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Diffstat (limited to 'vendor/golang.org/x/text/language/match.go')
| -rw-r--r-- | vendor/golang.org/x/text/language/match.go | 933 |
1 files changed, 0 insertions, 933 deletions
diff --git a/vendor/golang.org/x/text/language/match.go b/vendor/golang.org/x/text/language/match.go deleted file mode 100644 index 15b74d1..0000000 --- a/vendor/golang.org/x/text/language/match.go +++ /dev/null @@ -1,933 +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. - -package language - -import "errors" - -// A MatchOption configures a Matcher. -type MatchOption func(*matcher) - -// PreferSameScript will, in the absence of a match, result in the first -// preferred tag with the same script as a supported tag to match this supported -// tag. The default is currently true, but this may change in the future. -func PreferSameScript(preferSame bool) MatchOption { - return func(m *matcher) { m.preferSameScript = preferSame } -} - -// TODO(v1.0.0): consider making Matcher a concrete type, instead of interface. -// There doesn't seem to be too much need for multiple types. -// Making it a concrete type allows MatchStrings to be a method, which will -// improve its discoverability. - -// MatchStrings parses and matches the given strings until one of them matches -// the language in the Matcher. A string may be an Accept-Language header as -// handled by ParseAcceptLanguage. The default language is returned if no -// other language matched. -func MatchStrings(m Matcher, lang ...string) (tag Tag, index int) { - for _, accept := range lang { - desired, _, err := ParseAcceptLanguage(accept) - if err != nil { - continue - } - if tag, index, conf := m.Match(desired...); conf != No { - return tag, index - } - } - tag, index, _ = m.Match() - return -} - -// Matcher is the interface that wraps the Match method. -// -// Match returns the best match for any of the given tags, along with -// a unique index associated with the returned tag and a confidence -// score. -type Matcher interface { - Match(t ...Tag) (tag Tag, index int, c Confidence) -} - -// Comprehends reports the confidence score for a speaker of a given language -// to being able to comprehend the written form of an alternative language. -func Comprehends(speaker, alternative Tag) Confidence { - _, _, c := NewMatcher([]Tag{alternative}).Match(speaker) - return c -} - -// NewMatcher returns a Matcher that matches an ordered list of preferred tags -// against a list of supported tags based on written intelligibility, closeness -// of dialect, equivalence of subtags and various other rules. It is initialized -// with the list of supported tags. The first element is used as the default -// value in case no match is found. -// -// Its Match method matches the first of the given Tags to reach a certain -// confidence threshold. The tags passed to Match should therefore be specified -// in order of preference. Extensions are ignored for matching. -// -// The index returned by the Match method corresponds to the index of the -// matched tag in t, but is augmented with the Unicode extension ('u')of the -// corresponding preferred tag. This allows user locale options to be passed -// transparently. -func NewMatcher(t []Tag, options ...MatchOption) Matcher { - return newMatcher(t, options) -} - -func (m *matcher) Match(want ...Tag) (t Tag, index int, c Confidence) { - match, w, c := m.getBest(want...) - if match != nil { - t, index = match.tag, match.index - } else { - // TODO: this should be an option - t = m.default_.tag - if m.preferSameScript { - outer: - for _, w := range want { - script, _ := w.Script() - if script.scriptID == 0 { - // Don't do anything if there is no script, such as with - // private subtags. - continue - } - for i, h := range m.supported { - if script.scriptID == h.maxScript { - t, index = h.tag, i - break outer - } - } - } - } - // TODO: select first language tag based on script. - } - if w.region != 0 && t.region != 0 && t.region.contains(w.region) { - t, _ = Raw.Compose(t, Region{w.region}) - } - // Copy options from the user-provided tag into the result tag. This is hard - // to do after the fact, so we do it here. - // TODO: add in alternative variants to -u-va-. - // TODO: add preferred region to -u-rg-. - if e := w.Extensions(); len(e) > 0 { - t, _ = Raw.Compose(t, e) - } - return t, index, c -} - -type scriptRegionFlags uint8 - -const ( - isList = 1 << iota - scriptInFrom - regionInFrom -) - -func (t *Tag) setUndefinedLang(id langID) { - if t.lang == 0 { - t.lang = id - } -} - -func (t *Tag) setUndefinedScript(id scriptID) { - if t.script == 0 { - t.script = id - } -} - -func (t *Tag) setUndefinedRegion(id regionID) { - if t.region == 0 || t.region.contains(id) { - t.region = id - } -} - -// ErrMissingLikelyTagsData indicates no information was available -// to compute likely values of missing tags. -var ErrMissingLikelyTagsData = errors.New("missing likely tags data") - -// addLikelySubtags sets subtags to their most likely value, given the locale. -// In most cases this means setting fields for unknown values, but in some -// cases it may alter a value. It returns an ErrMissingLikelyTagsData error -// if the given locale cannot be expanded. -func (t Tag) addLikelySubtags() (Tag, error) { - id, err := addTags(t) - if err != nil { - return t, err - } else if id.equalTags(t) { - return t, nil - } - id.remakeString() - return id, nil -} - -// specializeRegion attempts to specialize a group region. -func specializeRegion(t *Tag) bool { - if i := regionInclusion[t.region]; i < nRegionGroups { - x := likelyRegionGroup[i] - if langID(x.lang) == t.lang && scriptID(x.script) == t.script { - t.region = regionID(x.region) - } - return true - } - return false -} - -func addTags(t Tag) (Tag, error) { - // We leave private use identifiers alone. - if t.private() { - return t, nil - } - if t.script != 0 && t.region != 0 { - if t.lang != 0 { - // already fully specified - specializeRegion(&t) - return t, nil - } - // Search matches for und-script-region. Note that for these cases - // region will never be a group so there is no need to check for this. - list := likelyRegion[t.region : t.region+1] - if x := list[0]; x.flags&isList != 0 { - list = likelyRegionList[x.lang : x.lang+uint16(x.script)] - } - for _, x := range list { - // Deviating from the spec. See match_test.go for details. - if scriptID(x.script) == t.script { - t.setUndefinedLang(langID(x.lang)) - return t, nil - } - } - } - if t.lang != 0 { - // Search matches for lang-script and lang-region, where lang != und. - if t.lang < langNoIndexOffset { - x := likelyLang[t.lang] - if x.flags&isList != 0 { - list := likelyLangList[x.region : x.region+uint16(x.script)] - if t.script != 0 { - for _, x := range list { - if scriptID(x.script) == t.script && x.flags&scriptInFrom != 0 { - t.setUndefinedRegion(regionID(x.region)) - return t, nil - } - } - } else if t.region != 0 { - count := 0 - goodScript := true - tt := t - for _, x := range list { - // We visit all entries for which the script was not - // defined, including the ones where the region was not - // defined. This allows for proper disambiguation within - // regions. - if x.flags&scriptInFrom == 0 && t.region.contains(regionID(x.region)) { - tt.region = regionID(x.region) - tt.setUndefinedScript(scriptID(x.script)) - goodScript = goodScript && tt.script == scriptID(x.script) - count++ - } - } - if count == 1 { - return tt, nil - } - // Even if we fail to find a unique Region, we might have - // an unambiguous script. - if goodScript { - t.script = tt.script - } - } - } - } - } else { - // Search matches for und-script. - if t.script != 0 { - x := likelyScript[t.script] - if x.region != 0 { - t.setUndefinedRegion(regionID(x.region)) - t.setUndefinedLang(langID(x.lang)) - return t, nil - } - } - // Search matches for und-region. If und-script-region exists, it would - // have been found earlier. - if t.region != 0 { - if i := regionInclusion[t.region]; i < nRegionGroups { - x := likelyRegionGroup[i] - if x.region != 0 { - t.setUndefinedLang(langID(x.lang)) - t.setUndefinedScript(scriptID(x.script)) - t.region = regionID(x.region) - } - } else { - x := likelyRegion[t.region] - if x.flags&isList != 0 { - x = likelyRegionList[x.lang] - } - if x.script != 0 && x.flags != scriptInFrom { - t.setUndefinedLang(langID(x.lang)) - t.setUndefinedScript(scriptID(x.script)) - return t, nil - } - } - } - } - - // Search matches for lang. - if t.lang < langNoIndexOffset { - x := likelyLang[t.lang] - if x.flags&isList != 0 { - x = likelyLangList[x.region] - } - if x.region != 0 { - t.setUndefinedScript(scriptID(x.script)) - t.setUndefinedRegion(regionID(x.region)) - } - specializeRegion(&t) - if t.lang == 0 { - t.lang = _en // default language - } - return t, nil - } - return t, ErrMissingLikelyTagsData -} - -func (t *Tag) setTagsFrom(id Tag) { - t.lang = id.lang - t.script = id.script - t.region = id.region -} - -// minimize removes the region or script subtags from t such that -// t.addLikelySubtags() == t.minimize().addLikelySubtags(). -func (t Tag) minimize() (Tag, error) { - t, err := minimizeTags(t) - if err != nil { - return t, err - } - t.remakeString() - return t, nil -} - -// minimizeTags mimics the behavior of the ICU 51 C implementation. -func minimizeTags(t Tag) (Tag, error) { - if t.equalTags(und) { - return t, nil - } - max, err := addTags(t) - if err != nil { - return t, err - } - for _, id := range [...]Tag{ - {lang: t.lang}, - {lang: t.lang, region: t.region}, - {lang: t.lang, script: t.script}, - } { - if x, err := addTags(id); err == nil && max.equalTags(x) { - t.setTagsFrom(id) - break - } - } - return t, nil -} - -// Tag Matching -// CLDR defines an algorithm for finding the best match between two sets of language -// tags. The basic algorithm defines how to score a possible match and then find -// the match with the best score -// (see http://www.unicode.org/reports/tr35/#LanguageMatching). -// Using scoring has several disadvantages. The scoring obfuscates the importance of -// the various factors considered, making the algorithm harder to understand. Using -// scoring also requires the full score to be computed for each pair of tags. -// -// We will use a different algorithm which aims to have the following properties: -// - clarity on the precedence of the various selection factors, and -// - improved performance by allowing early termination of a comparison. -// -// Matching algorithm (overview) -// Input: -// - supported: a set of supported tags -// - default: the default tag to return in case there is no match -// - desired: list of desired tags, ordered by preference, starting with -// the most-preferred. -// -// Algorithm: -// 1) Set the best match to the lowest confidence level -// 2) For each tag in "desired": -// a) For each tag in "supported": -// 1) compute the match between the two tags. -// 2) if the match is better than the previous best match, replace it -// with the new match. (see next section) -// b) if the current best match is Exact and pin is true the result will be -// frozen to the language found thusfar, although better matches may -// still be found for the same language. -// 3) If the best match so far is below a certain threshold, return "default". -// -// Ranking: -// We use two phases to determine whether one pair of tags are a better match -// than another pair of tags. First, we determine a rough confidence level. If the -// levels are different, the one with the highest confidence wins. -// Second, if the rough confidence levels are identical, we use a set of tie-breaker -// rules. -// -// The confidence level of matching a pair of tags is determined by finding the -// lowest confidence level of any matches of the corresponding subtags (the -// result is deemed as good as its weakest link). -// We define the following levels: -// Exact - An exact match of a subtag, before adding likely subtags. -// MaxExact - An exact match of a subtag, after adding likely subtags. -// [See Note 2]. -// High - High level of mutual intelligibility between different subtag -// variants. -// Low - Low level of mutual intelligibility between different subtag -// variants. -// No - No mutual intelligibility. -// -// The following levels can occur for each type of subtag: -// Base: Exact, MaxExact, High, Low, No -// Script: Exact, MaxExact [see Note 3], Low, No -// Region: Exact, MaxExact, High -// Variant: Exact, High -// Private: Exact, No -// -// Any result with a confidence level of Low or higher is deemed a possible match. -// Once a desired tag matches any of the supported tags with a level of MaxExact -// or higher, the next desired tag is not considered (see Step 2.b). -// Note that CLDR provides languageMatching data that defines close equivalence -// classes for base languages, scripts and regions. -// -// Tie-breaking -// If we get the same confidence level for two matches, we apply a sequence of -// tie-breaking