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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:13 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:13 +0000
commit218caa410aa38c29984be31a5229b9fa717560ee (patch)
treec54bd55eeb6e4c508940a30e94c0032fbd45d677 /vendor/ahash-0.7.6/src/random_state.rs
parentReleasing progress-linux version 1.67.1+dfsg1-1~progress7.99u1. (diff)
downloadrustc-218caa410aa38c29984be31a5229b9fa717560ee.tar.xz
rustc-218caa410aa38c29984be31a5229b9fa717560ee.zip
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/ahash-0.7.6/src/random_state.rs')
-rw-r--r--vendor/ahash-0.7.6/src/random_state.rs358
1 files changed, 358 insertions, 0 deletions
diff --git a/vendor/ahash-0.7.6/src/random_state.rs b/vendor/ahash-0.7.6/src/random_state.rs
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+#[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))]
+use crate::convert::Convert;
+#[cfg(feature = "specialize")]
+use crate::BuildHasherExt;
+
+#[cfg(any(
+ all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "aes", not(miri)),
+ all(any(target_arch = "arm", target_arch = "aarch64"), target_feature = "crypto", not(miri), feature = "stdsimd")
+))]
+pub use crate::aes_hash::*;
+
+#[cfg(not(any(
+ all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "aes", not(miri)),
+ all(any(target_arch = "arm", target_arch = "aarch64"), target_feature = "crypto", not(miri), feature = "stdsimd")
+)))]
+pub use crate::fallback_hash::*;
+
+#[cfg(all(feature = "compile-time-rng", any(not(feature = "runtime-rng"), test)))]
+use const_random::const_random;
+use core::any::{Any, TypeId};
+use core::fmt;
+use core::hash::BuildHasher;
+#[cfg(feature = "specialize")]
+use core::hash::Hash;
+use core::hash::Hasher;
+
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+#[cfg(feature = "std")]
+extern crate std as alloc;
+
+use alloc::boxed::Box;
+use core::sync::atomic::{AtomicUsize, Ordering};
+#[cfg(not(all(target_arch = "arm", target_os = "none")))]
+use once_cell::race::OnceBox;
+
+#[cfg(any(
+ all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "aes", not(miri)),
+ all(any(target_arch = "arm", target_arch = "aarch64"), target_feature = "crypto", not(miri), feature = "stdsimd")
+))]
+use crate::aes_hash::*;
+#[cfg(not(any(
+ all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "aes", not(miri)),
+ all(any(target_arch = "arm", target_arch = "aarch64"), target_feature = "crypto", not(miri), feature = "stdsimd")
+)))]
+use crate::fallback_hash::*;
+
+#[cfg(not(all(target_arch = "arm", target_os = "none")))]
+static RAND_SOURCE: OnceBox<Box<dyn RandomSource + Send + Sync>> = OnceBox::new();
+
+/// A supplier of Randomness used for different hashers.
+/// See [RandomState.set_random_source].
+pub trait RandomSource {
+
+ fn get_fixed_seeds(&self) -> &'static [[u64; 4]; 2];
+
+ fn gen_hasher_seed(&self) -> usize;
+
+}
+
+pub(crate) const PI: [u64; 4] = [
+ 0x243f_6a88_85a3_08d3,
+ 0x1319_8a2e_0370_7344,
+ 0xa409_3822_299f_31d0,
+ 0x082e_fa98_ec4e_6c89,
+];
+
+pub(crate) const PI2: [u64; 4] = [
+ 0x4528_21e6_38d0_1377,
+ 0xbe54_66cf_34e9_0c6c,
+ 0xc0ac_29b7_c97c_50dd,
+ 0x3f84_d5b5_b547_0917,
+];
+
+struct DefaultRandomSource {
+ counter: AtomicUsize,
+}
+
+impl DefaultRandomSource {
+ fn new() -> DefaultRandomSource {
+ DefaultRandomSource {
+ counter: AtomicUsize::new(&PI as *const _ as usize),
+ }
+ }
+
+ const fn default() -> DefaultRandomSource {
+ DefaultRandomSource {
+ counter: AtomicUsize::new(PI[3] as usize),
+ }
+ }
+}
+
+impl RandomSource for DefaultRandomSource {
+
+ #[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))]
+ fn get_fixed_seeds(&self) -> &'static [[u64; 4]; 2] {
+ static SEEDS: OnceBox<[[u64; 4]; 2]> = OnceBox::new();
+
+ SEEDS.get_or_init(|| {
+ let mut result: [u8; 64] = [0; 64];
+ getrandom::getrandom(&mut result).expect("getrandom::getrandom() failed.");
+ Box::new(result.convert())
+ })
+ }
+
+ #[cfg(all(feature = "compile-time-rng", any(not(feature = "runtime-rng"), test)))]
