a base64 adaptation for use with node.js

base64.js

/* adapted by Jed Schmidt for use as a node.js module */
 
this.encode = base64encode;
this.decode = base64decode;
this.chars = function( string ) {
  base64EncodeChars = string || "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  base64DecodeChars = [];

  for ( var i = 128; i--; ) {
    if ( base64DecodeChars[ i ] === undefined )
      base64DecodeChars[ i ] = -1;
  
    base64DecodeChars[ base64EncodeChars.charCodeAt( i ) ] = i;
  }

  return this;

};

this.chars();

/* Copyright (C) 1999 Masanao Izumo <iz@onicos.co.jp>
 * Version: 1.0
 * LastModified: Dec 25 1999
 * This library is free.  You can redistribute it and/or modify it.
 */

function base64encode( str ) {
    var out, i, len;
    var c1, c2, c3;

    len = str.length;
    i = 0;
    out = "";
    while(i < len) {
	c1 = str.charCodeAt(i++) & 0xff;
	if(i == len)
	{
	    out += base64EncodeChars.charAt(c1 >> 2);
	    out += base64EncodeChars.charAt((c1 & 0x3) << 4);
	    out += "==";
	    break;
	}
	c2 = str.charCodeAt(i++);
	if(i == len)
	{
	    out += base64EncodeChars.charAt(c1 >> 2);
	    out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
	    out += base64EncodeChars.charAt((c2 & 0xF) << 2);
	    out += "=";
	    break;
	}
	c3 = str.charCodeAt(i++);
	out += base64EncodeChars.charAt(c1 >> 2);
	out += base64EncodeChars.charAt(((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4));
	out += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6));
	out += base64EncodeChars.charAt(c3 & 0x3F);
    }
    return out;
}

function base64decode( str ) {
    var c1, c2, c3, c4;
    var i, len, out;

    len = str.length;
    i = 0;
    out = "";
    while(i < len) {
	/* c1 */
	do {
	    c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
	} while(i < len && c1 == -1);
	if(c1 == -1)
	    break;

	/* c2 */
	do {
	    c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff];
	} while(i < len && c2 == -1);
	if(c2 == -1)
	    break;

	out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

	/* c3 */
	do {
	    c3 = str.charCodeAt(i++) & 0xff;
	    if(c3 == 61)
		return out;
	    c3 = base64DecodeChars[c3];
	} while(i < len && c3 == -1);
	if(c3 == -1)
	    break;

	out += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));

	/* c4 */
	do {
	    c4 = str.charCodeAt(i++) & 0xff;
	    if(c4 == 61)
		return out;
	    c4 = base64DecodeChars[c4];
	} while(i < len && c4 == -1);
	if(c4 == -1)
	    break;
	out += String.fromCharCode(((c3 & 0x03) << 6) | c4);
    }
    return out;
}