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Rust 1.80

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Preserves the fn accessors within the Monero crates so that we can use statics
in some cfgs yet not all (in order to provide support for more low-memory
devices) with the exception of `H` (which truly should be cached).
This commit is contained in:
Luke Parker
2024-07-26 19:20:04 -04:00
parent 6f34c2ff77
commit 880565cb81
38 changed files with 147 additions and 195 deletions
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26
networks/monero/primitives/src/unreduced_scalar.rs
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@@ -1,6 +1,6 @@
use core::cmp::Ordering;
use std_shims::{
sync::OnceLock,
sync::LazyLock,
io::{self, *},
};
@@ -10,18 +10,14 @@ use curve25519_dalek::scalar::Scalar;
use monero_io::*;
static PRECOMPUTED_SCALARS_CELL: OnceLock<[Scalar; 8]> = OnceLock::new();
// Precomputed scalars used to recover an incorrectly reduced scalar.
#[allow(non_snake_case)]
fn PRECOMPUTED_SCALARS() -> [Scalar; 8] {
*PRECOMPUTED_SCALARS_CELL.get_or_init(|| {
let mut precomputed_scalars = [Scalar::ONE; 8];
for (i, scalar) in precomputed_scalars.iter_mut().enumerate().skip(1) {
*scalar = Scalar::from(u8::try_from((i * 2) + 1).unwrap());
}
precomputed_scalars
})
}
static PRECOMPUTED_SCALARS: LazyLock<[Scalar; 8]> = LazyLock::new(|| {
let mut precomputed_scalars = [Scalar::ONE; 8];
for (i, scalar) in precomputed_scalars.iter_mut().enumerate().skip(1) {
*scalar = Scalar::from(u8::try_from((i * 2) + 1).unwrap());
}
precomputed_scalars
});
/// An unreduced scalar.
///
@@ -127,14 +123,12 @@ impl UnreducedScalar {
return Scalar::from_bytes_mod_order(self.0);
}
let precomputed_scalars = PRECOMPUTED_SCALARS();
let mut recovered = Scalar::ZERO;
for &numb in self.non_adjacent_form().iter().rev() {
recovered += recovered;
match numb.cmp(&0) {
Ordering::Greater => recovered += precomputed_scalars[usize::try_from(numb).unwrap() / 2],
Ordering::Less => recovered -= precomputed_scalars[usize::try_from(-numb).unwrap() / 2],
Ordering::Greater => recovered += PRECOMPUTED_SCALARS[usize::try_from(numb).unwrap() / 2],
Ordering::Less => recovered -= PRECOMPUTED_SCALARS[usize::try_from(-numb).unwrap() / 2],
Ordering::Equal => (),
}
}