Make DeviceSlice a newtype around [()] (Rust-GPU#44)

Co-authored-by: DrMeepster <[email protected]>
Co-authored-by: Christian Legnitto <[email protected]>

Author: beepster4096

crates/cust/CHANGELOG.md

@@ -4,9 +4,17 @@ Notable changes to this project will be documented in this file.
 
 ## Unreleased
 
- - Add `memory::memcpy_dtoh` to allow copying from device to host.
- - Add support in `memory` for pitched malloc and 2D memcpy between device and host.
- - `Stream::add_callback` now internally uses `cuStreamAddCallback` again, since there are no current plans to remove it (https://stackoverflow.com/a/58173486). As a result, the function again takes a device status as a parameter and *does* execute on context error.
+- Add `memory::memcpy_dtoh` to allow copying from device to host.
+- `DeviceSlice` is represented as a slice again, but as `[()]` instead of `[T]`.
+- Reimplemented `Index` and `IndexMut` for `DeviceSlice` and removed `DeviceSlice::index`.
+- Methods that returned `DeviceSlice` by value now return references:
+    - `DeviceSlice::from_raw_parts`
+    - `DeviceSlice::from_raw_parts_mut`
+    - `DeviceSliceIndex::index`
+    - `DeviceSliceIndex::get_unchecked`
+- Added `DeviceSliceIndex::index_mut` and `DeviceSliceIndex::get_unchecked_mut`.
+- Add support in `memory` for pitched malloc and 2D memcpy between device and host.
+- `Stream::add_callback` now internally uses `cuStreamAddCallback` again, since there are no current plans to remove it (https://stackoverflow.com/a/58173486). As a result, the function again takes a device status as a parameter and *does* execute on context error.
 
 ## 0.3.2 - 2/16/22
 

crates/cust/src/memory/device/device_buffer.rs

@@ -406,13 +406,13 @@ impl<T: DeviceCopy> Deref for DeviceBuffer<T> {
     type Target = DeviceSlice<T>;
 
     fn deref(&self) -> &DeviceSlice<T> {
-        unsafe { &*(self as *const _ as *const DeviceSlice<T>) }
+        unsafe { DeviceSlice::from_raw_parts(self.buf, self.len) }
     }
 }
 
 impl<T: DeviceCopy> DerefMut for DeviceBuffer<T> {
     fn deref_mut(&mut self) -> &mut DeviceSlice<T> {
-        unsafe { &mut *(self as *mut _ as *mut DeviceSlice<T>) }
+        unsafe { DeviceSlice::from_raw_parts_mut(self.buf, self.len) }
     }
 }