asciiblaster/js/unicode.js

var unicode = (function(){
  var UNICODE_BLOCK_LIST = [
    0x0020, 0x007F, "Basic Latin",
    0x0080, 0x00FF, "Latin-1 Supplement",
    0x0100, 0x017F, "Latin Extended-A",
    0x0180, 0x024F, "Latin Extended-B",
    0x0250, 0x02AF, "IPA Extensions",
    0x02B0, 0x02FF, "Spacing Modifier Letters",
    0x0300, 0x036F, "Combining Diacritical Marks",
    0x0370, 0x03FF, "Greek and Coptic",
    0x0400, 0x04FF, "Cyrillic",
    0x0500, 0x052F, "Cyrillic Supplement",
    0x0530, 0x058F, "Armenian",
    0x0590, 0x05FF, "Hebrew",
    0x0600, 0x06FF, "Arabic",
    0x0700, 0x074F, "Syriac",
    0x0750, 0x077F, "Arabic Supplement",
    0x0780, 0x07BF, "Thaana",
    0x07C0, 0x07FF, "NKo",
    0x0800, 0x083F, "Samaritan",
    0x0840, 0x085F, "Mandaic",
    0x08A0, 0x08FF, "Arabic Extended-A",
    0x0900, 0x097F, "Devanagari",
    0x0980, 0x09FF, "Bengali",
    0x0A00, 0x0A7F, "Gurmukhi",
    0x0A80, 0x0AFF, "Gujarati",
    0x0B00, 0x0B7F, "Oriya",
    0x0B80, 0x0BFF, "Tamil",
    0x0C00, 0x0C7F, "Telugu",
    0x0C80, 0x0CFF, "Kannada",
    0x0D00, 0x0D7F, "Malayalam",
    0x0D80, 0x0DFF, "Sinhala",
    0x0E00, 0x0E7F, "Thai",
    0x0E80, 0x0EFF, "Lao",
    0x0F00, 0x0FFF, "Tibetan",
    0x1000, 0x109F, "Myanmar",
    0x10A0, 0x10FF, "Georgian",
    0x1100, 0x11FF, "Hangul Jamo",
    0x1200, 0x137F, "Ethiopic",
    0x1380, 0x139F, "Ethiopic Supplement",
    0x13A0, 0x13FF, "Cherokee",
    0x1400, 0x167F, "Unified Canadian Aboriginal Syllabics",
    0x1680, 0x169F, "Ogham",
    0x16A0, 0x16FF, "Runic",
    0x1700, 0x171F, "Tagalog",
    0x1720, 0x173F, "Hanunoo",
    0x1740, 0x175F, "Buhid",
    0x1760, 0x177F, "Tagbanwa",
    0x1780, 0x17FF, "Khmer",
    0x1800, 0x18AF, "Mongolian",
    0x18B0, 0x18FF, "Unified Canadian Aboriginal Syllabics Extended",
    0x1900, 0x194F, "Limbu",
    0x1950, 0x197F, "Tai Le",
    0x1980, 0x19DF, "New Tai Lue",
    0x19E0, 0x19FF, "Khmer Symbols",
    0x1A00, 0x1A1F, "Buginese",
    0x1A20, 0x1AAF, "Tai Tham",
    0x1AB0, 0x1AFF, "Combining Diacritical Marks Extended",
    0x1B00, 0x1B7F, "Balinese",
    0x1B80, 0x1BBF, "Sundanese",
    0x1BC0, 0x1BFF, "Batak",
    0x1C00, 0x1C4F, "Lepcha",
    0x1C50, 0x1C7F, "Ol Chiki",
    0x1CC0, 0x1CCF, "Sundanese Supplement",
    0x1CD0, 0x1CFF, "Vedic Extensions",
    0x1D00, 0x1D7F, "Phonetic Extensions",
    0x1D80, 0x1DBF, "Phonetic Extensions Supplement",
    0x1DC0, 0x1DFF, "Combining Diacritical Marks Supplement",
    0x1E00, 0x1EFF, "Latin Extended Additional",
    0x1F00, 0x1FFF, "Greek Extended",
    0x2000, 0x206F, "General Punctuation",
    0x2070, 0x209F, "Superscripts and Subscripts",
    0x20A0, 0x20CF, "Currency Symbols",
    0x20D0, 0x20FF, "Combining Diacritical Marks for Symbols",
    0x2100, 0x214F, "Letterlike Symbols",
