72 lines
1.5 KiB
Rust
72 lines
1.5 KiB
Rust
// Copyright 2019 The Fuchsia Authors
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//
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// Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0
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// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT
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// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option.
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// This file may not be copied, modified, or distributed except according to
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// those terms.
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#![allow(warnings)]
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use std::{marker::PhantomData, option::IntoIter};
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use {
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static_assertions::assert_impl_all,
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zerocopy::{FromBytes, FromZeroes},
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};
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// A union is `FromBytes` if:
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// - all fields are `FromBytes`
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#[derive(Clone, Copy, FromZeroes, FromBytes)]
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union Zst {
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a: (),
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}
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assert_impl_all!(Zst: FromBytes);
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#[derive(FromZeroes, FromBytes)]
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union One {
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a: u8,
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}
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assert_impl_all!(One: FromBytes);
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#[derive(FromZeroes, FromBytes)]
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union Two {
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a: u8,
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b: Zst,
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}
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assert_impl_all!(Two: FromBytes);
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#[derive(FromZeroes, FromBytes)]
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union TypeParams<'a, T: Copy, I: Iterator>
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where
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I::Item: Copy,
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{
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a: T,
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c: I::Item,
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d: u8,
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e: PhantomData<&'a [u8]>,
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f: PhantomData<&'static str>,
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g: PhantomData<String>,
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}
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assert_impl_all!(TypeParams<'static, (), IntoIter<()>>: FromBytes);
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// Deriving `FromBytes` should work if the union has bounded parameters.
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#[derive(FromZeroes, FromBytes)]
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#[repr(C)]
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union WithParams<'a: 'b, 'b: 'a, const N: usize, T: 'a + 'b + FromBytes>
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where
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'a: 'b,
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'b: 'a,
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T: 'a + 'b + Copy + FromBytes,
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{
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a: [T; N],
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b: PhantomData<&'a &'b ()>,
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}
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assert_impl_all!(WithParams<'static, 'static, 42, u8>: FromBytes);
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