| //! Generic hashing support. |
| //! |
| //! This module provides a generic way to compute the hash of a value. The |
| //! simplest way to make a type hashable is to use `#[derive(Hash)]`: |
| //! |
| //! # Examples |
| //! |
| //! ```rust |
| //! use std::collections::hash_map::DefaultHasher; |
| //! use std::hash::{Hash, Hasher}; |
| //! |
| //! #[derive(Hash)] |
| //! struct Person { |
| //! id: u32, |
| //! name: String, |
| //! phone: u64, |
| //! } |
| //! |
| //! let person1 = Person { |
| //! id: 5, |
| //! name: "Janet".to_string(), |
| //! phone: 555_666_7777, |
| //! }; |
| //! let person2 = Person { |
| //! id: 5, |
| //! name: "Bob".to_string(), |
| //! phone: 555_666_7777, |
| //! }; |
| //! |
| //! assert!(calculate_hash(&person1) != calculate_hash(&person2)); |
| //! |
| //! fn calculate_hash<T: Hash>(t: &T) -> u64 { |
| //! let mut s = DefaultHasher::new(); |
| //! t.hash(&mut s); |
| //! s.finish() |
| //! } |
| //! ``` |
| //! |
| //! If you need more control over how a value is hashed, you need to implement |
| //! the [`Hash`] trait: |
| //! |
| //! [`Hash`]: trait.Hash.html |
| //! |
| //! ```rust |
| //! use std::collections::hash_map::DefaultHasher; |
| //! use std::hash::{Hash, Hasher}; |
| //! |
| //! struct Person { |
| //! id: u32, |
| //! # #[allow(dead_code)] |
| //! name: String, |
| //! phone: u64, |
| //! } |
| //! |
| //! impl Hash for Person { |
| //! fn hash<H: Hasher>(&self, state: &mut H) { |
| //! self.id.hash(state); |
| //! self.phone.hash(state); |
| //! } |
| //! } |
| //! |
| //! let person1 = Person { |
| //! id: 5, |
| //! name: "Janet".to_string(), |
| //! phone: 555_666_7777, |
| //! }; |
| //! let person2 = Person { |
| //! id: 5, |
| //! name: "Bob".to_string(), |
| //! phone: 555_666_7777, |
| //! }; |
| //! |
| //! assert_eq!(calculate_hash(&person1), calculate_hash(&person2)); |
| //! |
| //! fn calculate_hash<T: Hash>(t: &T) -> u64 { |
| //! let mut s = DefaultHasher::new(); |
| //! t.hash(&mut s); |
| //! s.finish() |
| //! } |
| //! ``` |
| |
| // ignore-tidy-undocumented-unsafe |
| |
| #![stable(feature = "rust1", since = "1.0.0")] |
| |
| use crate::fmt; |
| use crate::marker; |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[allow(deprecated)] |
| pub use self::sip::SipHasher; |
| |
| #[unstable(feature = "hashmap_internals", issue = "0")] |
| #[allow(deprecated)] |
| #[doc(hidden)] |
| pub use self::sip::SipHasher13; |
| |
| mod sip; |
| |
| /// A hashable type. |
| /// |
| /// Types implementing `Hash` are able to be [`hash`]ed with an instance of |
| /// [`Hasher`]. |
| /// |
| /// ## Implementing `Hash` |
| /// |
| /// You can derive `Hash` with `#[derive(Hash)]` if all fields implement `Hash`. |
| /// The resulting hash will be the combination of the values from calling |
| /// [`hash`] on each field. |
| /// |
| /// ``` |
| /// #[derive(Hash)] |
| /// struct Rustacean { |
| /// name: String, |
| /// country: String, |
| /// } |
| /// ``` |
| /// |
| /// If you need more control over how a value is hashed, you can of course |
| /// implement the `Hash` trait yourself: |
| /// |
| /// ``` |
| /// use std::hash::{Hash, Hasher}; |
| /// |
| /// struct Person { |
| /// id: u32, |
| /// name: String, |
| /// phone: u64, |
| /// } |
| /// |
| /// impl Hash for Person { |
| /// fn hash<H: Hasher>(&self, state: &mut H) { |
| /// self.id.hash(state); |
| /// self.phone.hash(state); |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// ## `Hash` and `Eq` |
| /// |
| /// When implementing both `Hash` and [`Eq`], it is important that the following |
| /// property holds: |
| /// |
| /// ```text |
| /// k1 == k2 -> hash(k1) == hash(k2) |
| /// ``` |
| /// |
| /// In other words, if two keys are equal, their hashes must also be equal. |
| /// [`HashMap`] and [`HashSet`] both rely on this behavior. |
| /// |
| /// Thankfully, you won't need to worry about upholding this property when |
| /// deriving both [`Eq`] and `Hash` with `#[derive(PartialEq, Eq, Hash)]`. |
