arnaucube/ark-r1cs-std
1
0
Fork 0
mirror of https://github.com/arnaucube/ark-r1cs-std.git synced 2026-01-10 16:01:28 +01:00
Code Issues Projects Releases Wiki Activity

Add UInt128 for u128 (#21)

Browse Source
This commit is contained in:
Weikeng Chen
2020-11-23 15:26:10 -08:00
committed by GitHub
parent 77dfd7dac6
commit 68f08b94d2
3 changed files with 23 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
src/bits/mod.rs
View File

@@ -17,6 +17,7 @@ pub mod uint;
make_uint!(UInt16, 16, u16, uint16, "16");
make_uint!(UInt32, 32, u32, uint32, "32");
make_uint!(UInt64, 64, u64, uint64, "64");
make_uint!(UInt128, 128, u128, uint128, "128");
/// Specifies constraints for conversion to a little-endian bit representation
/// of `self`.

29
src/bits/uint.rs
View File

@@ -6,9 +6,11 @@ macro_rules! make_uint {
#[doc = $native_doc_name]
#[doc = "`type."]
pub mod $mod_name {
use ark_ff::{Field, FpParameters, PrimeField};
use ark_ff::{Field, FpParameters, One, PrimeField, Zero};
use core::borrow::Borrow;
use core::convert::TryFrom;
use num_bigint::BigUint;
use num_traits::cast::ToPrimitive;
use ark_relations::r1cs::{
ConstraintSystemRef, LinearCombination, Namespace, SynthesisError, Variable,
@@ -183,6 +185,9 @@ macro_rules! make_uint {
// in the scalar field
assert!(F::Params::MODULUS_BITS >= 2 * $size);
// Support up to 128
assert!($size <= 128);
assert!(operands.len() >= 1);
assert!($size * operands.len() <= F::Params::MODULUS_BITS as usize);
@@ -192,10 +197,10 @@ macro_rules! make_uint {
// Compute the maximum value of the sum so we allocate enough bits for
// the result
let mut max_value = (operands.len() as u128) * u128::from($native::max_value());
let mut max_value = BigUint::from($native::max_value()) * BigUint::from(operands.len());
// Keep track of the resulting value
let mut result_value = Some(0u128);
let mut result_value = Some(BigUint::zero());
// This is a linear combination that we will enforce to be "zero"
let mut lc = LinearCombination::zero();
@@ -207,7 +212,7 @@ macro_rules! make_uint {
// Accumulate the value
match op.value {
Some(val) => {
result_value.as_mut().map(|v| *v += u128::from(val));
result_value.as_mut().map(|v| *v += BigUint::from(val));
}
None => {
@@ -246,7 +251,12 @@ macro_rules! make_uint {
}
// The value of the actual result is modulo 2^$size
let modular_value = result_value.map(|v| v as $native);
let modular_value = result_value.clone().map(|v|
{
let modulus = BigUint::from(1u64) << ($size as u32);
(v % modulus).to_u128().unwrap() as $native
}
);
if all_constants && modular_value.is_some() {
// We can just return a constant, rather than
@@ -262,11 +272,9 @@ macro_rules! make_uint {
// Allocate each bit_gadget of the result
let mut coeff = F::one();
let mut i = 0;
while max_value != 0 {
while max_value != BigUint::zero() {
// Allocate the bit_gadget
let b = AllocatedBit::new_witness(cs.clone(), || {
result_value.map(|v| (v >> i) & 1 == 1).get()
})?;
let b = AllocatedBit::new_witness(cs.clone(), || result_value.clone().map(|v| (v >> i) & BigUint::one() == BigUint::one()).get())?;
// Subtract this bit_gadget from the linear combination to ensure the sums
// balance out
@@ -384,7 +392,7 @@ macro_rules! make_uint {
mod test {
use super::$name;
use crate::{bits::boolean::Boolean, prelude::*, Vec};
use ark_test_curves::bls12_381::Fr;
use ark_test_curves::mnt4_753::Fr;
use ark_relations::r1cs::{ConstraintSystem, SynthesisError};
use rand::{Rng, SeedableRng};
use rand_xorshift::XorShiftRng;
@@ -517,7 +525,6 @@ macro_rules! make_uint {
let r = $name::addmany(&[r, c_bit, d_bit]).unwrap();
assert!(cs.is_satisfied().unwrap());
assert!(r.value == Some(expected));
for b in r.bits.iter() {