Abhilash S.L | 3b49463 | 2019-07-16 15:51:09 +0530 | [diff] [blame] | 1 | // Copyright 2013 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | //go:generate go run gen.go gen_index.go -output tables.go |
| 6 | //go:generate go run gen_parents.go |
| 7 | |
| 8 | package compact |
| 9 | |
| 10 | // TODO: Remove above NOTE after: |
| 11 | // - verifying that tables are dropped correctly (most notably matcher tables). |
| 12 | |
| 13 | import ( |
| 14 | "strings" |
| 15 | |
| 16 | "golang.org/x/text/internal/language" |
| 17 | ) |
| 18 | |
| 19 | // Tag represents a BCP 47 language tag. It is used to specify an instance of a |
| 20 | // specific language or locale. All language tag values are guaranteed to be |
| 21 | // well-formed. |
| 22 | type Tag struct { |
| 23 | // NOTE: exported tags will become part of the public API. |
| 24 | language ID |
| 25 | locale ID |
| 26 | full fullTag // always a language.Tag for now. |
| 27 | } |
| 28 | |
| 29 | const _und = 0 |
| 30 | |
| 31 | type fullTag interface { |
| 32 | IsRoot() bool |
| 33 | Parent() language.Tag |
| 34 | } |
| 35 | |
| 36 | // Make a compact Tag from a fully specified internal language Tag. |
| 37 | func Make(t language.Tag) (tag Tag) { |
| 38 | if region := t.TypeForKey("rg"); len(region) == 6 && region[2:] == "zzzz" { |
| 39 | if r, err := language.ParseRegion(region[:2]); err == nil { |
| 40 | tFull := t |
| 41 | t, _ = t.SetTypeForKey("rg", "") |
| 42 | // TODO: should we not consider "va" for the language tag? |
| 43 | var exact1, exact2 bool |
| 44 | tag.language, exact1 = FromTag(t) |
| 45 | t.RegionID = r |
| 46 | tag.locale, exact2 = FromTag(t) |
| 47 | if !exact1 || !exact2 { |
| 48 | tag.full = tFull |
| 49 | } |
| 50 | return tag |
| 51 | } |
| 52 | } |
| 53 | lang, ok := FromTag(t) |
| 54 | tag.language = lang |
| 55 | tag.locale = lang |
| 56 | if !ok { |
| 57 | tag.full = t |
| 58 | } |
| 59 | return tag |
| 60 | } |
| 61 | |
| 62 | // Tag returns an internal language Tag version of this tag. |
| 63 | func (t Tag) Tag() language.Tag { |
| 64 | if t.full != nil { |
| 65 | return t.full.(language.Tag) |
| 66 | } |
| 67 | tag := t.language.Tag() |
| 68 | if t.language != t.locale { |
| 69 | loc := t.locale.Tag() |
| 70 | tag, _ = tag.SetTypeForKey("rg", strings.ToLower(loc.RegionID.String())+"zzzz") |
| 71 | } |
| 72 | return tag |
| 73 | } |
| 74 | |
| 75 | // IsCompact reports whether this tag is fully defined in terms of ID. |
| 76 | func (t *Tag) IsCompact() bool { |
| 77 | return t.full == nil |
| 78 | } |
| 79 | |
| 80 | // MayHaveVariants reports whether a tag may have variants. If it returns false |
| 81 | // it is guaranteed the tag does not have variants. |
| 82 | func (t Tag) MayHaveVariants() bool { |
| 83 | return t.full != nil || int(t.language) >= len(coreTags) |
| 84 | } |
| 85 | |
| 86 | // MayHaveExtensions reports whether a tag may have extensions. If it returns |
| 87 | // false it is guaranteed the tag does not have them. |
| 88 | func (t Tag) MayHaveExtensions() bool { |
| 89 | return t.full != nil || |
| 90 | int(t.language) >= len(coreTags) || |
| 91 | t.language != t.locale |
| 92 | } |
| 93 | |
| 94 | // IsRoot returns true if t is equal to language "und". |
| 95 | func (t Tag) IsRoot() bool { |
| 96 | if t.full != nil { |
| 97 | return t.full.IsRoot() |
| 98 | } |
| 99 | return t.language == _und |
| 100 | } |
| 101 | |
| 102 | // Parent returns the CLDR parent of t. In CLDR, missing fields in data for a |
| 103 | // specific language are substituted with fields from the parent language. |
| 104 | // The parent for a language may change for newer versions of CLDR. |
| 105 | func (t Tag) Parent() Tag { |
| 106 | if t.full != nil { |
| 107 | return Make(t.full.Parent()) |
| 108 | } |
| 109 | if t.language != t.locale { |
| 110 | // Simulate stripping -u-rg-xxxxxx |
| 111 | return Tag{language: t.language, locale: t.language} |
| 112 | } |
| 113 | // TODO: use parent lookup table once cycle from internal package is |
| 114 | // removed. Probably by internalizing the table and declaring this fast |
| 115 | // enough. |
| 116 | // lang := compactID(internal.Parent(uint16(t.language))) |
| 117 | lang, _ := FromTag(t.language.Tag().Parent()) |
| 118 | return Tag{language: lang, locale: lang} |
| 119 | } |
| 120 | |
| 121 | // returns token t and the rest of the string. |
| 122 | func nextToken(s string) (t, tail string) { |
| 123 | p := strings.Index(s[1:], "-") |
| 124 | if p == -1 { |
| 125 | return s[1:], "" |
| 126 | } |
| 127 | p++ |
| 128 | return s[1:p], s[p:] |
| 129 | } |
| 130 | |
| 131 | // LanguageID returns an index, where 0 <= index < NumCompactTags, for tags |
| 132 | // for which data exists in the text repository.The index will change over time |