    0x2150, 0x218F, "Number Forms",
    0x2190, 0x21FF, "Arrows",
    0x2200, 0x22FF, "Mathematical Operators",
    0x2300, 0x23FF, "Miscellaneous Technical",
    0x2400, 0x243F, "Control Pictures",
    0x2440, 0x245F, "Optical Character Recognition",
    0x2460, 0x24FF, "Enclosed Alphanumerics",
    0x2500, 0x257F, "Box Drawing",
    0x2580, 0x259F, "Block Elements",
    0x25A0, 0x25FF, "Geometric Shapes",
    0x2600, 0x26FF, "Miscellaneous Symbols",
    0x2700, 0x27BF, "Dingbats",
    0x27C0, 0x27EF, "Miscellaneous Mathematical Symbols-A",
    0x27F0, 0x27FF, "Supplemental Arrows-A",
    0x2800, 0x28FF, "Braille Patterns",
    0x2900, 0x297F, "Supplemental Arrows-B",
    0x2980, 0x29FF, "Miscellaneous Mathematical Symbols-B",
    0x2A00, 0x2AFF, "Supplemental Mathematical Operators",
    0x2B00, 0x2BFF, "Miscellaneous Symbols and Arrows",
    0x2C00, 0x2C5F, "Glagolitic",
    0x2C60, 0x2C7F, "Latin Extended-C",
    0x2C80, 0x2CFF, "Coptic",
    0x2D00, 0x2D2F, "Georgian Supplement",
    0x2D30, 0x2D7F, "Tifinagh",
    0x2D80, 0x2DDF, "Ethiopic Extended",
    0x2DE0, 0x2DFF, "Cyrillic Extended-A",
    0x2E00, 0x2E7F, "Supplemental Punctuation",
    0x2E80, 0x2EFF, "CJK Radicals Supplement",
    0x2F00, 0x2FDF, "Kangxi Radicals",
    0x2FF0, 0x2FFF, "Ideographic Description Characters",
    0x3000, 0x303F, "CJK Symbols and Punctuation",
    0x3040, 0x309F, "Hiragana",
    0x30A0, 0x30FF, "Katakana",
    0x3100, 0x312F, "Bopomofo",
    0x3130, 0x318F, "Hangul Compatibility Jamo",
    0x3190, 0x319F, "Kanbun",
    0x31A0, 0x31BF, "Bopomofo Extended",
    0x31C0, 0x31EF, "CJK Strokes",
    0x31F0, 0x31FF, "Katakana Phonetic Extensions",
    0x3200, 0x32FF, "Enclosed CJK Letters and Months",
    0x3300, 0x33FF, "CJK Compatibility",
    0x3400, 0x4DBF, "CJK Unified Ideographs Extension A",
    0x4DC0, 0x4DFF, "Yijing Hexagram Symbols",
    0x4E00, 0x9FFF, "CJK Unified Ideographs",
    0xA000, 0xA48F, "Yi Syllables",
    0xA490, 0xA4CF, "Yi Radicals",
    0xA4D0, 0xA4FF, "Lisu",
    0xA500, 0xA63F, "Vai",
    0xA640, 0xA69F, "Cyrillic Extended-B",
    0xA6A0, 0xA6FF, "Bamum",
    0xA700, 0xA71F, "Modifier Tone Letters",
    0xA720, 0xA7FF, "Latin Extended-D",
    0xA800, 0xA82F, "Syloti Nagri",
    0xA830, 0xA83F, "Common Indic Number Forms",
    0xA840, 0xA87F, "Phags-pa",
    0xA880, 0xA8DF, "Saurashtra",
    0xA8E0, 0xA8FF, "Devanagari Extended",
    0xA900, 0xA92F, "Kayah Li",
    0xA930, 0xA95F, "Rejang",
    0xA960, 0xA97F, "Hangul Jamo Extended-A",
    0xA980, 0xA9DF, "Javanese",
    0xA9E0, 0xA9FF, "Myanmar Extended-B",
    0xAA00, 0xAA5F, "Cham",
    0xAA60, 0xAA7F, "Myanmar Extended-A",
    0xAA80, 0xAADF, "Tai Viet",
    0xAAE0, 0xAAFF, "Meetei Mayek Extensions",
    0xAB00, 0xAB2F, "Ethiopic Extended-A",
    0xAB30, 0xAB6F, "Latin Extended-E",