rules. The first that succeeds defines the result. The rules are -// applied in the following order. -// 1) Original language was defined and was identical. -// 2) Original region was defined and was identical. -// 3) Distance between two maximized regions was the smallest. -// 4) Original script was defined and was identical. -// 5) Distance from want tag to have tag using the parent relation [see Note 5.] -// If there is still no winner after these rules are applied, the first match -// found wins. -// -// Notes: -// [2] In practice, as matching of Exact is done in a separate phase from -// matching the other levels, we reuse the Exact level to mean MaxExact in -// the second phase. As a consequence, we only need the levels defined by -// the Confidence type. The MaxExact confidence level is mapped to High in -// the public API. -// [3] We do not differentiate between maximized script values that were derived -// from suppressScript versus most likely tag data. We determined that in -// ranking the two, one ranks just after the other. Moreover, the two cannot -// occur concurrently. As a consequence, they are identical for practical -// purposes. -// [4] In case of deprecated, macro-equivalents and legacy mappings, we assign -// the MaxExact level to allow iw vs he to still be a closer match than -// en-AU vs en-US, for example. -// [5] In CLDR a locale inherits fields that are unspecified for this locale -// from its parent. Therefore, if a locale is a parent of another locale, -// it is a strong measure for closeness, especially when no other tie -// breaker rule applies. One could also argue it is inconsistent, for -// example, when pt-AO matches pt (which CLDR equates with pt-BR), even -// though its parent is pt-PT according to the inheritance rules. -// -// Implementation Details: -// There are several performance considerations worth pointing out. Most notably, -// we preprocess as much as possible (within reason) at the time of creation of a -// matcher. This includes: -// - creating a per-language map, which includes data for the raw base language -// and its canonicalized variant (if applicable), -// - expanding entries for the equivalence classes defined in CLDR's -// languageMatch data. -// The per-language map ensures that typically only a very small number of tags -// need to be considered. The pre-expansion of canonicalized subtags and -// equivalence classes reduces the amount of map lookups that need to be done at -// runtime. - -// matcher keeps a set of supported language tags, indexed by language. -type matcher struct { - default_ *haveTag - supported []*haveTag - index map[langID]*matchHeader - passSettings bool - preferSameScript bool -} - -// matchHeader has the lists of tags for exact matches and matches based on -// maximized and canonicalized tags for a given language. -type matchHeader struct { - haveTags []*haveTag - original bool -} - -// haveTag holds a supported Tag and its maximized script and region. The maximized -// or canonicalized language is not stored as it is not needed during matching. -type haveTag struct { - tag Tag - - // index of this tag in the original list of supported tags. - index int - - // conf is the maximum confidence that can result from matching this haveTag. - // When conf < Exact this means it was inserted after applying a CLDR equivalence rule. - conf Confidence - - // Maximized region and script. - maxRegion regionID - maxScript scriptID - - // altScript may be checked as an alternative match to maxScript. If altScript - // matches, the confidence level for this match is Low. Theoretically there - // could be multiple alternative scripts. This does not occur in practice. - altScript scriptID - - // nextMax is the index of the next haveTag with the same maximized tags. - nextMax uint16 -} - -func makeHaveTag(tag Tag, index int) (haveTag, langID) { - max := tag - if tag.lang != 0 || tag.region != 0 || tag.script != 0 { - max, _ = max.canonicalize(All) - max, _ = addTags(max) - max.remakeString() - } - return haveTag{tag, index, Exact, max.region, max.script, altScript(max.lang, max.script), 0}, max.lang -} - -// altScript returns an alternative script that may match the given script with -// a low confidence. At the moment, the langMatch data allows for at most one -// script to map to