1 //! This crate is a Rust port of Google's high-performance [SwissTable] hash
2 //! map, adapted to make it a drop-in replacement for Rust's standard `HashMap`
3 //! and `HashSet` types.
4 //!
5 //! The original C++ version of [SwissTable] can be found [here], and this
6 //! [CppCon talk] gives an overview of how the algorithm works.
7 //!
8 //! [SwissTable]: https://abseil.io/blog/20180927-swisstables
9 //! [here]: https://github.com/abseil/abseil-cpp/blob/master/absl/container/internal/raw_hash_set.h
10 //! [CppCon talk]: https://www.youtube.com/watch?v=ncHmEUmJZf4
11
12 #![no_std]
13 #![cfg_attr(
14 feature = "nightly",
15 feature(
16 test,
17 core_intrinsics,
18 dropck_eyepatch,
19 min_specialization,
20 extend_one,
21 allocator_api,
22 slice_ptr_get,
23 nonnull_slice_from_raw_parts,
24 maybe_uninit_array_assume_init,
25 build_hasher_simple_hash_one
26 )
27 )]
28 #![allow(
29 clippy::doc_markdown,
30 clippy::module_name_repetitions,
31 clippy::must_use_candidate,
32 clippy::option_if_let_else,
33 clippy::redundant_else,
34 clippy::manual_map,
35 clippy::missing_safety_doc,
36 clippy::missing_errors_doc
37 )]
38 #![warn(missing_docs)]
39 #![warn(rust_2018_idioms)]
40
41 #[cfg(test)]
42 #[macro_use]
43 extern crate std;
44
45 #[cfg_attr(test, macro_use)]
46 extern crate alloc;
47
48 #[cfg(feature = "nightly")]
49 #[cfg(doctest)]
50 doc_comment::doctest!("../README.md");
51
52 #[macro_use]
53 mod macros;
54
55 #[cfg(feature = "raw")]
56 /// Experimental and unsafe `RawTable` API. This module is only available if the
57 /// `raw` feature is enabled.
58 pub mod raw {
59 // The RawTable API is still experimental and is not properly documented yet.
60 #[allow(missing_docs)]
61 #[path = "mod.rs"]
62 mod inner;
63 pub use inner::*;
64
65 #[cfg(feature = "rayon")]
66 /// [rayon]-based parallel iterator types for hash maps.
67 /// You will rarely need to interact with it directly unless you have need
68 /// to name one of the iterator types.
69 ///
70 /// [rayon]: https://docs.rs/rayon/1.0/rayon
71 pub mod rayon {
72 pub use crate::external_trait_impls::rayon::raw::*;
73 }
74 }
75 #[cfg(not(feature = "raw"))]
76 mod raw;
77
78 mod external_trait_impls;
79 mod map;
80 #[cfg(feature = "rustc-internal-api")]
81 mod rustc_entry;
82 mod scopeguard;
83 mod set;
84
85 pub mod hash_map {
86 //! A hash map implemented with quadratic probing and SIMD lookup.
87 pub use crate::map::*;
88
89 #[cfg(feature = "rustc-internal-api")]
90 pub use crate::rustc_entry::*;
91
92 #[cfg(feature = "rayon")]
93 /// [rayon]-based parallel iterator types for hash maps.
94 /// You will rarely need to interact with it directly unless you have need
95 /// to name one of the iterator types.
96 ///
97 /// [rayon]: https://docs.rs/rayon/1.0/rayon
98 pub mod rayon {
99 pub use crate::external_trait_impls::rayon::map::*;
100 }
101 }
102 pub mod hash_set {
103 //! A hash set implemented as a `HashMap` where the value is `()`.
104 pub use crate::set::*;
105
106 #[cfg(feature = "rayon")]
107 /// [rayon]-based parallel iterator types for hash sets.
108 /// You will rarely need to interact with it directly unless you have need
109 /// to name one of the iterator types.
110 ///
111 /// [rayon]: https://docs.rs/rayon/1.0/rayon
112 pub mod rayon {
113 pub use crate::external_trait_impls::rayon::set::*;
114 }
115 }
116
117 pub use crate::map::HashMap;
118 pub use crate::set::HashSet;
119
120 /// The error type for `try_reserve` methods.
121 #[derive(Clone, PartialEq, Eq, Debug)]
122 pub enum TryReserveError {
123 /// Error due to the computed capacity exceeding the collection's maximum
124 /// (usually `isize::MAX` bytes).
125 CapacityOverflow,
126
127 /// The memory allocator returned an error
128 AllocError {
129 /// The layout of the allocation request that failed.
130 layout: alloc::alloc::Layout,
131 },
132 }
133
134 /// Wrapper around `Bump` which allows it to be used as an allocator for
135 /// `HashMap`, `HashSet` and `RawTable`.
136 ///
137 /// `Bump` can be used directly without this wrapper on nightly if you enable
138 /// the `allocator-api` feature of the `bumpalo` crate.
139 #[cfg(feature = "bumpalo")]
140 #[derive(Clone, Copy, Debug)]
141 pub struct BumpWrapper<'a>(pub &'a bumpalo::Bump);
142
143 #[cfg(feature = "bumpalo")]
144 #[test]
test_bumpalo()145 fn test_bumpalo() {
146 use bumpalo::Bump;
147 let bump = Bump::new();
148 let mut map = HashMap::new_in(BumpWrapper(&bump));
149 map.insert(0, 1);
150 }
151