Nodejs String from Ascii85 fromAscii85()

Method Source Code

String.prototype.fromAscii85 = function() {
  var ret = "";
  var str = this.replace(/\s+/g, "").replace("z", "!!!!!").slice(2, -2);
  for(var i=0; i<str.length; i+=5){
    var deficit = Math.max(0, 5+i-str.length);
    var nnn = 0;/* w w w  . j av a 2 s .c  o  m*/
    for(var j=0; j<5; j++){
      nnn = nnn*85 + (str.charCodeAt(i+j) || 117) - 33;
    }
    var codes = [];
    for(var j=0; j<4; j++){
      codes.push(nnn%256);
      nnn = nnn/256 | 0;
    }
    codes.reverse();
    var chunk = String.fromCharCode.apply(undefined, codes).slice(0, 4-deficit);
    ret+= chunk;
  }
  return ret;
}

Related

1. fromAscii85()

   String.prototype.fromAscii85 = function() {
     var str = this.slice(2, -2).replace(/\s/g, ''), result = ''
     while (str.length) {
       if (str[0] == 'z') {
         result += '\u0000\u0000\u0000\u0000'
         str = str.substr(1)
       } else {
         let num = 0, j = 5, i = 4
         while (j--) {
   ...
   

2. fromAscii85()

   String.prototype.fromAscii85 = function() {
     var str = this.slice(2, -2).replace(/z/g, '!!!!!').replace(/\s/g, '');
     var decoded = '';
     for(var i = 0, len = str.length; i < len; i+=5) {
       var n = 0;
       var us = 0;
       for(var j = 4; j >= 0; j--) {
         var c = str[j+i] || (us++, 'u'),
             code = c.charCodeAt(0) - 33;
   ...
   

3. fromAscii85()

   String.prototype.fromAscii85 = function() {
       console.log(this)
       let pad = 'u', addnum = 0, s = this.substring(2, this.length - 2).replace(/\s/g, ''), str = '', res = '';
       for (let i = 0; i < s.length; i++)
           str += s[i] === 'z' ? '!!!!!' : s[i];
       while (str.length % 5 !== 0)
           str += pad;
           addnum ++;
   ...