another and we rely on this to keep the code simple. -func altScript(l langID, s scriptID) scriptID { - for _, alt := range matchScript { - // TODO: also match cases where language is not the same. - if (langID(alt.wantLang) == l || langID(alt.haveLang) == l) && - scriptID(alt.haveScript) == s { - return scriptID(alt.wantScript) - } - } - return 0 -} - -// addIfNew adds a haveTag to the list of tags only if it is a unique tag. -// Tags that have the same maximized values are linked by index. -func (h *matchHeader) addIfNew(n haveTag, exact bool) { - h.original = h.original || exact - // Don't add new exact matches. - for _, v := range h.haveTags { - if v.tag.equalsRest(n.tag) { - return - } - } - // Allow duplicate maximized tags, but create a linked list to allow quickly - // comparing the equivalents and bail out. - for i, v := range h.haveTags { - if v.maxScript == n.maxScript && - v.maxRegion == n.maxRegion && - v.tag.variantOrPrivateTagStr() == n.tag.variantOrPrivateTagStr() { - for h.haveTags[i].nextMax != 0 { - i = int(h.haveTags[i].nextMax) - } - h.haveTags[i].nextMax = uint16(len(h.haveTags)) - break - } - } - h.haveTags = append(h.haveTags, &n) -} - -// header returns the matchHeader for the given language. It creates one if -// it doesn't already exist. -func (m *matcher) header(l langID) *matchHeader { - if h := m.index[l]; h != nil { - return h - } - h := &matchHeader{} - m.index[l] = h - return h -} - -func toConf(d uint8) Confidence { - if d <= 10 { - return High - } - if d < 30 { - return Low - } - return No -} - -// newMatcher builds an index for the given supported tags and returns it as -// a matcher. It also expands the index by considering various equivalence classes -// for a given tag. -func newMatcher(supported []Tag, options []MatchOption) *matcher { - m := &matcher{ - index: make(map[langID]*matchHeader), - preferSameScript: true, - } - for _, o := range options { - o(m) - } - if len(supported) == 0 { - m.default_ = &haveTag{} - return m - } - // Add supported languages to the index. Add exact matches first to give - // them precedence. - for i, tag := range supported { - pair, _ := makeHaveTag(tag, i) - m.header(tag.lang).addIfNew(pair, true) - m.supported = append(m.supported, &pair) - } - m.default_ = m.header(supported[0].lang).haveTags[0] - // Keep these in two different loops to support the case that two equivalent - // languages are distinguished, such as iw and he. - for i, tag := range supported { - pair, max := makeHaveTag(tag, i) - if max != tag.lang { - m.header(max).addIfNew(pair, true) - } - } - - // update is used to add indexes in the map for equivalent languages. - // update will only add entries to original indexes, thus not computing any - // transitive relations. - update := func(want, have uint16, conf Confidence) { - if hh := m.index[langID(have)]; hh != nil { - if !hh.original { - return - } - hw := m.header(langID(want)) - for _, ht := range hh.haveTags { - v := *ht - if conf < v.conf { - v.conf = conf - } - v.nextMax = 0 // this value needs to be recomputed - if v.altScript != 0 { - v.altScript = altScript(langID(want), v.maxScript) - } - hw.addIfNew(v, conf == Exact && hh.original) - } - } - } - - // Add entries for languages with mutual intelligibility as defined by CLDR's - // languageMatch data. - for _, ml := range matchLang { - update(ml.want, ml.have, toConf(ml.distance)) - if !ml.oneway { - update(ml.have, ml.want, toConf(ml.distance)) - } - } - - // Add entries for possible canonicalizations. This is an optimization to - // ensure that only one map lookup needs to be done at runtime per desired tag. - // First we match deprecated equivalents. If they are perfect equivalents - // (their canonicalization simply substitutes a different language code, but - // nothing else), the match confidence is Exact, otherwise it is High. - for i, lm := range langAliasMap { - // If deprecated codes match and there is no fiddling with the script or - // or region, we consider it an exact match. - conf := Exact - if langAliasTypes[i] != langMacro { - if !isExactEquivalent(langID(lm.from)) { - conf = High - } - update(lm.to, lm.from, conf) - } - update(lm.from, lm.to, conf) - } - return m -} - -// getBest gets the best matching tag in m for any of the given tags, taking into -// account the order of preference