gree_leran/node_modules/randombytes/browser.js

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2024-06-14 01:11:29 +00:00
'use strict'
// limit of Crypto.getRandomValues()
// https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues
var MAX_BYTES = 65536
// Node supports requesting up to this number of bytes
// https://github.com/nodejs/node/blob/master/lib/internal/crypto/random.js#L48
var MAX_UINT32 = 4294967295
function oldBrowser () {
throw new Error('Secure random number generation is not supported by this browser.\nUse Chrome, Firefox or Internet Explorer 11')
}
var Buffer = require('safe-buffer').Buffer
var crypto = global.crypto || global.msCrypto
if (crypto && crypto.getRandomValues) {
module.exports = randomBytes
} else {
module.exports = oldBrowser
}
function randomBytes (size, cb) {
// phantomjs needs to throw
if (size > MAX_UINT32) throw new RangeError('requested too many random bytes')
var bytes = Buffer.allocUnsafe(size)
if (size > 0) { // getRandomValues fails on IE if size == 0
if (size > MAX_BYTES) { // this is the max bytes crypto.getRandomValues
// can do at once see https://developer.mozilla.org/en-US/docs/Web/API/window.crypto.getRandomValues
for (var generated = 0; generated < size; generated += MAX_BYTES) {
// buffer.slice automatically checks if the end is past the end of
// the buffer so we don't have to here
crypto.getRandomValues(bytes.slice(generated, generated + MAX_BYTES))
}
} else {
crypto.getRandomValues(bytes)
}
}
if (typeof cb === 'function') {
return process.nextTick(function () {
cb(null, bytes)
})
}
return bytes
}