| 133 | // and should not be stored in persistent storage. If t does not match a compact |
| 134 | // index, exact will be false and the compact index will be returned for the |
| 135 | // first match after repeatedly taking the Parent of t. |
| 136 | func LanguageID(t Tag) (id ID, exact bool) { |
| 137 | return t.language, t.full == nil |
| 138 | } |
| 139 | |
| 140 | // RegionalID returns the ID for the regional variant of this tag. This index is |
| 141 | // used to indicate region-specific overrides, such as default currency, default |
| 142 | // calendar and week data, default time cycle, and default measurement system |
| 143 | // and unit preferences. |
| 144 | // |
| 145 | // For instance, the tag en-GB-u-rg-uszzzz specifies British English with US |
| 146 | // settings for currency, number formatting, etc. The CompactIndex for this tag |
| 147 | // will be that for en-GB, while the RegionalID will be the one corresponding to |
| 148 | // en-US. |
| 149 | func RegionalID(t Tag) (id ID, exact bool) { |
| 150 | return t.locale, t.full == nil |
| 151 | } |
| 152 | |
| 153 | // LanguageTag returns t stripped of regional variant indicators. |
| 154 | // |
| 155 | // At the moment this means it is stripped of a regional and variant subtag "rg" |
| 156 | // and "va" in the "u" extension. |
| 157 | func (t Tag) LanguageTag() Tag { |
| 158 | if t.full == nil { |
| 159 | return Tag{language: t.language, locale: t.language} |
| 160 | } |
| 161 | tt := t.Tag() |
| 162 | tt.SetTypeForKey("rg", "") |
| 163 | tt.SetTypeForKey("va", "") |
| 164 | return Make(tt) |
| 165 | } |
| 166 | |
| 167 | // RegionalTag returns the regional variant of the tag. |
| 168 | // |
| 169 | // At the moment this means that the region is set from the regional subtag |
| 170 | // "rg" in the "u" extension. |
| 171 | func (t Tag) RegionalTag() Tag { |
| 172 | rt := Tag{language: t.locale, locale: t.locale} |
| 173 | if t.full == nil { |
| 174 | return rt |
| 175 | } |
| 176 | b := language.Builder{} |
| 177 | tag := t.Tag() |
| 178 | // tag, _ = tag.SetTypeForKey("rg", "") |
| 179 | b.SetTag(t.locale.Tag()) |
| 180 | if v := tag.Variants(); v != "" { |
| 181 | for _, v := range strings.Split(v, "-") { |
| 182 | b.AddVariant(v) |
| 183 | } |
| 184 | } |
| 185 | for _, e := range tag.Extensions() { |
| 186 | b.AddExt(e) |
| 187 | } |
| 188 | return t |
| 189 | } |
| 190 | |
| 191 | // FromTag reports closest matching ID for an internal language Tag. |
| 192 | func FromTag(t language.Tag) (id ID, exact bool) { |
| 193 | // TODO: perhaps give more frequent tags a lower index. |
| 194 | // TODO: we could make the indexes stable. This will excluded some |
| 195 | // possibilities for optimization, so don't do this quite yet. |
| 196 | exact = true |
| 197 | |
| 198 | b, s, r := t.Raw() |
| 199 | if t.HasString() { |
| 200 | if t.IsPrivateUse() { |
| 201 | // We have no entries for user-defined tags. |
| 202 | return 0, false |
| 203 | } |
| 204 | hasExtra := false |
| 205 | if t.HasVariants() { |
| 206 | if t.HasExtensions() { |
| 207 | build := language.Builder{} |
| 208 | build.SetTag(language.Tag{LangID: b, ScriptID: s, RegionID: r}) |
| 209 | build.AddVariant(t.Variants()) |
| 210 | exact = false |
| 211 | t = build.Make() |
| 212 | } |
| 213 | hasExtra = true |
| 214 | } else if _, ok := t.Extension('u'); ok { |
| 215 | // TODO: va may mean something else. Consider not considering it. |
| 216 | // Strip all but the 'va' entry. |
| 217 | old := t |
| 218 | variant := t.TypeForKey("va") |
| 219 | t = language.Tag{LangID: b, ScriptID: s, RegionID: r} |
| 220 | if variant != "" { |
| 221 | t, _ = t.SetTypeForKey("va", variant) |
| 222 | hasExtra = true |
| 223 | } |
| 224 | exact = old == t |
| 225 | } else { |
| 226 | exact = false |
| 227 | } |
| 228 | if hasExtra { |
| 229 | // We have some variants. |
| 230 | for i, s := range specialTags { |
| 231 | if s == t { |
| 232 | return ID(i + len(coreTags)), exact |
| 233 | } |
| 234 | } |
| 235 | exact = false |
| 236 | } |
| 237 | } |
| 238 | if x, ok := getCoreIndex(t); ok { |
| 239 | return x, exact |
| 240 | } |
| 241 | exact = false |
| 242 | if r != 0 && s == 0 { |
| 243 | // Deal with cases where an extra script is inserted for the region. |
| 244 | t, _ := t.Maximize() |
| 245 | if x, ok := getCoreIndex(t); ok { |
| 246 | return x, exact |
| 247 | } |
| 248 | } |
| 249 | for t = t.Parent(); t != root; t = t.Parent() { |
| 250 | // No variants specified: just compare core components. |
| 251 | // The key has the form lllssrrr, where l, s, and r are nibbles for |
| 252 | // respectively the langID, scriptID, and regionID. |
| 253 | if x, ok := getCoreIndex(t); ok { |
| 254 | return x, exact |
| 255 | } |
| 256 | } |
| 257 | return 0, exact |
| 258 | } |
| 259 | |
| 260 | var root = language.Tag{} |