of the given tags. -func (m *matcher) getBest(want ...Tag) (got *haveTag, orig Tag, c Confidence) { - best := bestMatch{} - for i, w := range want { - var max Tag - // Check for exact match first. - h := m.index[w.lang] - if w.lang != 0 { - if h == nil { - continue - } - // Base language is defined. - max, _ = w.canonicalize(Legacy | Deprecated | Macro) - // A region that is added through canonicalization is stronger than - // a maximized region: set it in the original (e.g. mo -> ro-MD). - if w.region != max.region { - w.region = max.region - } - // TODO: should we do the same for scripts? - // See test case: en, sr, nl ; sh ; sr - max, _ = addTags(max) - } else { - // Base language is not defined. - if h != nil { - for i := range h.haveTags { - have := h.haveTags[i] - if have.tag.equalsRest(w) { - return have, w, Exact - } - } - } - if w.script == 0 && w.region == 0 { - // We skip all tags matching und for approximate matching, including - // private tags. - continue - } - max, _ = addTags(w) - if h = m.index[max.lang]; h == nil { - continue - } - } - pin := true - for _, t := range want[i+1:] { - if w.lang == t.lang { - pin = false - break - } - } - // Check for match based on maximized tag. - for i := range h.haveTags { - have := h.haveTags[i] - best.update(have, w, max.script, max.region, pin) - if best.conf == Exact { - for have.nextMax != 0 { - have = h.haveTags[have.nextMax] - best.update(have, w, max.script, max.region, pin) - } - return best.have, best.want, best.conf - } - } - } - if best.conf <= No { - if len(want) != 0 { - return nil, want[0], No - } - return nil, Tag{}, No - } - return best.have, best.want, best.conf -} - -// bestMatch accumulates the best match so far. -type bestMatch struct { - have *haveTag - want Tag - conf Confidence - pinnedRegion regionID - pinLanguage bool - sameRegionGroup bool - // Cached results from applying tie-breaking rules. - origLang bool - origReg bool - paradigmReg bool - regGroupDist uint8 - origScript bool -} - -// update updates the existing best match if the new pair is considered to be a -// better match. To determine if the given pair is a better match, it first -// computes the rough confidence level. If this surpasses the current match, it -// will replace it and update the tie-breaker rule cache. If there is a tie, it -// proceeds with applying a series of tie-breaker rules. If there is no -// conclusive winner after applying the tie-breaker rules, it leaves the current -// match as the preferred match. -// -// If pin is true and have and tag are a strong match, it will henceforth only -// consider matches for this language. This corresponds to the nothing that most -// users have a strong preference for the first defined language. A user can -// still prefer a second language over a dialect of the preferred language by -// explicitly specifying dialects, e.g. "en, nl, en-GB". In this case pin should -// be false. -func (m *bestMatch) update(have *haveTag, tag Tag, maxScript scriptID, maxRegion regionID, pin bool) { - // Bail if the maximum attainable confidence is below that of the current best match. - c := have.conf - if c < m.conf { - return - } - // Don't change the language once we already have found an exact match. - if m.pinLanguage && tag.lang != m.want.lang { - return - } - // Pin the region group if we are comparing tags for the same language. - if tag.lang == m.want.lang && m.sameRegionGroup { - _, sameGroup := regionGroupDist(m.pinnedRegion, have.maxRegion, have.maxScript, m.want.lang) - if !sameGroup { - return - } - } - if c == Exact && have.maxScript == maxScript { - // If there is another language and then another entry of this language, - // don't pin anything, otherwise pin the language. - m.pinLanguage = pin - } - if have.tag.equalsRest(tag) { - } else if have.maxScript != maxScript { - // There is usually very little comprehension between different scripts. - // In a few cases there may still be Low comprehension. This possibility - // is pre-computed and stored in have.altScript. - if Low < m.conf || have.altScript != maxScript { - return - } - c = Low - } else if have.maxRegion != maxRegion { - if High < c { - // There is usually a small difference between languages across regions. - c = High - } - } - - // We store the results of the computations of the tie-breaker rules