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Move tree_hash from ssz into own crate

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This commit is contained in:
Paul Hauner 2019-04-15 11:14:30 +10:00
parent 7132ee59c0
commit 0b5c10212d
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GPG Key ID: D362883A9218FCC6
10 changed files with 461 additions and 443 deletions
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1
Cargo.toml
View File

@ -18,6 +18,7 @@ members = [
"eth2/utils/ssz", "eth2/utils/ssz",
"eth2/utils/ssz_derive", "eth2/utils/ssz_derive",
"eth2/utils/swap_or_not_shuffle", "eth2/utils/swap_or_not_shuffle",
"eth2/utils/tree_hash",
"eth2/utils/fisher_yates_shuffle", "eth2/utils/fisher_yates_shuffle",
"eth2/utils/test_random_derive", "eth2/utils/test_random_derive",
"beacon_node", "beacon_node",

439
eth2/utils/ssz/src/cached_tree_hash.rs
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@ -1,439 +0,0 @@
use hashing::hash;
use int_to_bytes::int_to_bytes32;
use std::fmt::Debug;
use std::iter::Iterator;
use std::ops::Range;
mod impls;
mod resize;
mod tests;
const BYTES_PER_CHUNK: usize = 32;
const HASHSIZE: usize = 32;
const MERKLE_HASH_CHUNCK: usize = 2 * BYTES_PER_CHUNK;
#[derive(Debug, PartialEq, Clone)]
pub enum Error {
ShouldNotProduceBTreeOverlay,
NoFirstNode,
NoBytesForRoot,
UnableToObtainSlices,
UnableToGrowMerkleTree,
UnableToShrinkMerkleTree,
BytesAreNotEvenChunks(usize),
NoModifiedFieldForChunk(usize),
NoBytesForChunk(usize),
}
#[derive(Debug, PartialEq, Clone)]
pub enum ItemType {
Basic,
List,
Composite,
}
// TODO: remove debug requirement.
pub trait CachedTreeHash<Item>: Debug {
fn item_type() -> ItemType;
fn build_tree_hash_cache(&self) -> Result<TreeHashCache, Error>;
/// Return the number of bytes when this element is encoded as raw SSZ _without_ length
/// prefixes.
fn num_bytes(&self) -> usize;
fn offsets(&self) -> Result<Vec<usize>, Error>;
fn num_child_nodes(&self) -> usize;
fn packed_encoding(&self) -> Vec<u8>;
fn packing_factor() -> usize;
fn cached_hash_tree_root(
&self,
other: &Item,
cache: &mut TreeHashCache,
chunk: usize,
) -> Result<usize, Error>;
}
#[derive(Debug, PartialEq, Clone)]
pub struct TreeHashCache {
cache: Vec<u8>,
chunk_modified: Vec<bool>,
}
impl Into<Vec<u8>> for TreeHashCache {
fn into(self) -> Vec<u8> {
self.cache
}
}
impl TreeHashCache {
pub fn new<T>(item: &T) -> Result<Self, Error>
where
T: CachedTreeHash<T>,
{
item.build_tree_hash_cache()
}
pub fn from_elems(cache: Vec<u8>, chunk_modified: Vec<bool>) -> Self {
Self {
cache,
chunk_modified,
}
}
pub fn from_leaves_and_subtrees<T>(
item: &T,
leaves_and_subtrees: Vec<Self>,
) -> Result<Self, Error>
where
T: CachedTreeHash<T>,
{
let offset_handler = BTreeOverlay::new(item, 0)?;
// Note how many leaves were provided. If is not a power-of-two, we'll need to pad it out
// later.
let num_provided_leaf_nodes = leaves_and_subtrees.len();
// Allocate enough bytes to store the internal nodes and the leaves and subtrees, then fill
// all the to-be-built internal nodes with zeros and append the leaves and subtrees.
