https://sion.unac.edu.co/Scripts/Base64.js

1/*jslint adsafe: false, bitwise: true, browser: true, cap: false, css: false,
2  debug: false, devel: true, eqeqeq: true, es5: false, evil: false,
3  forin: false, fragment: false, immed: true, laxbreak: false, newcap: true,
4  nomen: false, on: false, onevar: true, passfail: false, plusplus: true,
5  regexp: false, rhino: true, safe: false, strict: false, sub: false,
6  undef: true, white: false, widget: false, windows: false */
7/*global jQuery: false, window: false */
8"use strict";
9
10/*
11 * Original code (c) 2010 Nick Galbreath
12 * http://code.google.com/p/stringencoders/source/browse/#svn/trunk/javascript
13 *
14 * jQuery port (c) 2010 Carlo Zottmann
15 * http://github.com/carlo/jquery-base64
16 *
17 * Permission is hereby granted, free of charge, to any person
18 * obtaining a copy of this software and associated documentation
19 * files (the "Software"), to deal in the Software without
20 * restriction, including without limitation the rights to use,
21 * copy, modify, merge, publish, distribute, sublicense, and/or sell
22 * copies of the Software, and to permit persons to whom the
23 * Software is furnished to do so, subject to the following
24 * conditions:
25 *
26 * The above copyright notice and this permission notice shall be
27 * included in all copies or substantial portions of the Software.
28 *
29 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
30 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
31 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
32 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
33 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
34 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
35 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
36 * OTHER DEALINGS IN THE SOFTWARE.
37*/
38
39/* base64 encode/decode compatible with window.btoa/atob
40 *
41 * window.atob/btoa is a Firefox extension to convert binary data (the "b")
42 * to base64 (ascii, the "a").
43 *
44 * It is also found in Safari and Chrome.  It is not available in IE.
45 *
46 * if (!window.btoa) window.btoa = $.base64.encode
47 * if (!window.atob) window.atob = $.base64.decode
48 *
49 * The original spec's for atob/btoa are a bit lacking
50 * https://developer.mozilla.org/en/DOM/window.atob
51 * https://developer.mozilla.org/en/DOM/window.btoa
52 *
53 * window.btoa and $.base64.encode takes a string where charCodeAt is [0,255]
54 * If any character is not [0,255], then an exception is thrown.
55 *
56 * window.atob and $.base64.decode take a base64-encoded string
57 * If the input length is not a multiple of 4, or contains invalid characters
58 *   then an exception is thrown.
59 */
60
61jQuery.base64 = (function ($) {
62
63    var _PADCHAR = "=",
64      _ALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
65      _VERSION = "1.0";
66
67
68    function _getbyte64(s, i) {
69        // This is oddly fast, except on Chrome/V8.
70        // Minimal or no improvement in performance by using a
71        // object with properties mapping chars to value (eg. 'A': 0)
72
73        var idx = _ALPHA.indexOf(s.charAt(i));
74
75        if (idx === -1) {
76            throw "Cannot decode base64";
77        }
78
79        return idx;
80    }
81
82
83    function _decode(s) {
84        var pads = 0,
85          i,
86          b10,
87          imax = s.length,
88          x = [];
89
90        s = String(s);
91
92        if (imax === 0) {
93            return s;
94        }
95
96        if (imax % 4 !== 0) {
97            throw "Cannot decode base64";
98        }
99
100        if (s.charAt(imax - 1) === _PADCHAR) {
101            pads = 1;
102
103            if (s.charAt(imax - 2) === _PADCHAR) {
104                pads = 2;
105            }
106
107            // either way, we want to ignore this last block
108            imax -= 4;
109        }
110
111        for (i = 0; i < imax; i += 4) {
112            b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12) | (_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
122            case 2:
123                b10 = (_getbyte64(s, i) << 18) | (_getbyte64(s, i + 1) << 12);
124                x.push(String.fromCharCode(b10 >> 16));
125                break;
126        }
127
128        return x.join("");
129    }
130
131
132    function _getbyte(s, i) {

133        var x = s.charCodeAt(i);
134
135        if (x > 255) {
136            throw "INVALID_CHARACTER_ERR: DOM Exception 5";
137        }
138
139        return x;
140    }
141
142
143    function _encode(s) {
144        if (arguments.length !== 1) {
145            throw "SyntaxError: exactly one argument required";
146        }
147
148        s = String(s);
149
150        var i,
151          b10,
152          x = [],
153          imax = s.length - s.length % 3;
154
155        if (s.length === 0) {
156            return s;
157        }
158
159        for (i = 0; i < imax; i += 3) {
160            b10 = (_getbyte(s, i) << 16) | (_getbyte(s, i + 1) << 8) | _getbyte(s, i + 2);
161            x.push(_ALPHA.charAt(b10 >> 18));
162            x.push(_ALPHA.charAt((b10 >> 12) & 0x3F));
163            x.push(_ALPHA.charAt((b10 >> 6) & 0x3f));
164            x.push(_ALPHA.charAt(b10 & 0x3f));
165        }
166
167        switch (s.length - imax) {
168            case 1:
169                b10 = _getbyte(s, i) << 16;
170                x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F) + _PADCHAR + _PADCHAR);
171                break;
172
173            case 2:
174                b10 = (_getbyte(s, i) << 16) | (_getbyte(s, i + 1) << 8);
175                x.push(_ALPHA.charAt(b10 >> 18) + _ALPHA.charAt((b10 >> 12) & 0x3F) + _ALPHA.charAt((b10 >> 6) & 0x3f) + _PADCHAR);
176                break;
177        }
178
179        return x.join("");
180    }
181
182
183    return {
184        decode: _decode,
185        encode: _encode,
186        VERSION: _VERSION
187    };
188
189}(jQuery));