Merge pull request #3582 from Amanieu/c-api-vec

Fix issues with the C API vector implementation

crates/c-api/src/vec.rs

@@ -29,7 +29,6 @@ macro_rules! declare_vecs {
         ))*
     ) => {$(
         #[repr(C)]
-        #[derive(Clone)]
         pub struct $name {
             size: usize,
             data: *mut $elem_ty,
@@ -80,6 +79,12 @@ macro_rules! declare_vecs {
             }
         }
 
+        impl Clone for $name {
+            fn clone(&self) -> Self {
+                self.as_slice().to_vec().into()
+            }
+        }
+
         impl From<Vec<$elem_ty>> for $name {
             fn from(vec: Vec<$elem_ty>) -> Self {
                 let mut vec = vec.into_boxed_slice();
@@ -115,8 +120,8 @@ macro_rules! declare_vecs {
             size: usize,
             ptr: *const $elem_ty,
         ) {
-            let slice = slice::from_raw_parts(ptr, size);
-            out.set_buffer(slice.to_vec());
+            let vec = (0..size).map(|i| ptr.add(i).read()).collect();
+            out.set_buffer(vec);
         }
 
         #[no_mangle]