let internal_node_bytes = offset_handler.num_internal_nodes * BYTES_PER_CHUNK;
let leaves_and_subtrees_bytes = leaves_and_subtrees
.iter()
.fold(0, |acc, t| acc + t.bytes_len());
let mut cache = Vec::with_capacity(leaves_and_subtrees_bytes + internal_node_bytes);
cache.resize(internal_node_bytes, 0);
// Allocate enough bytes to store all the leaves.
let mut leaves = Vec::with_capacity(offset_handler.num_leaf_nodes * HASHSIZE);
// Iterate through all of the leaves/subtrees, adding their root as a leaf node and then
// concatenating their merkle trees.
for t in leaves_and_subtrees {
leaves.append(&mut t.root()?);
cache.append(&mut t.into_merkle_tree());
}
// Pad the leaves to an even power-of-two, using zeros.
pad_for_leaf_count(num_provided_leaf_nodes, &mut cache);
// Merkleize the leaves, then split the leaf nodes off them. Then, replace all-zeros
// internal nodes created earlier with the internal nodes generated by `merkleize`.
let mut merkleized = merkleize(leaves);
merkleized.split_off(internal_node_bytes);
cache.splice(0..internal_node_bytes, merkleized);
Ok(Self {
chunk_modified: vec![false; cache.len() / BYTES_PER_CHUNK],
cache,
})
}
pub fn from_bytes(bytes: Vec<u8>, initial_modified_state: bool) -> Result<Self, Error> {
if bytes.len() % BYTES_PER_CHUNK > 0 {
return Err(Error::BytesAreNotEvenChunks(bytes.len()));
}
Ok(Self {
chunk_modified: vec![initial_modified_state; bytes.len() / BYTES_PER_CHUNK],
cache: bytes,
})
}
pub fn bytes_len(&self) -> usize {
self.cache.len()
}
pub fn root(&self) -> Result<Vec<u8>, Error> {
self.cache
.get(0..HASHSIZE)
.ok_or_else(|| Error::NoBytesForRoot)
.and_then(|slice| Ok(slice.to_vec()))
}
pub fn splice(&mut self, chunk_range: Range<usize>, replace_with: Self) {
let (bytes, bools) = replace_with.into_components();
// Update the `chunk_modified` vec, marking all spliced-in nodes as changed.
self.chunk_modified.splice(chunk_range.clone(), bools);
self.cache
.splice(node_range_to_byte_range(&chunk_range), bytes);
}
pub fn maybe_update_chunk(&mut self, chunk: usize, to: &[u8]) -> Result<(), Error> {
let start = chunk * BYTES_PER_CHUNK;
let end = start + BYTES_PER_CHUNK;
if !self.chunk_equals(chunk, to)? {
self.cache
.get_mut(start..end)
.ok_or_else(|| Error::NoModifiedFieldForChunk(chunk))?
.copy_from_slice(to);
self.chunk_modified[chunk] = true;
}
Ok(())
}
pub fn slices(&self, chunk_range: Range<usize>) -> Option<(&[u8], &[bool])> {
Some((
self.cache.get(node_range_to_byte_range(&chunk_range))?,
self.chunk_modified.get(chunk_range)?,
))
}
pub fn modify_chunk(&mut self, chunk: usize, to: &[u8]) -> Result<(), Error> {
let start = chunk * BYTES_PER_CHUNK;
let end = start + BYTES_PER_CHUNK;
self.cache
.get_mut(start..end)
.ok_or_else(|| Error::NoBytesForChunk(chunk))?
.copy_from_slice(to);
self.chunk_modified[chunk] = true;
Ok(())
}
pub fn get_chunk(&self, chunk: usize) -> Result<&[u8], Error> {
let start = chunk * BYTES_PER_CHUNK;
let end = start + BYTES_PER_CHUNK;
Ok(self
.cache
.get(start..end)
.ok_or_else(|| Error::NoModifiedFieldForChunk(chunk))?)
