Base64 Encode

annotated.js

function base64Encode(
    a, // string to encode
    b, // character table ie, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
    c, // placeholder
    d, // placeholder
    e, // placeholder
    f, // placeholder
    g, // placeholder
    h  // placeholder
){
    h="";
    for(d=0; // initialise the output buffer
        a[d]; // check if a value is returned
        h+=b[e>>2]+b[e<<4&63|f>>4]+b[f<<2&63|g>>6||64]+b[g&63||64]) // split into 6bits characters and find it in our character table

        for(c=4;c<7;)
            arguments[c++]=a.charCodeAt(d++) // copy the character code into a variable declared as a placeholder

    return h
}

index.js

function(a,b,c,d,e,f,g,h){h="";for(d=0;a[d];h+=b[e>>2]+b[e<<4&63|f>>4]+b[f<<2&63|g>>6||64]+b[g&63||64])for(c=4;c<7;)arguments[c++]=a.charCodeAt(d++);return h}

LICENSE.txt

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

 Copyright (C) 2011 Rob Griffiths http://bytespider.eu

 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": "Base64 Encode",
  "keywords": [
    "140bytes",
    "base64",
    "encode" 
  ]
}

I really don't know much about encoding strings and stuff, so you tell me if I'm doing something wrong, but...

Comparing to Base64 module for Ruby - http://ruby-doc.org/stdlib-1.9.3/libdoc/base64/rdoc/Base64.html - it gives something very different.

Here's my test:

function base64_encode(a, b, c, d, e, f, g, h) {
  b = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
  h = '';

  for(d = 0; a[d]; h += b[e >> 2] + b[e << 4 & 63 | f >> 4] + b[f << 2 & 63 | g >> 6 || 64 ] + b[g & 63 || 64]) {
    for(c = 4; c < 7;) {
      arguments[c++] = a.charCodeAt(d++);
    }    
  }

  return h;
}

console.log(base64_encode('123')); //=> AA==

And in Ruby 1.9.3:

require 'base64'; puts Base64.encode64('123') #=> MTIz\n

Note that I prepended the suggest character map into the function.

Correct it should be MTIz My implementation breaks because somewhere an undefined isnt being cast to 0. Ie this works
base64Encode("123", "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=", "", "", "", "", "", "");