/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "platform/text/LocaleToScriptMapping.h"

#include "wtf/HashMap.h"
#include "wtf/HashSet.h"
#include "wtf/text/StringHash.h"

namespace blink {

struct SubtagScript {
  const char* subtag;
  UScriptCode script;
};

using SubtagScriptMap = HashMap<String, UScriptCode, CaseFoldingHash>;

static void createSubtagScriptMap(SubtagScriptMap& map,
                                  const SubtagScript list[],
                                  size_t size) {
  map.reserveCapacityForSize(size);
  for (size_t i = 0; i < size; ++i)
    map.set(list[i].subtag, list[i].script);
}

UScriptCode scriptNameToCode(const String& scriptName) {
  // This generally maps an ISO 15924 script code to its UScriptCode, but
  // certain families of script codes are treated as a single script for
  // assigning a per-script font in Settings. For example, "hira" is mapped to
  // USCRIPT_KATAKANA_OR_HIRAGANA instead of USCRIPT_HIRAGANA, since we want all
  // Japanese scripts to be rendered using the same font setting.
  static const SubtagScript scriptNameCodeList[] = {
      {"zyyy", USCRIPT_COMMON},
      {"qaai", USCRIPT_INHERITED},
      {"arab", USCRIPT_ARABIC},
      {"armn", USCRIPT_ARMENIAN},
      {"beng", USCRIPT_BENGALI},
      {"bopo", USCRIPT_BOPOMOFO},
      {"cher", USCRIPT_CHEROKEE},
      {"copt", USCRIPT_COPTIC},
      {"cyrl", USCRIPT_CYRILLIC},
      {"dsrt", USCRIPT_DESERET},
      {"deva", USCRIPT_DEVANAGARI},
      {"ethi", USCRIPT_ETHIOPIC},
      {"geor", USCRIPT_GEORGIAN},
      {"goth", USCRIPT_GOTHIC},
      {"grek", USCRIPT_GREEK},
      {"gujr", USCRIPT_GUJARATI},
      {"guru", USCRIPT_GURMUKHI},
      {"hani", USCRIPT_HAN},
      {"hang", USCRIPT_HANGUL},
      {"hebr", USCRIPT_HEBREW},
      {"hira", USCRIPT_KATAKANA_OR_HIRAGANA},
      {"knda", USCRIPT_KANNADA},
      {"kana", USCRIPT_KATAKANA_OR_HIRAGANA},
      {"khmr", USCRIPT_KHMER},
      {"laoo", USCRIPT_LAO},
      {"latn", USCRIPT_LATIN},
      {"mlym", USCRIPT_MALAYALAM},
      {"mong", USCRIPT_MONGOLIAN},
      {"mymr", USCRIPT_MYANMAR},
      {"ogam", USCRIPT_OGHAM},
      {"ital", USCRIPT_OLD_ITALIC},
      {"orya", USCRIPT_ORIYA},
      {"runr", USCRIPT_RUNIC},
      {"sinh", USCRIPT_SINHALA},
      {"syrc", USCRIPT_SYRIAC},
      {"taml", USCRIPT_TAMIL},
      {"telu", USCRIPT_TELUGU},
      {"thaa", USCRIPT_THAANA},
      {"thai", USCRIPT_THAI},
      {"tibt", USCRIPT_TIBETAN},
      {"cans", USCRIPT_CANADIAN_ABORIGINAL},
      {"yiii", USCRIPT_YI},
      {"tglg", USCRIPT_TAGALOG},
