Method copy_to

crates/cust/src/memory/array.rs:795–835

Copy data from the array to the host. **This will not check if the formats match, it does however check for memory size mismatch**. For example, you can copy a `[u32; 2]` value to a `[u8; 8]` array just fine, but not to a `[u8; 10]` array.

(&self, val: &mut U)

    ///
    /// For example, you can copy a `[u32; 2]` value to a `[u8; 8]` array just fine, but not to a `[u8; 10]` array.
    pub fn copy_to<T: ArrayPrimitive, U: AsMut<[T]>>(&self, val: &mut U) -> CudaResult<()> {
        let val = val.as_mut();
        let desc = self.descriptor()?;
        let self_size = desc.width()
            * desc.height().max(1)
            * desc.depth().max(1)
            * desc.num_channels() as usize
            * desc.format().mem_size();
        let other_size = mem::size_of_val(val);
        assert_eq!(self_size, other_size, "Array and value sizes don't match");
        unsafe {
            if desc.height() == 0 && desc.depth() == 0 {
                cuMemcpyAtoH_v2(val.as_mut_ptr() as *mut c_void, self.handle, 0, self_size)
                    .to_result()
            } else if desc.depth() == 0 {
                let width = desc.width() * desc.num_channels() as usize * desc.format().mem_size();
                let desc = CUDA_MEMCPY2D {
                    Height: desc.height(),
                    WidthInBytes: width,
                    dstArray: null_mut(),
                    dstDevice: 0,
                    dstHost: val.as_mut_ptr() as *mut c_void,
                    dstMemoryType: cuda::CUmemorytype_enum::CU_MEMORYTYPE_HOST,
                    dstPitch: 0,
                    dstXInBytes: 0,
                    dstY: 0,
                    srcArray: self.handle,
                    srcDevice: 0,
                    srcHost: null(),
                    srcMemoryType: cuda::CUmemorytype_enum::CU_MEMORYTYPE_ARRAY,
                    srcPitch: 0,
                    srcXInBytes: 0,
                    srcY: 0,
                };
                cuMemcpy2D_v2(&desc as *const _).to_result()?;
                Ok(())
            } else {
                panic!();
            }
        }
    }

    /// Copy data from the array into a vec on the host. **This will not check if the formats match, it does
    /// however yield a correct vec**. Format mismatch and especially format size mismatch may yield incorrect (but not unsound!)