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factor out subtree-append logic

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Qyriad 2024-11-04 12:53:27 -07:00
parent ff9c8242ee
commit 95aeea9e07
1 changed files with 34 additions and 53 deletions
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87
src/merkle/smt/mod.rs
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@ -383,7 +383,7 @@ pub(crate) trait SparseMerkleTree<const DEPTH: u8> {
let hash = Self::hash_leaf(&leaf);
accumulator.nodes.insert(col, leaf);
accumulator.add_leaf(SubtreeLeaf { col, hash });
add_subtree_leaf(&mut accumulator.leaves, SubtreeLeaf { col, hash });
debug_assert!(current_leaf_buffer.is_empty());
}
@ -631,6 +631,7 @@ impl SubtreeLeaf {
}
}
/// Helper struct to organize the return value of [`SparseMerkleTree::sorted_pairs_to_leaves()`].
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) struct PairComputations<K, L> {
/// Literal leaves to be added to the sparse Merkle tree's internal mapping.
@ -639,36 +640,6 @@ pub(crate) struct PairComputations<K, L> {
pub leaves: Vec<Vec<SubtreeLeaf>>,
}
impl<K, L> PrecomputedSubtrees<K, L> {
pub fn add_leaf(&mut self, leaf: SubtreeLeaf) {
let last_subtree = match self.leaves.last_mut() {
// Base case.
None => {
self.leaves.push(vec![leaf]);
return;
},
Some(last_subtree) => last_subtree,
};
debug_assert!(!last_subtree.is_empty());
debug_assert!(last_subtree.len() <= COLS_PER_SUBTREE as usize);
// The multiple of 256 after 0 is 1, but 0 and 1 do not belong to different subtrees.
let last_subtree_col = u64::max(1, last_subtree.last().unwrap().col);
let next_subtree_col = if Integer::is_multiple_of(&last_subtree_col, &COLS_PER_SUBTREE) {
u64::next_multiple_of(last_subtree_col + 1, COLS_PER_SUBTREE)
} else {
last_subtree_col.next_multiple_of(COLS_PER_SUBTREE)
};
if leaf.col < next_subtree_col {
last_subtree.push(leaf);
} else {
let next_subtree = vec![leaf];
self.leaves.push(next_subtree);
}
}
}
// Derive requires `L` to impl Default, even though we don't actually need that.
impl<K, L> Default for PairComputations<K, L> {
fn default() -> Self {
@ -679,6 +650,36 @@ impl<K, L> Default for PairComputations<K, L> {
}
}
/// Handles the logic for figuring out whether the new leaf starts a new subtree or not.
fn add_subtree_leaf(subtrees: &mut Vec<Vec<SubtreeLeaf>>, leaf: SubtreeLeaf) {
let last_subtree = match subtrees.last_mut() {
// Base case.
None => {
subtrees.push(vec![leaf]);
return;
},
Some(last_subtree) => last_subtree,
};
debug_assert!(!last_subtree.is_empty());
debug_assert!(last_subtree.len() <= COLS_PER_SUBTREE as usize);
// The multiple of 256 after 0 is 1, but 0 and 1 do not belong to different subtrees.
let last_subtree_col = u64::max(1, last_subtree.last().unwrap().col);
let next_subtree_col = if Integer::is_multiple_of(&last_subtree_col, &COLS_PER_SUBTREE) {
u64::next_multiple_of(last_subtree_col + 1, COLS_PER_SUBTREE)
} else {
last_subtree_col.next_multiple_of(COLS_PER_SUBTREE)
};
if leaf.col < next_subtree_col {
last_subtree.push(leaf);
} else {
let next_subtree = vec![leaf];
subtrees.push(next_subtree);
}
}
// TESTS
// ================================================================================================
#[cfg(test)]
@ -687,9 +688,7 @@ mod test {
use alloc::{collections::BTreeMap, vec::Vec};
use num::Integer;
use super::{SparseMerkleTree, SubtreeLeaf, COLS_PER_SUBTREE};
use super::{SparseMerkleTree, SubtreeLeaf};
use crate::{
hash::rpo::RpoDigest,
merkle::{smt::InnerNode, NodeIndex, Smt, SmtLeaf, SMT_DEPTH},
@ -904,25 +903,7 @@ mod test {
accumulated_nodes.extend(nodes);
for subtree_leaf in next_leaves {
if leaf_subtrees.is_empty() {
leaf_subtrees.push(vec![subtree_leaf]);
continue;
}
let buffer_max_col =
u64::max(1, leaf_subtrees.last().unwrap().last().unwrap().col);
let next_subtree_col =
if Integer::is_multiple_of(&buffer_max_col, &COLS_PER_SUBTREE) {
u64::next_multiple_of(buffer_max_col + 1, COLS_PER_SUBTREE)
} else {
buffer_max_col.next_multiple_of(COLS_PER_SUBTREE)
};
if subtree_leaf.col < next_subtree_col {
leaf_subtrees.last_mut().unwrap().push(subtree_leaf);
} else {
leaf_subtrees.push(vec![subtree_leaf]);
}
super::add_subtree_leaf(&mut leaf_subtrees, subtree_leaf);
}
}