}
pub fn chunk_equals(&mut self, chunk: usize, other: &[u8]) -> Result<bool, Error> {
Ok(self.get_chunk(chunk)? == other)
}
pub fn changed(&self, chunk: usize) -> Result<bool, Error> {
self.chunk_modified
.get(chunk)
.cloned()
.ok_or_else(|| Error::NoModifiedFieldForChunk(chunk))
}
pub fn either_modified(&self, children: (&usize, &usize)) -> Result<bool, Error> {
Ok(self.changed(*children.0)? | self.changed(*children.1)?)
}
pub fn hash_children(&self, children: (&usize, &usize)) -> Result<Vec<u8>, Error> {
let mut child_bytes = Vec::with_capacity(BYTES_PER_CHUNK * 2);
child_bytes.append(&mut self.get_chunk(*children.0)?.to_vec());
child_bytes.append(&mut self.get_chunk(*children.1)?.to_vec());
Ok(hash(&child_bytes))
}
pub fn mix_in_length(&self, chunk: usize, length: usize) -> Result<Vec<u8>, Error> {
let mut bytes = Vec::with_capacity(2 * BYTES_PER_CHUNK);
bytes.append(&mut self.get_chunk(chunk)?.to_vec());
bytes.append(&mut int_to_bytes32(length as u64));
Ok(hash(&bytes))
}
pub fn into_merkle_tree(self) -> Vec<u8> {
self.cache
}
pub fn into_components(self) -> (Vec<u8>, Vec<bool>) {
(self.cache, self.chunk_modified)
}
}
fn children(parent: usize) -> (usize, usize) {
((2 * parent + 1), (2 * parent + 2))
}
fn num_nodes(num_leaves: usize) -> usize {
2 * num_leaves - 1
}
fn node_range_to_byte_range(node_range: &Range<usize>) -> Range<usize> {
node_range.start * HASHSIZE..node_range.end * HASHSIZE
}
#[derive(Debug)]
pub struct BTreeOverlay {
num_internal_nodes: usize,
pub num_leaf_nodes: usize,
first_node: usize,
next_node: usize,
offsets: Vec<usize>,
}
impl BTreeOverlay {
pub fn new<T>(item: &T, initial_offset: usize) -> Result<Self, Error>
where
T: CachedTreeHash<T>,
{
Self::from_lengths(initial_offset, item.offsets()?)
}
fn from_lengths(offset: usize, mut lengths: Vec<usize>) -> Result<Self, Error> {
// Extend it to the next power-of-two, if it is not already.
let num_leaf_nodes = if lengths.len().is_power_of_two() {
lengths.len()
} else {
let num_leaf_nodes = lengths.len().next_power_of_two();
lengths.resize(num_leaf_nodes, 1);
num_leaf_nodes
};
let num_nodes = num_nodes(num_leaf_nodes);
let num_internal_nodes = num_nodes - num_leaf_nodes;
let mut offsets = Vec::with_capacity(num_nodes);
offsets.append(&mut (offset..offset + num_internal_nodes).collect());
let mut next_node = num_internal_nodes + offset;
for i in 0..num_leaf_nodes {
offsets.push(next_node);
next_node += lengths[i];
}
Ok(Self {
num_internal_nodes,
num_leaf_nodes,
offsets,
first_node: offset,
next_node,
})
}
pub fn root(&self) -> usize {
self.first_node
}
pub fn height(&self) -> usize {
self.num_leaf_nodes.trailing_zeros() as usize
}
pub fn chunk_range(&self) -> Range<usize> {
self.first_node..self.next_node
}
pub fn total_chunks(&self) -> usize {
self.next_node - self.first_node
}
pub fn total_nodes(&self) -> usize {
self.num_internal_nodes + self.num_leaf_nodes
}
pub fn first_leaf_node(&self) -> Result<usize, Error> {
self.offsets
.get(self.num_internal_nodes)
.cloned()
.ok_or_else(|| Error::NoFirstNode)
}
pub fn next_node(&self) -> usize {
self.next_node
}
/// Returns an iterator visiting each internal node, providing the left and right child chunks
/// for the node.
