/*
 * $Id: base64.js,v 0.2 2008/06/18 08:01:50 dankogai Exp dankogai $
 */

(function(){

var b64chars 
	= 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
var b64tab = function(bin){
	var t = {};
	for (var i = 0, l = bin.length; i < l; i++) t[bin.charAt(i)] = i;
	return t;
}(b64chars);

var toBase64 = function(bin){
	if (bin.match(/[^\x00-\xFF]/)) throw 'unsupported character found' ;
	var padlen = 0;
	while(bin.length % 3) {
		bin += '\0';
		padlen++;
	};
	var b64 = '';
	for (var i = 0, l = bin.length; i < l; i += 3){
		var n = (bin.charCodeAt(i)	<< 16)
			  | (bin.charCodeAt(i+1) << 8)
			  | (bin.charCodeAt(i+2));
		b64 += b64chars.charAt( n >>> 18)
			 + b64chars.charAt((n >>> 12) & 63)
			 + b64chars.charAt((n >>>  6) & 63)
			 + b64chars.charAt( n		  & 63);
	}
	if (!padlen) return b64;
	b64 = b64.substr(0, b64.length - padlen);
	while(padlen--) b64 += '=';
	return b64;
};

var btoa = window.btoa || toBase64;

var fromBase64 = function(b64){
	b64 = b64.replace(/[^A-Za-z0-9\+\/]/g, '');
	var bin = '';
	var padlen = 0;
	while(b64.length % 4){
		b64 += 'A';
		padlen++;
	}
	for (var i = 0, l = b64.length; i < l; i += 4){
		var n = (b64tab[b64.charAt(i  )] << 18)
			|	(b64tab[b64.charAt(i+1)] << 12)
			|	(b64tab[b64.charAt(i+2)] <<	 6)
			|	(b64tab[b64.charAt(i+3)]);
		bin += String.fromCharCode(	 n >> 16 )
			+  String.fromCharCode( (n >>  8) & 0xff )
			+  String.fromCharCode(	 n		  & 0xff );
	}
	bin.length -= [0,0,2,1][padlen];
	return bin;
};

var atob = window.atob || fromBase64;

var utob = function(uni){
	var bin = '';
	for (var i = 0, l = uni.length; i < l; i++){
		var n = uni.charCodeAt(i);
		bin += n < 0x80	 ? uni.charAt(i)
			:  n < 0x800 ? String.fromCharCode(0xc0 | (n >>>  6))
						 + String.fromCharCode(0x80 | (n & 0x3f))
			:			   String.fromCharCode(0xe0 | ((n >>> 12) & 0x0f))
						 + String.fromCharCode(0x80 | ((n >>>  6) & 0x3f))
						 + String.fromCharCode(0x80 |  (n		  & 0x3f))
			;
	}
	return bin;
};

var btou = function(bin){
	var uni = '';
	for (var i = 0, l = bin.length; i < l; i++){
		var c0 = bin.charCodeAt(i);
		if	  (c0 < 0x80){
			uni += bin.charAt(i)
		}else{
			var c1 = bin.charCodeAt(++i);
			if(c0 < 0xe0){
				uni += String.fromCharCode(((c0 & 0x1f) << 6) | (c1 & 0x3f));
			}else{
				var c2 = bin.charCodeAt(++i);
				uni += String.fromCharCode(
					   ((c0 & 0x0f) << 12) | ((c1 & 0x3f) <<  6) | (c2 & 0x3f)
				);
			}
		}
	}
	return uni;
}

try{
	eval('Base64')
}catch(e){
	Base64 = {
		fromBase64:fromBase64,
		toBase64:toBase64,
		atob:atob,
		btoa:btoa,
		utob:utob,
		btou:btou,
		encode:function(u){ return btoa(utob(u)) },
		encodeURI:function(u){
			return btoa(utob(u)).replace(/[+\/]/g, function(m0){
				return m0 == '+' ? '-' : '_';
			}).replace(/=+$/, '');
		},
		decode:function(a){ 
			return btou(atob(a.replace(/[-_]/g, function(m0){
				return m0 == '-' ? '+' : '/';
			})));
		}
	};
}

})();