    0xABC0, 0xABFF, "Meetei Mayek",
    0xAC00, 0xD7AF, "Hangul Syllables",
    0xD7B0, 0xD7FF, "Hangul Jamo Extended-B",
    0xD800, 0xDB7F, "High Surrogates",
    0xDB80, 0xDBFF, "High Private Use Surrogates",
    0xDC00, 0xDFFF, "Low Surrogates",
    0xE000, 0xF8FF, "Private Use Area",
    0xF900, 0xFAFF, "CJK Compatibility Ideographs",
    0xFB00, 0xFB4F, "Alphabetic Presentation Forms",
    0xFB50, 0xFDFF, "Arabic Presentation Forms-A",
    0xFE00, 0xFE0F, "Variation Selectors",
    0xFE10, 0xFE1F, "Vertical Forms",
    0xFE20, 0xFE2F, "Combining Half Marks",
    0xFE30, 0xFE4F, "CJK Compatibility Forms",
    0xFE50, 0xFE6F, "Small Form Variants",
    0xFE70, 0xFEFF, "Arabic Presentation Forms-B",
    0xFF00, 0xFFEF, "Halfwidth and Fullwidth Forms",
    0xFFF0, 0xFFFF, "Specials",
    0x10000, 0x1007F, "Linear B Syllabary",
    0x10080, 0x100FF, "Linear B Ideograms",
    0x10100, 0x1013F, "Aegean Numbers",
    0x10140, 0x1018F, "Ancient Greek Numbers",
    0x10190, 0x101CF, "Ancient Symbols",
    0x101D0, 0x101FF, "Phaistos Disc",
    0x10280, 0x1029F, "Lycian",
    0x102A0, 0x102DF, "Carian",
    0x102E0, 0x102FF, "Coptic Epact Numbers",
    0x10300, 0x1032F, "Old Italic",
    0x10330, 0x1034F, "Gothic",
    0x10350, 0x1037F, "Old Permic",
    0x10380, 0x1039F, "Ugaritic",
    0x103A0, 0x103DF, "Old Persian",
    0x10400, 0x1044F, "Deseret",
    0x10450, 0x1047F, "Shavian",
    0x10480, 0x104AF, "Osmanya",
    0x10500, 0x1052F, "Elbasan",
    0x10530, 0x1056F, "Caucasian Albanian",
    0x10600, 0x1077F, "Linear A",
    0x10800, 0x1083F, "Cypriot Syllabary",
    0x10840, 0x1085F, "Imperial Aramaic",
    0x10860, 0x1087F, "Palmyrene",
    0x10880, 0x108AF, "Nabataean",
    0x10900, 0x1091F, "Phoenician",
    0x10920, 0x1093F, "Lydian",
    0x10980, 0x1099F, "Meroitic Hieroglyphs",
    0x109A0, 0x109FF, "Meroitic Cursive",
    0x10A00, 0x10A5F, "Kharoshthi",
    0x10A60, 0x10A7F, "Old South Arabian",
    0x10A80, 0x10A9F, "Old North Arabian",
    0x10AC0, 0x10AFF, "Manichaean",
    0x10B00, 0x10B3F, "Avestan",
    0x10B40, 0x10B5F, "Inscriptional Parthian",
    0x10B60, 0x10B7F, "Inscriptional Pahlavi",
    0x10B80, 0x10BAF, "Psalter Pahlavi",
    0x10C00, 0x10C4F, "Old Turkic",
    0x10E60, 0x10E7F, "Rumi Numeral Symbols",
    0x11000, 0x1107F, "Brahmi",
    0x11080, 0x110CF, "Kaithi",
    0x110D0, 0x110FF, "Sora Sompeng",
    0x11100, 0x1114F, "Chakma",
    0x11150, 0x1117F, "Mahajani",
    0x11180, 0x111DF, "Sharada",
    0x111E0, 0x111FF, "Sinhala Archaic Numbers",
    0x11200, 0x1124F, "Khojki",
    0x112B0, 0x112FF, "Khudawadi",
    0x11300, 0x1137F, "Grantha",
    0x11480, 0x114DF, "Tirhuta",
    0x11580, 0x115FF, "Siddham",
    0x11600, 0x1165F, "Modi",
    0x11680, 0x116CF, "Takri",
    0x118A0, 0x118FF, "Warang Citi",
