add UnalignedSlice

vulkano/autogen/properties.rs

@@ -94,7 +94,7 @@ fn properties_output(members: &[PropertiesMember]) -> TokenStream {
                         quote! {
                             properties_ffi.#ffi_member.map(|s|
                                 unsafe {
-                                    std::slice::from_raw_parts(
+                                    UnalignedSlice::new(
                                         s #ffi_member_field .#ffi_name .cast_const(),
                                         s #ffi_member_field .#len_field_name as _,
                                     )

vulkano/src/device/properties.rs

@@ -17,11 +17,29 @@ use crate::{
     shader::ShaderStages,
     DeviceSize, Version,
 };
-use std::ffi::c_char;
+use std::{ffi::c_char, mem};
 
 // Generated by build.rs
 include!(concat!(env!("OUT_DIR"), "/properties.rs"));
 
+/// Wrapper for holding and accessing a potentially unaligned sequence of pointers
+struct UnalignedSlice<T> {
+    ptr: *const T,
+    len: usize,
+}
+
+impl<T> UnalignedSlice<T> {
+    pub unsafe fn new(ptr: *const T, len: usize) -> UnalignedSlice<T> {
+        UnalignedSlice { ptr, len }
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &T> {
+        (0..self.len)
+            .into_iter()
+            .map(|idx| unsafe { &*self.ptr.add(idx * mem::size_of::<*const T>()) })
+    }
+}
+
 // A bit of a hack...
 // TODO: integrate into autogen?
 pub(crate) trait FromVulkan<F>
@@ -307,12 +325,10 @@ impl FromVulkan<ash::vk::ImageLayout> for ImageLayout {
     }
 }
 
-impl<U: for<'a> FromVulkan<&'a T>, T> FromVulkan<&[T]> for Vec<U> {
+impl<U: for<'a> FromVulkan<&'a T>, T> FromVulkan<UnalignedSlice<T>> for Vec<U> {
     #[inline]
-    fn from_vulkan(val: &[T]) -> Option<Vec<U>> {
-        val.iter()
-            .map(|it| U::from_vulkan(it))
-            .collect::<Option<Vec<_>>>()
+    fn from_vulkan(val: UnalignedSlice<T>) -> Option<Vec<U>> {
+        val.iter().map(U::from_vulkan).collect::<Option<Vec<_>>>()
     }
 }