| use core::alloc::Layout; |
| use core::mem::size_of; |
| use core::ptr::{self, NonNull}; |
| |
| #[test] |
| fn const_unchecked_layout() { |
| const SIZE: usize = 0x2000; |
| const ALIGN: usize = 0x1000; |
| const LAYOUT: Layout = unsafe { Layout::from_size_align_unchecked(SIZE, ALIGN) }; |
| const DANGLING: NonNull<u8> = LAYOUT.dangling(); |
| assert_eq!(LAYOUT.size(), SIZE); |
| assert_eq!(LAYOUT.align(), ALIGN); |
| assert_eq!(Some(DANGLING), NonNull::new(ptr::invalid_mut(ALIGN))); |
| } |
| |
| #[test] |
| fn layout_round_up_to_align_edge_cases() { |
| const MAX_SIZE: usize = isize::MAX as usize; |
| |
| for shift in 0..usize::BITS { |
| let align = 1_usize << shift; |
| let edge = (MAX_SIZE + 1) - align; |
| let low = edge.saturating_sub(10); |
| let high = edge.saturating_add(10); |
| assert!(Layout::from_size_align(low, align).is_ok()); |
| assert!(Layout::from_size_align(high, align).is_err()); |
| for size in low..=high { |
| assert_eq!( |
| Layout::from_size_align(size, align).is_ok(), |
| size.next_multiple_of(align) <= MAX_SIZE, |
| ); |
| } |
| } |
| } |
| |
| #[test] |
| fn layout_array_edge_cases() { |
| for_type::<i64>(); |
| for_type::<[i32; 0b10101]>(); |
| for_type::<[u8; 0b1010101]>(); |
| |
| // Make sure ZSTs don't lead to divide-by-zero |
| assert_eq!(Layout::array::<()>(usize::MAX).unwrap(), Layout::from_size_align(0, 1).unwrap()); |
| |
| fn for_type<T>() { |
| const MAX_SIZE: usize = isize::MAX as usize; |
| |
| let edge = (MAX_SIZE + 1) / size_of::<T>(); |
| let low = edge.saturating_sub(10); |
| let high = edge.saturating_add(10); |
| assert!(Layout::array::<T>(low).is_ok()); |
| assert!(Layout::array::<T>(high).is_err()); |
| for n in low..=high { |
| assert_eq!(Layout::array::<T>(n).is_ok(), n * size_of::<T>() <= MAX_SIZE); |
| } |
| } |
| } |
| |
| #[test] |
| fn layout_debug_shows_log2_of_alignment() { |
| // `Debug` is not stable, but here's what it does right now |
| let layout = Layout::from_size_align(24576, 8192).unwrap(); |
| let s = format!("{:?}", layout); |
| assert_eq!(s, "Layout { size: 24576, align: 8192 (1 << 13) }"); |
| } |
| |
| // Running this normally doesn't do much, but it's also run in Miri, which |
| // will double-check that these are allowed by the validity invariants. |
| #[test] |
| fn layout_accepts_all_valid_alignments() { |
| for align in 0..usize::BITS { |
| let layout = Layout::from_size_align(0, 1_usize << align).unwrap(); |
| assert_eq!(layout.align(), 1_usize << align); |
| } |
| } |