view awesome_js/Base64.js @ 75:874a6a2c28cf laserkard

session with nick. redisigned faq page
author Robert McIntyre <rlm@mit.edu>
date Tue, 29 Jun 2010 15:36:30 -0400
parents 021a9ab1ed5b
children
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1 /**
2 *
3 * Base64 encode / decode
4 * http://www.webtoolkit.info/
5 *
6 **/
8 var Base64 = {
10 // private property
11 _keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
13 // public method for encoding
14 encode : function (input) {
15 var output = "";
16 var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
17 var i = 0;
19 input = Base64._utf8_encode(input);
21 while (i < input.length) {
23 chr1 = input.charCodeAt(i++);
24 chr2 = input.charCodeAt(i++);
25 chr3 = input.charCodeAt(i++);
27 enc1 = chr1 >> 2;
28 enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
29 enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
30 enc4 = chr3 & 63;
32 if (isNaN(chr2)) {
33 enc3 = enc4 = 64;
34 } else if (isNaN(chr3)) {
35 enc4 = 64;
36 }
38 output = output +
39 this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
40 this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
42 }
44 return output;
45 },
47 // public method for decoding
48 decode : function (input) {
49 var output = "";
50 var chr1, chr2, chr3;
51 var enc1, enc2, enc3, enc4;
52 var i = 0;
54 input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
56 while (i < input.length) {
58 enc1 = this._keyStr.indexOf(input.charAt(i++));
59 enc2 = this._keyStr.indexOf(input.charAt(i++));
60 enc3 = this._keyStr.indexOf(input.charAt(i++));
61 enc4 = this._keyStr.indexOf(input.charAt(i++));
63 chr1 = (enc1 << 2) | (enc2 >> 4);
64 chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
65 chr3 = ((enc3 & 3) << 6) | enc4;
67 output = output + String.fromCharCode(chr1);
69 if (enc3 != 64) {
70 output = output + String.fromCharCode(chr2);
71 }
72 if (enc4 != 64) {
73 output = output + String.fromCharCode(chr3);
74 }
76 }
78 output = Base64._utf8_decode(output);
80 return output;
82 },
84 // private method for UTF-8 encoding
85 _utf8_encode : function (string) {
86 string = string.replace(/\r\n/g,"\n");
87 var utftext = "";
89 for (var n = 0; n < string.length; n++) {
91 var c = string.charCodeAt(n);
93 if (c < 128) {
94 utftext += String.fromCharCode(c);
95 }
96 else if((c > 127) && (c < 2048)) {
97 utftext += String.fromCharCode((c >> 6) | 192);
98 utftext += String.fromCharCode((c & 63) | 128);
99 }
100 else {
101 utftext += String.fromCharCode((c >> 12) | 224);
102 utftext += String.fromCharCode(((c >> 6) & 63) | 128);
103 utftext += String.fromCharCode((c & 63) | 128);
104 }
106 }
108 return utftext;
109 },
111 // private method for UTF-8 decoding
112 _utf8_decode : function (utftext) {
113 var string = "";
114 var i = 0;
115 var c = c1 = c2 = 0;
117 while ( i < utftext.length ) {
119 c = utftext.charCodeAt(i);
121 if (c < 128) {
122 string += String.fromCharCode(c);
123 i++;
124 }
125 else if((c > 191) && (c < 224)) {
126 c2 = utftext.charCodeAt(i+1);
127 string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
128 i += 2;
129 }
130 else {
131 c2 = utftext.charCodeAt(i+1);
132 c3 = utftext.charCodeAt(i+2);
133 string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
134 i += 3;
135 }
137 }
139 return string;
140 }
142 }