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use std::sync::Arc;
use crate::{
errors::MerkleError,
traits::{MerkleParameters, CRH},
};
use snarkvm_utilities::ToBytes;
pub type MerkleTreeDigest<P> = <<P as MerkleParameters>::H as CRH>::Output;
#[derive(Clone, Debug)]
pub struct MerklePath<P: MerkleParameters> {
pub parameters: Arc<P>,
pub path: Vec<(MerkleTreeDigest<P>, MerkleTreeDigest<P>)>,
}
impl<P: MerkleParameters> MerklePath<P> {
pub fn verify<L: ToBytes>(&self, root_hash: &MerkleTreeDigest<P>, leaf: &L) -> Result<bool, MerkleError> {
if self.path.len() != P::DEPTH {
return Ok(false);
}
if !self.path.is_empty() {
let hash_input_size_in_bytes = (P::H::INPUT_SIZE_BITS / 8) * 2;
let mut buffer = vec![0u8; hash_input_size_in_bytes];
let claimed_leaf_hash = self.parameters.hash_leaf::<L>(leaf, &mut buffer)?;
if claimed_leaf_hash != self.path[0].0 && claimed_leaf_hash != self.path[0].1 {
return Ok(false);
};
let mut previous_hash = claimed_leaf_hash;
let mut buffer = vec![0u8; hash_input_size_in_bytes];
for &(ref hash, ref sibling_hash) in &self.path {
if &previous_hash != hash && &previous_hash != sibling_hash {
return Ok(false);
};
previous_hash = self.parameters.hash_inner_node(hash, sibling_hash, &mut buffer)?;
}
if root_hash != &previous_hash {
return Ok(false);
}
Ok(true)
} else {
Ok(false)
}
}
}
impl<P: MerkleParameters> Default for MerklePath<P> {
fn default() -> Self {
let mut path = Vec::with_capacity(P::DEPTH);
for _i in 0..P::DEPTH {
path.push((MerkleTreeDigest::<P>::default(), MerkleTreeDigest::<P>::default()));
}
Self {
parameters: Arc::new(P::default()),
path,
}
}
}