lapo.it
1// Base64 JavaScript decoder
2// Copyright (c) 2008-2019 Lapo Luchini <lapo@lapo.it>
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(function (undefined) {
17"use strict";
18
19var Base64 = {},
20 decoder, // populated on first usage
21 haveU8 = ('Uint8Array' in (typeof window == 'object' ? window : global));
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 // RFC 3548 URL & file safe encoding
34 decoder['-'] = decoder['+'];
35 decoder['_'] = decoder['/'];
36 }
37 var out = haveU8 ? new Uint8Array(a.length * 3 >> 2) : [];
38 var bits = 0, char_count = 0, len = 0;
39 for (i = 0; i < a.length; ++i) {
40 var c = a.charAt(i);
41 if (c == '=')
42 break;
43 c = decoder[c];
44 if (c == -1)
45 continue;
46 if (c === undefined)
47 throw 'Illegal character at offset ' + i;
48 bits |= c;
49 if (++char_count >= 4) {
50 out[len++] = (bits >> 16);
51 out[len++] = (bits >> 8) & 0xFF;
52 out[len++] = bits & 0xFF;
53 bits = 0;
54 char_count = 0;
55 } else {
56 bits <<= 6;
57 }
58 }
59 switch (char_count) {
60 case 1:
61 throw "Base64 encoding incomplete: at least 2 bits missing";
62 case 2:
63 out[len++] = (bits >> 10);
64 break;
65 case 3:
66 out[len++] = (bits >> 16);
67 out[len++] = (bits >> 8) & 0xFF;
68 break;
69 }
70 if (haveU8 && out.length > len) // in case it was originally longer because of ignored characters
71 out = out.subarray(0, len);
72 return out;
73};
74
75Base64.pretty = function (str) {
76 // fix padding
77 if (str.length % 4 > 0)
78 str = (str + '===').slice(0, str.length + str.length % 4);
79 // convert RFC 3548 to standard Base64
80 str = str.replace(/-/g, '+').replace(/_/g, '/');
81 // 80 column width
82 return str.replace(/(.{80})/g, '$1\n');
83};
84
85Base64.re = /-----BEGIN [^-]+-----([A-Za-z0-9+\/=\s]+)-----END [^-]+-----|begin-base64[^\n]+\n([A-Za-z0-9+\/=\s]+)====/;
86Base64.unarmor = function (a) {
87 var m = Base64.re.exec(a);
88 if (m) {
89 if (m[1])
90 a = m[1];
91 else if (m[2])
92 a = m[2];
93 else
94 throw "RegExp out of sync";
95 }
96 return Base64.decode(a);
97};
98
99// export globals
100if (typeof module !== 'undefined') { module.exports = Base64; } else { window.Base64 = Base64; }
101})();