    0x11AC0, 0x11AFF, "Pau Cin Hau",
    0x12000, 0x123FF, "Cuneiform",
    0x12400, 0x1247F, "Cuneiform Numbers and Punctuation",
    0x13000, 0x1342F, "Egyptian Hieroglyphs",
    0x16800, 0x16A3F, "Bamum Supplement",
    0x16A40, 0x16A6F, "Mro",
    0x16AD0, 0x16AFF, "Bassa Vah",
    0x16B00, 0x16B8F, "Pahawh Hmong",
    0x16F00, 0x16F9F, "Miao",
    0x1B000, 0x1B0FF, "Kana Supplement",
    0x1BC00, 0x1BC9F, "Duployan",
    0x1BCA0, 0x1BCAF, "Shorthand Format Controls",
    0x1D000, 0x1D0FF, "Byzantine Musical Symbols",
    0x1D100, 0x1D1FF, "Musical Symbols",
    0x1D200, 0x1D24F, "Ancient Greek Musical Notation",
    0x1D300, 0x1D35F, "Tai Xuan Jing Symbols",
    0x1D360, 0x1D37F, "Counting Rod Numerals",
    0x1D400, 0x1D7FF, "Mathematical Alphanumeric Symbols",
    0x1E800, 0x1E8DF, "Mende Kikakui",
    0x1EE00, 0x1EEFF, "Arabic Mathematical Alphabetic Symbols",
    0x1F000, 0x1F02F, "Mahjong Tiles",
    0x1F030, 0x1F09F, "Domino Tiles",
    0x1F0A0, 0x1F0FF, "Playing Cards",
    0x1F100, 0x1F1FF, "Enclosed Alphanumeric Supplement",
    0x1F200, 0x1F2FF, "Enclosed Ideographic Supplement",
    0x1F300, 0x1F5FF, "Miscellaneous Symbols and Pictographs",
    0x1F600, 0x1F64F, "Emoticons",
    0x1F650, 0x1F67F, "Ornamental Dingbats",
    0x1F680, 0x1F6FF, "Transport and Map Symbols",
    0x1F700, 0x1F77F, "Alchemical Symbols",
    0x1F780, 0x1F7FF, "Geometric Shapes Extended",
    0x1F800, 0x1F8FF, "Supplemental Arrows-C",
    0x20000, 0x2A6DF, "CJK Unified Ideographs Extension B",
    0x2A700, 0x2B73F, "CJK Unified Ideographs Extension C",
    0x2B740, 0x2B81F, "CJK Unified Ideographs Extension D",
    0x2F800, 0x2FA1F, "CJK Compatibility Ideographs Supplement",
    0xE0000, 0xE007F, "Tags",
    0xE0100, 0xE01EF, "Variation Selectors Supplement",
    0xF0000, 0xFFFFF, "Supplementary Private Use Area-A",
    0x100000, 0x10FFFF, "Supplementary Private Use Area-B",
  ]
  var UNICODE_BLOCK_COUNT = UNICODE_BLOCK_LIST.length / 3
  var UNICODE_LOOKUP = {}
  for (var i = 0, len = UNICODE_BLOCK_LIST.length; i < len; i += 3) {
    UNICODE_LOOKUP[ UNICODE_BLOCK_LIST[i+2] ] = [ UNICODE_BLOCK_LIST[i], UNICODE_BLOCK_LIST[i+1] ]
  }

  function index (j) {
    return [ UNICODE_BLOCK_LIST[j*3], UNICODE_BLOCK_LIST[j*3+1], UNICODE_BLOCK_LIST[j*3+2], [] ]
  }
  function range(m,n){
    if (m > n) return []
    var a = new Array (n-m)
    for (var i = 0, j = m; j <= n; i++, j++) {
      a[i] = j
    }
    return a
  }
  function paginate (a, n){
    var aa = [], ai, i = 0
    while (i < 100) {
      ai = a.slice(i * n, (i+1) * n)
      if (! ai.length) break
      aa.push(ai)
      i++
    }
    return aa
  }
  function block (name, n){
    var b = UNICODE_LOOKUP[name]
    if (! b) return ""
    return range.apply(null, b).map(function(n){ return String.fromCharCode(n) })
