := addTags(Tag{lang: t.lang})
+ if base.script == t.script {
+ return Tag{lang: t.lang}
+ }
+ }
+ return t
+ }
+ if t.lang != 0 {
+ if t.region != 0 {
+ maxScript := t.script
+ if maxScript == 0 {
+ max, _ := addTags(t)
+ maxScript = max.script
+ }
+
+ for i := range parents {
+ if langID(parents[i].lang) == t.lang && scriptID(parents[i].maxScript) == maxScript {
+ for _, r := range parents[i].fromRegion {
+ if regionID(r) == t.region {
+ return Tag{
+ lang: t.lang,
+ script: scriptID(parents[i].script),
+ region: regionID(parents[i].toRegion),
+ }
+ }
+ }
+ }
+ }
+
+ // Strip the script if it is the default one.
+ base, _ := addTags(Tag{lang: t.lang})
+ if base.script != maxScript {
+ return Tag{lang: t.lang, script: maxScript}
+ }
+ return Tag{lang: t.lang}
+ } else if t.script != 0 {
+ // The parent for an base-script pair with a non-default script is
+ // "und" instead of the base language.
+ base, _ := addTags(Tag{lang: t.lang})
+ if base.script != t.script {
+ return und
+ }
+ return Tag{lang: t.lang}
+ }
+ }
+ return und
+}
+
+// returns token t and the rest of the string.
+func nextToken(s string) (t, tail string) {
+ p := strings.Index(s[1:], "-")
+ if p == -1 {
+ return s[1:], ""
+ }
+ p++
+ return s[1:p], s[p:]
+}
+
+// Extension is a single BCP 47 extension.
+type Extension struct {
+ s string
+}
+
+// String returns the string representation of the extension, including the
+// type tag.
+func (e Extension) String() string {
+ return e.s
+}
+
+// ParseExtension parses s as an extension and returns it on success.
+func ParseExtension(s string) (e Extension, err error) {
+ scan := makeScannerString(s)
+ var end int
+ if n := len(scan.token); n != 1 {
+ return Extension{}, errSyntax
+ }
+ scan.toLower(0, len(scan.b))
+ end = parseExtension(&scan)
+ if end != len(s) {
+ return Extension{}, errSyntax
+ }
+ return Extension{string(scan.b)}, nil
+}
+
+// Type returns the one-byte extension type of e. It returns 0 for the zero
+// exception.
+func (e Extension) Type() byte {
+ if e.s == "" {
+ return 0
+ }
+ return e.s[0]
+}
+
+// Tokens returns the list of tokens of e.
+func (e Extension) Tokens() []string {
+ return strings.Split(e.s, "-")
+}
+
+// Extension returns the extension of type x for tag t. It will return
+// false for ok if t does not have the requested extension. The returned
+// extension will be invalid in this case.
+func (t Tag) Extension(x byte) (ext Extension, ok bool) {
+ for i := int(t.pExt); i < len(t.str)-1; {
+ var ext string
+ i, ext = getExtension(t.str, i)
+ if ext[0] == x {
+ return Extension{ext}, true
+ }
+ }
+ return Extension{}, false
+}
+
+// Extensions returns all extensions of t.
+func (t Tag) Extensions() []Extension {
+ e := []Extension{}
+ for i := int(t.pExt); i < len(t.str)-1; {
+ var ext string
+ i, ext = getExtension(t.str, i)
+ e = append(e, Extension{ext})
+ }
+ return e
+}
+
+// TypeForKey returns the type associated with the given key, where key and type
+// are of the allowed values defined for the Unicode locale extension ('u') in
+// http://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers.
+// TypeForKey will traverse the inheritance chain to get the correct value.
+func (t Tag) TypeForKey(key string) string {
+ if start, end, _ := t.findTypeForKey(key); end != start {
+ return t.str[start:end]
+ }
+ return ""
+}
+
+var (
+ errPrivateUse = errors.New("cannot set a key on a private use tag")
+ errInvalidArguments = errors.New("invalid key or type")
+)
+
+// SetTypeForKey returns a new Tag with the key set to type, where key and type
+// are of the allowed values defined for the Unicode locale extension ('u') in
+// http://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers.
