plonky2/evm/src/util.rs
2022-08-25 20:19:18 -07:00

70 lines
2.5 KiB
Rust

use ethereum_types::{H160, U256};
use itertools::Itertools;
use plonky2::field::extension::Extendable;
use plonky2::field::packed::PackedField;
use plonky2::field::polynomial::PolynomialValues;
use plonky2::field::types::Field;
use plonky2::hash::hash_types::RichField;
use plonky2::iop::ext_target::ExtensionTarget;
use plonky2::util::transpose;
/// Construct an integer from its constituent bits (in little-endian order)
pub fn limb_from_bits_le<P: PackedField>(iter: impl IntoIterator<Item = P>) -> P {
// TODO: This is technically wrong, as 1 << i won't be canonical for all fields...
iter.into_iter()
.enumerate()
.map(|(i, bit)| bit * P::Scalar::from_canonical_u64(1 << i))
.sum()
}
/// Construct an integer from its constituent bits (in little-endian order): recursive edition
pub fn limb_from_bits_le_recursive<F: RichField + Extendable<D>, const D: usize>(
builder: &mut plonky2::plonk::circuit_builder::CircuitBuilder<F, D>,
iter: impl IntoIterator<Item = ExtensionTarget<D>>,
) -> ExtensionTarget<D> {
iter.into_iter()
.enumerate()
.fold(builder.zero_extension(), |acc, (i, bit)| {
// TODO: This is technically wrong, as 1 << i won't be canonical for all fields...
builder.mul_const_add_extension(F::from_canonical_u64(1 << i), bit, acc)
})
}
/// A helper function to transpose a row-wise trace and put it in the format that `prove` expects.
pub fn trace_rows_to_poly_values<F: Field, const COLUMNS: usize>(
trace_rows: Vec<[F; COLUMNS]>,
) -> Vec<PolynomialValues<F>> {
let trace_row_vecs = trace_rows.into_iter().map(|row| row.to_vec()).collect_vec();
let trace_col_vecs: Vec<Vec<F>> = transpose(&trace_row_vecs);
trace_col_vecs
.into_iter()
.map(|column| PolynomialValues::new(column))
.collect()
}
/// Returns the 32-bit little-endian limbs of a `U256`.
pub(crate) fn u256_limbs<F: Field>(u256: U256) -> [F; 8] {
u256.0
.into_iter()
.flat_map(|limb_64| {
let lo = (limb_64 & 0xFFFFFFFF) as u32;
let hi = (limb_64 >> 32) as u32;
[lo, hi]
})
.map(F::from_canonical_u32)
.collect_vec()
.try_into()
.unwrap()
}
/// Returns the 32-bit limbs of a `U160`.
pub(crate) fn h160_limbs<F: Field>(h160: H160) -> [F; 5] {
h160.0
.chunks(4)
.map(|chunk| u32::from_le_bytes(chunk.try_into().unwrap()))
.map(F::from_canonical_u32)
.collect_vec()
.try_into()
.unwrap()
}