+ fn get_fixed_seeds(&self) -> &'static [[u64; 4]; 2] {
+ const RAND: [[u64; 4]; 2] = [
+ [
+ const_random!(u64),
+ const_random!(u64),
+ const_random!(u64),
+ const_random!(u64),
+ ], [
+ const_random!(u64),
+ const_random!(u64),
+ const_random!(u64),
+ const_random!(u64),
+ ]
+ ];
+ &RAND
+ }
+
+ #[cfg(all(not(feature = "runtime-rng"), not(feature = "compile-time-rng")))]
+ fn get_fixed_seeds(&self) -> &'static [[u64; 4]; 2] {
+ &[PI, PI2]
+ }
+
+ #[cfg(not(all(target_arch = "arm", target_os = "none")))]
+ fn gen_hasher_seed(&self) -> usize {
+ let stack = self as *const _ as usize;
+ self.counter.fetch_add(stack, Ordering::Relaxed)
+ }
+
+ #[cfg(all(target_arch = "arm", target_os = "none"))]
+ fn gen_hasher_seed(&self) -> usize {
+ let stack = self as *const _ as usize;
+ let previous = self.counter.load(Ordering::Relaxed);
+ let new = previous.wrapping_add(stack);
+ self.counter.store(new, Ordering::Relaxed);
+ new
+ }
+}
+
+/// Provides a [Hasher] factory. This is typically used (e.g. by [HashMap]) to create
+/// [AHasher]s in order to hash the keys of the map. See `build_hasher` below.
+///
+/// [build_hasher]: ahash::
+/// [Hasher]: std::hash::Hasher
+/// [BuildHasher]: std::hash::BuildHasher
+/// [HashMap]: std::collections::HashMap
+#[derive(Clone)]
+pub struct RandomState {
+ pub(crate) k0: u64,
+ pub(crate) k1: u64,
+ pub(crate) k2: u64,
+ pub(crate) k3: u64,
+}
+
+impl fmt::Debug for RandomState {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.pad("RandomState { .. }")
+ }
+}
+
+impl RandomState {
+
+ /// Provides an optional way to manually supply a source of randomness for Hasher keys.
+ ///
+ /// The provided [RandomSource] will be used to be used as a source of randomness by [RandomState] to generate new states.
+ /// If this method is not invoked the standard source of randomness is used as described in the Readme.
+ ///
+ /// The source of randomness can only be set once, and must be set before the first RandomState is created.
+ /// If the source has already been specified `Err` is returned with a `bool` indicating if the set failed because
+ /// method was previously invoked (true) or if the default source is already being used (false).
+ #[cfg(not(all(target_arch = "arm", target_os = "none")))]
+ pub fn set_random_source(source: impl RandomSource + Send + Sync + 'static) -> Result<(), bool> {
+ RAND_SOURCE.set(Box::new(Box::new(source))).map_err(|s| s.as_ref().type_id() != TypeId::of::<&DefaultRandomSource>())
+ }
+
+ #[inline]
+ #[cfg(not(all(target_arch = "arm", target_os = "none")))]
+ fn get_src() -> &'static dyn RandomSource {
+ RAND_SOURCE.get_or_init(|| Box::new(Box::new(DefaultRandomSource::new()))).as_ref()
+ }
+
+ #[inline]
+ #[cfg(all(target_arch = "arm", target_os = "none"))]
+ fn get_src() -> &'static dyn RandomSource {
+ static RAND_SOURCE: DefaultRandomSource = DefaultRandomSource::default();
+ &RAND_SOURCE
+ }
+
+ /// Use randomly generated keys
+ #[inline]
+ pub fn new() -> RandomState {
+ let src = Self::get_src();
+ let fixed = src.get_fixed_seeds();
+ Self::from_keys(&fixed[0], &fixed[1], src.gen_hasher_seed())
+ }
+
+ /// Allows for supplying seeds, but each time it is called the resulting state will be different.
+ /// This is done using a static counter, so it can safely be used with a fixed keys.
+ #[inline]
+ pub fn generate_with(k0: u64, k1: u64, k2: u64, k3: u64) -> RandomState {
+ let src = Self::get_src();
+ let fixed = src.get_fixed_seeds();
+ RandomState::from_keys(&fixed[0], &[k0, k1, k2, k3], src.gen_hasher_seed())
+ }
+
+ fn from_keys(a: &[u64; 4], b: &[u64; 4], c: usize) -> RandomState {
+ let &[k0, k1, k2, k3] = a;
+ let mut hasher = AHasher::from_random_state(&RandomState { k0, k1, k2, k3 });
+ hasher.write_usize(c);
+ let mix = |k: u64| {
+ let mut h = hasher.clone();
+ h.write_u64(k);
+ h.finish()
+ };
+ RandomState {
+ k0: mix(b[0]),
+ k1: mix(b[1]),
+ k2: mix(b[2]),
+ k3: mix(b[3]),
+ }
+ }
+
+ /// Internal. Used by Default.
