Files
librustzcash/src/tests/repr.rs
2018-05-17 16:50:40 +12:00

99 lines
2.4 KiB
Rust

use rand::{SeedableRng, XorShiftRng};
use PrimeFieldRepr;
pub fn random_repr_tests<R: PrimeFieldRepr>() {
random_encoding_tests::<R>();
random_shl_tests::<R>();
random_shr_tests::<R>();
}
fn random_encoding_tests<R: PrimeFieldRepr>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let r = R::rand(&mut rng);
// Big endian
{
let mut rdecoded = R::default();
let mut v: Vec<u8> = vec![];
r.write_be(&mut v).unwrap();
rdecoded.read_be(&v[0..]).unwrap();
assert_eq!(r, rdecoded);
}
// Little endian
{
let mut rdecoded = R::default();
let mut v: Vec<u8> = vec![];
r.write_le(&mut v).unwrap();
rdecoded.read_le(&v[0..]).unwrap();
assert_eq!(r, rdecoded);
}
{
let mut rdecoded_le = R::default();
let mut rdecoded_be_flip = R::default();
let mut v: Vec<u8> = vec![];
r.write_le(&mut v).unwrap();
// This reads in little-endian, so we are done.
rdecoded_le.read_le(&v[..]).unwrap();
// This reads in big-endian, so we perform a swap of the
// bytes beforehand.
let v: Vec<u8> = v.into_iter().rev().collect();
rdecoded_be_flip.read_be(&v[..]).unwrap();
assert_eq!(rdecoded_le, rdecoded_be_flip);
}
}
}
fn random_shl_tests<R: PrimeFieldRepr>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..100 {
let r = R::rand(&mut rng);
for shift in 0..(r.num_bits() + 1) {
let mut r1 = r;
let mut r2 = r;
for _ in 0..shift {
r1.mul2();
}
r2.shl(shift);
assert_eq!(r1, r2);
}
}
}
fn random_shr_tests<R: PrimeFieldRepr>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..100 {
let r = R::rand(&mut rng);
for shift in 0..(r.num_bits() + 1) {
let mut r1 = r;
let mut r2 = r;
for _ in 0..shift {
r1.div2();
}
r2.shr(shift);
assert_eq!(r1, r2);
}
}
}