https://gethttpsforfree.com/js/asn1js/base64.js

1// Base64 JavaScript decoder
2// Copyright (c) 2008-2014 Lapo Luchini <[email protected]>
3
4// Permission to use, copy, modify, and/or distribute this software for any
5// purpose with or without fee is hereby granted, provided that the above
6// copyright notice and this permission notice appear in all copies.
7// 
8// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15
16/*jshint browser: true, strict: true, immed: true, latedef: true, undef: true, regexdash: false */
17(function (undefined) {
18"use strict";
19
20var Base64 = {},
21    decoder;
22
23Base64.decode = function (a) {
24    var i;
25    if (decoder === undefined) {
26        var b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",
27            ignore = "= \f\n\r\t\u00A0\u2028\u2029";
28        decoder = [];
29        for (i = 0; i < 64; ++i)
30            decoder[b64.charAt(i)] = i;
31        for (i = 0; i < ignore.length; ++i)
32            decoder[ignore.charAt(i)] = -1;
33    }
34    var out = [];
35    var bits = 0, char_count = 0;
36    for (i = 0; i < a.length; ++i) {
37        var c = a.charAt(i);
38        if (c == '=')
39            break;
40        c = decoder[c];
41        if (c == -1)
42            continue;
43        if (c === undefined)
44            throw 'Illegal character at offset ' + i;
45        bits |= c;
46        if (++char_count >= 4) {
47            out[out.length] = (bits >> 16);
48            out[out.length] = (bits >> 8) & 0xFF;
49            out[out.length] = bits & 0xFF;
50            bits = 0;
51            char_count = 0;
52        } else {
53            bits <<= 6;
54        }
55    }
56    switch (char_count) {
57      case 1:
58        throw "Base64 encoding incomplete: at least 2 bits missing";
59      case 2:
60        out[out.length] = (bits >> 10);
61        break;
62      case 3:
63        out[out.length] = (bits >> 16);
64        out[out.length] = (bits >> 8) & 0xFF;
65        break;
66    }
67    return out;
68};
69
70Base64.re = /-----BEGIN [^-]+-----([A-Za-z0-9+\/=\s]+)-----END [^-]+-----|begin-base64[^\n]+\n([A-Za-z0-9+\/=\s]+)====/;
71Base64.unarmor = function (a) {
72    var m = Base64.re.exec(a);
73    if (m) {
74        if (m[1])
75            a = m[1];
76        else if (m[2])
77            a = m[2];
78        else
79            throw "RegExp out of sync";
80    }
81    return Base64.decode(a);
82};
83
84// export globals
85if (typeof module !== 'undefined') { module.exports = Base64; } else { window.Base64 = Base64; }
86})();
87