Merge pull request #333 from rust-ndarray/lax-strict-memory-management

Strict memory management for `lax::Eig_`

Author: termoshtt

lax/src/alloc.rs

@@ -33,18 +33,34 @@ impl_as_ptr!(MaybeUninit<c32>, lapack_sys::__BindgenComplex<f32>);
 impl_as_ptr!(MaybeUninit<c64>, lapack_sys::__BindgenComplex<f64>);
 
 pub(crate) trait VecAssumeInit {
-    type Target;
-    unsafe fn assume_init(self) -> Self::Target;
+    type Elem;
+    unsafe fn assume_init(self) -> Vec<Self::Elem>;
+
+    /// An replacement of unstable API
+    /// https://doc.rust-lang.org/std/mem/union.MaybeUninit.html#method.slice_assume_init_ref
+    unsafe fn slice_assume_init_ref(&self) -> &[Self::Elem];
+
+    /// An replacement of unstable API
+    /// https://doc.rust-lang.org/std/mem/union.MaybeUninit.html#method.slice_assume_init_mut
+    unsafe fn slice_assume_init_mut(&mut self) -> &mut [Self::Elem];
 }
 
 impl<T> VecAssumeInit for Vec<MaybeUninit<T>> {
-    type Target = Vec<T>;
-    unsafe fn assume_init(self) -> Self::Target {
+    type Elem = T;
+    unsafe fn assume_init(self) -> Vec<T> {
         // FIXME use Vec::into_raw_parts instead after stablized
         // https://doc.rust-lang.org/std/vec/struct.Vec.html#method.into_raw_parts
         let mut me = std::mem::ManuallyDrop::new(self);
         Vec::from_raw_parts(me.as_mut_ptr() as *mut T, me.len(), me.capacity())
     }
+
+    unsafe fn slice_assume_init_ref(&self) -> &[T] {
+        std::slice::from_raw_parts(self.as_ptr() as *const T, self.len())
+    }
+
+    unsafe fn slice_assume_init_mut(&mut self) -> &mut [T] {
+        std::slice::from_raw_parts_mut(self.as_mut_ptr() as *mut T, self.len())
+    }
 }
 
 /// Create a vector without initialization