zvault/src/util/hash.rs

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Rust
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2017-03-10 11:43:32 +00:00
use serde::{self, Serialize, Deserialize};
use serde::de::Error;
use serde::bytes::{ByteBuf, Bytes};
use murmurhash3::murmurhash3_x64_128;
use blake2::blake2b::blake2b;
use std::mem;
use std::fmt;
use std::u64;
#[repr(packed)]
#[derive(Clone, Copy, PartialEq, Debug, Hash, Eq)]
pub struct Hash {
pub high: u64,
pub low: u64
}
impl Hash {
#[inline]
pub fn hash(&self) -> u64 {
self.low
}
#[inline]
pub fn empty() -> Self {
Hash{high: 0, low: 0}
}
}
impl fmt::Display for Hash {
#[inline]
fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(fmt, "{:16x}{:16x}", self.high, self.low)
}
}
impl Serialize for Hash {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: serde::Serializer {
let hash = Hash{high: u64::to_le(self.high), low: u64::to_le(self.low)};
let dat: [u8; 16] = unsafe { mem::transmute(hash) };
Bytes::from(&dat as &[u8]).serialize(serializer)
}
}
impl Deserialize for Hash {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: serde::Deserializer {
let dat: Vec<u8> = try!(ByteBuf::deserialize(deserializer)).into();
if dat.len() != 16 {
return Err(D::Error::custom("Invalid key length"));
}
let hash = unsafe { &*(dat.as_ptr() as *const Hash) };
Ok(Hash{high: u64::from_le(hash.high), low: u64::from_le(hash.low)})
}
}
#[derive(Debug, Clone, Copy)]
pub enum HashMethod {
Blake2,
Murmur3
}
serde_impl!(HashMethod(u64) {
Blake2 => 1,
Murmur3 => 2
});
impl HashMethod {
#[inline]
pub fn hash(&self, data: &[u8]) -> Hash {
match *self {
HashMethod::Blake2 => {
let hash = blake2b(16, &[], data);
let hash = unsafe { &*mem::transmute::<_, *mut (u64, u64)>(hash.as_bytes().as_ptr()) };
Hash { high: u64::from_be(hash.0), low: u64::from_be(hash.1) }
},
HashMethod::Murmur3 => {
let (a, b) = murmurhash3_x64_128(data, 0);
Hash { high: a, low: b }
}
}
}
#[inline]
pub fn from(name: &str) -> Result<Self, &'static str> {
match name {
"blake2" => Ok(HashMethod::Blake2),
"murmur3" => Ok(HashMethod::Murmur3),
_ => Err("Unsupported hash method")
}
}
#[inline]
pub fn name(&self) -> &'static str {
match *self {
HashMethod::Blake2 => "blake2",
HashMethod::Murmur3 => "murmur3"
}
}
}