Files
Graphite/node-graph/libraries/graphene-hash/src/lib.rs

378 lines
8.6 KiB
Rust

#![cfg_attr(not(feature = "std"), no_std)]
#[cfg(feature = "std")]
extern crate std;
#[cfg(feature = "derive")]
pub use graphene_hash_derive::CacheHash;
pub trait CacheHash {
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H);
}
/// Wrapper that implements `std::hash::Hash` by delegating to `CacheHash`.
///
/// Use this to store `CacheHash` types in `HashMap`/`HashSet` keys,
/// making it explicit that float fields are hashed via bit patterns.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct CacheHashWrapper<T>(pub T);
impl<T: CacheHash> core::hash::Hash for CacheHashWrapper<T> {
fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
self.0.cache_hash(state);
}
}
impl<T: CacheHash> CacheHash for core::ops::RangeInclusive<T> {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
self.start().cache_hash(state);
self.end().cache_hash(state);
}
}
impl<T> core::ops::Deref for CacheHashWrapper<T> {
type Target = T;
fn deref(&self) -> &T {
&self.0
}
}
// Bulk impl for types that already implement std::hash::Hash — delegates directly.
#[macro_export]
macro_rules! impl_via_hash {
($($t:ty),* $(,)?) => {
$(
impl $crate::CacheHash for $t {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
core::hash::Hash::hash(self, state);
}
}
)*
};
}
impl_via_hash! {
bool, char,
u8, u16, u32, u64, u128, usize,
i8, i16, i32, i64, i128, isize,
// glam integer vector types have Hash
glam::UVec2, glam::UVec3, glam::UVec4,
glam::IVec2, glam::IVec3, glam::IVec4,
glam::I64Vec2, glam::I64Vec3, glam::I64Vec4,
glam::U64Vec2, glam::U64Vec3, glam::U64Vec4,
glam::BVec2, glam::BVec3, glam::BVec4,
}
#[cfg(feature = "std")]
impl_via_hash! {
String,
core::time::Duration,
}
impl<'a> CacheHash for std::borrow::Cow<'a, str> {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
core::hash::Hash::hash(self, state);
}
}
impl CacheHash for str {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
core::hash::Hash::hash(self, state);
}
}
impl CacheHash for () {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, _state: &mut H) {}
}
// f32 and f64: hash via bit pattern so NaN is handled deterministically.
impl CacheHash for f32 {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
core::hash::Hash::hash(&self.to_bits(), state);
}
}
impl CacheHash for f64 {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
core::hash::Hash::hash(&self.to_bits(), state);
}
}
// glam float vector/matrix types: hash each component via to_bits().
macro_rules! impl_glam_array {
($($t:ty),* $(,)?) => {
$(
impl CacheHash for $t {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
for v in self.to_array() {
CacheHash::cache_hash(&v, state);
}
}
}
)*
};
}
macro_rules! impl_glam_cols {
($($t:ty),* $(,)?) => {
$(
impl CacheHash for $t {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
for v in self.to_cols_array() {
CacheHash::cache_hash(&v, state);
}
}
}
)*
};
}
impl_glam_array! {
glam::Vec2, glam::Vec3, glam::Vec3A, glam::Vec4,
glam::DVec2, glam::DVec3, glam::DVec4,
}
impl_glam_cols! {
glam::Mat2, glam::Mat3, glam::Mat3A, glam::Mat4,
glam::DMat2, glam::DMat3, glam::DMat4,
glam::Affine2, glam::Affine3A,
glam::DAffine2, glam::DAffine3,
}
// Quat / DQuat — to_array gives [x, y, z, w] as floats
impl_glam_array! {
glam::Quat, glam::DQuat,
}
// Generic container impls.
impl<T: CacheHash> CacheHash for Option<T> {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
match self {
None => core::hash::Hash::hash(&0u8, state),
Some(v) => {
core::hash::Hash::hash(&1u8, state);
v.cache_hash(state);
}
}
}
}
impl<T: CacheHash> CacheHash for [T] {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
core::hash::Hash::hash(&self.len(), state);
for item in self {
item.cache_hash(state);
}
}
}
impl<T: CacheHash, const N: usize> CacheHash for [T; N] {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
for item in self {
item.cache_hash(state);
}
}
}
#[cfg(feature = "std")]
impl<T: CacheHash> CacheHash for Vec<T> {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
self.as_slice().cache_hash(state);
}
}
#[cfg(feature = "std")]
impl<T: CacheHash + ?Sized> CacheHash for Box<T> {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
(**self).cache_hash(state);
}
}
#[cfg(feature = "std")]
impl<T: CacheHash + ?Sized> CacheHash for std::sync::Arc<T> {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
(**self).cache_hash(state);
}
}
impl<T: CacheHash + ?Sized> CacheHash for &T {
#[inline]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
(**self).cache_hash(state);
}
}
// Tuple impls.
macro_rules! impl_tuple {
($($T:ident),+) => {
impl<$($T: CacheHash),+> CacheHash for ($($T,)+) {
#[inline]
#[allow(non_snake_case)]
fn cache_hash<H: core::hash::Hasher>(&self, state: &mut H) {
let ($($T,)+) = self;
$($T.cache_hash(state);)+
}
}
};
}
impl_tuple!(A, B);
impl_tuple!(A, B, C);
impl_tuple!(A, B, C, D);
impl_tuple!(A, B, C, D, E);
impl_tuple!(A, B, C, D, E, F);
/// rustc-hash's polynomial hash with the state pinned to u64, so keys match across native and wasm targets.