+// An empty value removes an existing pair with the same key.
+func (t Tag) SetTypeForKey(key, value string) (Tag, error) {
+ if t.private() {
+ return t, errPrivateUse
+ }
+ if len(key) != 2 {
+ return t, errInvalidArguments
+ }
+
+ // Remove the setting if value is "".
+ if value == "" {
+ start, end, _ := t.findTypeForKey(key)
+ if start != end {
+ // Remove key tag and leading '-'.
+ start -= 4
+
+ // Remove a possible empty extension.
+ if (end == len(t.str) || t.str[end+2] == '-') && t.str[start-2] == '-' {
+ start -= 2
+ }
+ if start == int(t.pVariant) && end == len(t.str) {
+ t.str = ""
+ t.pVariant, t.pExt = 0, 0
+ } else {
+ t.str = fmt.Sprintf("%s%s", t.str[:start], t.str[end:])
+ }
+ }
+ return t, nil
+ }
+
+ if len(value) < 3 || len(value) > 8 {
+ return t, errInvalidArguments
+ }
+
+ var (
+ buf [maxCoreSize + maxSimpleUExtensionSize]byte
+ uStart int // start of the -u extension.
+ )
+
+ // Generate the tag string if needed.
+ if t.str == "" {
+ uStart = t.genCoreBytes(buf[:])
+ buf[uStart] = '-'
+ uStart++
+ }
+
+ // Create new key-type pair and parse it to verify.
+ b := buf[uStart:]
+ copy(b, "u-")
+ copy(b[2:], key)
+ b[4] = '-'
+ b = b[:5+copy(b[5:], value)]
+ scan := makeScanner(b)
+ if parseExtensions(&scan); scan.err != nil {
+ return t, scan.err
+ }
+
+ // Assemble the replacement string.
+ if t.str == "" {
+ t.pVariant, t.pExt = byte(uStart-1), uint16(uStart-1)
+ t.str = string(buf[:uStart+len(b)])
+ } else {
+ s := t.str
+ start, end, hasExt := t.findTypeForKey(key)
+ if start == end {
+ if hasExt {
+ b = b[2:]
+ }
+ t.str = fmt.Sprintf("%s-%s%s", s[:start], b, s[end:])
+ } else {
+ t.str = fmt.Sprintf("%s%s%s", s[:start], value, s[end:])
+ }
+ }
+ return t, nil
+}
+
+// findKeyAndType returns the start and end position for the type corresponding
+// to key or the point at which to insert the key-value pair if the type
+// wasn't found. The hasExt return value reports whether an -u extension was present.
+// Note: the extensions are typically very small and are likely to contain
+// only one key-type pair.
+func (t Tag) findTypeForKey(key string) (start, end int, hasExt bool) {
+ p := int(t.pExt)
+ if len(key) != 2 || p == len(t.str) || p == 0 {
+ return p, p, false
+ }
+ s := t.str
+
+ // Find the correct extension.
+ for p++; s[p] != 'u'; p++ {
+ if s[p] > 'u' {
+ p--
+ return p, p, false
+ }
+ if p = nextExtension(s, p); p == len(s) {
+ return len(s), len(s), false
+ }
+ }
+ // Proceed to the hyphen following the extension name.
+ p++
+
+ // curKey is the key currently being processed.
+ curKey := ""
+
+ // Iterate over keys until we get the end of a section.
+ for {
+ // p points to the hyphen preceding the current token.
+ if p3 := p + 3; s[p3] == '-' {
+ // Found a key.
+ // Check whether we just processed the key that was requested.
+ if curKey == key {
+ return start, p, true
+ }
+ // Set to the next key and continue scanning type tokens.
