Implement BinRead for all array lengths using const generics.
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This increases the minimum supported Rust version to 1.51.0. I sadly had to introduce another unsafe statement, because: * `Default` is only implemented for array lengths up to 32 (rust-lang/rust#61415) * arr_macro doesn't support const generics (JoshMcguigan/arr_macro#2) * Direct initialization via [T; N] adds a trait bound `BinRead: Copy`
jam1garner
requested changes
Mar 27, 2021
binread/src/binread_impls.rs
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| } | ||
| } | ||
| )* | ||
| let mut arr: [B; N] = unsafe { core::mem::MaybeUninit::uninit().assume_init() }; |
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It's only safe to .assume_init() immediately on a MaybeUninit<[T; N]> if T is itself MaybeUninit<U> so the above line should look something like:
let mut arr: [MabyeUninit<B>; N] = unsafe { core::mem::MaybeUninit::uninit().assume_init() };then each item should be assigned MaybeUninit::new(some_val), and then the entire array should be transmuted to [B; N]
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Fixed that, restored the old implementation, and put my new code behind a feature gate "const_generics".
Previous Rust compatibility is preserved while Rust 1.51+ users can benefit from const generics :)
Feel free to merge this PR or squash all commits into one.
jam1garner
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Mar 28, 2021
jam1garner
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Mar 28, 2021
* Implement `BinRead` for all array lengths using const generics. * Fix array initialization via `MaybeUninit`. * Restore the old code and put the new one behind a feature gate. * Use the array-init crate over manual unsafe initialization. Ported from jam1garner/binread#41
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This increases the minimum supported Rust version to 1.51.0.
I sadly had to introduce another unsafe statement, because:
Defaultis only implemented for array lengths up to 32 (Use const generics for arrayDefaultimpl rust-lang/rust#61415)constvariable in array init JoshMcguigan/arr_macro#2)BinRead: Copy