pub fn iter_internal_nodes<'a>(
&'a self,
) -> impl DoubleEndedIterator<Item = (&'a usize, (&'a usize, &'a usize))> {
let internal_nodes = &self.offsets[0..self.num_internal_nodes];
internal_nodes.iter().enumerate().map(move |(i, parent)| {
let children = children(i);
(
parent,
(&self.offsets[children.0], &self.offsets[children.1]),
)
})
}
/// Returns an iterator visiting each leaf node, providing the chunk for that node.
pub fn iter_leaf_nodes<'a>(&'a self) -> impl DoubleEndedIterator<Item = &'a usize> {
let leaf_nodes = &self.offsets[self.num_internal_nodes..];
leaf_nodes.iter()
}
}
/// Split `values` into a power-of-two, identical-length chunks (padding with `0`) and merkleize
/// them, returning the entire merkle tree.
///
/// The root hash is `merkleize(values)[0..BYTES_PER_CHUNK]`.
pub fn merkleize(values: Vec<u8>) -> Vec<u8> {
let values = sanitise_bytes(values);
let leaves = values.len() / HASHSIZE;
if leaves == 0 {
panic!("No full leaves");
}
if !leaves.is_power_of_two() {
panic!("leaves is not power of two");
}
let mut o: Vec<u8> = vec![0; (num_nodes(leaves) - leaves) * HASHSIZE];
o.append(&mut values.to_vec());
let mut i = o.len();
let mut j = o.len() - values.len();
while i >= MERKLE_HASH_CHUNCK {
i -= MERKLE_HASH_CHUNCK;
let hash = hash(&o[i..i + MERKLE_HASH_CHUNCK]);
j -= HASHSIZE;
o[j..j + HASHSIZE].copy_from_slice(&hash);
}
o
}
pub fn sanitise_bytes(mut bytes: Vec<u8>) -> Vec<u8> {
let present_leaves = num_unsanitized_leaves(bytes.len());
let required_leaves = present_leaves.next_power_of_two();
if (present_leaves != required_leaves) | last_leaf_needs_padding(bytes.len()) {
bytes.resize(num_bytes(required_leaves), 0);
}
bytes
}
fn pad_for_leaf_count(num_leaves: usize, bytes: &mut Vec<u8>) {
let required_leaves = num_leaves.next_power_of_two();
bytes.resize(
bytes.len() + (required_leaves - num_leaves) * BYTES_PER_CHUNK,
0,
);
}
fn last_leaf_needs_padding(num_bytes: usize) -> bool {
num_bytes % HASHSIZE != 0
}
/// Rounds up
fn num_unsanitized_leaves(num_bytes: usize) -> usize {
(num_bytes + HASHSIZE - 1) / HASHSIZE
}
/// Rounds up
fn num_sanitized_leaves(num_bytes: usize) -> usize {
let leaves = (num_bytes + HASHSIZE - 1) / HASHSIZE;
leaves.next_power_of_two()
}
fn num_bytes(num_leaves: usize) -> usize {
num_leaves * HASHSIZE
}

1
eth2/utils/ssz/src/lib.rs
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@ -10,7 +10,6 @@
extern crate bytes; extern crate bytes;
extern crate ethereum_types; extern crate ethereum_types;
mod cached_tree_hash;
pub mod decode; pub mod decode;
pub mod encode; pub mod encode;
mod signed_root; mod signed_root;

11
eth2/utils/tree_hash/Cargo.toml Normal file
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@ -0,0 +1,11 @@
[package]
name = "tree_hash"
version = "0.1.0"
authors = ["Paul Hauner <paul@paulhauner.com>"]
edition = "2018"
[dependencies]
ethereum-types = "0.5"
hashing = { path = "../hashing" }
int_to_bytes = { path = "../int_to_bytes" }
ssz = { path = "../ssz" }

0
eth2/utils/tree_hash/src/btree_overlay.rs Normal file
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193
eth2/utils/tree_hash/src/cached_tree_hash.rs Normal file
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@ -0,0 +1,193 @@
