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node_modules/mdurl/decode.js 2.81 KB
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  'use strict';
  
  
  /* eslint-disable no-bitwise */
  
  var decodeCache = {};
  
  function getDecodeCache(exclude) {
    var i, ch, cache = decodeCache[exclude];
    if (cache) { return cache; }
  
    cache = decodeCache[exclude] = [];
  
    for (i = 0; i < 128; i++) {
      ch = String.fromCharCode(i);
      cache.push(ch);
    }
  
    for (i = 0; i < exclude.length; i++) {
      ch = exclude.charCodeAt(i);
      cache[ch] = '%' + ('0' + ch.toString(16).toUpperCase()).slice(-2);
    }
  
    return cache;
  }
  
  
  // Decode percent-encoded string.
  //
  function decode(string, exclude) {
    var cache;
  
    if (typeof exclude !== 'string') {
      exclude = decode.defaultChars;
    }
  
    cache = getDecodeCache(exclude);
  
    return string.replace(/(%[a-f0-9]{2})+/gi, function(seq) {
      var i, l, b1, b2, b3, b4, chr,
          result = '';
  
      for (i = 0, l = seq.length; i < l; i += 3) {
        b1 = parseInt(seq.slice(i + 1, i + 3), 16);
  
        if (b1 < 0x80) {
          result += cache[b1];
          continue;
        }
  
        if ((b1 & 0xE0) === 0xC0 && (i + 3 < l)) {
          // 110xxxxx 10xxxxxx
          b2 = parseInt(seq.slice(i + 4, i + 6), 16);
  
          if ((b2 & 0xC0) === 0x80) {
            chr = ((b1 << 6) & 0x7C0) | (b2 & 0x3F);
  
            if (chr < 0x80) {
              result += '\ufffd\ufffd';
            } else {
              result += String.fromCharCode(chr);
            }
  
            i += 3;
            continue;
          }
        }
  
        if ((b1 & 0xF0) === 0xE0 && (i + 6 < l)) {
          // 1110xxxx 10xxxxxx 10xxxxxx
          b2 = parseInt(seq.slice(i + 4, i + 6), 16);
          b3 = parseInt(seq.slice(i + 7, i + 9), 16);
  
          if ((b2 & 0xC0) === 0x80 && (b3 & 0xC0) === 0x80) {
            chr = ((b1 << 12) & 0xF000) | ((b2 << 6) & 0xFC0) | (b3 & 0x3F);
  
            if (chr < 0x800 || (chr >= 0xD800 && chr <= 0xDFFF)) {
              result += '\ufffd\ufffd\ufffd';
            } else {
              result += String.fromCharCode(chr);
            }
  
            i += 6;
            continue;
          }
        }
  
        if ((b1 & 0xF8) === 0xF0 && (i + 9 < l)) {
          // 111110xx 10xxxxxx 10xxxxxx 10xxxxxx
          b2 = parseInt(seq.slice(i + 4, i + 6), 16);
          b3 = parseInt(seq.slice(i + 7, i + 9), 16);
          b4 = parseInt(seq.slice(i + 10, i + 12), 16);
  
          if ((b2 & 0xC0) === 0x80 && (b3 & 0xC0) === 0x80 && (b4 & 0xC0) === 0x80) {
            chr = ((b1 << 18) & 0x1C0000) | ((b2 << 12) & 0x3F000) | ((b3 << 6) & 0xFC0) | (b4 & 0x3F);
  
            if (chr < 0x10000 || chr > 0x10FFFF) {
              result += '\ufffd\ufffd\ufffd\ufffd';
            } else {
              chr -= 0x10000;
              result += String.fromCharCode(0xD800 + (chr >> 10), 0xDC00 + (chr & 0x3FF));
            }
  
            i += 9;
            continue;
          }
        }
  
        result += '\ufffd';
      }
  
      return result;
    });
  }
  
  
  decode.defaultChars   = ';/?:@&=+$,#';
  decode.componentChars = '';
  
  
  module.exports = decode;