291a924518
Casting ZST to non-ZST will result in a slice length of 0. Casting non-ZST to ZST will only work if the input slice has length 0, and results in a slice length of 0; if the input slice is not of length 0, PodCastError::OutputSliceWouldHaveSlop is returned. Updates the docs of the PodCastError variants to reflect when they can occur. Updates the docs of try_cast_slice (and checked::) to remove note about ZST <-> non-ZST not being allowed. Update bytes_of(_mut) to remove ZST check, since casting [ZST] -> [u8] is now allowed directly using cast_slice(_mut). Update must_cast_slice checks and doctests to allow [ZST] -> [non-ZST], but disallow [non-ZST] -> [ZST]. |
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| Cargo.toml | ||
| changelog.md | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| LICENSE-ZLIB | ||
| pedantic.bat | ||
| README.md | ||
| rustfmt.toml | ||
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
askeyword - This is not like the
Fromtrait - 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
bytemuckin bigger projects. - The default build of the
bytemuckcrate will continue to work withrustc-1.34for at least the rest of the1.y.zversions. - 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.