mirror of
https://github.com/Lokathor/bytemuck.git
synced 2024-11-22 06:42:25 +00:00
122 lines
3.0 KiB
Rust
122 lines
3.0 KiB
Rust
//! Cargo miri doesn't run doctests yet, so we duplicate these here. It's
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//! probably not that important to sweat keeping these perfectly up to date, but
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//! we should try to catch the cases where the primary tests are doctests.
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use bytemuck::*;
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// Miri doesn't run on doctests, so... copypaste to the rescue.
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#[test]
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fn test_transparent_slice() {
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#[repr(transparent)]
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struct Slice<T>([T]);
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unsafe impl<T> TransparentWrapper<[T]> for Slice<T> {}
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let s = Slice::wrap_ref(&[1u32, 2, 3]);
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assert_eq!(&s.0, &[1, 2, 3]);
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let mut buf = [1, 2, 3u8];
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let _sm = Slice::wrap_mut(&mut buf);
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}
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#[test]
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fn test_transparent_basic() {
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#[derive(Default)]
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struct SomeStruct(u32);
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#[repr(transparent)]
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struct MyWrapper(SomeStruct);
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unsafe impl TransparentWrapper<SomeStruct> for MyWrapper {}
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// interpret a reference to &SomeStruct as a &MyWrapper
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let thing = SomeStruct::default();
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let wrapped_ref: &MyWrapper = MyWrapper::wrap_ref(&thing);
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// Works with &mut too.
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let mut mut_thing = SomeStruct::default();
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let wrapped_mut: &mut MyWrapper = MyWrapper::wrap_mut(&mut mut_thing);
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let _ = (wrapped_ref, wrapped_mut);
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}
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// Work around miri not running doctests
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#[test]
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fn test_contiguous_doc() {
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#[repr(u8)]
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#[derive(Debug, Copy, Clone, PartialEq)]
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enum Foo {
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A = 0,
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B = 1,
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C = 2,
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D = 3,
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E = 4,
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}
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unsafe impl Contiguous for Foo {
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type Int = u8;
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const MIN_VALUE: u8 = Foo::A as u8;
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const MAX_VALUE: u8 = Foo::E as u8;
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}
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assert_eq!(Foo::from_integer(3).unwrap(), Foo::D);
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assert_eq!(Foo::from_integer(8), None);
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assert_eq!(Foo::C.into_integer(), 2);
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assert_eq!(Foo::B.into_integer(), Foo::B as u8);
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}
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#[test]
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fn test_offsetof_vertex() {
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#[repr(C)]
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struct Vertex {
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pos: [f32; 2],
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uv: [u16; 2],
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color: [u8; 4],
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}
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unsafe impl Zeroable for Vertex {}
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let pos = offset_of!(Zeroable::zeroed(), Vertex, pos);
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let uv = offset_of!(Zeroable::zeroed(), Vertex, uv);
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let color = offset_of!(Zeroable::zeroed(), Vertex, color);
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assert_eq!(pos, 0);
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assert_eq!(uv, 8);
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assert_eq!(color, 12);
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}
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#[test]
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fn test_offsetof_nonpod() {
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#[derive(Default)]
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struct Foo {
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a: u8,
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b: &'static str,
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c: i32,
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}
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let a_offset = offset_of!(Default::default(), Foo, a);
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let b_offset = offset_of!(Default::default(), Foo, b);
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let c_offset = offset_of!(Default::default(), Foo, c);
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assert_ne!(a_offset, b_offset);
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assert_ne!(b_offset, c_offset);
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// We can't check against hardcoded values for a repr(Rust) type,
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// but prove to ourself this way.
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let foo = Foo::default();
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// Note: offsets are in bytes.
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let as_bytes = &foo as *const _ as *const u8;
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// we're using wrapping_offset here becasue it's not worth
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// the unsafe block, but it would be valid to use `add` instead,
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// as it cannot overflow.
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assert_eq!(
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&foo.a as *const _ as usize,
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as_bytes.wrapping_add(a_offset) as usize
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);
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assert_eq!(
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&foo.b as *const _ as usize,
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as_bytes.wrapping_add(b_offset) as usize
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);
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assert_eq!(
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&foo.c as *const _ as usize,
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as_bytes.wrapping_add(c_offset) as usize
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);
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}
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