  }
  function entities (a) {
    return a.map(function(k){ return "&#" + k.join(";&#") + ";" }).join("<br>")
  }
  function findGroups (chars){
    var groups = [], row, list
    for (var i = 0, j = -1, next = -1, len = chars.length; i < len; i++) {
      if (chars[i] < next) {
        list.push(chars[i])
        continue
      }
      do {
        j += 1
        next = UNICODE_BLOCK_LIST[(j+1)*3]
      } while (chars[i] > next)
      row = index(j)
      list = row[3]
      groups.push( row )
    }
    return groups
  }
  
  // encodes unicode characters as escaped utf16 - \xFFFF
  // encodes ONLY non-ascii characters
  function escapeToUtf16 (txt) {
    var escaped_txt = "", kode
    for (var i = 0; i < txt.length; i++) {
      kode = txt.charCodeAt(i)
      if (kode > 0x7f) {
        kode = kode.toString(16)
        switch (kode.length) {
          case 2:
            kode = "0" + kode
          case 3:
            kode = "0" + kode
        }
        escaped_txt += "\\u" + kode
      }
      else {
        escaped_txt += txt[i]
      }
    }
    return escaped_txt
  }

  // encodes unicode characters as escaped bytes - \xFF
  // encodes ONLY non-ascii characters
  function escapeToEscapedBytes (txt) {
    var escaped_txt = "", kode, utf8_bytes
    for (var i = 0; i < txt.length; i++) {
      kode = txt.charCodeAt(i)
      if (kode > 0x7f) {
        utf8_bytes = convertUnicodeCodePointToUtf8Bytes(kode)
        escaped_txt += convertBytesToEscapedString(utf8_bytes, 16)
      }
      else {
        escaped_txt += txt[i]
      }
    }
    return escaped_txt
  }

  // encodes unicode characters as escaped bytes - \xFF
  // encodes an ENTIRE string
  function escapeAllToEscapedBytes(str, base) {
    var unicode_codes = convertStringToUnicodeCodePoints(str);
    var data_bytes = convertUnicodeCodePointsToBytes(unicode_codes);
    return convertBytesToEscapedString(data_bytes, 16);
  }
  // [ 0xE3, 0x81, 0x82, 0xE3, 0x81, 0x84 ] => '\xE3\x81\x82\xE3\x81\x84'
  // [ 0343, 0201, 0202, 0343, 0201, 0204 ] => '\343\201\202\343\201\204'
  function convertBytesToEscapedString(data_bytes, base) {
    var escaped = '';
    for (var i = 0; i < data_bytes.length; ++i) {
      var prefix = (base == 16 ? "\\x" : "\\");
      var num_digits = base == 16 ? 2 : 3;
      var escaped_byte = prefix + formatNumber(data_bytes[i], base, num_digits)
      escaped += escaped_byte;
    }
    return escaped;
  }
  // [ 0x3042, 0x3044 ] => [ 0xE3, 0x81, 0x82, 0xE3, 0x81, 0x84 ]
  function convertUnicodeCodePointsToBytes(unicode_codes) {
    var utf8_bytes = [];
    for (var i = 0; i < unicode_codes.length; ++i) {
      var bytes = convertUnicodeCodePointToUtf8Bytes(unicode_codes[i]);
      utf8_bytes = utf8_bytes.concat(bytes);
    }
    return utf8_bytes;