use super::*;
#[derive(Debug, PartialEq, Clone)]
pub struct TreeHashCache {
cache: Vec<u8>,
chunk_modified: Vec<bool>,
}
impl Into<Vec<u8>> for TreeHashCache {
fn into(self) -> Vec<u8> {
self.cache
}
}
impl TreeHashCache {
pub fn new<T>(item: &T) -> Result<Self, Error>
where
T: CachedTreeHash<T>,
{
item.build_tree_hash_cache()
}
pub fn from_elems(cache: Vec<u8>, chunk_modified: Vec<bool>) -> Self {
Self {
cache,
chunk_modified,
}
}
pub fn from_leaves_and_subtrees<T>(
item: &T,
leaves_and_subtrees: Vec<Self>,
) -> Result<Self, Error>
where
T: CachedTreeHash<T>,
{
let offset_handler = BTreeOverlay::new(item, 0)?;
// Note how many leaves were provided. If is not a power-of-two, we'll need to pad it out
// later.
let num_provided_leaf_nodes = leaves_and_subtrees.len();
// Allocate enough bytes to store the internal nodes and the leaves and subtrees, then fill
// all the to-be-built internal nodes with zeros and append the leaves and subtrees.
let internal_node_bytes = offset_handler.num_internal_nodes * BYTES_PER_CHUNK;
let leaves_and_subtrees_bytes = leaves_and_subtrees
.iter()
.fold(0, |acc, t| acc + t.bytes_len());
let mut cache = Vec::with_capacity(leaves_and_subtrees_bytes + internal_node_bytes);
cache.resize(internal_node_bytes, 0);
// Allocate enough bytes to store all the leaves.
let mut leaves = Vec::with_capacity(offset_handler.num_leaf_nodes * HASHSIZE);
// Iterate through all of the leaves/subtrees, adding their root as a leaf node and then
// concatenating their merkle trees.
for t in leaves_and_subtrees {
leaves.append(&mut t.root()?);
cache.append(&mut t.into_merkle_tree());
}
// Pad the leaves to an even power-of-two, using zeros.
pad_for_leaf_count(num_provided_leaf_nodes, &mut cache);
// Merkleize the leaves, then split the leaf nodes off them. Then, replace all-zeros
// internal nodes created earlier with the internal nodes generated by `merkleize`.
let mut merkleized = merkleize(leaves);
merkleized.split_off(internal_node_bytes);
cache.splice(0..internal_node_bytes, merkleized);
Ok(Self {
chunk_modified: vec![false; cache.len() / BYTES_PER_CHUNK],
cache,
})
}
pub fn from_bytes(bytes: Vec<u8>, initial_modified_state: bool) -> Result<Self, Error> {
if bytes.len() % BYTES_PER_CHUNK > 0 {
return Err(Error::BytesAreNotEvenChunks(bytes.len()));
}
Ok(Self {
chunk_modified: vec![initial_modified_state; bytes.len() / BYTES_PER_CHUNK],
cache: bytes,
})
}
pub fn bytes_len(&self) -> usize {
self.cache.len()
}
pub fn root(&self) -> Result<Vec<u8>, Error> {
self.cache
.get(0..HASHSIZE)
.ok_or_else(|| Error::NoBytesForRoot)
.and_then(|slice| Ok(slice.to_vec()))
}
pub fn splice(&mut self, chunk_range: Range<usize>, replace_with: Self) {
let (bytes, bools) = replace_with.into_components();
// Update the `chunk_modified` vec, marking all spliced-in nodes as changed.
self.chunk_modified.splice(chunk_range.clone(), bools);
self.cache
.splice(node_range_to_byte_range(&chunk_range), bytes);
}
pub fn maybe_update_chunk(&mut self, chunk: usize, to: &[u8]) -> Result<(), Error> {
let start = chunk * BYTES_PER_CHUNK;
let end = start + BYTES_PER_CHUNK;
if !self.chunk_equals(chunk, to)? {
self.cache
.get_mut(start..end)
.ok_or_else(|| Error::NoModifiedFieldForChunk(chunk))?