along - // with the best match. There is no need to do the checks once we determine - // we have a winner, but we do still need to do the tie-breaker computations. - // We use "beaten" to keep track if we still need to do the checks. - beaten := false // true if the new pair defeats the current one. - if c != m.conf { - if c < m.conf { - return - } - beaten = true - } - - // Tie-breaker rules: - // We prefer if the pre-maximized language was specified and identical. - origLang := have.tag.lang == tag.lang && tag.lang != 0 - if !beaten && m.origLang != origLang { - if m.origLang { - return - } - beaten = true - } - - // We prefer if the pre-maximized region was specified and identical. - origReg := have.tag.region == tag.region && tag.region != 0 - if !beaten && m.origReg != origReg { - if m.origReg { - return - } - beaten = true - } - - regGroupDist, sameGroup := regionGroupDist(have.maxRegion, maxRegion, maxScript, tag.lang) - if !beaten && m.regGroupDist != regGroupDist { - if regGroupDist > m.regGroupDist { - return - } - beaten = true - } - - paradigmReg := isParadigmLocale(tag.lang, have.maxRegion) - if !beaten && m.paradigmReg != paradigmReg { - if !paradigmReg { - return - } - beaten = true - } - - // Next we prefer if the pre-maximized script was specified and identical. - origScript := have.tag.script == tag.script && tag.script != 0 - if !beaten && m.origScript != origScript { - if m.origScript { - return - } - beaten = true - } - - // Update m to the newly found best match. - if beaten { - m.have = have - m.want = tag - m.conf = c - m.pinnedRegion = maxRegion - m.sameRegionGroup = sameGroup - m.origLang = origLang - m.origReg = origReg - m.paradigmReg = paradigmReg - m.origScript = origScript - m.regGroupDist = regGroupDist - } -} - -func isParadigmLocale(lang langID, r regionID) bool { - for _, e := range paradigmLocales { - if langID(e[0]) == lang && (r == regionID(e[1]) || r == regionID(e[2])) { - return true - } - } - return false -} - -// regionGroupDist computes the distance between two regions based on their -// CLDR grouping. -func regionGroupDist(a, b regionID, script scriptID, lang langID) (dist uint8, same bool) { - const defaultDistance = 4 - - aGroup := uint(regionToGroups[a]) << 1 - bGroup := uint(regionToGroups[b]) << 1 - for _, ri := range matchRegion { - if langID(ri.lang) == lang && (ri.script == 0 || scriptID(ri.script) == script) { - group := uint(1 << (ri.group &^ 0x80)) - if 0x80&ri.group == 0 { - if aGroup&bGroup&group != 0 { // Both regions are in the group. - return ri.distance, ri.distance == defaultDistance - } - } else { - if (aGroup|bGroup)&group == 0 { // Both regions are not in the group. - return ri.distance, ri.distance == defaultDistance - } - } - } - } - return defaultDistance, true -} - -func (t Tag) variants() string { - if t.pVariant == 0 { - return "" - } - return t.str[t.pVariant:t.pExt] -} - -// variantOrPrivateTagStr returns variants or private use tags. -func (t Tag) variantOrPrivateTagStr() string { - if t.pExt > 0 { - return t.str[t.pVariant:t.pExt] - } - return t.str[t.pVariant:] -} - -// equalsRest compares everything except the language. -func (a Tag) equalsRest(b Tag) bool { - // TODO: don't include extensions in this comparison. To do this efficiently, - // though, we should handle private tags separately. - return a.script == b.script && a.region == b.region && a.variantOrPrivateTagStr() == b.variantOrPrivateTagStr() -} - -// isExactEquivalent returns true if canonicalizing the language will not alter -// the script or region of a tag. -func isExactEquivalent(l langID) bool { - for _, o := range notEquivalent { - if o == l { - return false - } - } - return true -} - -var notEquivalent []langID - -func init() { - // Create a list of all languages for which canonicalization may alter the - // script or region. - for _, lm := range langAliasMap { - tag := Tag{lang: langID(lm.from)} - if tag, _ = tag.canonicalize(All); tag.script != 0 || tag.region != 0 { - notEquivalent = append(notEquivalent, langID(lm.from)) - } - } - // Maximize undefined regions of paradigm locales. - for i, v := range paradigmLocales { - max, _ := addTags(Tag{lang: langID(v[0])}) - if v[1] == 0 { - paradigmLocales[i][1] = uint16(max.region) - } - if v[2] == 0 { - paradigmLocales[i][2] = uint16(max.region) - } - } -} |