  }
  // 0x3042 => [ 0xE3, 0x81, 0x82 ]
  function convertUnicodeCodePointToUtf8Bytes(unicode_code) {
    var utf8_bytes = [];
    if (unicode_code < 0x80) {  // 1-byte
      utf8_bytes.push(unicode_code);
    } else if (unicode_code < (1 << 11)) {  // 2-byte
      utf8_bytes.push((unicode_code >>> 6) | 0xC0);
      utf8_bytes.push((unicode_code & 0x3F) | 0x80);
    } else if (unicode_code < (1 << 16)) {  // 3-byte
      utf8_bytes.push((unicode_code >>> 12) | 0xE0);
      utf8_bytes.push(((unicode_code >> 6) & 0x3f) | 0x80);
      utf8_bytes.push((unicode_code & 0x3F) | 0x80);
    } else if (unicode_code < (1 << 21)) {  // 4-byte
      utf8_bytes.push((unicode_code >>> 18) | 0xF0);
      utf8_bytes.push(((unicode_code >> 12) & 0x3F) | 0x80);
      utf8_bytes.push(((unicode_code >> 6) & 0x3F) | 0x80);
      utf8_bytes.push((unicode_code & 0x3F) | 0x80);
    }
    return utf8_bytes;
  }
  // "あい" => [ 0x3042,  0x3044 ]
  function convertStringToUnicodeCodePoints(str) {
    var surrogate_1st = 0;
    var unicode_codes = [];
    for (var i = 0; i < str.length; ++i) {
      var utf16_code = str.charCodeAt(i);
      if (surrogate_1st != 0) {
        if (utf16_code >= 0xDC00 && utf16_code <= 0xDFFF) {
          var surrogate_2nd = utf16_code;
          var unicode_code = (surrogate_1st - 0xD800) * (1 << 10) + (1 << 16) +
                             (surrogate_2nd - 0xDC00);
          unicode_codes.push(unicode_code);
        } else {
          // Malformed surrogate pair ignored.
        }
        surrogate_1st = 0;
      } else if (utf16_code >= 0xD800 && utf16_code <= 0xDBFF) {
        surrogate_1st = utf16_code;
      } else {
        unicode_codes.push(utf16_code);
      }
    }
    return unicode_codes;
  }
  // 0xff => "ff"
  // 0xff => "377"
  function formatNumber(number, base, num_digits) {
    var str = number.toString(base).toUpperCase();
    for (var i = str.length; i < num_digits; ++i) {
      str = "0" + str;
    }
    return str;
  }

  // convert \xFF\xFF\xFF to unicode
  function unescapeFromEscapedBytes (str) {
    var data_bytes = convertEscapedBytesToBytes(str);
    var unicode_codes = convertUtf8BytesToUnicodeCodePoints(data_bytes);
    return convertUnicodeCodePointsToString(unicode_codes);
  }
  // r'\xE3\x81\x82\xE3\x81\x84' => [ 0xE3, 0x81, 0x82, 0xE3, 0x81, 0x84 ]
  // r'\343\201\202\343\201\204' => [ 0343, 0201, 0202, 0343, 0201, 0204 ]
  function convertEscapedBytesToBytes(str) {
    var parts = str.split("\\x");
    parts.shift();  // Trim the first element.
    var codes = [];
    var max = Math.pow(2, 8);
    for (var i = 0; i < parts.length; ++i) {
      var code = parseInt(parts[i], 16);
      if (code >= 0 && code < max) {
        codes.push(code);
      } else {
        // Malformed code ignored.