.copy_from_slice(to);
self.chunk_modified[chunk] = true;
}
Ok(())
}
pub fn slices(&self, chunk_range: Range<usize>) -> Option<(&[u8], &[bool])> {
Some((
self.cache.get(node_range_to_byte_range(&chunk_range))?,
self.chunk_modified.get(chunk_range)?,
))
}
pub fn modify_chunk(&mut self, chunk: usize, to: &[u8]) -> Result<(), Error> {
let start = chunk * BYTES_PER_CHUNK;
let end = start + BYTES_PER_CHUNK;
self.cache
.get_mut(start..end)
.ok_or_else(|| Error::NoBytesForChunk(chunk))?
.copy_from_slice(to);
self.chunk_modified[chunk] = true;
Ok(())
}
pub fn get_chunk(&self, chunk: usize) -> Result<&[u8], Error> {
let start = chunk * BYTES_PER_CHUNK;
let end = start + BYTES_PER_CHUNK;
Ok(self
.cache
.get(start..end)
.ok_or_else(|| Error::NoModifiedFieldForChunk(chunk))?)
}
pub fn chunk_equals(&mut self, chunk: usize, other: &[u8]) -> Result<bool, Error> {
Ok(self.get_chunk(chunk)? == other)
}
pub fn changed(&self, chunk: usize) -> Result<bool, Error> {
self.chunk_modified
.get(chunk)
.cloned()
.ok_or_else(|| Error::NoModifiedFieldForChunk(chunk))
}
pub fn either_modified(&self, children: (&usize, &usize)) -> Result<bool, Error> {
Ok(self.changed(*children.0)? | self.changed(*children.1)?)
}
pub fn hash_children(&self, children: (&usize, &usize)) -> Result<Vec<u8>, Error> {
let mut child_bytes = Vec::with_capacity(BYTES_PER_CHUNK * 2);
child_bytes.append(&mut self.get_chunk(*children.0)?.to_vec());
child_bytes.append(&mut self.get_chunk(*children.1)?.to_vec());
Ok(hash(&child_bytes))
}
pub fn mix_in_length(&self, chunk: usize, length: usize) -> Result<Vec<u8>, Error> {
let mut bytes = Vec::with_capacity(2 * BYTES_PER_CHUNK);
bytes.append(&mut self.get_chunk(chunk)?.to_vec());
bytes.append(&mut int_to_bytes32(length as u64));
Ok(hash(&bytes))
}
pub fn into_merkle_tree(self) -> Vec<u8> {
self.cache
}
pub fn into_components(self) -> (Vec<u8>, Vec<bool>) {
(self.cache, self.chunk_modified)
}
}

2
eth2/utils/ssz/src/cached_tree_hash/impls.rs → eth2/utils/tree_hash/src/impls.rs
View File

@ -1,6 +1,6 @@
use super::resize::{grow_merkle_cache, shrink_merkle_cache}; use super::resize::{grow_merkle_cache, shrink_merkle_cache};
use super::*; use super::*;
use crate::ssz_encode; use ssz::ssz_encode;
impl CachedTreeHash<u64> for u64 { impl CachedTreeHash<u64> for u64 {
fn item_type() -> ItemType { fn item_type() -> ItemType {

249
eth2/utils/tree_hash/src/lib.rs Normal file
View File

@ -0,0 +1,249 @@
use hashing::hash;
use int_to_bytes::int_to_bytes32;
use std::fmt::Debug;
use std::iter::Iterator;
use std::ops::Range;
mod cached_tree_hash;
mod impls;
mod resize;
pub use cached_tree_hash::TreeHashCache;
pub const BYTES_PER_CHUNK: usize = 32;
pub const HASHSIZE: usize = 32;
pub const MERKLE_HASH_CHUNCK: usize = 2 * BYTES_PER_CHUNK;
#[derive(Debug, PartialEq, Clone)]
pub enum Error {
ShouldNotProduceBTreeOverlay,
NoFirstNode,
NoBytesForRoot,
UnableToObtainSlices,
UnableToGrowMerkleTree,
UnableToShrinkMerkleTree,
BytesAreNotEvenChunks(usize),
NoModifiedFieldForChunk(usize),
NoBytesForChunk(usize),
}
#[derive(Debug, PartialEq, Clone)]
pub enum ItemType {
Basic,
List,
Composite,
}
// TODO: remove debug requirement.
