205 lines
6.1 KiB
Rust
205 lines
6.1 KiB
Rust
|
// Rust Bitcoin Library
|
||
|
// Written in 2014 by
|
||
|
// Andrew Poelstra <apoelstra@wpsoftware.net>
|
||
|
// To the extent possible under law, the author(s) have dedicated all
|
||
|
// copyright and related and neighboring rights to this software to
|
||
|
// the public domain worldwide. This software is distributed without
|
||
|
// any warranty.
|
||
|
//
|
||
|
// You should have received a copy of the CC0 Public Domain Dedication
|
||
|
// along with this software.
|
||
|
// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
|
||
|
//
|
||
|
|
||
|
//! # Hash functions
|
||
|
//!
|
||
|
//! Utility functions related to hashing data, including merkleization
|
||
|
|
||
|
use collections::bitv::{Bitv, from_bytes};
|
||
|
use core::char::from_digit;
|
||
|
use core::cmp::min;
|
||
|
use std::fmt;
|
||
|
use std::io::{IoResult, IoError, InvalidInput};
|
||
|
use std::mem::transmute;
|
||
|
|
||
|
use crypto::digest::Digest;
|
||
|
use crypto::sha2;
|
||
|
|
||
|
use network::serialize::Serializable;
|
||
|
use util::iter::FixedTakeable;
|
||
|
use util::uint::Uint128;
|
||
|
use util::uint::Uint256;
|
||
|
|
||
|
/// A Bitcoin hash, 32-bytes, computed from x as SHA256(SHA256(x))
|
||
|
pub struct Sha256dHash([u8, ..32]);
|
||
|
|
||
|
/// Returns the all-zeroes "hash"
|
||
|
pub fn zero_hash() -> Sha256dHash { Sha256dHash([0u8, ..32]) }
|
||
|
|
||
|
impl Sha256dHash {
|
||
|
/// Create a hash by hashing some data
|
||
|
pub fn from_data(data: &[u8]) -> Sha256dHash {
|
||
|
let Sha256dHash(mut ret) = zero_hash();
|
||
|
let mut sha2 = sha2::Sha256::new();
|
||
|
sha2.input(data);
|
||
|
sha2.result(ret.as_mut_slice());
|
||
|
sha2.reset();
|
||
|
sha2.input(ret.as_slice());
|
||
|
sha2.result(ret.as_mut_slice());
|
||
|
Sha256dHash(ret)
|
||
|
}
|
||
|
|
||
|
/// Returns a slice containing the bytes of the has
|
||
|
pub fn as_slice<'a>(&'a self) -> &'a [u8] {
|
||
|
let &Sha256dHash(ref data) = self;
|
||
|
data.as_slice()
|
||
|
}
|
||
|
|
||
|
/// Converts a hash to a bit vector
|
||
|
pub fn as_bitv(&self) -> Bitv {
|
||
|
from_bytes(self.as_slice())
|
||
|
}
|
||
|
|
||
|
/// Converts a hash to a Uint256, interpreting it as a little endian encoding.
|
||
|
pub fn as_uint256(&self) -> Uint256 {
|
||
|
let &Sha256dHash(data) = self;
|
||
|
unsafe { Uint256(transmute(data)) }
|
||
|
}
|
||
|
|
||
|
/// Converts a hash to a Uint128, interpreting it as a little endian encoding.
|
||
|
pub fn as_uint128(&self) -> Uint128 {
|
||
|
let &Sha256dHash(data) = self;
|
||
|
unsafe { Uint128(transmute([data[16], data[17], data[18], data[19], data[20],
|
||
|
data[21], data[22], data[23], data[24], data[25],
|
||
|
data[26], data[27], data[28], data[29], data[30],
|
||
|
data[31]])) }
|
||
|
}
|
||
|
|
||
|
/// Human-readable hex output
|
||
|
pub fn le_hex_string(&self) -> String {
|
||
|
let &Sha256dHash(data) = self;
|
||
|
let mut ret = String::with_capacity(64);
|
||
|
for i in range(0u, 32).rev() {
|
||
|
ret.push_char(from_digit((data[i] / 0x10) as uint, 16).unwrap());
|
||
|
ret.push_char(from_digit((data[i] & 0x0f) as uint, 16).unwrap());
|
||
|
}
|
||
|
ret
|
||
|
}
|
||
|
}
|
||
|
|
||
|
impl Clone for Sha256dHash {
|
||
|
fn clone(&self) -> Sha256dHash {
|
||
|
*self
|
||
|
}
|
||
|
}
|
||
|
|
||
|
impl PartialEq for Sha256dHash {
|
||
|
fn eq(&self, other: &Sha256dHash) -> bool {
|
||
|
let &Sha256dHash(ref mydata) = self;
|
||
|
let &Sha256dHash(ref yourdata) = other;
|
||
|
for i in range(0u, 32) {
|
||
|
if mydata[i] != yourdata[i] {