      {"hano", USCRIPT_HANUNOO},
      {"buhd", USCRIPT_BUHID},
      {"tagb", USCRIPT_TAGBANWA},
      {"brai", USCRIPT_BRAILLE},
      {"cprt", USCRIPT_CYPRIOT},
      {"limb", USCRIPT_LIMBU},
      {"linb", USCRIPT_LINEAR_B},
      {"osma", USCRIPT_OSMANYA},
      {"shaw", USCRIPT_SHAVIAN},
      {"tale", USCRIPT_TAI_LE},
      {"ugar", USCRIPT_UGARITIC},
      {"hrkt", USCRIPT_KATAKANA_OR_HIRAGANA},
      {"bugi", USCRIPT_BUGINESE},
      {"glag", USCRIPT_GLAGOLITIC},
      {"khar", USCRIPT_KHAROSHTHI},
      {"sylo", USCRIPT_SYLOTI_NAGRI},
      {"talu", USCRIPT_NEW_TAI_LUE},
      {"tfng", USCRIPT_TIFINAGH},
      {"xpeo", USCRIPT_OLD_PERSIAN},
      {"bali", USCRIPT_BALINESE},
      {"batk", USCRIPT_BATAK},
      {"blis", USCRIPT_BLISSYMBOLS},
      {"brah", USCRIPT_BRAHMI},
      {"cham", USCRIPT_CHAM},
      {"cirt", USCRIPT_CIRTH},
      {"cyrs", USCRIPT_OLD_CHURCH_SLAVONIC_CYRILLIC},
      {"egyd", USCRIPT_DEMOTIC_EGYPTIAN},
      {"egyh", USCRIPT_HIERATIC_EGYPTIAN},
      {"egyp", USCRIPT_EGYPTIAN_HIEROGLYPHS},
      {"geok", USCRIPT_KHUTSURI},
      {"hans", USCRIPT_SIMPLIFIED_HAN},
      {"hant", USCRIPT_TRADITIONAL_HAN},
      {"hmng", USCRIPT_PAHAWH_HMONG},
      {"hung", USCRIPT_OLD_HUNGARIAN},
      {"inds", USCRIPT_HARAPPAN_INDUS},
      {"java", USCRIPT_JAVANESE},
      {"kali", USCRIPT_KAYAH_LI},
      {"latf", USCRIPT_LATIN_FRAKTUR},
      {"latg", USCRIPT_LATIN_GAELIC},
      {"lepc", USCRIPT_LEPCHA},
      {"lina", USCRIPT_LINEAR_A},
      {"mand", USCRIPT_MANDAEAN},
      {"maya", USCRIPT_MAYAN_HIEROGLYPHS},
      {"mero", USCRIPT_MEROITIC},
      {"nkoo", USCRIPT_NKO},
      {"orkh", USCRIPT_ORKHON},
      {"perm", USCRIPT_OLD_PERMIC},
      {"phag", USCRIPT_PHAGS_PA},
      {"phnx", USCRIPT_PHOENICIAN},
      {"plrd", USCRIPT_PHONETIC_POLLARD},
      {"roro", USCRIPT_RONGORONGO},
      {"sara", USCRIPT_SARATI},
      {"syre", USCRIPT_ESTRANGELO_SYRIAC},
      {"syrj", USCRIPT_WESTERN_SYRIAC},
      {"syrn", USCRIPT_EASTERN_SYRIAC},
      {"teng", USCRIPT_TENGWAR},
      {"vaii", USCRIPT_VAI},
      {"visp", USCRIPT_VISIBLE_SPEECH},
      {"xsux", USCRIPT_CUNEIFORM},
      {"jpan", USCRIPT_KATAKANA_OR_HIRAGANA},
      {"kore", USCRIPT_HANGUL},
      {"zxxx", USCRIPT_UNWRITTEN_LANGUAGES},
      {"zzzz", USCRIPT_UNKNOWN}};
  DEFINE_STATIC_LOCAL(SubtagScriptMap, scriptNameCodeMap, ());
  if (scriptNameCodeMap.isEmpty())
    createSubtagScriptMap(scriptNameCodeMap, scriptNameCodeList,
                          WTF_ARRAY_LENGTH(scriptNameCodeList));