| /// |
| /// [`Eq`]: ../../std/cmp/trait.Eq.html |
| /// [`Hasher`]: trait.Hasher.html |
| /// [`HashMap`]: ../../std/collections/struct.HashMap.html |
| /// [`HashSet`]: ../../std/collections/struct.HashSet.html |
| /// [`hash`]: #tymethod.hash |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait Hash { |
| /// Feeds this value into the given [`Hasher`]. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::hash_map::DefaultHasher; |
| /// use std::hash::{Hash, Hasher}; |
| /// |
| /// let mut hasher = DefaultHasher::new(); |
| /// 7920.hash(&mut hasher); |
| /// println!("Hash is {:x}!", hasher.finish()); |
| /// ``` |
| /// |
| /// [`Hasher`]: trait.Hasher.html |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn hash<H: Hasher>(&self, state: &mut H); |
| |
| /// Feeds a slice of this type into the given [`Hasher`]. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::hash_map::DefaultHasher; |
| /// use std::hash::{Hash, Hasher}; |
| /// |
| /// let mut hasher = DefaultHasher::new(); |
| /// let numbers = [6, 28, 496, 8128]; |
| /// Hash::hash_slice(&numbers, &mut hasher); |
| /// println!("Hash is {:x}!", hasher.finish()); |
| /// ``` |
| /// |
| /// [`Hasher`]: trait.Hasher.html |
| #[stable(feature = "hash_slice", since = "1.3.0")] |
| fn hash_slice<H: Hasher>(data: &[Self], state: &mut H) |
| where |
| Self: Sized, |
| { |
| for piece in data { |
| piece.hash(state); |
| } |
| } |
| } |
| |
| // Separate module to reexport the macro `Hash` from prelude without the trait `Hash`. |
| pub(crate) mod macros { |
| /// Derive macro generating an impl of the trait `Hash`. |
| #[rustc_builtin_macro] |
| #[stable(feature = "builtin_macro_prelude", since = "1.38.0")] |
| #[allow_internal_unstable(core_intrinsics)] |
| pub macro Hash($item:item) { |
| /* compiler built-in */ |
| } |
| } |
| #[stable(feature = "builtin_macro_prelude", since = "1.38.0")] |
| #[doc(inline)] |
| pub use macros::Hash; |
| |
| /// A trait for hashing an arbitrary stream of bytes. |
| /// |
| /// Instances of `Hasher` usually represent state that is changed while hashing |
| /// data. |
| /// |
| /// `Hasher` provides a fairly basic interface for retrieving the generated hash |
| /// (with [`finish`]), and writing integers as well as slices of bytes into an |
| /// instance (with [`write`] and [`write_u8`] etc.). Most of the time, `Hasher` |
| /// instances are used in conjunction with the [`Hash`] trait. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::hash_map::DefaultHasher; |
| /// use std::hash::Hasher; |
| /// |
| /// let mut hasher = DefaultHasher::new(); |
| /// |
| /// hasher.write_u32(1989); |
| /// hasher.write_u8(11); |
| /// hasher.write_u8(9); |
| /// hasher.write(b"Huh?"); |
| /// |
| /// println!("Hash is {:x}!", hasher.finish()); |
| /// ``` |
| /// |
| /// [`Hash`]: trait.Hash.html |
| /// [`finish`]: #tymethod.finish |
| /// [`write`]: #tymethod.write |
| /// [`write_u8`]: #method.write_u8 |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait Hasher { |
| /// Returns the hash value for the values written so far. |
| /// |
| /// Despite its name, the method does not reset the hasher’s internal |
| /// state. Additional [`write`]s will continue from the current value. |
| /// If you need to start a fresh hash value, you will have to create |
| /// a new hasher. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::hash_map::DefaultHasher; |
| /// use std::hash::Hasher; |
| /// |
| /// let mut hasher = DefaultHasher::new(); |
| /// hasher.write(b"Cool!"); |
| /// |
| /// println!("Hash is {:x}!", hasher.finish()); |
| /// ``` |
| /// |
| /// [`write`]: #tymethod.write |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn finish(&self) -> u64; |
| |
| /// Writes some data into this `Hasher`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::hash_map::DefaultHasher; |
| /// use std::hash::Hasher; |
| /// |
| /// let mut hasher = DefaultHasher::new(); |
| /// let data = [0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef]; |
