var b64map="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
var b64pad="=";

function hex2b64(h) {
	var i;
	var c;
	var ret = "";
	for(i = 0; i+3 <= h.length; i+=3) {
		c = parseInt(h.substring(i,i+3),16);
		ret += b64map.charAt(c >> 6) + b64map.charAt(c & 63);
	}
	if(i+1 == h.length) {
		c = parseInt(h.substring(i,i+1),16);
		ret += b64map.charAt(c << 2);
	}
	else if(i+2 == h.length) {
		c = parseInt(h.substring(i,i+2),16);
		ret += b64map.charAt(c >> 2) + b64map.charAt((c & 3) << 4);
	}
	while((ret.length & 3) > 0) ret += b64pad;
	return ret;
}

// convert a base64 string to hex
function b64tohex(s) {
	var ret = "";
	var i;
	var k = 0; // b64 state, 0-3
	var slop;
	for(i = 0; i < s.length; ++i) {
		if(s.charAt(i) == b64pad) break;
		v = b64map.indexOf(s.charAt(i));
		if(v < 0) continue;
		if(k == 0) {
			ret += int2char(v >> 2);
			slop = v & 3;
			k = 1;
		}
		else if(k == 1) {
			ret += int2char((slop << 2) | (v >> 4));
			slop = v & 0xf;
			k = 2;
		}
		else if(k == 2) {
			ret += int2char(slop);
			ret += int2char(v >> 2);
			slop = v & 3;
			k = 3;
		}
		else {
			ret += int2char((slop << 2) | (v >> 4));
			ret += int2char(v & 0xf);
			k = 0;
		}
	}
	if(k == 1)
		ret += int2char(slop << 2);
	return ret;
}

// convert a base64 string to a byte/number array
function b64toBA(s) {
	//piggyback on b64tohex for now, optimize later
	var h = b64tohex(s);
	var i;
	var a = new Array();
	for(i = 0; 2*i < h.length; ++i) {
		a[i] = parseInt(h.substring(2*i,2*i+2),16);
	}
	return a;
}