var base64_key = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
				 "abcdefghijklmnopqrstuvwxyz" +
				 "0123456789+/=";

function base64_encode(input) {
	var result = "";
	var expanded_input = "";
	var i;
	// 8 bit bytes
	var chr1, chr2, chr3
	// 6-bit encoded chars
	var enc1, enc2, enc3, enc4;
	
	// break up multi-byte characters
	for (i = 0; i < input.length; i++) {
		var c = input.charCodeAt(i);
		
		// single byte
		if (c < 0x80){
			expanded_input += String.fromCharCode(c);
		}
		// 2 bytes
		else if (c < 0x800) {
			expanded_input += String.fromCharCode((c >> 6) | 0xC0);
			expanded_input += String.fromCharCode((c & 0x3F) | 0x80);
		}
		// 3 bytes
		else {
			expanded_input += String.fromCharCode((c >> 0xC) | 0xE0);
			expanded_input += String.fromCharCode(((c >> 0x6) & 0x3F) | 0x80);
			expanded_input += String.fromCharCode((c & 0x3F) | 0x80);
		}
	}
	
	// encode each set of 3 bytes to 4 6-bit values 
	i = 0;
	while (i < expanded_input.length) {
		 
		chr1 = expanded_input.charCodeAt(i++);
		chr2 = expanded_input.charCodeAt(i++);
		chr3 = expanded_input.charCodeAt(i++);

		enc1 = chr1 >> 2;
		enc2 = ((chr1 & 0x3) << 4) | (chr2 >> 4);
		enc3 = ((chr2 & 0xF) << 2) | (chr3 >> 6);
		enc4 = chr3 & 63;

		// pad end chars
		if (isNaN(chr2)) {
			enc3 = enc4 = 64;
		} else if (isNaN(chr3)) {
			enc4 = 64;
		}

		result = result +
		base64_key.charAt(enc1) + base64_key.charAt(enc2) +
		base64_key.charAt(enc3) + base64_key.charAt(enc4);

	}

	return result;
	
}

function base64_decode(input) {
	var result = "";
	var expanded_output = "";
	// 8 bit bytes
	var chr1, chr2, chr3
	// 6-bit encoded chars
	var enc1, enc2, enc3, enc4;
	var i = 0;

	input = input.replace(/[^A-Za-z0-9+/=]/g, "");

	
	while (i < input.length) {

		enc1 = base64_key.indexOf(input.charAt(i++));
		enc2 = base64_key.indexOf(input.charAt(i++));
		enc3 = base64_key.indexOf(input.charAt(i++));
		enc4 = base64_key.indexOf(input.charAt(i++));

		chr1 = (enc1 << 2) | (enc2 >> 4);
		chr2 = ((enc2 & 0xF) << 4) | (enc3 >> 2);
		chr3 = ((enc3 & 0x3) << 6) | enc4;

		expanded_output += String.fromCharCode(chr1);

		if (enc3 != 64) {
			expanded_output += String.fromCharCode(chr2);
		}
		if (enc4 != 64) {
			expanded_output += String.fromCharCode(chr3);
		}

	}

	// combine multi-byte characters
	i = 0;
	while ( i < expanded_output.length ) {
		 
		chr1 = expanded_output.charCodeAt(i);

		// single byte
		if (chr1 < 0xC0) {
			result += String.fromCharCode(chr1);
			i++;
		}
		// 2 bytes
		else if (chr1 < 0xE0) {
			chr2 = expanded_output.charCodeAt(i+1);
			result += String.fromCharCode(((chr1 & 0x1F) << 6) | (chr2 & 0x3F));
			i += 2;
		}
		// 3 bytes
		else {
			chr2 = expanded_output.charCodeAt(i+1);
			chr3 = expanded_output.charCodeAt(i+2);
			result += String.fromCharCode(((chr1 & 0xF) << 12) | ((chr2 & 0x3F) << 6) | (chr3 & 0x3F));
			i += 3;
		}

	}

	return result;

}