| /// |
| /// hasher.write(&data); |
| /// |
| /// println!("Hash is {:x}!", hasher.finish()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn write(&mut self, bytes: &[u8]); |
| |
| /// Writes a single `u8` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_u8(&mut self, i: u8) { |
| self.write(&[i]) |
| } |
| /// Writes a single `u16` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_u16(&mut self, i: u16) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `u32` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_u32(&mut self, i: u32) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `u64` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_u64(&mut self, i: u64) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `u128` into this hasher. |
| #[inline] |
| #[stable(feature = "i128", since = "1.26.0")] |
| fn write_u128(&mut self, i: u128) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `usize` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_usize(&mut self, i: usize) { |
| self.write(&i.to_ne_bytes()) |
| } |
| |
| /// Writes a single `i8` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_i8(&mut self, i: i8) { |
| self.write_u8(i as u8) |
| } |
| /// Writes a single `i16` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_i16(&mut self, i: i16) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `i32` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_i32(&mut self, i: i32) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `i64` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_i64(&mut self, i: i64) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `i128` into this hasher. |
| #[inline] |
| #[stable(feature = "i128", since = "1.26.0")] |
| fn write_i128(&mut self, i: i128) { |
| self.write(&i.to_ne_bytes()) |
| } |
| /// Writes a single `isize` into this hasher. |
| #[inline] |
| #[stable(feature = "hasher_write", since = "1.3.0")] |
| fn write_isize(&mut self, i: isize) { |
| self.write(&i.to_ne_bytes()) |
| } |
| } |
| |
| #[stable(feature = "indirect_hasher_impl", since = "1.22.0")] |
| impl<H: Hasher + ?Sized> Hasher for &mut H { |
| fn finish(&self) -> u64 { |
| (**self).finish() |
| } |
| fn write(&mut self, bytes: &[u8]) { |
| (**self).write(bytes) |
| } |
| fn write_u8(&mut self, i: u8) { |
| (**self).write_u8(i) |
| } |
| fn write_u16(&mut self, i: u16) { |
| (**self).write_u16(i) |
| } |
| fn write_u32(&mut self, i: u32) { |
| (**self).write_u32(i) |
| } |
| fn write_u64(&mut self, i: u64) { |
| (**self).write_u64(i) |
| } |
| fn write_u128(&mut self, i: u128) { |
| (**self).write_u128(i) |
| } |
| fn write_usize(&mut self, i: usize) { |
| (**self).write_usize(i) |
| } |
| fn write_i8(&mut self, i: i8) { |
| (**self).write_i8(i) |
| } |
| fn write_i16(&mut self, i: i16) { |
| (**self).write_i16(i) |
| } |
| fn write_i32(&mut self, i: i32) { |
| (**self).write_i32(i) |
| } |
| fn write_i64(&mut self, i: i64) { |
| (**self).write_i64(i) |
| } |
| fn write_i128(&mut self, i: i128) { |
| (**self).write_i128(i) |
| } |
| fn write_isize(&mut self, i: isize) { |
| (**self).write_isize(i) |
| } |
| } |
| |
| /// A trait for creating instances of [`Hasher`]. |
| /// |
| /// A `BuildHasher` is typically used (e.g., by [`HashMap`]) to create |
| /// [`Hasher`]s for each key such that they are hashed independently of one |
| /// another, since [`Hasher`]s contain state. |
| /// |
| /// For each instance of `BuildHasher`, the [`Hasher`]s created by |
| /// [`build_hasher`] should be identical. That is, if the same stream of bytes |
| /// is fed into each hasher, the same output will also be generated. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::hash_map::RandomState; |
| /// use std::hash::{BuildHasher, Hasher}; |
| /// |
| /// let s = RandomState::new(); |
| /// let mut hasher_1 = s.build_hasher(); |
| /// let mut hasher_2 = s.build_hasher(); |
| /// |
| /// hasher_1.write_u32(8128); |
| /// hasher_2.write_u32(8128); |
| /// |
