2020-09-25 21:10:24 +00:00
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use std::cell::Cell;
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2019-10-16 18:33:55 +00:00
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use std::mem::MaybeUninit;
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2019-11-30 03:30:49 +00:00
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use std::ptr::NonNull;
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2019-10-16 18:33:55 +00:00
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#[test]
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fn unitialized_zero_size_box() {
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assert_eq!(
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&*Box::<()>::new_uninit() as *const _,
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NonNull::<MaybeUninit<()>>::dangling().as_ptr(),
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);
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assert_eq!(
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Box::<[()]>::new_uninit_slice(4).as_ptr(),
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NonNull::<MaybeUninit<()>>::dangling().as_ptr(),
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);
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assert_eq!(
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Box::<[String]>::new_uninit_slice(0).as_ptr(),
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NonNull::<MaybeUninit<String>>::dangling().as_ptr(),
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);
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}
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2020-05-23 15:51:02 +00:00
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#[derive(Clone, PartialEq, Eq, Debug)]
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struct Dummy {
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_data: u8,
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}
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#[test]
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fn box_clone_and_clone_from_equivalence() {
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for size in (0..8).map(|i| 2usize.pow(i)) {
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let control = vec![Dummy { _data: 42 }; size].into_boxed_slice();
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let clone = control.clone();
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let mut copy = vec![Dummy { _data: 84 }; size].into_boxed_slice();
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copy.clone_from(&control);
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assert_eq!(control, clone);
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assert_eq!(control, copy);
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}
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}
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2021-08-24 15:56:39 +00:00
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/// This test might give a false positive in case the box reallocates,
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/// but the allocator keeps the original pointer.
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2020-05-29 10:18:15 +00:00
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///
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2021-08-24 15:56:39 +00:00
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/// On the other hand, it won't give a false negative: If it fails, then the
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/// memory was definitely not reused.
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2020-05-23 15:51:02 +00:00
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#[test]
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fn box_clone_from_ptr_stability() {
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for size in (0..8).map(|i| 2usize.pow(i)) {
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let control = vec![Dummy { _data: 42 }; size].into_boxed_slice();
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let mut copy = vec![Dummy { _data: 84 }; size].into_boxed_slice();
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let copy_raw = copy.as_ptr() as usize;
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copy.clone_from(&control);
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assert_eq!(copy.as_ptr() as usize, copy_raw);
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}
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}
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2020-09-08 21:38:23 +00:00
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#[test]
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fn box_deref_lval() {
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let x = Box::new(Cell::new(5));
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x.set(1000);
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assert_eq!(x.get(), 1000);
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}
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