/// The state starts at a nonzero seed: zero-initialized fx absorbs leading zero words, which produced
/// a real wrong-value memo hit in the prototype.
#[derive(Clone)]
pub struct FxHasher64 {
hash: u64,
}
const K: u64 = 0xf1357aea2e62a9c5;
const SEED: u64 = 0x517cc1b727220a95;
const SEED1: u64 = 0x243f6a8885a308d3;
const SEED2: u64 = 0x13198a2e03707344;
const PREVENT_TRIVIAL_ZERO_COLLAPSE: u64 = 0xa4093822299f31d0;
impl Default for FxHasher64 {
fn default() -> Self {
Self::new()
}
}
impl FxHasher64 {
pub const fn new() -> Self {
Self { hash: SEED }
}
#[inline]
fn add_to_hash(&mut self, i: u64) {
self.hash = self.hash.wrapping_add(i).wrapping_mul(K);
}
}
impl core::hash::Hasher for FxHasher64 {
#[inline]
fn write(&mut self, bytes: &[u8]) {
self.add_to_hash(hash_bytes(bytes));
}
#[inline]
fn write_u8(&mut self, i: u8) {
self.add_to_hash(i as u64);
}
#[inline]
fn write_u16(&mut self, i: u16) {
self.add_to_hash(i as u64);
}
#[inline]
fn write_u32(&mut self, i: u32) {
self.add_to_hash(i as u64);
}
#[inline]
fn write_u64(&mut self, i: u64) {
self.add_to_hash(i);
}
#[inline]
fn write_u128(&mut self, i: u128) {
self.add_to_hash(i as u64);
self.add_to_hash((i >> 64) as u64);
}
#[inline]
fn write_usize(&mut self, i: usize) {
self.add_to_hash(i as u64);
}
#[inline]
fn finish(&self) -> u64 {
self.hash.rotate_left(26)
}
}
#[inline]
fn multiply_mix(x: u64, y: u64) -> u64 {
let full = (x as u128) * (y as u128);
(full as u64) ^ ((full >> 64) as u64)
}
#[inline]
fn hash_bytes(bytes: &[u8]) -> u64 {
let len = bytes.len();
let mut s0 = SEED1;
let mut s1 = SEED2;
if len <= 16 {
if len >= 8 {
s0 ^= u64::from_le_bytes(bytes[0..8].try_into().unwrap());
s1 ^= u64::from_le_bytes(bytes[len - 8..].try_into().unwrap());
} else if len >= 4 {
s0 ^= u32::from_le_bytes(bytes[0..4].try_into().unwrap()) as u64;
s1 ^= u32::from_le_bytes(bytes[len - 4..].try_into().unwrap()) as u64;
} else if len > 0 {
let lo = bytes[0];
let mid = bytes[len / 2];
let hi = bytes[len - 1];
s0 ^= lo as u64;
s1 ^= ((hi as u64) << 8) | mid as u64;
}
} else {
let mut off = 0;
while off < len - 16 {
let x = u64::from_le_bytes(bytes[off..off + 8].try_into().unwrap());
let y = u64::from_le_bytes(bytes[off + 8..off + 16].try_into().unwrap());
let t = multiply_mix(s0 ^ x, PREVENT_TRIVIAL_ZERO_COLLAPSE ^ y);
s0 = s1;
s1 = t;
off += 16;
}
let suffix = &bytes[len - 16..];
s0 ^= u64::from_le_bytes(suffix[0..8].try_into().unwrap());
s1 ^= u64::from_le_bytes(suffix[8..16].try_into().unwrap());
}
multiply_mix(s0, s1) ^ (len as u64)
}
#[cfg(test)]
mod tests {
use super::FxHasher64;
use core::hash::Hasher;
#[test]
fn leading_zero_words_are_not_absorbed() {
let hash_words = |words: &[u64]| {
let mut hasher = FxHasher64::new();
for &word in words {
hasher.write_u64(word);
}
hasher.finish()
};
assert_ne!(hash_words(&[]), hash_words(&[0]), "a zero word must change the hash of the empty input");
assert_ne!(hash_words(&[0]), hash_words(&[0, 0]), "zero words must accumulate distinct states");
assert_ne!(hash_words(&[0, 7]), hash_words(&[7]), "a leading zero word must not be absorbed");
}
}