X-Git-Url: http://git.osdn.net/view?p=bytom%2Fvapor.git;a=blobdiff_plain;f=vendor%2Fgolang.org%2Fx%2Ftext%2Flanguage%2Flanguage.go;fp=vendor%2Fgolang.org%2Fx%2Ftext%2Flanguage%2Flanguage.go;h=0000000000000000000000000000000000000000;hp=ed1011f1867152ed501a8b41a862c6cf811e990e;hb=d09b7a78d44dc259725902b8141cdba0d716b121;hpb=ee01d543fdfe1fd0a4d548965c66f7923ea7b062 diff --git a/vendor/golang.org/x/text/language/language.go b/vendor/golang.org/x/text/language/language.go deleted file mode 100644 index ed1011f1..00000000 --- a/vendor/golang.org/x/text/language/language.go +++ /dev/null @@ -1,887 +0,0 @@ -// 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 -}