mirror of
https://github.com/Lokathor/bytemuck.git
synced 2024-10-30 05:40:50 +00:00
90 lines
2.8 KiB
Rust
90 lines
2.8 KiB
Rust
use core::mem::size_of;
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use bytemuck::*;
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#[test]
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fn test_try_cast_slice() {
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// some align4 data
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let u32_slice: &[u32] = &[4, 5, 6];
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// the same data as align1
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let the_bytes: &[u8] = try_cast_slice(u32_slice).unwrap();
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assert_eq!(
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u32_slice.as_ptr() as *const u32 as usize,
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the_bytes.as_ptr() as *const u8 as usize
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);
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assert_eq!(
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u32_slice.len() * size_of::<u32>(),
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the_bytes.len() * size_of::<u8>()
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);
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// by taking one byte off the front, we're definitely mis-aligned for u32.
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let mis_aligned_bytes = &the_bytes[1..];
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assert_eq!(
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try_cast_slice::<u8, u32>(mis_aligned_bytes),
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Err(PodCastError::TargetAlignmentGreaterAndInputNotAligned)
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);
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// by taking one byte off the end, we're aligned but would have slop bytes for u32
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let the_bytes_len_minus1 = the_bytes.len() - 1;
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let slop_bytes = &the_bytes[..the_bytes_len_minus1];
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assert_eq!(
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try_cast_slice::<u8, u32>(slop_bytes),
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Err(PodCastError::OutputSliceWouldHaveSlop)
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);
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// if we don't mess with it we can up-alignment cast
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try_cast_slice::<u8, u32>(the_bytes).unwrap();
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}
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#[test]
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fn test_try_cast_slice_mut() {
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// some align4 data
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let u32_slice: &mut [u32] = &mut [4, 5, 6];
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let u32_len = u32_slice.len();
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let u32_ptr = u32_slice.as_ptr();
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// the same data as align1
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let the_bytes: &mut [u8] = try_cast_slice_mut(u32_slice).unwrap();
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let the_bytes_len = the_bytes.len();
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let the_bytes_ptr = the_bytes.as_ptr();
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assert_eq!(
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u32_ptr as *const u32 as usize,
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the_bytes_ptr as *const u8 as usize
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);
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assert_eq!(u32_len * size_of::<u32>(), the_bytes_len * size_of::<u8>());
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// by taking one byte off the front, we're definitely mis-aligned for u32.
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let mis_aligned_bytes = &mut the_bytes[1..];
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assert_eq!(
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try_cast_slice_mut::<u8, u32>(mis_aligned_bytes),
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Err(PodCastError::TargetAlignmentGreaterAndInputNotAligned)
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);
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// by taking one byte off the end, we're aligned but would have slop bytes for u32
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let the_bytes_len_minus1 = the_bytes.len() - 1;
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let slop_bytes = &mut the_bytes[..the_bytes_len_minus1];
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assert_eq!(
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try_cast_slice_mut::<u8, u32>(slop_bytes),
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Err(PodCastError::OutputSliceWouldHaveSlop)
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);
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// if we don't mess with it we can up-alignment cast
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try_cast_slice_mut::<u8, u32>(the_bytes).unwrap();
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}
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#[test]
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fn test_types() {
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let _: i32 = cast(1.0_f32);
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let _: &mut i32 = cast_mut(&mut 1.0_f32);
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let _: &i32 = cast_ref(&1.0_f32);
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let _: &[i32] = cast_slice(&[1.0_f32]);
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let _: &mut [i32] = cast_slice_mut(&mut [1.0_f32]);
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//
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let _: Result<i32, PodCastError> = try_cast(1.0_f32);
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let _: Result<&mut i32, PodCastError> = try_cast_mut(&mut 1.0_f32);
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let _: Result<&i32, PodCastError> = try_cast_ref(&1.0_f32);
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let _: Result<&[i32], PodCastError> = try_cast_slice(&[1.0_f32]);
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let _: Result<&mut [i32], PodCastError> = try_cast_slice_mut(&mut [1.0_f32]);
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}
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