  const auto& it = scriptNameCodeMap.find(scriptName);
  if (it != scriptNameCodeMap.end())
    return it->value;
  return USCRIPT_INVALID_CODE;
}

UScriptCode localeToScriptCodeForFontSelection(const String& locale) {
  static const SubtagScript localeScriptList[] = {
      {"aa", USCRIPT_LATIN},
      {"ab", USCRIPT_CYRILLIC},
      {"ady", USCRIPT_CYRILLIC},
      {"aeb", USCRIPT_ARABIC},
      {"af", USCRIPT_LATIN},
      {"ak", USCRIPT_LATIN},
      {"am", USCRIPT_ETHIOPIC},
      {"ar", USCRIPT_ARABIC},
      {"arq", USCRIPT_ARABIC},
      {"ary", USCRIPT_ARABIC},
      {"arz", USCRIPT_ARABIC},
      {"as", USCRIPT_BENGALI},
      {"ast", USCRIPT_LATIN},
      {"av", USCRIPT_CYRILLIC},
      {"ay", USCRIPT_LATIN},
      {"az", USCRIPT_LATIN},
      {"azb", USCRIPT_ARABIC},
      {"ba", USCRIPT_CYRILLIC},
      {"bal", USCRIPT_ARABIC},
      {"be", USCRIPT_CYRILLIC},
      {"bej", USCRIPT_ARABIC},
      {"bg", USCRIPT_CYRILLIC},
      {"bi", USCRIPT_LATIN},
      {"bn", USCRIPT_BENGALI},
      {"bo", USCRIPT_TIBETAN},
      {"bqi", USCRIPT_ARABIC},
      {"brh", USCRIPT_ARABIC},
      {"bs", USCRIPT_LATIN},
      {"ca", USCRIPT_LATIN},
      {"ce", USCRIPT_CYRILLIC},
      {"ceb", USCRIPT_LATIN},
      {"ch", USCRIPT_LATIN},
      {"chk", USCRIPT_LATIN},
      {"cja", USCRIPT_ARABIC},
      {"cjm", USCRIPT_ARABIC},
      {"ckb", USCRIPT_ARABIC},
      {"cs", USCRIPT_LATIN},
      {"cy", USCRIPT_LATIN},
      {"da", USCRIPT_LATIN},
      {"dcc", USCRIPT_ARABIC},
      {"de", USCRIPT_LATIN},
      {"doi", USCRIPT_ARABIC},
      {"dv", USCRIPT_THAANA},
      {"dyo", USCRIPT_ARABIC},
      {"dz", USCRIPT_TIBETAN},
      {"ee", USCRIPT_LATIN},
      {"efi", USCRIPT_LATIN},
      {"el", USCRIPT_GREEK},
      {"en", USCRIPT_LATIN},
      {"es", USCRIPT_LATIN},
      {"et", USCRIPT_LATIN},
      {"eu", USCRIPT_LATIN},
      {"fa", USCRIPT_ARABIC},
      {"fi", USCRIPT_LATIN},
      {"fil", USCRIPT_LATIN},
      {"fj", USCRIPT_LATIN},
      {"fo", USCRIPT_LATIN},
      {"fr", USCRIPT_LATIN},
      {"fur", USCRIPT_LATIN},
      {"fy", USCRIPT_LATIN},
      {"ga", USCRIPT_LATIN},
      {"gaa", USCRIPT_LATIN},
      {"gba", USCRIPT_ARABIC},
      {"gbz", USCRIPT_ARABIC},
      {"gd", USCRIPT_LATIN},
      {"gil", USCRIPT_LATIN},
      {"gl", USCRIPT_LATIN},
      {"gjk", USCRIPT_ARABIC},
      {"gju", USCRIPT_ARABIC},
      {"glk", USCRIPT_ARABIC},
      {"gn", USCRIPT_LATIN},
      {"gsw", USCRIPT_LATIN},
      {"gu", USCRIPT_GUJARATI},
      {"ha", USCRIPT_LATIN},
      {"haw", USCRIPT_LATIN},
      {"haz", USCRIPT_ARABIC},
      {"he", USCRIPT_HEBREW},
      {"hi", USCRIPT_DEVANAGARI},
      {"hil", USCRIPT_LATIN},
      {"hnd", USCRIPT_ARABIC},
      {"hno", USCRIPT_ARABIC},
      {"ho", USCRIPT_LATIN},
      {"hr", USCRIPT_LATIN},
      {"ht", USCRIPT_LATIN},
      {"hu", USCRIPT_LATIN},
      {"hy", USCRIPT_ARMENIAN},
      {"id", USCRIPT_LATIN},
      {"ig", USCRIPT_LATIN},
      {"ii", USCRIPT_YI},
      {"ilo", USCRIPT_LATIN},
      {"inh", USCRIPT_CYRILLIC},
      {"is", USCRIPT_LATIN},
      {"it", USCRIPT_LATIN},
      {"iu", USCRIPT_CANADIAN_ABORIGINAL},