pub trait CachedTreeHash<Item>: Debug {
fn item_type() -> ItemType;
fn build_tree_hash_cache(&self) -> Result<TreeHashCache, Error>;
/// Return the number of bytes when this element is encoded as raw SSZ _without_ length
/// prefixes.
fn num_bytes(&self) -> usize;
fn offsets(&self) -> Result<Vec<usize>, Error>;
fn num_child_nodes(&self) -> usize;
fn packed_encoding(&self) -> Vec<u8>;
fn packing_factor() -> usize;
fn cached_hash_tree_root(
&self,
other: &Item,
cache: &mut TreeHashCache,
chunk: usize,
) -> Result<usize, Error>;
}
fn children(parent: usize) -> (usize, usize) {
((2 * parent + 1), (2 * parent + 2))
}
fn num_nodes(num_leaves: usize) -> usize {
2 * num_leaves - 1
}
fn node_range_to_byte_range(node_range: &Range<usize>) -> Range<usize> {
node_range.start * HASHSIZE..node_range.end * HASHSIZE
}
#[derive(Debug)]
pub struct BTreeOverlay {
num_internal_nodes: usize,
pub num_leaf_nodes: usize,
first_node: usize,
next_node: usize,
offsets: Vec<usize>,
}
impl BTreeOverlay {
pub fn new<T>(item: &T, initial_offset: usize) -> Result<Self, Error>
where
T: CachedTreeHash<T>,
{
Self::from_lengths(initial_offset, item.offsets()?)
}
fn from_lengths(offset: usize, mut lengths: Vec<usize>) -> Result<Self, Error> {
// Extend it to the next power-of-two, if it is not already.
let num_leaf_nodes = if lengths.len().is_power_of_two() {
lengths.len()
} else {
let num_leaf_nodes = lengths.len().next_power_of_two();
lengths.resize(num_leaf_nodes, 1);
num_leaf_nodes
};
let num_nodes = num_nodes(num_leaf_nodes);
let num_internal_nodes = num_nodes - num_leaf_nodes;
let mut offsets = Vec::with_capacity(num_nodes);
offsets.append(&mut (offset..offset + num_internal_nodes).collect());
let mut next_node = num_internal_nodes + offset;
for i in 0..num_leaf_nodes {
offsets.push(next_node);
next_node += lengths[i];
}
Ok(Self {
num_internal_nodes,
num_leaf_nodes,
offsets,
first_node: offset,
next_node,
})
}
pub fn root(&self) -> usize {
self.first_node
}
pub fn height(&self) -> usize {
self.num_leaf_nodes.trailing_zeros() as usize
}
pub fn chunk_range(&self) -> Range<usize> {
self.first_node..self.next_node
}
pub fn total_chunks(&self) -> usize {
self.next_node - self.first_node
}
pub fn total_nodes(&self) -> usize {
self.num_internal_nodes + self.num_leaf_nodes
}
pub fn first_leaf_node(&self) -> Result<usize, Error> {
self.offsets
.get(self.num_internal_nodes)
.cloned()
.ok_or_else(|| Error::NoFirstNode)
}
pub fn next_node(&self) -> usize {
self.next_node
}
/// Returns an iterator visiting each internal node, providing the left and right child chunks
/// for the node.
