121 lines
3.1 KiB
Rust
121 lines
3.1 KiB
Rust
use ff::{Field, PrimeField};
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use pairing::Engine;
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use crate::{ConstraintSystem, LinearCombination, SynthesisError, Variable};
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pub struct MultiEq<E: Engine, CS: ConstraintSystem<E>> {
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cs: CS,
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ops: usize,
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bits_used: usize,
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lhs: LinearCombination<E>,
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rhs: LinearCombination<E>,
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}
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impl<E: Engine, CS: ConstraintSystem<E>> MultiEq<E, CS> {
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pub fn new(cs: CS) -> Self {
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MultiEq {
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cs: cs,
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ops: 0,
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bits_used: 0,
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lhs: LinearCombination::zero(),
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rhs: LinearCombination::zero(),
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}
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}
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fn accumulate(&mut self) {
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let ops = self.ops;
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let lhs = self.lhs.clone();
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let rhs = self.rhs.clone();
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self.cs.enforce(
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|| format!("multieq {}", ops),
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|_| lhs,
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|lc| lc + CS::one(),
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|_| rhs,
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);
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self.lhs = LinearCombination::zero();
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self.rhs = LinearCombination::zero();
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self.bits_used = 0;
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self.ops += 1;
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}
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pub fn enforce_equal(
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&mut self,
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num_bits: usize,
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lhs: &LinearCombination<E>,
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rhs: &LinearCombination<E>,
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) {
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// Check if we will exceed the capacity
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if (E::Fr::CAPACITY as usize) <= (self.bits_used + num_bits) {
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self.accumulate();
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}
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assert!((E::Fr::CAPACITY as usize) > (self.bits_used + num_bits));
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let coeff = E::Fr::from_str("2").unwrap().pow(&[self.bits_used as u64]);
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self.lhs = self.lhs.clone() + (coeff, lhs);
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self.rhs = self.rhs.clone() + (coeff, rhs);
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self.bits_used += num_bits;
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}
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}
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impl<E: Engine, CS: ConstraintSystem<E>> Drop for MultiEq<E, CS> {
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fn drop(&mut self) {
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if self.bits_used > 0 {
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self.accumulate();
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}
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}
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}
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impl<E: Engine, CS: ConstraintSystem<E>> ConstraintSystem<E> for MultiEq<E, CS> {
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type Root = Self;
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fn one() -> Variable {
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CS::one()
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}
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fn alloc<F, A, AR>(&mut self, annotation: A, f: F) -> Result<Variable, SynthesisError>
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where
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F: FnOnce() -> Result<E::Fr, SynthesisError>,
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A: FnOnce() -> AR,
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AR: Into<String>,
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{
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self.cs.alloc(annotation, f)
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}
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fn alloc_input<F, A, AR>(&mut self, annotation: A, f: F) -> Result<Variable, SynthesisError>
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where
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F: FnOnce() -> Result<E::Fr, SynthesisError>,
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A: FnOnce() -> AR,
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AR: Into<String>,
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{
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self.cs.alloc_input(annotation, f)
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}
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fn enforce<A, AR, LA, LB, LC>(&mut self, annotation: A, a: LA, b: LB, c: LC)
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where
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A: FnOnce() -> AR,
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AR: Into<String>,
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LA: FnOnce(LinearCombination<E>) -> LinearCombination<E>,
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LB: FnOnce(LinearCombination<E>) -> LinearCombination<E>,
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LC: FnOnce(LinearCombination<E>) -> LinearCombination<E>,
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{
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self.cs.enforce(annotation, a, b, c)
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}
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fn push_namespace<NR, N>(&mut self, name_fn: N)
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where
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NR: Into<String>,
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N: FnOnce() -> NR,
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{
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self.cs.get_root().push_namespace(name_fn)
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}
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fn pop_namespace(&mut self) {
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self.cs.get_root().pop_namespace()
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}
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fn get_root(&mut self) -> &mut Self::Root {
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self
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}
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}
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