      {"ja", USCRIPT_KATAKANA_OR_HIRAGANA},
      {"jv", USCRIPT_LATIN},
      {"ka", USCRIPT_GEORGIAN},
      {"kaj", USCRIPT_LATIN},
      {"kam", USCRIPT_LATIN},
      {"kbd", USCRIPT_CYRILLIC},
      {"kha", USCRIPT_LATIN},
      {"khw", USCRIPT_ARABIC},
      {"kk", USCRIPT_CYRILLIC},
      {"kl", USCRIPT_LATIN},
      {"km", USCRIPT_KHMER},
      {"kn", USCRIPT_KANNADA},
      {"ko", USCRIPT_HANGUL},
      {"kok", USCRIPT_DEVANAGARI},
      {"kos", USCRIPT_LATIN},
      {"kpe", USCRIPT_LATIN},
      {"krc", USCRIPT_CYRILLIC},
      {"ks", USCRIPT_ARABIC},
      {"ku", USCRIPT_ARABIC},
      {"kum", USCRIPT_CYRILLIC},
      {"kvx", USCRIPT_ARABIC},
      {"kxp", USCRIPT_ARABIC},
      {"ky", USCRIPT_CYRILLIC},
      {"la", USCRIPT_LATIN},
      {"lah", USCRIPT_ARABIC},
      {"lb", USCRIPT_LATIN},
      {"lez", USCRIPT_CYRILLIC},
      {"lki", USCRIPT_ARABIC},
      {"ln", USCRIPT_LATIN},
      {"lo", USCRIPT_LAO},
      {"lrc", USCRIPT_ARABIC},
      {"lt", USCRIPT_LATIN},
      {"luz", USCRIPT_ARABIC},
      {"lv", USCRIPT_LATIN},
      {"mai", USCRIPT_DEVANAGARI},
      {"mdf", USCRIPT_CYRILLIC},
      {"mfa", USCRIPT_ARABIC},
      {"mg", USCRIPT_LATIN},
      {"mh", USCRIPT_LATIN},
      {"mi", USCRIPT_LATIN},
      {"mk", USCRIPT_CYRILLIC},
      {"ml", USCRIPT_MALAYALAM},
      {"mn", USCRIPT_CYRILLIC},
      {"mr", USCRIPT_DEVANAGARI},
      {"ms", USCRIPT_LATIN},
      {"mt", USCRIPT_LATIN},
      {"mvy", USCRIPT_ARABIC},
      {"my", USCRIPT_MYANMAR},
      {"myv", USCRIPT_CYRILLIC},
      {"mzn", USCRIPT_ARABIC},
      {"na", USCRIPT_LATIN},
      {"nb", USCRIPT_LATIN},
      {"ne", USCRIPT_DEVANAGARI},
      {"niu", USCRIPT_LATIN},
      {"nl", USCRIPT_LATIN},
      {"nn", USCRIPT_LATIN},
      {"nr", USCRIPT_LATIN},
      {"nso", USCRIPT_LATIN},
      {"ny", USCRIPT_LATIN},
      {"oc", USCRIPT_LATIN},
      {"om", USCRIPT_LATIN},
      {"or", USCRIPT_ORIYA},
      {"os", USCRIPT_CYRILLIC},
      {"pa", USCRIPT_GURMUKHI},
      {"pag", USCRIPT_LATIN},
      {"pap", USCRIPT_LATIN},
      {"pau", USCRIPT_LATIN},
      {"pl", USCRIPT_LATIN},
      {"pon", USCRIPT_LATIN},
      {"prd", USCRIPT_ARABIC},
      {"prs", USCRIPT_ARABIC},
      {"ps", USCRIPT_ARABIC},
      {"pt", USCRIPT_LATIN},
      {"qu", USCRIPT_LATIN},
      {"rm", USCRIPT_LATIN},
      {"rmt", USCRIPT_ARABIC},
      {"rn", USCRIPT_LATIN},
      {"ro", USCRIPT_LATIN},
      {"ru", USCRIPT_CYRILLIC},
      {"rw", USCRIPT_LATIN},
      {"sa", USCRIPT_DEVANAGARI},
      {"sah", USCRIPT_CYRILLIC},
      {"sat", USCRIPT_LATIN},
      {"sd", USCRIPT_ARABIC},
      {"sdh", USCRIPT_ARABIC},
      {"se", USCRIPT_LATIN},
      {"sg", USCRIPT_LATIN},
      {"shi", USCRIPT_ARABIC},
      {"si", USCRIPT_SINHALA},
      {"sid", USCRIPT_LATIN},
      {"sk", USCRIPT_LATIN},
      {"skr", USCRIPT_ARABIC},
      {"sl", USCRIPT_LATIN},
      {"sm", USCRIPT_LATIN},
      {"so", USCRIPT_LATIN},
      {"sq", USCRIPT_LATIN},
      {"sr", USCRIPT_CYRILLIC},
      {"ss", USCRIPT_LATIN},
      {"st", USCRIPT_LATIN},
      {"su", USCRIPT_LATIN},
      {"sus", USCRIPT_ARABIC},
      {"sv", USCRIPT_LATIN},
      {"sw", USCRIPT_LATIN},
