percentEncode.js : RFC3986 規定のパーセントエンコーディング

percentEncode.js

/**
 * percentEncode.js
 *
 * @version 0.9.2
 * @author think49
 * @url https://gist.github.com/805428
 */


var percentEncode = (function () {

  // decimal number to hex number
  function decimalToHex (number) {
    var positiveNumber, result, map, tmp, floor;

    number = +number;

    if (isNaN(number)) {
      return number;
    }

    floor = Math.floor;
    positiveNumber = number < 0 ? -1 : 1;
    number *= positiveNumber;
    map = {10: 'A', 11: 'B', 12: 'C', 13: 'D', 14: 'E', 15: 'F'};
    result = [];

    do {
      tmp = number % 16;
      result.unshift(map.hasOwnProperty(tmp) ? map[tmp]: tmp);
      number = floor(number / 16);
    } while (number > 0);

    result = result.join('');

    return positiveNumber ? result : '-' + result;
  }

  // Percent-Encoding (RFC3986-2.1 Percent-Encoding)
  function percentEncode (string) {
    var fromCharCode = String.fromCharCode;

    // If target character is not a "Unreserved Character", Percent-Encode the target character. (RFC3986-2.3: http://www.studyinghttp.net/rfc_ja/rfc3986#Sec2.3 )
    return (string + '').replace(/[^a-zA-Z\d-._~]/g, function (token) {
      var hex, result, reg, match, error;

      hex = decimalToHex(token.charCodeAt(0));

      if (typeof hex !== 'string') {
        throw new TypeError(hex + ' is not a String');
      }

      if (hex.length % 2 !== 0) {
        hex = '0' + hex;
      }

      if (!/^(?:[\da-fA-F]{2})+$/.test(hex)) {
        throw new Error('not well-formed hex characters\r\n"' + hex + '"');
      }

      reg = /[\da-fA-F]{2}/g;
      result = [];

      do {
        match = reg.exec(hex);
        if (match) {
          result.push('%' + match[0]);
        }
      } while (match);

/*
      console.log(hex);
      console.log(result);
*/
      if (hex.length / 2 !== result.length) {
        throw new Error('not well-formed Percent-Encoding Characters\r\n[' + result.join(', ') + ']');
      }

      return result.join('');
    });
  }

  return percentEncode;
})();