mirror of https://github.com/zcash/halo2.git
66 lines
1.9 KiB
Rust
66 lines
1.9 KiB
Rust
//! Gadget and chips for the Sinsemilla hash function.
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use ff::{Field, PrimeFieldBits};
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use halo2_proofs::circuit::{AssignedCell, Cell, Value};
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use std::fmt::Debug;
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/// A [`Message`] composed of several [`MessagePiece`]s.
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#[derive(Clone, Debug)]
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pub struct Message<F: Field, const K: usize, const MAX_WORDS: usize>(Vec<MessagePiece<F, K>>);
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impl<F: PrimeFieldBits, const K: usize, const MAX_WORDS: usize> From<Vec<MessagePiece<F, K>>>
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for Message<F, K, MAX_WORDS>
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{
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fn from(pieces: Vec<MessagePiece<F, K>>) -> Self {
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// A message cannot contain more than `MAX_WORDS` words.
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assert!(pieces.iter().map(|piece| piece.num_words()).sum::<usize>() < MAX_WORDS);
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Message(pieces)
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}
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}
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impl<F: PrimeFieldBits, const K: usize, const MAX_WORDS: usize> std::ops::Deref
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for Message<F, K, MAX_WORDS>
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{
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type Target = [MessagePiece<F, K>];
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fn deref(&self) -> &[MessagePiece<F, K>] {
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&self.0
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}
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}
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/// A [`MessagePiece`] of some bitlength.
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///
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/// The piece must fit within a base field element, which means its length
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/// cannot exceed the base field's `NUM_BITS`.
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#[derive(Clone, Debug)]
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pub struct MessagePiece<F: Field, const K: usize> {
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cell_value: AssignedCell<F, F>,
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/// The number of K-bit words in this message piece.
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num_words: usize,
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}
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impl<F: PrimeFieldBits, const K: usize> MessagePiece<F, K> {
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pub fn new(cell_value: AssignedCell<F, F>, num_words: usize) -> Self {
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assert!(num_words * K < F::NUM_BITS as usize);
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Self {
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cell_value,
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num_words,
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}
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}
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pub fn num_words(&self) -> usize {
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self.num_words
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}
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pub fn cell(&self) -> Cell {
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self.cell_value.cell()
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}
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pub fn field_elem(&self) -> Value<F> {
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self.cell_value.value().cloned()
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}
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pub fn cell_value(&self) -> AssignedCell<F, F> {
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self.cell_value.clone()
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}
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}
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