      {"swb", USCRIPT_ARABIC},
      {"syr", USCRIPT_ARABIC},
      {"ta", USCRIPT_TAMIL},
      {"te", USCRIPT_TELUGU},
      {"tet", USCRIPT_LATIN},
      {"tg", USCRIPT_CYRILLIC},
      {"th", USCRIPT_THAI},
      {"ti", USCRIPT_ETHIOPIC},
      {"tig", USCRIPT_ETHIOPIC},
      {"tk", USCRIPT_LATIN},
      {"tkl", USCRIPT_LATIN},
      {"tl", USCRIPT_LATIN},
      {"tn", USCRIPT_LATIN},
      {"to", USCRIPT_LATIN},
      {"tpi", USCRIPT_LATIN},
      {"tr", USCRIPT_LATIN},
      {"trv", USCRIPT_LATIN},
      {"ts", USCRIPT_LATIN},
      {"tt", USCRIPT_CYRILLIC},
      {"ttt", USCRIPT_ARABIC},
      {"tvl", USCRIPT_LATIN},
      {"tw", USCRIPT_LATIN},
      {"ty", USCRIPT_LATIN},
      {"tyv", USCRIPT_CYRILLIC},
      {"udm", USCRIPT_CYRILLIC},
      {"ug", USCRIPT_ARABIC},
      {"uk", USCRIPT_CYRILLIC},
      {"und", USCRIPT_LATIN},
      {"ur", USCRIPT_ARABIC},
      {"uz", USCRIPT_CYRILLIC},
      {"ve", USCRIPT_LATIN},
      {"vi", USCRIPT_LATIN},
      {"wal", USCRIPT_ETHIOPIC},
      {"war", USCRIPT_LATIN},
      {"wo", USCRIPT_LATIN},
      {"xh", USCRIPT_LATIN},
      {"yap", USCRIPT_LATIN},
      {"yo", USCRIPT_LATIN},
      {"za", USCRIPT_LATIN},
      {"zdj", USCRIPT_ARABIC},
      {"zh", USCRIPT_SIMPLIFIED_HAN},
      {"zu", USCRIPT_LATIN},
      // Encompassed languages within the Chinese macrolanguage.
      // http://www-01.sil.org/iso639-3/documentation.asp?id=zho
      // http://lists.w3.org/Archives/Public/public-i18n-cjk/2016JulSep/0022.html
      {"cdo", USCRIPT_SIMPLIFIED_HAN},
      {"cjy", USCRIPT_SIMPLIFIED_HAN},
      {"cmn", USCRIPT_SIMPLIFIED_HAN},
      {"cpx", USCRIPT_SIMPLIFIED_HAN},
      {"czh", USCRIPT_SIMPLIFIED_HAN},
      {"czo", USCRIPT_SIMPLIFIED_HAN},
      {"gan", USCRIPT_SIMPLIFIED_HAN},
      {"hsn", USCRIPT_SIMPLIFIED_HAN},
      {"mnp", USCRIPT_SIMPLIFIED_HAN},
      {"wuu", USCRIPT_SIMPLIFIED_HAN},
      {"hak", USCRIPT_TRADITIONAL_HAN},
      {"lzh", USCRIPT_TRADITIONAL_HAN},
      {"nan", USCRIPT_TRADITIONAL_HAN},
      {"yue", USCRIPT_TRADITIONAL_HAN},
      {"zh-cdo", USCRIPT_SIMPLIFIED_HAN},
      {"zh-cjy", USCRIPT_SIMPLIFIED_HAN},
      {"zh-cmn", USCRIPT_SIMPLIFIED_HAN},
      {"zh-cpx", USCRIPT_SIMPLIFIED_HAN},
      {"zh-czh", USCRIPT_SIMPLIFIED_HAN},
      {"zh-czo", USCRIPT_SIMPLIFIED_HAN},
      {"zh-gan", USCRIPT_SIMPLIFIED_HAN},
      {"zh-hsn", USCRIPT_SIMPLIFIED_HAN},
      {"zh-mnp", USCRIPT_SIMPLIFIED_HAN},
      {"zh-wuu", USCRIPT_SIMPLIFIED_HAN},
      {"zh-hak", USCRIPT_TRADITIONAL_HAN},
      {"zh-lzh", USCRIPT_TRADITIONAL_HAN},
      {"zh-nan", USCRIPT_TRADITIONAL_HAN},
      {"zh-yue", USCRIPT_TRADITIONAL_HAN},
      // Chinese with regions. Logically, regions should be handled
      // separately, but this works for the current purposes.
      {"zh-hk", USCRIPT_TRADITIONAL_HAN},
      {"zh-mo", USCRIPT_TRADITIONAL_HAN},
      {"zh-tw", USCRIPT_TRADITIONAL_HAN},
  };
  DEFINE_STATIC_LOCAL(SubtagScriptMap, localeScriptMap, ());
  if (localeScriptMap.isEmpty())
    createSubtagScriptMap(localeScriptMap, localeScriptList,
                          WTF_ARRAY_LENGTH(localeScriptList));

