Dynastie/dynastie/sites/blog.soutade.fr/js/base64.js

/**
 *
 *  Base64 encode / decode
 *  http://www.webtoolkit.info/
 *
 **/

var Base64 = {
    
    // private property
    _keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
    
    // public method for encoding
    encode : function (input) {
	var output = "";
	var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
	var i = 0;
	
	input = Base64._utf8_encode(input);
	
	while (i < input.length) {
	    
	    chr1 = input.charCodeAt(i++);
	    chr2 = input.charCodeAt(i++);
	    chr3 = input.charCodeAt(i++);
	    
	    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;
	    }
	    
	    output = output +
		this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
		this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
	    
	}
	
	return output;
    },
    
    // public method for decoding
    decode : function (input) {
	var output = "";
	var chr1, chr2, chr3;
	var enc1, enc2, enc3, enc4;
	var i = 0;
	
	input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
	
	while (i < input.length) {
	    
	    enc1 = this._keyStr.indexOf(input.charAt(i++));
	    enc2 = this._keyStr.indexOf(input.charAt(i++));
	    enc3 = this._keyStr.indexOf(input.charAt(i++));
	    enc4 = this._keyStr.indexOf(input.charAt(i++));
	    
	    chr1 = (enc1 << 2) | (enc2 >> 4);
	    chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
	    chr3 = ((enc3 & 3) << 6) | enc4;
	    
	    output = output + String.fromCharCode(chr1);
	    
	    if (enc3 != 64) {
		output = output + String.fromCharCode(chr2);
	    }
	    if (enc4 != 64) {
		output = output + String.fromCharCode(chr3);
	    }
	    
	}
	
	output = Base64._utf8_decode(output);
	
	return output;
	
    },
    
    // private method for UTF-8 encoding
    _utf8_encode : function (string) {
	string = string.replace(/\r\n/g,"\n");
	var utftext = "";
	
	for (var n = 0; n < string.length; n++) {
	    
	    var c = string.charCodeAt(n);
	    
	    if (c < 128) {
		utftext += String.fromCharCode(c);
	    }
	    else if((c > 127) && (c < 2048)) {
		utftext += String.fromCharCode((c >> 6) | 192);
		utftext += String.fromCharCode((c & 63) | 128);
	    }
	    else {
		utftext += String.fromCharCode((c >> 12) | 224);
		utftext += String.fromCharCode(((c >> 6) & 63) | 128);
		utftext += String.fromCharCode((c & 63) | 128);
	    }
	    
	}
	
	return utftext;
    },
    
    // private method for UTF-8 decoding
    _utf8_decode : function (utftext) {
	var string = "";
	var i = 0;
	var c = c1 = c2 = 0;
	
	while ( i < utftext.length ) {
	    
	    c = utftext.charCodeAt(i);
	    
	    if (c < 128) {
		string += String.fromCharCode(c);
		i++;
	    }
	    else if((c > 191) && (c < 224)) {
		c2 = utftext.charCodeAt(i+1);
		string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
		i += 2;
	    }
	    else {
		c2 = utftext.charCodeAt(i+1);
		c3 = utftext.charCodeAt(i+2);
		string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
		i += 3;
	    }
	    
	}
	
	return string;
    }
    
}