diff options
Diffstat (limited to 'src/dma/vendor/golang.org/x/text/internal/language/match.go')
| -rw-r--r-- | src/dma/vendor/golang.org/x/text/internal/language/match.go | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/dma/vendor/golang.org/x/text/internal/language/match.go b/src/dma/vendor/golang.org/x/text/internal/language/match.go new file mode 100644 index 00000000..75a2dbca --- /dev/null +++ b/src/dma/vendor/golang.org/x/text/internal/language/match.go @@ -0,0 +1,226 @@ +// 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" + +type scriptRegionFlags uint8 + +const ( + isList = 1 << iota + scriptInFrom + regionInFrom +) + +func (t *Tag) setUndefinedLang(id Language) { + if t.LangID == 0 { + t.LangID = id + } +} + +func (t *Tag) setUndefinedScript(id Script) { + if t.ScriptID == 0 { + t.ScriptID = id + } +} + +func (t *Tag) setUndefinedRegion(id Region) { + if t.RegionID == 0 || t.RegionID.Contains(id) { + t.RegionID = 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.RegionID]; i < nRegionGroups { + x := likelyRegionGroup[i] + if Language(x.lang) == t.LangID && Script(x.script) == t.ScriptID { + t.RegionID = Region(x.region) + } + return true + } + return false +} + +// Maximize returns a new tag with missing tags filled in. +func (t Tag) Maximize() (Tag, error) { + return addTags(t) +} + +func addTags(t Tag) (Tag, error) { + // We leave private use identifiers alone. + if t.IsPrivateUse() { + return t, nil + } + if t.ScriptID != 0 && t.RegionID != 0 { + if t.LangID != 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.RegionID : t.RegionID+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 Script(x.script) == t.ScriptID { + t.setUndefinedLang(Language(x.lang)) + return t, nil + } + } + } + if t.LangID != 0 { + // Search matches for lang-script and lang-region, where lang != und. + if t.LangID < langNoIndexOffset { + x := likelyLang[t.LangID] + if x.flags&isList != 0 { + list := likelyLangList[x.region : x.region+uint16(x.script)] + if t.ScriptID != 0 { + for _, x := range list { + if Script(x.script) == t.ScriptID && x.flags&scriptInFrom != 0 { + t.setUndefinedRegion(Region(x.region)) + return t, nil + } + } + } else if t.RegionID != 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.RegionID.Contains(Region(x.region)) { + tt.RegionID = Region(x.region) + tt.setUndefinedScript(Script(x.script)) + goodScript = goodScript && tt.ScriptID == Script(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.ScriptID = tt.ScriptID + } + } + } + } + } else { + // Search matches for und-script. + if t.ScriptID != 0 { + x := likelyScript[t.ScriptID] + if x.region != 0 { + t.setUndefinedRegion(Region(x.region)) + t.setUndefinedLang(Language(x.lang)) + return t, nil + } + } + // Search matches for und-region. If und-script-region exists, it would + // have been found earlier. + if t.RegionID != 0 { + if i := regionInclusion[t.RegionID]; i < nRegionGroups { + x := likelyRegionGroup[i] + if x.region != 0 { + t.setUndefinedLang(Language(x.lang)) + t.setUndefinedScript(Script(x.script)) + t.RegionID = Region(x.region) + } + } else { + x := likelyRegion[t.RegionID] + if x.flags&isList != 0 { + x = likelyRegionList[x.lang] + } + if x.script != 0 && x.flags != scriptInFrom { + t.setUndefinedLang(Language(x.lang)) + t.setUndefinedScript(Script(x.script)) + return t, nil + } + } + } + } + + // Search matches for lang. + if t.LangID < langNoIndexOffset { + x := likelyLang[t.LangID] + if x.flags&isList != 0 { + x = likelyLangList[x.region] + } + if x.region != 0 { + t.setUndefinedScript(Script(x.script)) + t.setUndefinedRegion(Region(x.region)) + } + specializeRegion(&t) + if t.LangID == 0 { + t.LangID = _en // default language + } + return t, nil + } + return t, ErrMissingLikelyTagsData +} + +func (t *Tag) setTagsFrom(id Tag) { + t.LangID = id.LangID + t.ScriptID = id.ScriptID + t.RegionID = id.RegionID +} + +// 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{ + {LangID: t.LangID}, + {LangID: t.LangID, RegionID: t.RegionID}, + {LangID: t.LangID, ScriptID: t.ScriptID}, + } { + if x, err := addTags(id); err == nil && max.equalTags(x) { + t.setTagsFrom(id) + break + } + } + return t, nil +} |