source: trip-planner-front/node_modules/node-forge/lib/baseN.js

Last change on this file was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1/**
2 * Base-N/Base-X encoding/decoding functions.
3 *
4 * Original implementation from base-x:
5 * https://github.com/cryptocoinjs/base-x
6 *
7 * Which is MIT licensed:
8 *
9 * The MIT License (MIT)
10 *
11 * Copyright base-x contributors (c) 2016
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this software and associated documentation files (the "Software"), to deal
15 * in the Software without restriction, including without limitation the rights
16 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
17 * copies of the Software, and to permit persons to whom the Software is
18 * furnished to do so, subject to the following conditions:
19 *
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
29 * DEALINGS IN THE SOFTWARE.
30 */
31var api = {};
32module.exports = api;
33
34// baseN alphabet indexes
35var _reverseAlphabets = {};
36
37/**
38 * BaseN-encodes a Uint8Array using the given alphabet.
39 *
40 * @param input the Uint8Array to encode.
41 * @param maxline the maximum number of encoded characters per line to use,
42 * defaults to none.
43 *
44 * @return the baseN-encoded output string.
45 */
46api.encode = function(input, alphabet, maxline) {
47 if(typeof alphabet !== 'string') {
48 throw new TypeError('"alphabet" must be a string.');
49 }
50 if(maxline !== undefined && typeof maxline !== 'number') {
51 throw new TypeError('"maxline" must be a number.');
52 }
53
54 var output = '';
55
56 if(!(input instanceof Uint8Array)) {
57 // assume forge byte buffer
58 output = _encodeWithByteBuffer(input, alphabet);
59 } else {
60 var i = 0;
61 var base = alphabet.length;
62 var first = alphabet.charAt(0);
63 var digits = [0];
64 for(i = 0; i < input.length; ++i) {
65 for(var j = 0, carry = input[i]; j < digits.length; ++j) {
66 carry += digits[j] << 8;
67 digits[j] = carry % base;
68 carry = (carry / base) | 0;
69 }
70
71 while(carry > 0) {
72 digits.push(carry % base);
73 carry = (carry / base) | 0;
74 }
75 }
76
77 // deal with leading zeros
78 for(i = 0; input[i] === 0 && i < input.length - 1; ++i) {
79 output += first;
80 }
81 // convert digits to a string
82 for(i = digits.length - 1; i >= 0; --i) {
83 output += alphabet[digits[i]];
84 }
85 }
86
87 if(maxline) {
88 var regex = new RegExp('.{1,' + maxline + '}', 'g');
89 output = output.match(regex).join('\r\n');
90 }
91
92 return output;
93};
94
95/**
96 * Decodes a baseN-encoded (using the given alphabet) string to a
97 * Uint8Array.
98 *
99 * @param input the baseN-encoded input string.
100 *
101 * @return the Uint8Array.
102 */
103api.decode = function(input, alphabet) {
104 if(typeof input !== 'string') {
105 throw new TypeError('"input" must be a string.');
106 }
107 if(typeof alphabet !== 'string') {
108 throw new TypeError('"alphabet" must be a string.');
109 }
110
111 var table = _reverseAlphabets[alphabet];
112 if(!table) {
113 // compute reverse alphabet
114 table = _reverseAlphabets[alphabet] = [];
115 for(var i = 0; i < alphabet.length; ++i) {
116 table[alphabet.charCodeAt(i)] = i;
117 }
118 }
119
120 // remove whitespace characters
121 input = input.replace(/\s/g, '');
122
123 var base = alphabet.length;
124 var first = alphabet.charAt(0);
125 var bytes = [0];
126 for(var i = 0; i < input.length; i++) {
127 var value = table[input.charCodeAt(i)];
128 if(value === undefined) {
129 return;
130 }
131
132 for(var j = 0, carry = value; j < bytes.length; ++j) {
133 carry += bytes[j] * base;
134 bytes[j] = carry & 0xff;
135 carry >>= 8;
136 }
137
138 while(carry > 0) {
139 bytes.push(carry & 0xff);
140 carry >>= 8;
141 }
142 }
143
144 // deal with leading zeros
145 for(var k = 0; input[k] === first && k < input.length - 1; ++k) {
146 bytes.push(0);
147 }
148
149 if(typeof Buffer !== 'undefined') {
150 return Buffer.from(bytes.reverse());
151 }
152
153 return new Uint8Array(bytes.reverse());
154};
155
156function _encodeWithByteBuffer(input, alphabet) {
157 var i = 0;
158 var base = alphabet.length;
159 var first = alphabet.charAt(0);
160 var digits = [0];
161 for(i = 0; i < input.length(); ++i) {
162 for(var j = 0, carry = input.at(i); j < digits.length; ++j) {
163 carry += digits[j] << 8;
164 digits[j] = carry % base;
165 carry = (carry / base) | 0;
166 }
167
168 while(carry > 0) {
169 digits.push(carry % base);
170 carry = (carry / base) | 0;
171 }
172 }
173
174 var output = '';
175
176 // deal with leading zeros
177 for(i = 0; input.at(i) === 0 && i < input.length() - 1; ++i) {
178 output += first;
179 }
180 // convert digits to a string
181 for(i = digits.length - 1; i >= 0; --i) {
182 output += alphabet[digits[i]];
183 }
184
185 return output;
186}
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