1 files changed, 73 insertions, 0 deletions
diff --git a/rendy-memory/src/mapping/write.rs b/rendy-memory/src/mapping/write.rs
new file mode 100644
index 0000000..d067a61
--- /dev/null
+++ b/rendy-memory/src/mapping/write.rs
@@ -0,0 +1,73 @@
+use std::ptr::copy_nonoverlapping;
+
+/// Trait for memory region suitable for host writes.
+pub trait Write<T: Copy> {
+    /// Get mutable slice of `T` bound to mapped range.
+    ///
+    /// # Safety
+    ///
+    /// * Returned slice should not be read.
+    unsafe fn slice(&mut self) -> &mut [T];
+
+    /// Write data into mapped memory sub-region.
+    ///
+    /// # Panic
+    ///
+    /// Panics if `data.len()` is greater than this sub-region len.
+    fn write(&mut self, data: &[T]) {
+        unsafe {
+            let slice = self.slice();
+            assert!(data.len() <= slice.len());
+            copy_nonoverlapping(data.as_ptr(), slice.as_mut_ptr(), data.len());
+        }
+    }
+}
+
+#[derive(Debug)]
+pub(super) struct WriteFlush<'a, T, F: FnOnce() + 'a> {
+    pub(super) slice: &'a mut [T],
+    pub(super) flush: Option<F>,
+}
+
+impl<'a, T, F> Drop for WriteFlush<'a, T, F>
+where
+    T: 'a,
+    F: FnOnce() + 'a,
+{
+    fn drop(&mut self) {
+        if let Some(f) = self.flush.take() {
+            f();
+        }
+    }
+}
+
+impl<'a, T, F> Write<T> for WriteFlush<'a, T, F>
+where
+    T: Copy + 'a,
+    F: FnOnce() + 'a,
+{
+    /// # Safety
+    ///
+    /// [See doc comment for trait method](trait.Write#method.slice)
+    unsafe fn slice(&mut self) -> &mut [T] {
+        self.slice
+    }
+}
+
+#[warn(dead_code)]
+#[derive(Debug)]
+pub(super) struct WriteCoherent<'a, T> {
+    pub(super) slice: &'a mut [T],
+}
+
+impl<'a, T> Write<T> for WriteCoherent<'a, T>
+where
+    T: Copy + 'a,
+{
+    /// # Safety
+    ///
+    /// [See doc comment for trait method](trait.Write#method.slice)
+    unsafe fn slice(&mut self) -> &mut [T] {
+        self.slice
+    }
+}