      }
    }
    return codes;
  }
  // [ 0xE3, 0x81, 0x82, 0xE3, 0x81, 0x84 ] => [ 0x3042, 0x3044 ]
  function convertUtf8BytesToUnicodeCodePoints(utf8_bytes) {
    var unicode_codes = [];
    var unicode_code = 0;
    var num_followed = 0;
    for (var i = 0; i < utf8_bytes.length; ++i) {
      var utf8_byte = utf8_bytes[i];
      if (utf8_byte >= 0x100) {
        // Malformed utf8 byte ignored.
      } else if ((utf8_byte & 0xC0) == 0x80) {
        if (num_followed > 0) {
          unicode_code = (unicode_code << 6) | (utf8_byte & 0x3f);
          num_followed -= 1;
        } else {
          // Malformed UTF-8 sequence ignored.
        }
      } else {
        if (num_followed == 0) {
          unicode_codes.push(unicode_code);
        } else {
          // Malformed UTF-8 sequence ignored.
        }
        if (utf8_byte < 0x80){  // 1-byte
          unicode_code = utf8_byte;
          num_followed = 0;
        } else if ((utf8_byte & 0xE0) == 0xC0) {  // 2-byte
          unicode_code = utf8_byte & 0x1f;
          num_followed = 1;
        } else if ((utf8_byte & 0xF0) == 0xE0) {  // 3-byte
          unicode_code = utf8_byte & 0x0f;
          num_followed = 2;
        } else if ((utf8_byte & 0xF8) == 0xF0) {  // 4-byte
          unicode_code = utf8_byte & 0x07;
          num_followed = 3;
        } else {
          // Malformed UTF-8 sequence ignored.
        }
      }
    }
    if (num_followed == 0) {
      unicode_codes.push(unicode_code);
    } else {
      // Malformed UTF-8 sequence ignored.
    }
    unicode_codes.shift();  // Trim the first element.
    return unicode_codes;
  }
  // [ 0x3042, 0x3044 ] => [ 0x3042, 0x3044 ]
  // [ 0xD840, 0xDC0B ] => [ 0x2000B ]  // A surrogate pair.
  function convertUnicodeCodePointsToUtf16Codes(unicode_codes) {
    var utf16_codes = [];
    for (var i = 0; i < unicode_codes.length; ++i) {
      var unicode_code = unicode_codes[i];
      if (unicode_code < (1 << 16)) {
        utf16_codes.push(unicode_code);
      } else {
        var first = ((unicode_code - (1 << 16)) / (1 << 10)) + 0xD800;
        var second = (unicode_code % (1 << 10)) + 0xDC00;
        utf16_codes.push(first)
        utf16_codes.push(second)
      }
    }
    return utf16_codes;
  }
  // [ 0x3042, 0x3044 ] => "あい"
  function convertUnicodeCodePointsToString(unicode_codes) {
    var utf16_codes = convertUnicodeCodePointsToUtf16Codes(unicode_codes);
    return convertUtf16CodesToString(utf16_codes);
  }
  // [ 0x3042, 0x3044 ] => "あい"
  function convertUtf16CodesToString(utf16_codes) {
    var unescaped = '';
    for (var i = 0; i < utf16_codes.length; ++i) {
      unescaped += String.fromCharCode(utf16_codes[i]);
    }
    return unescaped;
  }

  return {
    raw: UNICODE_BLOCK_LIST,
    lookup: UNICODE_LOOKUP,
    index: index,
    range: range,
    block: block,
    findGroups: findGroups,
    paginate: paginate,
    escapeToEscapedBytes: escapeToEscapedBytes,
    unescapeFromEscapedBytes: unescapeFromEscapedBytes,
  }
})()