/*
 ======================================================================
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE PRODUCER OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.

THE PRODUCER:
Andreas Imhof
EDV-Dienstleistungen
CH-Guemligen, Switzerland
www.aiedv.ch

CREATED: 2006
Version: 1.0
Version date: 20061125
======================================================================

Base64 encoder and decoder

This code is derived (copied) from Adrian Bacon's code

*/
//First things first, set up our array that we are going to use.
var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + //all caps
			"abcdefghijklmnopqrstuvwxyz" + //all lowercase
			"0123456789+/="; // all numbers plus +/=

//Heres the encode function
function encode64(inp) {
	var out = ""; //This is the output
	var chr1, chr2, chr3 = ""; //These are the 3 bytes to be encoded
	var enc1, enc2, enc3, enc4 = ""; //These are the 4 encoded bytes
	var i = 0; //Position counter
	
	do { //Set up the loop here
		chr1 = inp.charCodeAt(i++); //Grab the first byte
		chr2 = inp.charCodeAt(i++); //Grab the second byte
		chr3 = inp.charCodeAt(i++); //Grab the third byte
		
		//Here is the actual base64 encode part.
		//There really is only one way to do it.
		enc1 = chr1 >> 2;
		enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
		enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
		enc4 = chr3 & 63;
		
		if (isNaN(chr2)) {
			enc3 = enc4 = 64;
		} else if (isNaN(chr3)) {
			enc4 = 64;
		}
		
		//Lets spit out the 4 encoded bytes
		out = out + keyStr.charAt(enc1) + keyStr.charAt(enc2) + keyStr.charAt(enc3) +
		keyStr.charAt(enc4);
		
		// OK, now clean out the variables used.
		chr1 = chr2 = chr3 = "";
		enc1 = enc2 = enc3 = enc4 = "";
	
	} while (i < inp.length); //And finish off the loop
	
	//Now return the encoded values.
	return out;
}

//Heres the decode function
function decode64(inp) {
	var out = ""; //This is the output
	var chr1, chr2, chr3 = ""; //These are the 3 decoded bytes
	var enc1, enc2, enc3, enc4 = ""; //These are the 4 bytes to be decoded
	var i = 0; //Position counter
	
	// remove all characters that are not A-Z, a-z, 0-9, +, /, or =
	var base64test = /[^A-Za-z0-9\+\/\=]/g;
	
	if (base64test.exec(inp)) { //Do some error checking
		alert("There were invalid base64 characters in the input text.\n" +
		"Valid base64 characters are A-Z, a-z, 0-9, ?+?, ?/?, and ?=?\n" +
		"Expect errors in decoding.");
	}
	inp = inp.replace(/[^A-Za-z0-9\+\/\=]/g, "");
	
	do { //HereÕs the decode loop.
		
		//Grab 4 bytes of encoded content.
		enc1 = keyStr.indexOf(inp.charAt(i++));
		enc2 = keyStr.indexOf(inp.charAt(i++));
		enc3 = keyStr.indexOf(inp.charAt(i++));
		enc4 = keyStr.indexOf(inp.charAt(i++));
		
		//Heres the decode part. ThereÕs really only one way to do it.
		chr1 = (enc1 << 2) | (enc2 >> 4);
		chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
		chr3 = ((enc3 & 3) << 6) | enc4;
		
		//Start to output decoded content
		out = out + String.fromCharCode(chr1);
		
		if (enc3 != 64) {
			out = out + String.fromCharCode(chr2);
		}
		if (enc4 != 64) {
			out = out + String.fromCharCode(chr3);
		}
		
		//now clean out the variables used
		chr1 = chr2 = chr3 = "";
		enc1 = enc2 = enc3 = enc4 = "";
	
	} while (i < inp.length); //finish off the loop
	
	//Now return the decoded values.
	return out;
}