Add an API to install extra data

1 files changed, 26 insertions, 0 deletions

diff --git a/openssl/src/ex_data.rs b/openssl/src/ex_data.rs
new file mode 100644
index 00000000..450dd113
--- /dev/null
+++ b/openssl/src/ex_data.rs
@@ -0,0 +1,26 @@
+use libc::c_int;
+use std::marker::PhantomData;
+
+/// A slot in a type's "extra data" structure.
+///
+/// It is parameterized over the type containing the extra data as well as the
+/// type of the data in the slot.
+pub struct Index<T, U>(c_int, PhantomData<(T, U)>);
+
+impl<T, U> Copy for Index<T, U> {}
+
+impl<T, U> Clone for Index<T, U> {
+    fn clone(&self) -> Index<T, U> {
+        *self
+    }
+}
+
+impl<T, U> Index<T, U> {
+    pub unsafe fn from_raw(idx: c_int) -> Index<T, U> {
+        Index(idx, PhantomData)
+    }
+
+    pub fn as_raw(&self) -> c_int {
+        self.0
+    }
+}