lapo.it
1// Base64 JavaScript decoder
2// Copyright (c) 2008-2023 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(typeof define != 'undefined' ? define : function (factory) { 'use strict';
17 if (typeof module == 'object') module.exports = factory();
18 else window.base64 = factory();
19})(function () {
20'use strict';
21
22const
23 haveU8 = (typeof Uint8Array == 'function');
24
25let decoder; // populated on first usage
26
27class Base64 {
28
29 static decode(a) {
30 let isString = (typeof a == 'string');
31 let i;
32 if (decoder === undefined) {
33 let b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/',
34 ignore = '= \f\n\r\t\u00A0\u2028\u2029';
35 decoder = [];
36 for (i = 0; i < 64; ++i)
37 decoder[b64.charCodeAt(i)] = i;
38 for (i = 0; i < ignore.length; ++i)
39 decoder[ignore.charCodeAt(i)] = -1;
40 // RFC 3548 URL & file safe encoding
41 decoder['-'.charCodeAt(0)] = decoder['+'.charCodeAt(0)];
42 decoder['_'.charCodeAt(0)] = decoder['/'.charCodeAt(0)];
43 }
44 let out = haveU8 ? new Uint8Array(a.length * 3 >> 2) : [];
45 let bits = 0, char_count = 0, len = 0;
46 for (i = 0; i < a.length; ++i) {
47 let c = isString ? a.charCodeAt(i) : a[i];
48 if (c == 61) // '='.charCodeAt(0)
49 break;
50 c = decoder[c];
51 if (c == -1)
52 continue;
53 if (c === undefined)
54 throw 'Illegal character at offset ' + i;
55 bits |= c;
56 if (++char_count >= 4) {
57 out[len++] = (bits >> 16);
58 out[len++] = (bits >> 8) & 0xFF;
59 out[len++] = bits & 0xFF;
60 bits = 0;
61 char_count = 0;
62 } else {
63 bits <<= 6;
64 }
65 }
66 switch (char_count) {
67 case 1:
68 throw 'Base64 encoding incomplete: at least 2 bits missing';
69 case 2:
70 out[len++] = (bits >> 10);
71 break;
72 case 3:
73 out[len++] = (bits >> 16);
74 out[len++] = (bits >> 8) & 0xFF;
75 break;
76 }
77 if (haveU8 && out.length > len) // in case it was originally longer because of ignored characters
78 out = out.subarray(0, len);
79 return out;
80 }
81
82 static pretty(str) {
83 // fix padding
84 if (str.length % 4 > 0)
85 str = (str + '===').slice(0, str.length + str.length % 4);
86 // convert RFC 3548 to standard Base64
87 str = str.replace(/-/g, '+').replace(/_/g, '/');
88 // 80 column width
89 return str.replace(/(.{80})/g, '$1\n');
90 }
91
92 static unarmor(a) {
93 let m = Base64.re.exec(a);
94 if (m) {
95 if (m[1])
96 a = m[1];
97 else if (m[2])
98 a = m[2];
99 else if (m[3])
100 a = m[3];
101 else
102 throw 'RegExp out of sync';
103 }
104 return Base64.decode(a);
105 }
106
107}
108
109Base64.re = /-----BEGIN [^-]+-----([A-Za-z0-9+/=\s]+)-----END [^-]+-----|begin-base64[^\n]+\n([A-Za-z0-9+/=\s]+)====|^([A-Za-z0-9+/=\s]+)$/;
110
111return Base64;
112
113});