rust/src/libstd/hash.rs
Alex Crichton eabf11b9cb Don't allow impls to force public types
This code in resolve accidentally forced all types with an impl to become
public. This fixes it by default inheriting the privacy of what was previously
there and then becoming `true` if nothing else exits.

Closes #10545
2013-12-17 09:38:57 -08:00

509 lines
16 KiB
Rust

// 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
* strong _keyed_ hashing. Key your hashtables from a strong RNG,
* such as rand::rng.
*
* Although the SipHash algorithm is considered to be cryptographically
* strong, this implementation has not been reviewed for such purposes.
* As such, all cryptographic uses of this implementation are strongly
* discouraged.
*/
#[allow(missing_doc)];
use container::Container;
use iter::Iterator;
use option::{Some, None};
use io::Writer;
use str::OwnedStr;
use to_bytes::IterBytes;
use vec::ImmutableVector;
use num::ToStrRadix;
// 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;
#[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);
self.iter_bytes(true, |bytes| {
s.input(bytes);
true
});
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 b in r.iter() {
s.push_str((*b as uint).to_str_radix(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 super::SipState;
// Hash just the bytes of the slice, without length prefix
struct Bytes<'a>(&'a [u8]);
impl<'a> IterBytes for Bytes<'a> {
fn iter_bytes(&self, _lsb0: bool, f: |&[u8]| -> bool) -> bool {
f(**self)
}
}
#[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 b in r.iter() {
s.push_str((*b as uint).to_str_radix(16u));
}
s
}
while t < 64 {
debug!("siphash test {}", t);
let vec = u8to64_le!(vecs[t], 0);
let out = Bytes(buf.as_slice()).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!("{}: ({}) => inc={} full={}", 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());
}
#[test]
fn test_hash_no_concat_alias() {
let s = ("aa", "bb");
let t = ("aabb", "");
let u = ("a", "abb");
let v = (&[1u8], &[0u8, 0], &[0u8]);
let w = (&[1u8, 0, 0, 0], &[], &[]);
assert!(v != w);
assert!(s.hash() != t.hash() && s.hash() != u.hash());
assert!(v.hash() != w.hash());
}
}