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android / platform / external / rust / crates / bytemuck / refs/heads/android14-qpr2-release
commitc50e5677605e7119266663c7aef76acefdeecb3b[log] [tgz]
authorAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>Fri Nov 10 00:10:31 2023 +0000
committerAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>Fri Nov 10 00:10:31 2023 +0000
tree4209f66f61ffef543aa6398aef4b389b4ef7add0
parent3529164642eaf65e758b4b0d4654531558444bb0 [diff]
parentaed9482b38fd582aee0c711082f0c31b21af3eed [diff]
Snap for 11078623 from aed9482b38fd582aee0c711082f0c31b21af3eed to 24Q1-release

Change-Id: If3d00478221093edfbda72cbcf91628ae6f0ecdd
tree: 4209f66f61ffef543aa6398aef4b389b4ef7add0
  1. .github/
  2. src/
  3. tests/
  4. LICENSE ⇨ LICENSE-APACHE
  5. .cargo_vcs_info.json
  6. .gitignore
  7. Android.bp
  8. Cargo.toml
  9. Cargo.toml.orig
  10. cargo_embargo.json
  11. changelog.md
  12. LICENSE-APACHE
  13. LICENSE-MIT
  14. LICENSE-ZLIB
  15. METADATA
  16. MODULE_LICENSE_APACHE2
  17. OWNERS
  18. README.md
  19. rustfmt.toml
README.md

License:Zlib Minimum Rust Version crates.io

bytemuck

A crate for mucking around with piles of bytes.

This crate lets you safely perform “bit cast” operations between data types. That's where you take a value and just reinterpret the bits as being some other type of value, without changing the bits.

  • This is not like the as keyword
  • This is not like the From trait
  • It is most like f32::to_bits, just generalized to let you convert between all sorts of data types.

Here‘s the part you’re more likely to care about: you can do this with slices too!

When a slice is involved it‘s not a direct bitcast. Instead, the cast_slice and cast_slice_mut functions will pull apart a slice’s data and give you a new slice that‘s the same span of memory just viewed as the new type. If the size of the slice’s element changes then the length of the slice you get back will be changed accordingly.

This lets you cast a slice of color values into a slice of u8 and send it to the GPU, or things like that. I‘m sure there’s other examples, but honestly this crate is as popular as it is mostly because of Rust's 3D graphics community wanting to cast slices of different types into byte slices for sending to the GPU. Hi friends! Push those vertices, or whatever it is that you all do.

See Also

While bytemuck is full of unsafe code, I've also started a “sibling crate” called bitfrob, which is where operations that are 100% safe will be added.

Stability

  • The crate is 1.0 and I consider this it to be “basically done”. New features are usually being accepted when other people want to put in the work, but myself I wanna move on to using bytemuck in bigger projects.
  • The default build of the bytemuck crate will continue to work with rustc-1.34 for at least the rest of the 1.y.z versions.
  • Any other cargo features of the crate are not held to the same standard, and may work only on the latest Stable or even only on latest Nightly.

Future Plans: Once the Safe Transmute Project completes and stabilizes (“eventually”) this crate will be updated to use that as the underlying mechanism for transmutation bounds, and a 2.0 version of bytemuck will be released. The hope is for the 1.0 to 2.0 transition to be as seamless as possible, but the future is always uncertain.