| commit | e92df7e900e757e2b304c42b5aac1082551b38d8 | [log] [tgz] |
|---|---|---|
| author | android-build-team Robot <android-build-team-robot@google.com> | Sun Feb 21 02:05:08 2021 +0000 |
| committer | android-build-team Robot <android-build-team-robot@google.com> | Sun Feb 21 02:05:08 2021 +0000 |
| tree | 16244a35292a0f1c14f6fbc0d6998e7e774c4ad7 | |
| parent | 330df252651c61ec8589b0e7b2dcaa04d09a5ca0 [diff] | |
| parent | 58b25a674bcfcaea0bb1834bb593d8147324c403 [diff] |
Snap for 7160100 from 58b25a674bcfcaea0bb1834bb593d8147324c403 to tm-release Change-Id: Ic7715e4004615f757b233daaaba167b1e503f9c6
- src/
- LICENSE ⇨ LICENSE-APACHE
- .cargo_vcs_info.json
- .gitignore
- Android.bp
- Cargo.toml
- Cargo.toml.orig
- CODE_OF_CONDUCT.md
- LICENSE-APACHE
- LICENSE-MIT
- METADATA
- MODULE_LICENSE_APACHE2
- OWNERS
- README.md
- TEST_MAPPING
rustc-hash
A speedy hash algorithm used within rustc. The hashmap in liballoc by default uses SipHash which isn't quite as speedy as we want. In the compiler we're not really worried about DOS attempts, so we use a fast non-cryptographic hash.
This is the same as the algorithm used by Firefox -- which is a homespun one not based on any widely-known algorithm -- though modified to produce 64-bit hash values instead of 32-bit hash values. It consistently out-performs an FNV-based hash within rustc itself -- the collision rate is similar or slightly worse than FNV, but the speed of the hash function itself is much higher because it works on up to 8 bytes at a time.
Usage
use rustc_hash::FxHashMap; let mut map: FxHashMap<u32, u32> = FxHashMap::default(); map.insert(22, 44);
no_std
This crate can be used as a no_std crate by disabling the std feature, which is on by default, as follows:
rustc-hash = { version = "1.0", default-features = false }
In this configuration, FxHasher is the only export, and the FxHashMap/FxHashSet type aliases are omitted.