107 lines
2.4 KiB
JavaScript
107 lines
2.4 KiB
JavaScript
"use strict";
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var randomBytes = require('randombytes');
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var Charset = require('./charset.js');
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function unsafeRandomBytes(length) {
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var stack = [];
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for (var i = 0; i < length; i++) {
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stack.push(Math.floor(Math.random() * 255));
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}
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return {
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length,
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readUInt8: function (index) {
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return stack[index];
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}
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};
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}
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function safeRandomBytes(length) {
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try {
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return randomBytes(length);
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} catch (e) {
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/* React/React Native Fix + Eternal loop removed */
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return unsafeRandomBytes(length);
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}
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}
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function processString(buf, initialString, chars, reqLen, maxByte) {
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var string = initialString;
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for (var i = 0; i < buf.length && string.length < reqLen; i++) {
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var randomByte = buf.readUInt8(i);
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if (randomByte < maxByte) {
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string += chars.charAt(randomByte % chars.length);
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}
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}
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return string;
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}
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function getAsyncString(string, chars, length, maxByte, cb) {
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randomBytes(length, function(err, buf) {
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if (err) {
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// Since it is waiting for entropy, errors are legit and we shouldn't just keep retrying
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cb(err);
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}
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var generatedString = processString(buf, string, chars, length, maxByte);
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if (generatedString.length < length) {
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getAsyncString(generatedString, chars, length, maxByte, cb);
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} else {
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cb(null, generatedString);
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}
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})
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}
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exports.generate = function(options, cb) {
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var charset = new Charset();
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var length, chars, capitalization, string = '';
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// Handle options
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if (typeof options === 'object') {
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length = typeof options.length === 'number' ? options.length : 32;
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if (options.charset) {
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charset.setType(options.charset);
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}
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else {
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charset.setType('alphanumeric');
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}
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if (options.capitalization) {
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charset.setcapitalization(options.capitalization);
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}
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if (options.readable) {
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charset.removeUnreadable();
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}
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charset.removeDuplicates();
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}
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else if (typeof options === 'number') {
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length = options;
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charset.setType('alphanumeric');
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}
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else {
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length = 32;
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charset.setType('alphanumeric');
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}
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// Generate the string
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var charsLen = charset.chars.length;
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var maxByte = 256 - (256 % charsLen);
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if (!cb) {
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while (string.length < length) {
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var buf = safeRandomBytes(Math.ceil(length * 256 / maxByte));
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string = processString(buf, string, charset.chars, length, maxByte);
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}
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return string;
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}
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getAsyncString(string, charset.chars, length, maxByte, cb);
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};
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