140byt.es - Base64 encoder

README.md

140byt.es - Base64 Encoder

A simple base64 encoder. Simply pass your string and a reference to the function to get back the encoded string.

Example

var 
  map ="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
  sample = "140bytes rocks!",
  encoded = base64Encode(sample, map);

Acknowledgment

Artur Honzawa @arturhonzawa hacked the main code and further compression was done by me (@aemkei). Thanks to Rob Griffiths @bytespider and Jed Schmidt @jedschmidt for some pretty good hints!

Issues

• Proper "=" padding does not work
• IE's JScript fails with the RegExp
• Doesn't encode null bytes

Feel free to fork and improve!

annotated.js

var base64Encode = function(
  a, // input string
  b, // map string
  c, // placeholder
  d, // placeholder
  e, // placeholder
  f, // placeholder
  g // placeholder
){

  for(
    g = c = e = "";
    (d = a.charCodeAt(g)) && 
    (c += /.{8}$/(
      1e7 + // make sure leading zeroes are there
      d.toString(2) // convert to binary
    )),
    f = c.substr(g++ * 6, 6); // pick bits in groups of 6
  ) e += b[parseInt(f, 2)]; // build result string

  return e
}

index.js

function(a,b,c,d,e,f,g){for(g=c=e="";(d=a.charCodeAt(g))&&(c+=/.{8}$/(1e7+d.toString(2))),f=c.substr(g++*6,6);)e+=b[parseInt(f,2)];return e}

LICENSE.txt

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2011 YOUR_NAME_HERE <YOUR_URL_HERE>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

package.json

{

  "name": "Base64Encoder",

  "description": "A JavaScript Base64 encoder in 140 Bytes.",

  "contributors": [
    { 
      "name" : "Artur Honzawa", 
      "url" : "https://github.com/arturh"
    },
    { 
      "name" : "Martin Kleppe", 
      "url" : "https://github.com/aemkei"
    }
  ],

  "keywords": [
    "base64",
    "encode"
  ]
}

Some ideas and notes:

• You can use base-4 (toString(4) and parseInt(f,4)) instead of base-2. This does not save a byte but saves memory.
• f can be omitted. Reuse d instead.
• Is /.../(...) a shortcut for /.../.exec(...)? This does not work in any of my browsers (Firefox, Opera, IE8).

Here is the shortest working version I found:

function(a,b,c,d,e,f){for(f=c=e="";(d=a.charCodeAt(f))&&(c+=(256+d).toString(4).slice(-4)),d=c.substr(f++*3,3);)e+=b[parseInt(d,4)];return e}

See @nignag's version with correct padding: the https://gist.github.com/999166 - It is 110 bytes only!