+ curKey = s[p+1 : p3]
+ if curKey > key {
+ return p, p, true
+ }
+ // Start of the type token sequence.
+ start = p + 4
+ // A type is at least 3 characters long.
+ p += 7 // 4 + 3
+ } else {
+ // Attribute or type, which is at least 3 characters long.
+ p += 4
+ }
+ // p points past the third character of a type or attribute.
+ max := p + 5 // maximum length of token plus hyphen.
+ if len(s) < max {
+ max = len(s)
+ }
+ for ; p < max && s[p] != '-'; p++ {
+ }
+ // Bail if we have exhausted all tokens or if the next token starts
+ // a new extension.
+ if p == len(s) || s[p+2] == '-' {
+ if curKey == key {
+ return start, p, true
+ }
+ return p, p, true
+ }
+ }
+}
+
+// CompactIndex returns an index, where 0 <= index < NumCompactTags, for tags
+// for which data exists in the text repository. The index will change over time
+// and should not be stored in persistent storage. Extensions, except for the
+// 'va' type of the 'u' extension, are ignored. It will return 0, false if no
+// compact tag exists, where 0 is the index for the root language (Und).
+func CompactIndex(t Tag) (index int, ok bool) {
+ // TODO: perhaps give more frequent tags a lower index.
+ // TODO: we could make the indexes stable. This will excluded some
+ // possibilities for optimization, so don't do this quite yet.
+ b, s, r := t.Raw()
+ if len(t.str) > 0 {
+ if strings.HasPrefix(t.str, "x-") {
+ // We have no entries for user-defined tags.
+ return 0, false
+ }
+ if uint16(t.pVariant) != t.pExt {
+ // There are no tags with variants and an u-va type.
+ if t.TypeForKey("va") != "" {
+ return 0, false
+ }
+ t, _ = Raw.Compose(b, s, r, t.Variants())
+ } else if _, ok := t.Extension('u'); ok {
+ // Strip all but the 'va' entry.
+ variant := t.TypeForKey("va")
+ t, _ = Raw.Compose(b, s, r)
+ t, _ = t.SetTypeForKey("va", variant)
+ }
+ if len(t.str) > 0 {
+ // We have some variants.
+ for i, s := range specialTags {
+ if s == t {
+ return i + 1, true
+ }
+ }
+ return 0, false
+ }
+ }
+ // No variants specified: just compare core components.
+ // The key has the form lllssrrr, where l, s, and r are nibbles for
+ // respectively the langID, scriptID, and regionID.
+ key := uint32(b.langID) << (8 + 12)
+ key |= uint32(s.scriptID) << 12
+ key |= uint32(r.regionID)
+ x, ok := coreTags[key]
+ return int(x), ok
+}
+
+// Base is an ISO 639 language code, used for encoding the base language
+// of a language tag.
+type Base struct {
+ langID
+}
+
+// ParseBase parses a 2- or 3-letter ISO 639 code.
+// It returns a ValueError if s is a well-formed but unknown language identifier
+// or another error if another error occurred.
+func ParseBase(s string) (Base, error) {
+ if n := len(s); n < 2 || 3 < n {
+ return Base{}, errSyntax
+ }
+ var buf [3]byte
+ l, err := getLangID(buf[:copy(buf[:], s)])
+ return Base{l}, err
+}
+
+// Script is a 4-letter ISO 15924 code for representing scripts.
+// It is idiomatically represented in title case.
+type Script struct {
+ scriptID
+}
+
+// ParseScript parses a 4-letter ISO 15924 code.
+// It returns a ValueError if s is a well-formed but unknown script identifier
+// or another error if another error occurred.
+func ParseScript(s string) (Script, error) {
+ if len(s) != 4 {
+ return Script{}, errSyntax
+ }
+ var buf [4]byte
+ sc, err := getScriptID(script, buf[:copy(buf[:], s)])
+ return Script{sc}, err
+}
+
+// Region is an ISO 3166-1 or UN M.49 code for representing countries and regions.
