openethereum/accounts/ethstore/src/random.rs

// Copyright 2015-2019 Parity Technologies (UK) Ltd.
// This file is part of Parity Ethereum.

// Parity Ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity Ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.

use rand::{Rng, RngCore, rngs::OsRng, distributions::Alphanumeric};

pub trait Random {
	fn random() -> Self where Self: Sized;
}

impl Random for [u8; 16] {
	fn random() -> Self {
		let mut result = [0u8; 16];
		let mut rng = OsRng::new().unwrap();
		rng.fill_bytes(&mut result);
		result
	}
}

impl Random for [u8; 32] {
	fn random() -> Self {
		let mut result = [0u8; 32];
		let mut rng = OsRng::new().unwrap();
		rng.fill_bytes(&mut result);
		result
	}
}

/// Generate a random string of given length.
pub fn random_string(length: usize) -> String {
	let mut rng = OsRng::new().expect("Not able to operate without random source.");
	rng.sample_iter(&Alphanumeric).take(length).collect()
}