| /// assert_eq!(hasher_1.finish(), hasher_2.finish()); |
| /// ``` |
| /// |
| /// [`build_hasher`]: #tymethod.build_hasher |
| /// [`Hasher`]: trait.Hasher.html |
| /// [`HashMap`]: ../../std/collections/struct.HashMap.html |
| #[stable(since = "1.7.0", feature = "build_hasher")] |
| pub trait BuildHasher { |
| /// Type of the hasher that will be created. |
| #[stable(since = "1.7.0", feature = "build_hasher")] |
| type Hasher: Hasher; |
| |
| /// Creates a new hasher. |
| /// |
| /// Each call to `build_hasher` on the same instance should produce identical |
| /// [`Hasher`]s. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use std::collections::hash_map::RandomState; |
| /// use std::hash::BuildHasher; |
| /// |
| /// let s = RandomState::new(); |
| /// let new_s = s.build_hasher(); |
| /// ``` |
| /// |
| /// [`Hasher`]: trait.Hasher.html |
| #[stable(since = "1.7.0", feature = "build_hasher")] |
| fn build_hasher(&self) -> Self::Hasher; |
| } |
| |
| /// Used to create a default [`BuildHasher`] instance for types that implement |
| /// [`Hasher`] and [`Default`]. |
| /// |
| /// `BuildHasherDefault<H>` can be used when a type `H` implements [`Hasher`] and |
| /// [`Default`], and you need a corresponding [`BuildHasher`] instance, but none is |
| /// defined. |
| /// |
| /// Any `BuildHasherDefault` is [zero-sized]. It can be created with |
| /// [`default`][method.Default]. When using `BuildHasherDefault` with [`HashMap`] or |
| /// [`HashSet`], this doesn't need to be done, since they implement appropriate |
| /// [`Default`] instances themselves. |
| /// |
| /// # Examples |
| /// |
| /// Using `BuildHasherDefault` to specify a custom [`BuildHasher`] for |
| /// [`HashMap`]: |
| /// |
| /// ``` |
| /// use std::collections::HashMap; |
| /// use std::hash::{BuildHasherDefault, Hasher}; |
| /// |
| /// #[derive(Default)] |
| /// struct MyHasher; |
| /// |
| /// impl Hasher for MyHasher { |
| /// fn write(&mut self, bytes: &[u8]) { |
| /// // Your hashing algorithm goes here! |
| /// unimplemented!() |
| /// } |
| /// |
| /// fn finish(&self) -> u64 { |
| /// // Your hashing algorithm goes here! |
| /// unimplemented!() |
| /// } |
| /// } |
| /// |
| /// type MyBuildHasher = BuildHasherDefault<MyHasher>; |
| /// |
| /// let hash_map = HashMap::<u32, u32, MyBuildHasher>::default(); |
| /// ``` |
| /// |
| /// [`BuildHasher`]: trait.BuildHasher.html |
| /// [`Default`]: ../default/trait.Default.html |
| /// [method.default]: #method.default |
| /// [`Hasher`]: trait.Hasher.html |
| /// [`HashMap`]: ../../std/collections/struct.HashMap.html |
| /// [`HashSet`]: ../../std/collections/struct.HashSet.html |
| /// [zero-sized]: https://doc.rust-lang.org/nomicon/exotic-sizes.html#zero-sized-types-zsts |
| #[stable(since = "1.7.0", feature = "build_hasher")] |
| pub struct BuildHasherDefault<H>(marker::PhantomData<H>); |
| |
| #[stable(since = "1.9.0", feature = "core_impl_debug")] |
| impl<H> fmt::Debug for BuildHasherDefault<H> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.pad("BuildHasherDefault") |
| } |
| } |
| |
| #[stable(since = "1.7.0", feature = "build_hasher")] |
| impl<H: Default + Hasher> BuildHasher for BuildHasherDefault<H> { |
| type Hasher = H; |
| |
| fn build_hasher(&self) -> H { |
| H::default() |
| } |
| } |
| |
| #[stable(since = "1.7.0", feature = "build_hasher")] |
| impl<H> Clone for BuildHasherDefault<H> { |
| fn clone(&self) -> BuildHasherDefault<H> { |
| BuildHasherDefault(marker::PhantomData) |
| } |
| } |
| |
| #[stable(since = "1.7.0", feature = "build_hasher")] |
| impl<H> Default for BuildHasherDefault<H> { |
| fn default() -> BuildHasherDefault<H> { |
| BuildHasherDefault(marker::PhantomData) |
| } |
| } |
| |
| #[stable(since = "1.29.0", feature = "build_hasher_eq")] |
| impl<H> PartialEq for BuildHasherDefault<H> { |
| fn eq(&self, _other: &BuildHasherDefault<H>) -> bool { |
| true |
| } |
| } |
| |
| #[stable(since = "1.29.0", feature = "build_hasher_eq")] |
| impl<H> Eq for BuildHasherDefault<H> {} |