|
||
|
return false;
|
||
|
}
|
||
|
}
|
||
|
return true;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
impl Serializable for Sha256dHash {
|
||
|
fn serialize(&self) -> Vec<u8> {
|
||
|
let &Sha256dHash(ref data) = self;
|
||
|
data.iter().map(|n| *n).collect()
|
||
|
}
|
||
|
|
||
|
fn deserialize<I: Iterator<u8>>(iter: I) -> IoResult<Sha256dHash> {
|
||
|
let Sha256dHash(mut ret) = zero_hash();
|
||
|
let mut fixediter = iter.enumerate().fixed_take(32);
|
||
|
for (n, data) in fixediter {
|
||
|
ret[n] = data;
|
||
|
}
|
||
|
match fixediter.is_err() {
|
||
|
false => Ok(Sha256dHash(ret)),
|
||
|
true => Err(IoError {
|
||
|
kind: InvalidInput,
|
||
|
desc: "unexpected end of input",
|
||
|
detail: Some(format!("Need 32 bytes, was {:} short.", fixediter.remaining()))
|
||
|
})
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
impl fmt::LowerHex for Sha256dHash {
|
||
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
|
let &Sha256dHash(ref data) = self;
|
||
|
let mut rv = [0, ..64];
|
||
|
let mut hex = data.iter().rev().map(|n| *n).enumerate();
|
||
|
for (i, ch) in hex {
|
||
|
rv[2*i] = from_digit(ch as uint / 16, 16).unwrap() as u8;
|
||
|
rv[2*i + 1] = from_digit(ch as uint % 16, 16).unwrap() as u8;
|
||
|
}
|
||
|
f.write(rv.as_slice())
|
||
|
}
|
||
|
}
|
||
|
|
||
|
impl fmt::Show for Sha256dHash {
|
||
|
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||
|
write!(f, "{:x}", *self)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
//TODO: this should be an impl and the function have first parameter self.
|
||
|
//See https://github.com/rust-lang/rust/issues/15060 for why this isn't so.
|
||
|
//impl<T: Serializable> Vec<T> {
|
||
|
/// Construct a merkle tree from a vector, with elements ordered as
|
||
|
/// they were in the original vector, and return the merkle root.
|
||
|
pub fn merkle_root<T: Serializable>(data: &[T]) -> Sha256dHash {
|
||
|
fn merkle_root(data: Vec<Sha256dHash>) -> Sha256dHash {
|
||
|
// Base case
|
||
|
if data.len() < 1 {
|
||
|
return zero_hash();
|
||
|
}
|
||
|
if data.len() < 2 {
|
||
|
return data[0];
|
||
|
}
|
||
|
// Recursion
|
||
|
let mut next = vec![];
|
||
|
for idx in range(0, (data.len() + 1) / 2) {
|
||
|
let idx1 = 2 * idx;
|
||
|
let idx2 = min(idx1 + 1, data.len() - 1);
|
||
|
let to_hash = data[idx1].hash().serialize().append(data[idx2].hash().serialize().as_slice());
|
||
|
next.push(to_hash.hash());
|
||
|
}
|
||
|
merkle_root(next)
|
||
|
}
|
||
|
merkle_root(data.iter().map(|obj| obj.hash()).collect())
|
||
|
}
|
||
|
//}
|
||
|
|
||
|
|
||
|
#[cfg(test)]
|
||
|
mod tests {
|
||
|
use std::prelude::*;
|
||
|
use collections::bitv::from_bytes;
|
||
|
|
||
|
use util::hash::Sha256dHash;
|
||
|
use util::misc::hex_bytes;
|
||
|
|
||
|
#[test]
|
||
|
fn test_sha256d() {
|
||
|
assert_eq!(Sha256dHash::from_data(&[]).as_slice(),
|
||
|
hex_bytes("5df6e0e2761359d30a8275058e299fcc0381534545f55cf43e41983f5d4c9456").unwrap().as_slice());
|
||
|
assert_eq!(Sha256dHash::from_data(&[]).le_hex_string(),
|
||
|
"56944c5d3f98413ef45cf54545538103cc9f298e0575820ad3591376e2e0f65d".to_string());
|
||
|
assert_eq!(Sha256dHash::from_data(b"TEST").as_slice(),
|
||
|
hex_bytes("d7bd34bfe44a18d2aa755a344fe3e6b06ed0473772e6dfce16ac71ba0b0a241c").unwrap().as_slice());
|
||
|
}
|
||
|
|
||
|
#[test]
|
||
|
fn test_hash_to_bitvset() {
|
||
|
assert_eq!(Sha256dHash::from_data(&[]).as_bitv(),
|
||
|
from_bytes(hex_bytes("5df6e0e2761359d30a8275058e299fcc0381534545f55cf43e41983f5d4c9456").unwrap().as_slice()));
|
||
|
}
|
||
|
}
|
||
|
|