  // BCP 47 uses '-' as the delimiter but ICU uses '_'.
  // https://tools.ietf.org/html/bcp47
  String canonicalLocale = locale;
  canonicalLocale.replace('_', '-');
  while (!canonicalLocale.isEmpty()) {
    const auto& it = localeScriptMap.find(canonicalLocale);
    if (it != localeScriptMap.end())
      return it->value;
    size_t pos = canonicalLocale.reverseFind('-');
    if (pos == kNotFound)
      break;
    // script = 4ALPHA
    if (canonicalLocale.length() - (pos + 1) == 4) {
      UScriptCode code = scriptNameToCode(canonicalLocale.substring(pos + 1));
      if (code != USCRIPT_INVALID_CODE && code != USCRIPT_UNKNOWN)
        return code;
    }
    canonicalLocale = canonicalLocale.substring(0, pos);
  }
  return USCRIPT_COMMON;
}

static UScriptCode scriptCodeForHanFromRegion(const String& region) {
  static const SubtagScript regionScriptList[] = {
      {"hk", USCRIPT_TRADITIONAL_HAN}, {"jp", USCRIPT_KATAKANA_OR_HIRAGANA},
      {"kr", USCRIPT_HANGUL},          {"mo", USCRIPT_TRADITIONAL_HAN},
      {"tw", USCRIPT_TRADITIONAL_HAN},
  };
  DEFINE_STATIC_LOCAL(SubtagScriptMap, regionScriptMap, ());
  if (regionScriptMap.isEmpty())
    createSubtagScriptMap(regionScriptMap, regionScriptList,
                          WTF_ARRAY_LENGTH(regionScriptList));

  const auto& it = regionScriptMap.find(region);
  return it != regionScriptMap.end() ? it->value : USCRIPT_COMMON;
}

UScriptCode scriptCodeForHanFromSubtags(const String& locale, char delimiter) {
  // Some sites emit lang="en-JP" when English is set as the preferred
  // language. Use script/region subtags of the content locale to pick the
  // fallback font for unified Han ideographs.
  for (size_t end = locale.find(delimiter); end != kNotFound;) {
    size_t begin = end + 1;
    end = locale.find(delimiter, begin);
    size_t len = (end == kNotFound ? locale.length() : end) - begin;
    UScriptCode script;
    switch (len) {
      case 2:  // region = 2ALPHA / 3DIGIT
        script = scriptCodeForHanFromRegion(locale.substring(begin, len));
        if (script != USCRIPT_COMMON)
          return script;
        break;
      case 4:  // script = 4ALPHA
        script = scriptNameToCode(locale.substring(begin, len));
        if (isUnambiguousHanScript(script))
          return script;
    }
  }

  return USCRIPT_COMMON;
}

}  // namespace blink