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rust/src/libstd/hash.rs
Patrick Walton a1531ed946 librustc: Remove the broken overloaded assign-ops from the language. 
They evaluated the receiver twice. They should be added back with
`AddAssign`, `SubAssign`, etc., traits.
2013-06-28 10:44:16 -04:00

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Rust
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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
/*!
* Implementation of SipHash 2-4
*
* See: http://131002.net/siphash/
*
* Consider this as a main "general-purpose" hash for all hashtables: it
* runs at good speed (competitive with spooky and city) and permits
* cryptographically strong _keyed_ hashing. Key your hashtables from a
* CPRNG like rand::rng.
*/
#[allow(missing_doc)];
use container::Container;
use iterator::IteratorUtil;
use rt::io::Writer;
use str::OwnedStr;
use to_bytes::IterBytes;
use uint;
use vec::ImmutableVector;
// Alias `SipState` to `State`.
pub use State = hash::SipState;
/**
* Types that can meaningfully be hashed should implement this.
*
* Note that this trait is likely to change somewhat as it is
* closely related to `to_bytes::IterBytes` and in almost all
* cases presently the two are (and must be) used together.
*
* In general, most types only need to implement `IterBytes`,
* and the implementation of `Hash` below will take care of
* the rest. This is the recommended approach, since constructing
* good keyed hash functions is quite difficult.
*/
pub trait Hash {
/**
* Compute a "keyed" hash of the value implementing the trait,
* taking `k0` and `k1` as "keying" parameters that randomize or
* otherwise perturb the hash function in such a way that a
* hash table built using such "keyed hash functions" cannot
* be made to perform linearly by an attacker controlling the
* hashtable's contents.
*
* In practical terms, we implement this using the SipHash 2-4
* function and require most types to only implement the
* IterBytes trait, that feeds SipHash.
*/
fn hash_keyed(&self, k0: u64, k1: u64) -> u64;
}
// When we have default methods, won't need this.
pub trait HashUtil {
fn hash(&self) -> u64;
}
impl<A:Hash> HashUtil for A {
#[inline]
fn hash(&self) -> u64 { self.hash_keyed(0,0) }
}
/// Streaming hash-functions should implement this.
pub trait Streaming {
fn input(&mut self, &[u8]);
// These can be refactored some when we have default methods.
fn result_bytes(&mut self) -> ~[u8];
fn result_str(&mut self) -> ~str;
fn result_u64(&mut self) -> u64;
fn reset(&mut self);
}
impl<A:IterBytes> Hash for A {
#[inline]
fn hash_keyed(&self, k0: u64, k1: u64) -> u64 {
let mut s = State::new(k0, k1);
for self.iter_bytes(true) |bytes| {
s.input(bytes);
}
s.result_u64()
}
}
fn hash_keyed_2<A: IterBytes,
B: IterBytes>(a: &A, b: &B, k0: u64, k1: u64) -> u64 {
let mut s = State::new(k0, k1);
for a.iter_bytes(true) |bytes| {
s.input(bytes);
}
for b.iter_bytes(true) |bytes| {
s.input(bytes);
}
s.result_u64()
}
fn hash_keyed_3<A: IterBytes,
B: IterBytes,