pub fn iter_internal_nodes<'a>(
&'a self,
) -> impl DoubleEndedIterator<Item = (&'a usize, (&'a usize, &'a usize))> {
let internal_nodes = &self.offsets[0..self.num_internal_nodes];
internal_nodes.iter().enumerate().map(move |(i, parent)| {
let children = children(i);
(
parent,
(&self.offsets[children.0], &self.offsets[children.1]),
)
})
}
/// Returns an iterator visiting each leaf node, providing the chunk for that node.
pub fn iter_leaf_nodes<'a>(&'a self) -> impl DoubleEndedIterator<Item = &'a usize> {
let leaf_nodes = &self.offsets[self.num_internal_nodes..];
leaf_nodes.iter()
}
}
/// Split `values` into a power-of-two, identical-length chunks (padding with `0`) and merkleize
/// them, returning the entire merkle tree.
///
/// The root hash is `merkleize(values)[0..BYTES_PER_CHUNK]`.
pub fn merkleize(values: Vec<u8>) -> Vec<u8> {
let values = sanitise_bytes(values);
let leaves = values.len() / HASHSIZE;
if leaves == 0 {
panic!("No full leaves");
}
if !leaves.is_power_of_two() {
panic!("leaves is not power of two");
}
let mut o: Vec<u8> = vec![0; (num_nodes(leaves) - leaves) * HASHSIZE];
o.append(&mut values.to_vec());
let mut i = o.len();
let mut j = o.len() - values.len();
while i >= MERKLE_HASH_CHUNCK {
i -= MERKLE_HASH_CHUNCK;
let hash = hash(&o[i..i + MERKLE_HASH_CHUNCK]);
j -= HASHSIZE;
o[j..j + HASHSIZE].copy_from_slice(&hash);
}
o
}
pub fn sanitise_bytes(mut bytes: Vec<u8>) -> Vec<u8> {
let present_leaves = num_unsanitized_leaves(bytes.len());
let required_leaves = present_leaves.next_power_of_two();
if (present_leaves != required_leaves) | last_leaf_needs_padding(bytes.len()) {
bytes.resize(num_bytes(required_leaves), 0);
}
bytes
}
fn pad_for_leaf_count(num_leaves: usize, bytes: &mut Vec<u8>) {
let required_leaves = num_leaves.next_power_of_two();
bytes.resize(
bytes.len() + (required_leaves - num_leaves) * BYTES_PER_CHUNK,
0,
);
}
fn last_leaf_needs_padding(num_bytes: usize) -> bool {
num_bytes % HASHSIZE != 0
}
/// Rounds up
fn num_unsanitized_leaves(num_bytes: usize) -> usize {
(num_bytes + HASHSIZE - 1) / HASHSIZE
}
/// Rounds up
fn num_sanitized_leaves(num_bytes: usize) -> usize {
let leaves = (num_bytes + HASHSIZE - 1) / HASHSIZE;
leaves.next_power_of_two()
}
fn num_bytes(num_leaves: usize) -> usize {
num_leaves * HASHSIZE
}

0
eth2/utils/ssz/src/cached_tree_hash/resize.rs → eth2/utils/tree_hash/src/resize.rs
View File

8
eth2/utils/ssz/src/cached_tree_hash/tests.rs → eth2/utils/tree_hash/tests/tests.rs
View File

@ -1,6 +1,10 @@
#![cfg(test)] use hashing::hash;
use super::*;
use int_to_bytes::{int_to_bytes32, int_to_bytes8}; use int_to_bytes::{int_to_bytes32, int_to_bytes8};
use tree_hash::*;
fn num_nodes(num_leaves: usize) -> usize {
2 * num_leaves - 1
}
#[derive(Clone, Debug)] #[derive(Clone, Debug)]
pub struct Inner { pub struct Inner {