| |
| mod impls { |
| use crate::mem; |
| use crate::slice; |
| |
| use super::*; |
| |
| macro_rules! impl_write { |
| ($(($ty:ident, $meth:ident),)*) => {$( |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Hash for $ty { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| state.$meth(*self) |
| } |
| |
| fn hash_slice<H: Hasher>(data: &[$ty], state: &mut H) { |
| let newlen = data.len() * mem::size_of::<$ty>(); |
| let ptr = data.as_ptr() as *const u8; |
| state.write(unsafe { slice::from_raw_parts(ptr, newlen) }) |
| } |
| } |
| )*} |
| } |
| |
| impl_write! { |
| (u8, write_u8), |
| (u16, write_u16), |
| (u32, write_u32), |
| (u64, write_u64), |
| (usize, write_usize), |
| (i8, write_i8), |
| (i16, write_i16), |
| (i32, write_i32), |
| (i64, write_i64), |
| (isize, write_isize), |
| (u128, write_u128), |
| (i128, write_i128), |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Hash for bool { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| state.write_u8(*self as u8) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Hash for char { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| state.write_u32(*self as u32) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Hash for str { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| state.write(self.as_bytes()); |
| state.write_u8(0xff) |
| } |
| } |
| |
| #[stable(feature = "never_hash", since = "1.29.0")] |
| impl Hash for ! { |
| fn hash<H: Hasher>(&self, _: &mut H) { |
| *self |
| } |
| } |
| |
| macro_rules! impl_hash_tuple { |
| () => ( |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Hash for () { |
| fn hash<H: Hasher>(&self, _state: &mut H) {} |
| } |
| ); |
| |
| ( $($name:ident)+) => ( |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<$($name: Hash),+> Hash for ($($name,)+) where last_type!($($name,)+): ?Sized { |
| #[allow(non_snake_case)] |
| fn hash<S: Hasher>(&self, state: &mut S) { |
| let ($(ref $name,)+) = *self; |
| $($name.hash(state);)+ |
| } |
| } |
| ); |
| } |
| |
| macro_rules! last_type { |
| ($a:ident,) => { $a }; |
| ($a:ident, $($rest_a:ident,)+) => { last_type!($($rest_a,)+) }; |
| } |
| |
| impl_hash_tuple! {} |
| impl_hash_tuple! { A } |
| impl_hash_tuple! { A B } |
| impl_hash_tuple! { A B C } |
| impl_hash_tuple! { A B C D } |
| impl_hash_tuple! { A B C D E } |
| impl_hash_tuple! { A B C D E F } |
| impl_hash_tuple! { A B C D E F G } |
| impl_hash_tuple! { A B C D E F G H } |
| impl_hash_tuple! { A B C D E F G H I } |
| impl_hash_tuple! { A B C D E F G H I J } |
| impl_hash_tuple! { A B C D E F G H I J K } |
| impl_hash_tuple! { A B C D E F G H I J K L } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: Hash> Hash for [T] { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| self.len().hash(state); |
| Hash::hash_slice(self, state) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized + Hash> Hash for &T { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| (**self).hash(state); |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized + Hash> Hash for &mut T { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| (**self).hash(state); |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> Hash for *const T { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| if mem::size_of::<Self>() == mem::size_of::<usize>() { |
| // Thin pointer |
| state.write_usize(*self as *const () as usize); |
| } else { |
| // Fat pointer |
| let (a, b) = unsafe { *(self as *const Self as *const (usize, usize)) }; |
| state.write_usize(a); |
| state.write_usize(b); |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> Hash for *mut T { |
| fn hash<H: Hasher>(&self, state: &mut H) { |
| if mem::size_of::<Self>() == mem::size_of::<usize>() { |
| // Thin pointer |
| state.write_usize(*self as *const () as usize); |
| } else { |
| // Fat pointer |
| let (a, b) = unsafe { *(self as *const Self as *const (usize, usize)) }; |
| state.write_usize(a); |
| state.write_usize(b); |
| } |
| } |
| } |
| } |