openethereum/src/triehash.rs
2016-01-06 13:53:23 +01:00

342 lines
8.7 KiB
Rust

//! Generetes trie root.
//!
//! This module should be used to generate trie root hash.
use std::collections::BTreeMap;
use std::cmp;
use hash::*;
use sha3::*;
use rlp;
use rlp::{RlpStream, Stream};
use vector::SharedPrefix;
/// Generates a trie root hash for a vector of values
///
/// ```rust
/// extern crate ethcore_util as util;
/// use std::str::FromStr;
/// use util::triehash::*;
/// use util::hash::*;
///
/// fn main() {
/// let v = vec![From::from("doe"), From::from("reindeer")];
/// let root = "e766d5d51b89dc39d981b41bda63248d7abce4f0225eefd023792a540bcffee3";
/// assert_eq!(ordered_trie_root(v), H256::from_str(root).unwrap());
/// }
/// ```
pub fn ordered_trie_root(input: Vec<Vec<u8>>) -> H256 {
let gen_input = input
// first put elements into btree to sort them by nibbles
// optimize it later
.into_iter()
.fold(BTreeMap::new(), | mut acc, vec | {
let len = acc.len();
acc.insert(rlp::encode(&len), vec);
acc
})
// then move them to a vector
.into_iter()
.map(|(k, v)| (as_nibbles(&k), v) )
.collect();
gen_trie_root(gen_input)
}
/// Generates a trie root hash for a vector of key-values
///
/// ```rust
/// extern crate ethcore_util as util;
/// use std::str::FromStr;
/// use util::triehash::*;
/// use util::hash::*;
///
/// fn main() {
/// let v = vec![
/// (From::from("doe"), From::from("reindeer")),
/// (From::from("dog"), From::from("puppy")),
/// (From::from("dogglesworth"), From::from("cat")),
/// ];
///
/// let root = "8aad789dff2f538bca5d8ea56e8abe10f4c7ba3a5dea95fea4cd6e7c3a1168d3";
/// assert_eq!(trie_root(v), H256::from_str(root).unwrap());
/// }
/// ```
pub fn trie_root(input: Vec<(Vec<u8>, Vec<u8>)>) -> H256 {
let gen_input = input
// first put elements into btree to sort them and to remove duplicates
.into_iter()
.fold(BTreeMap::new(), | mut acc, (k, v) | {
acc.insert(k, v);
acc
})
// then move them to a vector
.into_iter()
.map(|(k, v)| (as_nibbles(&k), v) )
.collect();
gen_trie_root(gen_input)
}
/// Generates a key-hashed (secure) trie root hash for a vector of key-values.
///
/// ```rust
/// extern crate ethcore_util as util;
/// use std::str::FromStr;
/// use util::triehash::*;
/// use util::hash::*;
///
/// fn main() {
/// let v = vec![
/// (From::from("doe"), From::from("reindeer")),
/// (From::from("dog"), From::from("puppy")),
/// (From::from("dogglesworth"), From::from("cat")),
/// ];
///
/// let root = "d4cd937e4a4368d7931a9cf51686b7e10abb3dce38a39000fd7902a092b64585";
/// assert_eq!(sec_trie_root(v), H256::from_str(root).unwrap());
/// }
/// ```
pub fn sec_trie_root(input: Vec<(Vec<u8>, Vec<u8>)>) -> H256 {
let gen_input = input
// first put elements into btree to sort them and to remove duplicates
.into_iter()
.fold(BTreeMap::new(), | mut acc, (k, v) | {
acc.insert(k.sha3().to_vec(), v);
acc
})
// then move them to a vector
.into_iter()
.map(|(k, v)| (as_nibbles(&k), v) )
.collect();
gen_trie_root(gen_input)
}
fn gen_trie_root(input: Vec<(Vec<u8>, Vec<u8>)>) -> H256 {
let mut stream = RlpStream::new();
hash256rlp(&input, 0, &mut stream);
stream.out().sha3()
}
/// Hex-prefix Notation. First nibble has flags: oddness = 2^0 & termination = 2^1.
///
/// The "termination marker" and "leaf-node" specifier are completely equivalent.
///
/// Input values are in range `[0, 0xf]`.
///
/// ```markdown
/// [0,0,1,2,3,4,5] 0x10012345 // 7 > 4
/// [0,1,2,3,4,5] 0x00012345 // 6 > 4
/// [1,2,3,4,5] 0x112345 // 5 > 3
/// [0,0,1,2,3,4] 0x00001234 // 6 > 3
/// [0,1,2,3,4] 0x101234 // 5 > 3
/// [1,2,3,4] 0x001234 // 4 > 3
/// [0,0,1,2,3,4,5,T] 0x30012345 // 7 > 4
/// [0,0,1,2,3,4,T] 0x20001234 // 6 > 4
/// [0,1,2,3,4,5,T] 0x20012345 // 6 > 4
/// [1,2,3,4,5,T] 0x312345 // 5 > 3
/// [1,2,3,4,T] 0x201234 // 4 > 3
/// ```
fn hex_prefix_encode(nibbles: &[u8], leaf: bool) -> Vec<u8> {
let inlen = nibbles.len();
let oddness_factor = inlen % 2;
// next even number divided by two
let reslen = (inlen + 2) >> 1;
let mut res = vec![];
res.reserve(reslen);
let first_byte = {
let mut bits = ((inlen as u8 & 1) + (2 * leaf as u8)) << 4;
if oddness_factor == 1 {
bits += nibbles[0];
}
bits
};
res.push(first_byte);
let mut offset = oddness_factor;
while offset < inlen {
let byte = (nibbles[offset] << 4) + nibbles[offset + 1];
res.push(byte);
offset += 2;
}
res
}
/// Converts slice of bytes to nibbles.
