/rust/registry/src/index.crates.io-1949cf8c6b5b557f/hashbrown-0.16.0/src/hasher.rs

Source
#[cfg(feature = "default-hasher")]
use {
    core::hash::{BuildHasher, Hasher},
    foldhash::fast::RandomState,
};

/// Default hash builder for the `S` type parameter of
/// [`HashMap`](crate::HashMap) and [`HashSet`](crate::HashSet).
///
/// This only implements `BuildHasher` when the "default-hasher" crate feature
/// is enabled; otherwise it just serves as a placeholder, and a custom `S` type
/// must be used to have a fully functional `HashMap` or `HashSet`.
#[derive(Clone, Debug, Default)]
pub struct DefaultHashBuilder {
    #[cfg(feature = "default-hasher")]
    inner: RandomState,
}

#[cfg(feature = "default-hasher")]
impl BuildHasher for DefaultHashBuilder {
    type Hasher = DefaultHasher;

    #[inline(always)]
    fn build_hasher(&self) -> Self::Hasher {
        DefaultHasher {
            inner: self.inner.build_hasher(),
        }
    }
}

/// Default hasher for [`HashMap`](crate::HashMap) and [`HashSet`](crate::HashSet).
#[cfg(feature = "default-hasher")]
#[derive(Clone)]
pub struct DefaultHasher {
    inner: <RandomState as BuildHasher>::Hasher,
}

#[cfg(feature = "default-hasher")]
macro_rules! forward_writes {
    ($( $write:ident ( $ty:ty ) , )*) => {$(
        #[inline(always)]
        fn $write(&mut self, arg: $ty) {
            self.inner.$write(arg);
        }
    )*}
}

#[cfg(feature = "default-hasher")]
impl Hasher for DefaultHasher {
    forward_writes! {
        write(&[u8]),
        write_u8(u8),
        write_u16(u16),
        write_u32(u32),
        write_u64(u64),
        write_u128(u128),
        write_usize(usize),
        write_i8(i8),
        write_i16(i16),
        write_i32(i32),
        write_i64(i64),
        write_i128(i128),
        write_isize(isize),
    }

    // feature(hasher_prefixfree_extras)
    #[cfg(feature = "nightly")]
    forward_writes! {
        write_length_prefix(usize),
        write_str(&str),
    }

    #[inline(always)]
    fn finish(&self) -> u64 {
        self.inner.finish()
    }
}

Coverage Report

Created: 2025-09-27 07:05

Line	Count	Source
1		#[cfg(feature = "default-hasher")]
2		use {
3		core::hash::{BuildHasher, Hasher},
4		foldhash::fast::RandomState,
5		};
6
7		/// Default hash builder for the `S` type parameter of
8		/// [`HashMap`](crate::HashMap) and [`HashSet`](crate::HashSet).
9		///
10		/// This only implements `BuildHasher` when the "default-hasher" crate feature
11		/// is enabled; otherwise it just serves as a placeholder, and a custom `S` type
12		/// must be used to have a fully functional `HashMap` or `HashSet`.
13		#[derive(Clone, Debug, Default)]
14		pub struct DefaultHashBuilder {
15		#[cfg(feature = "default-hasher")]
16		inner: RandomState,
17		}
18
19		#[cfg(feature = "default-hasher")]
20		impl BuildHasher for DefaultHashBuilder {
21		type Hasher = DefaultHasher;
22
23		#[inline(always)]
24	0	fn build_hasher(&self) -> Self::Hasher {
25	0	DefaultHasher {
26	0	inner: self.inner.build_hasher(),
27	0	}
28	0	}
29		}
30
31		/// Default hasher for [`HashMap`](crate::HashMap) and [`HashSet`](crate::HashSet).
32		#[cfg(feature = "default-hasher")]
33		#[derive(Clone)]
34		pub struct DefaultHasher {
35		inner: <RandomState as BuildHasher>::Hasher,
36		}
37
38		#[cfg(feature = "default-hasher")]
39		macro_rules! forward_writes {
40		($( $write:ident ( $ty:ty ) , )*) => {$(
41		#[inline(always)]
42	0	fn $write(&mut self, arg: $ty) {
43	0	self.inner.$write(arg);
44	0	} Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_i128 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_u128 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_isize Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_usize Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_i8 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_u8 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_i16 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_i32 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_i64 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_u16 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_u32 Unexecuted instantiation: <hashbrown::hasher::DefaultHasher as core::hash::Hasher>::write_u64
45		)*}
46		}
47
48		#[cfg(feature = "default-hasher")]
49		impl Hasher for DefaultHasher {
50		forward_writes! {
51		write(&[u8]),
52		write_u8(u8),
53		write_u16(u16),
54		write_u32(u32),
55		write_u64(u64),
56		write_u128(u128),
57		write_usize(usize),
58		write_i8(i8),
59		write_i16(i16),
60		write_i32(i32),
61		write_i64(i64),
62		write_i128(i128),
63		write_isize(isize),
64		}
65
66		// feature(hasher_prefixfree_extras)
67		#[cfg(feature = "nightly")]
68		forward_writes! {
69		write_length_prefix(usize),
70		write_str(&str),
71		}
72
73		#[inline(always)]
74	0	fn finish(&self) -> u64 {
75	0	self.inner.finish()
76	0	}
77		}