+type Region struct {
+ regionID
+}
+
+// EncodeM49 returns the Region for the given UN M.49 code.
+// It returns an error if r is not a valid code.
+func EncodeM49(r int) (Region, error) {
+ rid, err := getRegionM49(r)
+ return Region{rid}, err
+}
+
+// ParseRegion parses a 2- or 3-letter ISO 3166-1 or a UN M.49 code.
+// It returns a ValueError if s is a well-formed but unknown region identifier
+// or another error if another error occurred.
+func ParseRegion(s string) (Region, error) {
+ if n := len(s); n < 2 || 3 < n {
+ return Region{}, errSyntax
+ }
+ var buf [3]byte
+ r, err := getRegionID(buf[:copy(buf[:], s)])
+ return Region{r}, err
+}
+
+// IsCountry returns whether this region is a country or autonomous area. This
+// includes non-standard definitions from CLDR.
+func (r Region) IsCountry() bool {
+ if r.regionID == 0 || r.IsGroup() || r.IsPrivateUse() && r.regionID != _XK {
+ return false
+ }
+ return true
+}
+
+// IsGroup returns whether this region defines a collection of regions. This
+// includes non-standard definitions from CLDR.
+func (r Region) IsGroup() bool {
+ if r.regionID == 0 {
+ return false
+ }
+ return int(regionInclusion[r.regionID]) < len(regionContainment)
+}
+
+// Contains returns whether Region c is contained by Region r. It returns true
+// if c == r.
+func (r Region) Contains(c Region) bool {
+ return r.regionID.contains(c.regionID)
+}
+
+func (r regionID) contains(c regionID) bool {
+ if r == c {
+ return true
+ }
+ g := regionInclusion[r]
+ if g >= nRegionGroups {
+ return false
+ }
+ m := regionContainment[g]
+
+ d := regionInclusion[c]
+ b := regionInclusionBits[d]
+
+ // A contained country may belong to multiple disjoint groups. Matching any
+ // of these indicates containment. If the contained region is a group, it
+ // must strictly be a subset.
+ if d >= nRegionGroups {
+ return b&m != 0
+ }
+ return b&^m == 0
+}
+
+var errNoTLD = errors.New("language: region is not a valid ccTLD")
+
+// TLD returns the country code top-level domain (ccTLD). UK is returned for GB.
+// In all other cases it returns either the region itself or an error.
+//
+// This method may return an error for a region for which there exists a
+// canonical form with a ccTLD. To get that ccTLD canonicalize r first. The
+// region will already be canonicalized it was obtained from a Tag that was
+// obtained using any of the default methods.
+func (r Region) TLD() (Region, error) {
+ // See http://en.wikipedia.org/wiki/Country_code_top-level_domain for the
+ // difference between ISO 3166-1 and IANA ccTLD.
+ if r.regionID == _GB {
+ r = Region{_UK}
+ }
+ if (r.typ() & ccTLD) == 0 {
+ return Region{}, errNoTLD
+ }
+ return r, nil
+}
+
+// Canonicalize returns the region or a possible replacement if the region is
+// deprecated. It will not return a replacement for deprecated regions that
+// are split into multiple regions.
+func (r Region) Canonicalize() Region {
+ if cr := normRegion(r.regionID); cr != 0 {
+ return Region{cr}
+ }
+ return r
+}
+
+// Variant represents a registered variant of a language as defined by BCP 47.
+type Variant struct {
+ variant string
+}
+
+// ParseVariant parses and returns a Variant. An error is returned if s is not
+// a valid variant.
+func ParseVariant(s string) (Variant, error) {
+ s = strings.ToLower(s)
+ if _, ok := variantIndex[s]; ok {
+ return Variant{s}, nil
+ }
+ return Variant{}, mkErrInvalid([]byte(s))
+}
+
+// String returns the string representation of the variant.
+func (v Variant) String() string {
+ return v.variant
+}
OSDN Git Service