fn as_nibbles(bytes: &[u8]) -> Vec<u8> {
let mut res = vec![];
res.reserve(bytes.len() * 2);
for i in 0..bytes.len() {
res.push(bytes[i] >> 4);
res.push((bytes[i] << 4) >> 4);
}
res
}
fn hash256rlp(input: &[(Vec<u8>, Vec<u8>)], pre_len: usize, stream: &mut RlpStream) {
let inlen = input.len();
// in case of empty slice, just append empty data
if inlen == 0 {
stream.append_empty_data();
return;
}
// take slices
let key: &Vec<u8> = &input[0].0;
let value: &[u8] = &input[0].1;
// if the slice contains just one item, append the suffix of the key
// and then append value
if inlen == 1 {
stream.append_list(2);
stream.append(&hex_prefix_encode(&key[pre_len..], true));
stream.append(&value);
return;
}
// get length of the longest shared prefix in slice keys
let shared_prefix = input.iter()
// skip first element
.skip(1)
// get minimum number of shared nibbles between first and each successive
.fold(key.len(), | acc, &(ref k, _) | {
cmp::min(key.shared_prefix_len(&k), acc)
});
// if shared prefix is higher than current prefix append its
// new part of the key to the stream
// then recursively append suffixes of all items who had this key
if shared_prefix > pre_len {
stream.append_list(2);
stream.append(&hex_prefix_encode(&key[pre_len..shared_prefix], false));
hash256aux(input, shared_prefix, stream);
return;
}
// an item for every possible nibble/suffix
// + 1 for data
stream.append_list(17);
// if first key len is equal to prefix_len, move to next element
let mut begin = match pre_len == key.len() {
true => 1,
false => 0
};
// iterate over all possible nibbles
for i in 0..16 {
// cout how many successive elements have same next nibble
let len = match begin < input.len() {
true => input[begin..].iter()
.take_while(| pair | pair.0[pre_len] == i )
.count(),
false => 0
};
// if at least 1 successive element has the same nibble
// append their suffixes
match len {
0 => { stream.append_empty_data(); },
_ => hash256aux(&input[begin..(begin + len)], pre_len + 1, stream)
}
begin += len;
}
// if fist key len is equal prefix, append it's value
match pre_len == key.len() {
true => { stream.append(&value); },
false => { stream.append_empty_data(); }
};
}
fn hash256aux(input: &[(Vec<u8>, Vec<u8>)], pre_len: usize, stream: &mut RlpStream) {
let mut s = RlpStream::new();
hash256rlp(input, pre_len, &mut s);
let out = s.out();
match out.len() {
0...31 => stream.append_raw(&out, 1),
_ => stream.append(&out.sha3())
};
}
#[test]
fn test_nibbles() {
let v = vec![0x31, 0x23, 0x45];
let e = vec![3, 1, 2, 3, 4, 5];
assert_eq!(as_nibbles(&v), e);
// A => 65 => 0x41 => [4, 1]
let v: Vec<u8> = From::from("A");
let e = vec![4, 1];
assert_eq!(as_nibbles(&v), e);
}
#[test]
fn test_hex_prefix_encode() {
let v = vec![0, 0, 1, 2, 3, 4, 5];
let e = vec![0x10, 0x01, 0x23, 0x45];
let h = hex_prefix_encode(&v, false);
assert_eq!(h, e);
let v = vec![0, 1, 2, 3, 4, 5];
let e = vec![0x00, 0x01, 0x23, 0x45];
let h = hex_prefix_encode(&v, false);
assert_eq!(h, e);
let v = vec![0, 1, 2, 3, 4, 5];
let e = vec![0x20, 0x01, 0x23, 0x45];
let h = hex_prefix_encode(&v, true);
assert_eq!(h, e);
let v = vec![1, 2, 3, 4, 5];
let e = vec![0x31, 0x23, 0x45];
let h = hex_prefix_encode(&v, true);
assert_eq!(h, e);
let v = vec![1, 2, 3, 4];
let e = vec![0x00, 0x12, 0x34];
let h = hex_prefix_encode(&v, false);
assert_eq!(h, e);
let v = vec![4, 1];
let e = vec![0x20, 0x41];
let h = hex_prefix_encode(&v, true);
assert_eq!(h, e);
}
#[cfg(test)]
mod tests {
extern crate json_tests;
use self::json_tests::*;
use hash::*;
use triehash::*;
#[test]
fn test_triehash_out_of_order() {
assert!(trie_root(vec![
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
(vec![0x81u8, 0x23], vec![0x81u8, 0x23]),
(vec![0xf1u8, 0x23], vec![0xf1u8, 0x23]),
]) ==
trie_root(vec![
(vec![0x01u8, 0x23], vec![0x01u8, 0x23]),
(vec![0xf1u8, 0x23], vec![0xf1u8, 0x23]),
(vec![0x81u8, 0x23], vec![0x81u8, 0x23]),
]));
}
#[test]
fn test_triehash_json() {
execute_tests_from_directory::<trie::TriehashTest, _>("json-tests/json/trie/*.json", &mut | file, input, output | {
println!("file: {}, output: {:?}", file, output);
assert_eq!(trie_root(input), H256::from_slice(&output));
});
}
}