C: IterBytes>(a: &A, b: &B, c: &C, k0: u64, k1: u64) -> u64 {
let mut s = State::new(k0, k1);
for a.iter_bytes(true) |bytes| {
s.input(bytes);
}
for b.iter_bytes(true) |bytes| {
s.input(bytes);
}
for c.iter_bytes(true) |bytes| {
s.input(bytes);
}
s.result_u64()
}
fn hash_keyed_4<A: IterBytes,
B: IterBytes,
C: IterBytes,
D: IterBytes>(
a: &A,
b: &B,
c: &C,
d: &D,
k0: u64,
k1: u64)
-> u64 {
let mut s = State::new(k0, k1);
for a.iter_bytes(true) |bytes| {
s.input(bytes);
}
for b.iter_bytes(true) |bytes| {
s.input(bytes);
}
for c.iter_bytes(true) |bytes| {
s.input(bytes);
}
for d.iter_bytes(true) |bytes| {
s.input(bytes);
}
s.result_u64()
}
fn hash_keyed_5<A: IterBytes,
B: IterBytes,
C: IterBytes,
D: IterBytes,
E: IterBytes>(
a: &A,
b: &B,
c: &C,
d: &D,
e: &E,
k0: u64,
k1: u64)
-> u64 {
let mut s = State::new(k0, k1);
for a.iter_bytes(true) |bytes| {
s.input(bytes);
}
for b.iter_bytes(true) |bytes| {
s.input(bytes);
}
for c.iter_bytes(true) |bytes| {
s.input(bytes);
}
for d.iter_bytes(true) |bytes| {
s.input(bytes);
}
for e.iter_bytes(true) |bytes| {
s.input(bytes);
}
s.result_u64()
}
#[inline]
pub fn default_state() -> State {
State::new(0, 0)
}
struct SipState {
k0: u64,
k1: u64,
length: uint, // how many bytes we've processed
v0: u64, // hash state
v1: u64,
v2: u64,
v3: u64,
tail: [u8, ..8], // unprocessed bytes
ntail: uint, // how many bytes in tail are valid
}
impl SipState {
#[inline]
fn new(key0: u64, key1: u64) -> SipState {
let mut state = SipState {
k0: key0,
k1: key1,
length: 0,
v0: 0,
v1: 0,
v2: 0,
v3: 0,
tail: [ 0, 0, 0, 0, 0, 0, 0, 0 ],
ntail: 0,
};
state.reset();
state
}
}
// sadly, these macro definitions can't appear later,
// because they're needed in the following defs;
// this design could be improved.
macro_rules! u8to64_le (
($buf:expr, $i:expr) =>
($buf[0+$i] as u64 |
$buf[1+$i] as u64 << 8 |
$buf[2+$i] as u64 << 16 |
$buf[3+$i] as u64 << 24 |
$buf[4+$i] as u64 << 32 |
$buf[5+$i] as u64 << 40 |
$buf[6+$i] as u64 << 48 |
$buf[7+$i] as u64 << 56)
)
macro_rules! rotl (
($x:expr, $b:expr) =>
(($x << $b) | ($x >> (64 - $b)))
)
macro_rules! compress (
($v0:expr, $v1:expr, $v2:expr, $v3:expr) =>
({
$v0 += $v1; $v1 = rotl!($v1, 13); $v1 ^= $v0;
$v0 = rotl!($v0, 32);
$v2 += $v3; $v3 = rotl!($v3, 16); $v3 ^= $v2;
$v0 += $v3; $v3 = rotl!($v3, 21); $v3 ^= $v0;
$v2 += $v1; $v1 = rotl!($v1, 17); $v1 ^= $v2;
$v2 = rotl!($v2, 32);
})
)
impl Writer for SipState {
// Methods for io::writer
#[inline]
fn write(&mut self, msg: &[u8]) {
let length = msg.len();
self.length += length;
let mut needed = 0u;
if self.ntail != 0 {
needed = 8 - self.ntail;
if length < needed {
let mut t = 0;
while t < length {
self.tail[self.ntail+t] = msg[t];
t += 1;
}
self.ntail += length;
return;
}
let mut t = 0;
while t < needed {
self.tail[self.ntail+t] = msg[t];
t += 1;
}
let m = u8to64_le!(self.tail, 0);
self.v3 ^= m;
compress!(self.v0, self.v1, self.v2, self.v3);
compress!(self.v0, self.v1, self.v2, self.v3);
self.v0 ^= m;
self.ntail = 0;
}
// Buffered tail is now flushed, process new input.
