https://ipueiras.ce.gov.br/js/base64.js

1
2/**
3*
4*  Base64 encode / decode
5*  http://www.webtoolkit.info/
6*
7**/
8
9var Base64 = {
10
11	// private property
12	_keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
13
14	// public method for encoding
15	encode : function (input) {
16		var output = "";
17		var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
18		var i = 0;
19
20		input = Base64._utf8_encode(input);
21
22		while (i < input.length) {
23
24			chr1 = input.charCodeAt(i++);
25			chr2 = input.charCodeAt(i++);
26			chr3 = input.charCodeAt(i++);
27
28			enc1 = chr1 >> 2;
29			enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
30			enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
31			enc4 = chr3 & 63;
32
33			if (isNaN(chr2)) {
34				enc3 = enc4 = 64;
35			} else if (isNaN(chr3)) {
36				enc4 = 64;
37			}
38
39			output = output +
40			this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
41			this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
42
43		}
44
45		return output;
46	},
47
48	// public method for decoding
49	decode : function (input) {
50		var output = "";
51		var chr1, chr2, chr3;
52		var enc1, enc2, enc3, enc4;
53		var i = 0;
54
55		input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
56
57		while (i < input.length) {
58
59			enc1 = this._keyStr.indexOf(input.charAt(i++));
60			enc2 = this._keyStr.indexOf(input.charAt(i++));
61			enc3 = this._keyStr.indexOf(input.charAt(i++));
62			enc4 = this._keyStr.indexOf(input.charAt(i++));
63
64			chr1 = (enc1 << 2) | (enc2 >> 4);
65			chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
66			chr3 = ((enc3 & 3) << 6) | enc4;
67
68			output = output + String.fromCharCode(chr1);
69
70			if (enc3 != 64) {
71				output = output + String.fromCharCode(chr2);
72			}
73			if (enc4 != 64) {
74				output = output + String.fromCharCode(chr3);
75			}
76
77		}
78
79		output = Base64._utf8_decode(output);
80
81		return output;
82
83	},
84
85	// private method for UTF-8 encoding
86	_utf8_encode : function (string) {
87		string = string.replace(/\r\n/g,"\n");
88		var utftext = "";
89
90		for (var n = 0; n < string.length; n++) {
91
92			var c = string.charCodeAt(n);
93
94			if (c < 128) {
95				utftext += String.fromCharCode(c);
96			}
97			else if((c > 127) && (c < 2048)) {
98				utftext += String.fromCharCode((c >> 6) | 192);
99				utftext += String.fromCharCode((c & 63) | 128);
100			}
101			else {
102				utftext += String.fromCharCode((c >> 12) | 224);
103				utftext += String.fromCharCode(((c >> 6) & 63) | 128);
104				utftext += String.fromCharCode((c & 63) | 128);
105			}
106
107		}
108
109		return utftext;
110	},
111
112	// private method for UTF-8 decoding
113	_utf8_decode : function (utftext) {
114		var string = "";
115		var i = 0;
116		var c = c1 = c2 = 0;
117
118		while ( i < utftext.length ) {
119
120			c = utftext.charCodeAt(i);
121
122			if (c < 128) {
123				string += String.fromCharCode(c);
124				i++;
125			}
126			else if((c > 191) && (c < 224)) {
127				c2 = utftext.charCodeAt(i+1);
128				string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
129				i += 2;
130			}
131			else {
132				c2 = utftext.charCodeAt(i+1);
133				c3 = utftext.charCodeAt(i+2);
134				string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
135				i += 3;
136			}
137
138		}
139
140		return string;
141	}
142
143}