var ky = 'izyoption';
var ch = 'check';
var characters = '1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxz';

function sk(k){
    if(k) ky = k;
    characters = characters.replace(ky.split(''),'');
}

function e(s){
    s += ch;
    var l = s.length;
    var et = new Array();

    for(var i=0;i<l;i++){
        var eh = s[i];
        var vl = eh.charCodeAt(0);
        et.push(flgh(eh,vl));
    }
    return trim(et.join(""),ky);
}

function d(s){
    var k = ky;
    s = s.replace(k.split(''),'-');
    s = s.split('-');
    var t_c = s.length;
    var a_w = new Array();
    for(var i=0;i<t_c;i++){
        a_w.push(flChkh(s[i]));
    }
    s = a_w.join("");
    var p = s.indexOf(ch);
    if(!p || p<0){
        return '';
    }else{
        return s.substr(0, - ch.length);
    }
}

function flgh(t,v){
    var s = ky;
    var kyl = s.length - 1;
    var ltl = characters.length - 1;
    var sm = 0;
    var ov = new Array();
    var cv = new Array();
    while(true){
        if(sm > v){
            ov.pop();
            cv.pop();
            var fval = v - ov.sum();
            ov.push(fval);
            cv.push(characters[fval]);
            return cv.join("") + s[mt_rand(0,kyl)];
        }else{
            var ra = mt_rand(0,ltl);
            ov.push(ra);
            var ratx = characters[ra];
            cv.push(ratx);
            sm = ov.sum();
        }
    }
}

function flChkh(w){
    var al = characters;
    var ntr = new Array();
    var c = w.length;
    for(var i=0;i<c;i++){
        ntr.push(al.indexOf(w[i]));
    }
    return String.fromCharCode(ntr.sum());
}

Array.prototype.sum = function(selector) {
    if (typeof selector !== 'function') {
        selector = function(item) {
            return item;
        }
    }
    var sum = 0;
    for (var i = 0; i < this.length; i++) {
        sum += parseFloat(selector(this[i]));
    }
    return sum;
};

function mt_rand(min, max) {
    var argc = arguments.length;
    if (argc === 0) {
        min = 0;
        max = 2147483647;
    }else if(argc === 1){
        throw new Error('Warning: mt_rand() expects exactly 2 parameters, 1 given');
    }else{
        min = parseInt(min, 10);
        max = parseInt(max, 10);
    }
    return Math.floor(Math.random() * (max - min + 1)) + min;
}

function trim(str, charlist) {
  //  discuss at: http://phpjs.org/functions/trim/
  // original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // improved by: mdsjack (http://www.mdsjack.bo.it)
  // improved by: Alexander Ermolaev (http://snippets.dzone.com/user/AlexanderErmolaev)
  // improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // improved by: Steven Levithan (http://blog.stevenlevithan.com)
  // improved by: Jack
  //    input by: Erkekjetter
  //    input by: DxGx
  // bugfixed by: Onno Marsman
  //   example 1: trim('    Kevin van Zonneveld    ');
  //   returns 1: 'Kevin van Zonneveld'
  //   example 2: trim('Hello World', 'Hdle');
  //   returns 2: 'o Wor'
  //   example 3: trim(16, 1);
  //   returns 3: 6
  var whitespace, l = 0,
    i = 0;
  str += '';

  if (!charlist) {
    // default list
    whitespace =
      ' \n\r\t\f\x0b\xa0\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u2028\u2029\u3000';
  } else {
    // preg_quote custom list
    charlist += '';
    whitespace = charlist.replace(/([\[\]\(\)\.\?\/\*\{\}\+\$\^\:])/g, '$1');
  }

  l = str.length;
  for (i = 0; i < l; i++) {
    if (whitespace.indexOf(str.charAt(i)) === -1) {
      str = str.substring(i);
      break;
    }
  }

  l = str.length;
  for (i = l - 1; i >= 0; i--) {
    if (whitespace.indexOf(str.charAt(i)) === -1) {
      str = str.substring(0, i + 1);
      break;
    }
  }
  return whitespace.indexOf(str.charAt(0)) === -1 ? str : '';
}