let len = length - needed;
let end = len & (!0x7);
let left = len & 0x7;
let mut i = needed;
while i < end {
let mi = u8to64_le!(msg, i);
self.v3 ^= mi;
compress!(self.v0, self.v1, self.v2, self.v3);
compress!(self.v0, self.v1, self.v2, self.v3);
self.v0 ^= mi;
i += 8;
}
let mut t = 0u;
while t < left {
self.tail[t] = msg[i+t];
t += 1
}
self.ntail = left;
}
fn flush(&mut self) {
// No-op
}
}
impl Streaming for SipState {
#[inline]
fn input(&mut self, buf: &[u8]) {
self.write(buf);
}
#[inline]
fn result_u64(&mut self) -> u64 {
let mut v0 = self.v0;
let mut v1 = self.v1;
let mut v2 = self.v2;
let mut v3 = self.v3;
let mut b : u64 = (self.length as u64 & 0xff) << 56;
if self.ntail > 0 { b |= self.tail[0] as u64 << 0; }
if self.ntail > 1 { b |= self.tail[1] as u64 << 8; }
if self.ntail > 2 { b |= self.tail[2] as u64 << 16; }
if self.ntail > 3 { b |= self.tail[3] as u64 << 24; }
if self.ntail > 4 { b |= self.tail[4] as u64 << 32; }
if self.ntail > 5 { b |= self.tail[5] as u64 << 40; }
if self.ntail > 6 { b |= self.tail[6] as u64 << 48; }
v3 ^= b;
compress!(v0, v1, v2, v3);
compress!(v0, v1, v2, v3);
v0 ^= b;
v2 ^= 0xff;
compress!(v0, v1, v2, v3);
compress!(v0, v1, v2, v3);
compress!(v0, v1, v2, v3);
compress!(v0, v1, v2, v3);
return (v0 ^ v1 ^ v2 ^ v3);
}
fn result_bytes(&mut self) -> ~[u8] {
let h = self.result_u64();
~[(h >> 0) as u8,
(h >> 8) as u8,
(h >> 16) as u8,
(h >> 24) as u8,
(h >> 32) as u8,
(h >> 40) as u8,
(h >> 48) as u8,
(h >> 56) as u8,
]
}
fn result_str(&mut self) -> ~str {
let r = self.result_bytes();
let mut s = ~"";
for r.iter().advance |b| {
s.push_str(uint::to_str_radix(*b as uint, 16u));
}
s
}
#[inline]
fn reset(&mut self) {
self.length = 0;
self.v0 = self.k0 ^ 0x736f6d6570736575;
self.v1 = self.k1 ^ 0x646f72616e646f6d;
self.v2 = self.k0 ^ 0x6c7967656e657261;
self.v3 = self.k1 ^ 0x7465646279746573;
self.ntail = 0;
}
}
#[cfg(test)]
mod tests {
use super::*;
use prelude::*;
use uint;
#[test]
fn test_siphash() {
let vecs : [[u8, ..8], ..64] = [
[ 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72, ],
[ 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74, ],
[ 0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d, ],
[ 0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85, ],
[ 0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf, ],
[ 0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18, ],
[ 0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb, ],
[ 0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab, ],
[ 0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93, ],
[ 0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e, ],
[ 0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a, ],
[ 0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4, ],
[ 0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75, ],
[ 0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14, ],
[ 0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7, ],
[ 0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1, ],
[ 0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f, ],
[ 0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69, ],
[ 0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b, ],
[ 0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb, ],
[ 0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe, ],
[ 0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0, ],
[ 0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93, ],
[ 0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8, ],
[ 0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8, ],
[ 0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc, ],
[ 0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17, ],
[ 0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f, ],
[ 0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde, ],
[ 0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6, ],
[ 0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad, ],
[ 0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32, ],
[ 0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71, ],
[ 0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7, ],
[ 0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12, ],
[ 0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15, ],
[ 0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31, ],
[ 0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02, ],