+ #[inline]
+ pub(crate) fn with_fixed_keys() -> RandomState {
+ let [k0, k1, k2, k3] = Self::get_src().get_fixed_seeds()[0];
+ RandomState { k0, k1, k2, k3 }
+ }
+
+ /// Allows for explicitly setting a seed to used.
+ ///
+ /// Note: This method does not require the provided seed to be strong.
+ #[inline]
+ pub fn with_seed(key: usize) -> RandomState {
+ let fixed = Self::get_src().get_fixed_seeds();
+ RandomState::from_keys(&fixed[0], &fixed[1], key)
+ }
+
+ /// Allows for explicitly setting the seeds to used.
+ ///
+ /// Note: This method is robust against 0s being passed for one or more of the parameters
+ /// or the same value being passed for more than one parameter.
+ #[inline]
+ pub const fn with_seeds(k0: u64, k1: u64, k2: u64, k3: u64) -> RandomState {
+ RandomState { k0: k0 ^ PI2[0], k1: k1 ^ PI2[1], k2: k2 ^ PI2[2], k3: k3 ^ PI2[3] }
+ }
+}
+
+impl Default for RandomState {
+ #[inline]
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl BuildHasher for RandomState {
+ type Hasher = AHasher;
+
+ /// Constructs a new [AHasher] with keys based on this [RandomState] object.
+ /// This means that two different [RandomState]s will will generate
+ /// [AHasher]s that will return different hashcodes, but [Hasher]s created from the same [BuildHasher]
+ /// will generate the same hashes for the same input data.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use ahash::{AHasher, RandomState};
+ /// use std::hash::{Hasher, BuildHasher};
+ ///
+ /// let build_hasher = RandomState::new();
+ /// let mut hasher_1 = build_hasher.build_hasher();
+ /// let mut hasher_2 = build_hasher.build_hasher();
+ ///
+ /// hasher_1.write_u32(1234);
+ /// hasher_2.write_u32(1234);
+ ///
+ /// assert_eq!(hasher_1.finish(), hasher_2.finish());
+ ///
+ /// let other_build_hasher = RandomState::new();
+ /// let mut different_hasher = other_build_hasher.build_hasher();
+ /// different_hasher.write_u32(1234);
+ /// assert_ne!(different_hasher.finish(), hasher_1.finish());
+ /// ```
+ /// [Hasher]: std::hash::Hasher
+ /// [BuildHasher]: std::hash::BuildHasher
+ /// [HashMap]: std::collections::HashMap
+ #[inline]
+ fn build_hasher(&self) -> AHasher {
+ AHasher::from_random_state(self)
+ }
+}
+
+#[cfg(feature = "specialize")]
+impl BuildHasherExt for RandomState {
+ #[inline]
+ fn hash_as_u64<T: Hash + ?Sized>(&self, value: &T) -> u64 {
+ let mut hasher = AHasherU64 {
+ buffer: self.k0,
+ pad: self.k1,
+ };
+ value.hash(&mut hasher);
+ hasher.finish()
+ }
+
+ #[inline]
+ 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 {
+ let mut hasher = AHasherStr(self.build_hasher());
+ value.hash(&mut hasher);
+ hasher.finish()
+ }
+}
+
+#[cfg(test)]
+mod test {
+ use super::*;
+
+ #[test]
+ fn test_unique() {
+ let a = RandomState::new();
+ let b = RandomState::new();
+ assert_ne!(a.build_hasher().finish(), b.build_hasher().finish());
+ }
+
+ #[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))]
+ #[test]
+ fn test_not_pi() {
+ assert_ne!(PI, RandomState::get_src().get_fixed_seeds()[0]);
+ }
+
+ #[cfg(all(feature = "compile-time-rng", any(not(feature = "runtime-rng"), test)))]
+ #[test]
+ fn test_not_pi_const() {
+ assert_ne!(PI, RandomState::get_src().get_fixed_seeds()[0]);
+ }
+
+ #[cfg(all(not(feature = "runtime-rng"), not(feature = "compile-time-rng")))]
+ #[test]
+ fn test_pi() {
+ assert_eq!(PI, RandomState::get_src().get_fixed_seeds()[0]);
+ }
+
+ #[test]
+ fn test_with_seeds_const() {
+ const _CONST_RANDOM_STATE: RandomState = RandomState::with_seeds(17, 19, 21, 23);
+ }
+}