add dynamic casting abilities to BufferSlice

src/buffer/mod.rs

@@ -1,3 +1,5 @@
+use core::mem;
+use core::slice;
 use core::ops::{Deref, DerefMut, Range};
 
 use alloc::Vec;
@@ -89,6 +91,24 @@ where
     }
 }
 
+impl<'a> BufferSlice<'a, u8> {
+    pub fn dynamic_cast<T: Copy>(&self) -> (T, usize) {
+        assert!(self.inner.len() >= mem::size_of::<T>());
+        let index = self.index;
+        let cast = unsafe {
+            mem::transmute_copy(self.inner.as_ptr().as_ref().unwrap())
+        };
+        (cast, index)
+    }
+
+    pub fn from_cast<T: Copy>(cast: &T, index: usize) -> BufferSlice<'a, u8> {
+        let len = mem::size_of::<T>();
+        let ptr = cast as *const T as *const u8;
+        let slice = unsafe { slice::from_raw_parts(ptr, len) };
+        BufferSlice::new(slice, index)
+    }
+}
+
 impl<'a, T> BufferSlice<'a, T>
 where
     [T]: ToOwned<Owned = Vec<T>>,