[ 0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca, ],
[ 0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a, ],
[ 0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e, ],
[ 0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad, ],
[ 0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18, ],
[ 0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4, ],
[ 0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9, ],
[ 0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9, ],
[ 0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb, ],
[ 0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0, ],
[ 0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6, ],
[ 0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7, ],
[ 0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee, ],
[ 0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1, ],
[ 0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a, ],
[ 0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81, ],
[ 0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f, ],
[ 0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24, ],
[ 0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7, ],
[ 0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea, ],
[ 0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60, ],
[ 0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66, ],
[ 0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c, ],
[ 0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f, ],
[ 0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5, ],
[ 0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95, ]
];
let k0 = 0x_07_06_05_04_03_02_01_00_u64;
let k1 = 0x_0f_0e_0d_0c_0b_0a_09_08_u64;
let mut buf : ~[u8] = ~[];
let mut t = 0;
let mut stream_inc = SipState::new(k0, k1);
let mut stream_full = SipState::new(k0, k1);
fn to_hex_str(r: &[u8, ..8]) -> ~str {
let mut s = ~"";
for r.iter().advance |b| {
s.push_str(uint::to_str_radix(*b as uint, 16u));
}
s
}
while t < 64 {
debug!("siphash test %?", t);
let vec = u8to64_le!(vecs[t], 0);
let out = buf.hash_keyed(k0, k1);
debug!("got %?, expected %?", out, vec);
assert_eq!(vec, out);
stream_full.reset();
stream_full.input(buf);
let f = stream_full.result_str();
let i = stream_inc.result_str();
let v = to_hex_str(&vecs[t]);
debug!("%d: (%s) => inc=%s full=%s", t, v, i, f);
assert!(f == i && f == v);
buf.push(t as u8);
stream_inc.input([t as u8]);
t += 1;
}
}
#[test] #[cfg(target_arch = "arm")]
fn test_hash_uint() {
let val = 0xdeadbeef_deadbeef_u64;
assert!((val as u64).hash() != (val as uint).hash());
assert_eq!((val as u32).hash(), (val as uint).hash());
}
#[test] #[cfg(target_arch = "x86_64")]
fn test_hash_uint() {
let val = 0xdeadbeef_deadbeef_u64;
assert_eq!((val as u64).hash(), (val as uint).hash());
assert!((val as u32).hash() != (val as uint).hash());
}
#[test] #[cfg(target_arch = "x86")]
fn test_hash_uint() {
let val = 0xdeadbeef_deadbeef_u64;
assert!((val as u64).hash() != (val as uint).hash());
assert_eq!((val as u32).hash(), (val as uint).hash());
}
#[test]
fn test_hash_idempotent() {
let val64 = 0xdeadbeef_deadbeef_u64;
val64.hash() == val64.hash();
let val32 = 0xdeadbeef_u32;
val32.hash() == val32.hash();
}
#[test]
fn test_hash_no_bytes_dropped_64() {
let val = 0xdeadbeef_deadbeef_u64;
assert!(val.hash() != zero_byte(val, 0).hash());
assert!(val.hash() != zero_byte(val, 1).hash());
assert!(val.hash() != zero_byte(val, 2).hash());
assert!(val.hash() != zero_byte(val, 3).hash());
assert!(val.hash() != zero_byte(val, 4).hash());
assert!(val.hash() != zero_byte(val, 5).hash());
assert!(val.hash() != zero_byte(val, 6).hash());
assert!(val.hash() != zero_byte(val, 7).hash());
fn zero_byte(val: u64, byte: uint) -> u64 {
assert!(byte < 8);
val & !(0xff << (byte * 8))
}
}
#[test]
fn test_hash_no_bytes_dropped_32() {
let val = 0xdeadbeef_u32;
assert!(val.hash() != zero_byte(val, 0).hash());
assert!(val.hash() != zero_byte(val, 1).hash());
assert!(val.hash() != zero_byte(val, 2).hash());
assert!(val.hash() != zero_byte(val, 3).hash());
fn zero_byte(val: u32, byte: uint) -> u32 {
assert!(byte < 4);
val & !(0xff << (byte * 8))
}
}
#[test]
fn test_float_hashes_differ() {
assert!(0.0.hash() != 1.0.hash());
assert!(1.0.hash() != (-1.0).hash());
}
#[test]
fn test_float_hashes_of_zero() {
assert_eq!(0.0.hash(), (-0.0).hash());
}
}
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