1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68

// Copyright (C) 2019-2022 Aleo Systems Inc.
// This file is part of the snarkVM library.

// The snarkVM library 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.

// The snarkVM library 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 the snarkVM library. If not, see <https://www.gnu.org/licenses/>.

use rand::{
    distributions::{Distribution, Standard},
    rngs::StdRng,
    Rng,
    SeedableRng,
};
use rand_xorshift::XorShiftRng;

/// A trait for a uniform random number generator.
pub trait Uniform: Sized {
    /// Samples a random value from a uniform distribution.
    fn rand<R: Rng + ?Sized>(rng: &mut R) -> Self;
}

impl<T> Uniform for T
where
    Standard: Distribution<T>,
{
    #[inline]
    fn rand<R: Rng + ?Sized>(rng: &mut R) -> Self {
        rng.sample(Standard)
    }
}

/// A fast RNG used **solely** for testing and benchmarking, **not** for any real world purposes.
pub fn test_rng() -> XorShiftRng {
    // Obtain the initial seed using entropy provided by the OS.
    let seed = StdRng::from_entropy().gen();

    // Print the seed, so it's displayed if any of the tests using `test_rng` fails.
    println!("\nInitializing 'test_rng' with seed '{seed}'\n");

    // Use the seed to initialize a fast, non-cryptographic Rng.
    XorShiftRng::seed_from_u64(seed)
}

/// A function that can be used in order to reproduce any failing test cases that use `test_rng`.
pub fn test_rng_fixed(seed: u64) -> XorShiftRng {
    // Use the seed to initialize a fast, non-cryptographic Rng.
    XorShiftRng::seed_from_u64(seed)
}

/// A CryptoRNG used **solely** for testing and benchmarking, **not** for any real world purposes.
pub fn test_crypto_rng() -> StdRng {
    StdRng::from_entropy()
}

/// A fixed CryptoRNG used **solely** for **debugging** tests, **not** for any real world purposes.
pub fn test_crypto_rng_fixed() -> StdRng {
    let seed = 1245897092u64;
    StdRng::seed_from_u64(seed)
}