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Merged
tkaitchuck merged 3 commits into from
May 4, 2025
Merged

Make CallHasher specific to ahash::RandomState #261

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1eb998c
Make CallHasher specific to ahash::RandomState
dtolnay Apr 25, 2025
e7b3ba1
Eliminate BuildHasherExt trait
dtolnay Apr 25, 2025
8ac8706
Rename argument of CallHasher to random_state
dtolnay Apr 25, 2025
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61 changes: 2 additions & 59 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -146,8 +146,6 @@ mod specialize;
pub use crate::random_state::RandomState;

use core::hash::BuildHasher;
use core::hash::Hash;
use core::hash::Hasher;

#[cfg(feature = "std")]
/// A convenience trait that can be used together with the type aliases defined to
Expand Down Expand Up @@ -248,63 +246,6 @@ impl Default for AHasher {
}
}

/// Used for specialization. (Sealed)
pub(crate) trait BuildHasherExt: BuildHasher {
#[doc(hidden)]
fn hash_as_u64<T: Hash + ?Sized>(&self, value: &T) -> u64;

#[doc(hidden)]
fn hash_as_fixed_length<T: Hash + ?Sized>(&self, value: &T) -> u64;

#[doc(hidden)]
fn hash_as_str<T: Hash + ?Sized>(&self, value: &T) -> u64;
}

impl<B: BuildHasher> BuildHasherExt for B {
#[inline]
#[cfg(feature = "specialize")]
default fn hash_as_u64<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = self.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
#[inline]
#[cfg(not(feature = "specialize"))]
fn hash_as_u64<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = self.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
#[inline]
#[cfg(feature = "specialize")]
default fn hash_as_fixed_length<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = self.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
#[inline]
#[cfg(not(feature = "specialize"))]
fn hash_as_fixed_length<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = self.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
#[inline]
#[cfg(feature = "specialize")]
default fn hash_as_str<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = self.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
#[inline]
#[cfg(not(feature = "specialize"))]
fn hash_as_str<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = self.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
}

// #[inline(never)]
// #[doc(hidden)]
// pub fn hash_test(input: &[u8]) -> u64 {
Expand All @@ -318,6 +259,8 @@ mod test {
use crate::convert::Convert;
use crate::specialize::CallHasher;
use crate::*;
use core::hash::Hash;
use core::hash::Hasher;
use std::collections::HashMap;

#[test]
Expand Down
13 changes: 4 additions & 9 deletions src/random_state.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,11 +10,6 @@ cfg_if::cfg_if! {
use crate::fallback_hash::*;
}
}
cfg_if::cfg_if! {
if #[cfg(feature = "specialize")]{
use crate::BuildHasherExt;
}
}
cfg_if::cfg_if! {
if #[cfg(feature = "std")] {
extern crate std as alloc;
Expand Down Expand Up @@ -466,9 +461,9 @@ impl BuildHasher for RandomState {
}

#[cfg(feature = "specialize")]
impl BuildHasherExt for RandomState {
impl RandomState {
#[inline]
fn hash_as_u64<T: Hash + ?Sized>(&self, value: &T) -> u64 {
pub(crate) fn hash_as_u64<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = AHasherU64 {
buffer: self.k1,
pad: self.k0,
Expand All @@ -478,14 +473,14 @@ impl BuildHasherExt for RandomState {
}

#[inline]
fn hash_as_fixed_length<T: Hash + ?Sized>(&self, value: &T) -> u64 {
pub(crate) fn hash_as_fixed_length<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = AHasherFixed(self.build_hasher());
value.hash(&mut hasher);
hasher.finish()
}

#[inline]
fn hash_as_str<T: Hash + ?Sized>(&self, value: &T) -> u64 {
pub(crate) fn hash_as_str<T: Hash + ?Sized>(&self, value: &T) -> u64 {
let mut hasher = AHasherStr(self.build_hasher());
value.hash(&mut hasher);
hasher.finish()
Expand Down
37 changes: 18 additions & 19 deletions src/specialize.rs
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Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
use crate::RandomState;
use core::hash::BuildHasher;
use core::hash::Hash;
use core::hash::Hasher;
Expand All @@ -7,8 +8,6 @@ extern crate alloc;
#[cfg(feature = "std")]
extern crate std as alloc;

#[cfg(feature = "specialize")]
use crate::BuildHasherExt;
#[cfg(feature = "specialize")]
use alloc::string::String;
#[cfg(feature = "specialize")]
Expand All @@ -18,7 +17,7 @@ use alloc::vec::Vec;
/// Rather than using a Hasher generically which can hash any value, this provides a way to get a specialized hash
/// for a specific type. So this may be faster for primitive types.
pub(crate) trait CallHasher {
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64;
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64;
}

#[cfg(not(feature = "specialize"))]
Expand All @@ -27,8 +26,8 @@ where
T: Hash + ?Sized,
{
#[inline]
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
let mut hasher = build_hasher.build_hasher();
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
let mut hasher = random_state.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
Expand All @@ -40,8 +39,8 @@ where
T: Hash + ?Sized,
{
#[inline]
default fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
let mut hasher = build_hasher.build_hasher();
default fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
let mut hasher = random_state.build_hasher();
value.hash(&mut hasher);
hasher.finish()
}
Expand All @@ -52,8 +51,8 @@ macro_rules! call_hasher_impl_u64 {
#[cfg(feature = "specialize")]
impl CallHasher for $typ {
#[inline]
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
build_hasher.hash_as_u64(value)
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
random_state.hash_as_u64(value)
}
}
};
Expand All @@ -80,8 +79,8 @@ macro_rules! call_hasher_impl_fixed_length{
#[cfg(feature = "specialize")]
impl CallHasher for $typ {
#[inline]
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
build_hasher.hash_as_fixed_length(value)
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
random_state.hash_as_fixed_length(value)
}
}
};
Expand All @@ -99,32 +98,32 @@ call_hasher_impl_fixed_length!(&isize);
#[cfg(feature = "specialize")]
impl CallHasher for [u8] {
#[inline]
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
build_hasher.hash_as_str(value)
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
random_state.hash_as_str(value)
}
}

#[cfg(feature = "specialize")]
impl CallHasher for Vec<u8> {
#[inline]
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
build_hasher.hash_as_str(value)
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
random_state.hash_as_str(value)
}
}

#[cfg(feature = "specialize")]
impl CallHasher for str {
#[inline]
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
build_hasher.hash_as_str(value)
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
random_state.hash_as_str(value)
}
}

#[cfg(all(feature = "specialize"))]
impl CallHasher for String {
#[inline]
fn get_hash<H: Hash + ?Sized, B: BuildHasher>(value: &H, build_hasher: &B) -> u64 {
build_hasher.hash_as_str(value)
fn get_hash<H: Hash + ?Sized>(value: &H, random_state: &RandomState) -> u64 {
random_state.hash_as_str(value)
}
}

Expand Down
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