https://www.imprentanacional.go.cr/js_srv/thirdparty/base64.js

1/*
2 * Copyright (c) 2010 Nick Galbreath
3 * http://code.google.com/p/stringencoders/source/browse/#svn/trunk/javascript
4 *
5 * Permission is hereby granted, free of charge, to any person
6 * obtaining a copy of this software and associated documentation
7 * files (the "Software"), to deal in the Software without
8 * restriction, including without limitation the rights to use,
9 * copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following
12 * conditions:
13 *
14 * The above copyright notice and this permission notice shall be
15 * included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 * OTHER DEALINGS IN THE SOFTWARE.
25 */
26
27/* base64 encode/decode compatible with window.btoa/atob
28 *
29 * window.atob/btoa is a Firefox extension to convert binary data (the "b")
30 * to base64 (ascii, the "a").
31 *
32 * It is also found in Safari and Chrome.  It is not available in IE.
33 *
34 * if (!window.btoa) window.btoa = base64.encode
35 * if (!window.atob) window.atob = base64.decode
36 *
37 * The original spec's for atob/btoa are a bit lacking
38 * https://developer.mozilla.org/en/DOM/window.atob
39 * https://developer.mozilla.org/en/DOM/window.btoa
40 *
41 * window.btoa and base64.encode takes a string where charCodeAt is [0,255]
42 * If any character is not [0,255], then an DOMException(5) is thrown.
43 *
44 * window.atob and base64.decode take a base64-encoded string
45 * If the input length is not a multiple of 4, or contains invalid characters
46 *   then an DOMException(5) is thrown.
47 */
48var base64 = {};
49base64.PADCHAR = '=';
50base64.ALPHA = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
51
52base64.makeDOMException = function() {
53    // sadly in FF,Safari,Chrome you can't make a DOMException
54    var e, tmp;
55
56    try {
57        return new DOMException(DOMException.INVALID_CHARACTER_ERR);
58    } catch (tmp) {
59        // not available, just passback a duck-typed equiv
60        // https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Error
61        // https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Error/prototype
62        var ex = new Error("DOM Exception 5");
63
64        // ex.number and ex.description is IE-specific.
65        ex.code = ex.number = 5;
66        ex.name = ex.description = "INVALID_CHARACTER_ERR";
67
68        // Safari/Chrome output format
69        ex.toString = function() { return 'Error: ' + ex.name + ': ' + ex.message; };
70        return ex;
71    }
72}
73
74base64.getbyte64 = function(s,i) {
75    // This is oddly fast, except on Chrome/V8.
76    //  Minimal or no improvement in performance by using a
77    //   object with properties mapping chars to value (eg. 'A': 0)
78    var idx = base64.ALPHA.indexOf(s.charAt(i));
79    if (idx === -1) {
80        throw base64.makeDOMException();
81    }
82    return idx;
83}
84
85base64.decode = function(s) {
86    // convert to string
87    s = '' + s;
88    var getbyte64 = base64.getbyte64;
89    var pads, i, b10;
90    var imax = s.length
91    if (imax === 0) {
92        return s;
93    }
94
95    if (imax % 4 !== 0) {
96        throw base64.makeDOMException();
97    }
98
99    pads = 0
100    if (s.charAt(imax - 1) === base64.PADCHAR) {
101        pads = 1;
102        if (s.charAt(imax - 2) === base64.PADCHAR) {
103            pads = 2;
104        }
105        // either way, we want to ignore this last block
106        imax -= 4;
107    }
108
109    var x = [];
110    for (i = 0; i < imax; i += 4) {
111        b10 = (getbyte64(s,i) << 18) | (getbyte64(s,i+1) << 12) |
112            (getbyte64(s,i+2) << 6) | getbyte64(s,i+3);
113        x.push(String.fromCharCode(b10 >> 16, (b10 >> 8) & 0xff, b10 & 0xff));
114    }
115
116    switch (pads) {
117    case 1:
118        b10 = (getbyte64(s,i) << 18) | (getbyte64(s,i+1) << 12) | (getbyte64(s,i+2) << 6);
119        x.push(String.fromCharCode(b10 >> 16, (b10 >> 8) & 0xff));
120        break;
121    case 2:
122        b10 = (getbyte64(s,i) << 18) | (getbyte64(s,i+1) << 12);
123        x.push(String.fromCharCode(b10 >> 16));
124        break;
125    }
126    return x.join('');
127}
128
129base64.getbyte = function(s,i) {

130    var x = s.charCodeAt(i);
131    if (x > 255) {
132        throw base64.makeDOMException();
133    }
134    return x;
135}
136
137base64.encode = function(s) {
138    if (arguments.length !== 1) {
139        throw new SyntaxError("Not enough arguments");
140    }
141    var padchar = base64.PADCHAR;
142    var alpha   = base64.ALPHA;
143    var getbyte = base64.getbyte;
144
145    var i, b10;
146    var x = [];
147
148    // convert to string
149    s = '' + s;
150
151    var imax = s.length - s.length % 3;
152
153    if (s.length === 0) {
154        return s;
155    }
156    for (i = 0; i < imax; i += 3) {
157        b10 = (getbyte(s,i) << 16) | (getbyte(s,i+1) << 8) | getbyte(s,i+2);
158        x.push(alpha.charAt(b10 >> 18));
159        x.push(alpha.charAt((b10 >> 12) & 0x3F));
160        x.push(alpha.charAt((b10 >> 6) & 0x3f));
161        x.push(alpha.charAt(b10 & 0x3f));
162    }
163    switch (s.length - imax) {
164    case 1:
165        b10 = getbyte(s,i) << 16;
166        x.push(alpha.charAt(b10 >> 18) + alpha.charAt((b10 >> 12) & 0x3F) +
167               padchar + padchar);
168        break;
169    case 2:
170        b10 = (getbyte(s,i) << 16) | (getbyte(s,i+1) << 8);
171        x.push(alpha.charAt(b10 >> 18) + alpha.charAt((b10 >> 12) & 0x3F) +
172               alpha.charAt((b10 >> 6) & 0x3f) + padchar);
173        break;
174    }
175    return x.join('');
176}
177
178
179if (!window.atob) {
180    window.atob = base64.encode;
181}
182
183if (!window.btoa) {
184    window.atob = base64.decode;
185}
186