use zeroize::Zeroize;
use crypto_bigint::{U512, U1024};
use crate::field;
#[derive(Clone, Copy, PartialEq, Eq, Default, Debug, Zeroize)]
pub struct FieldElement(pub(crate) U512);
pub const MODULUS: FieldElement = FieldElement(U512::from_be_hex(concat!(
"00000000000000",
"00",
"fffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
"ffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
)));
const WIDE_MODULUS: U1024 = U1024::from_be_hex(concat!(
"0000000000000000000000000000000000000000000000000000000000000000",
"0000000000000000000000000000000000000000000000000000000000000000",
"00000000000000",
"00",
"fffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
"ffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
));
pub(crate) const Q_4: FieldElement =
FieldElement(MODULUS.0.saturating_add(&U512::ONE).wrapping_div(&U512::from_u8(4)));
field!(FieldElement, MODULUS, WIDE_MODULUS, 448);
#[test]
fn repr() {
assert_eq!(FieldElement::from_repr(FieldElement::one().to_repr()).unwrap(), FieldElement::one());
}
#[test]
fn one_two() {
assert_eq!(FieldElement::one() * FieldElement::one().double(), FieldElement::from(2u8));
assert_eq!(
FieldElement::from_repr(FieldElement::from(2u8).to_repr()).unwrap(),
FieldElement::from(2u8)
);
}
#[test]
fn pow() {
assert_eq!(FieldElement::one().pow(FieldElement::one()), FieldElement::one());
let two = FieldElement::one().double();
assert_eq!(two.pow(two), two.double());
let three = two + FieldElement::one();
assert_eq!(three.pow(three), three * three * three);
}
#[test]
fn invert() {
assert_eq!(FieldElement::one().invert().unwrap(), FieldElement::one());
}