/
randomBytes.ts
69 lines (63 loc) · 1.73 KB
/
randomBytes.ts
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import { Buffer } from "../buffer.ts";
export const MAX_RANDOM_VALUES = 65536;
export const MAX_SIZE = 4294967295;
function generateRandomBytes(size: number) {
if (size > MAX_SIZE) {
throw new RangeError(
`The value of "size" is out of range. It must be >= 0 && <= ${MAX_SIZE}. Received ${size}`,
);
}
const bytes = Buffer.allocUnsafe(size);
//Work around for getRandomValues max generation
if (size > MAX_RANDOM_VALUES) {
for (let generated = 0; generated < size; generated += MAX_RANDOM_VALUES) {
crypto.getRandomValues(
bytes.slice(generated, generated + MAX_RANDOM_VALUES),
);
}
} else {
crypto.getRandomValues(bytes);
}
return bytes;
}
/**
* @param size Buffer length, must be equal or greater than zero
*/
export default function randomBytes(size: number): Buffer;
export default function randomBytes(
size: number,
cb?: (err: Error | null, buf?: Buffer) => void,
): void;
export default function randomBytes(
size: number,
cb?: (err: Error | null, buf?: Buffer) => void,
): Buffer | void {
if (typeof cb === "function") {
let err: Error | null = null, bytes: Buffer;
try {
bytes = generateRandomBytes(size);
} catch (e) {
//NodeJS nonsense
//If the size is out of range it will throw sync, otherwise throw async
if (
e instanceof RangeError &&
e.message.includes('The value of "size" is out of range')
) {
throw e;
} else if (e instanceof Error) {
err = e;
} else {
err = new Error("[non-error thrown]");
}
}
setTimeout(() => {
if (err) {
cb(err);
} else {
cb(null, bytes);
}
}, 0);
} else {
return generateRandomBytes(size);
}
}