add ref.hpp

ref.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <openssl/evp.h>
+#include <openssl/x509.h>
+
+#include <memory>
+
+template <typename T, void Free(T*)>
+struct FnDeleter {
+    auto operator()(T *ptr) const -> void { Free(ptr); }
+};
+
+template <typename T, void(Free)(T*)>
+using Ref = std::unique_ptr<T, FnDeleter<T, Free>>;
+
+using EVP_PKEY_CTX_Ref = Ref<EVP_PKEY_CTX, EVP_PKEY_CTX_free>;
+using X509_Ref = Ref<X509, X509_free>;
+using EVP_PKEY_Ref = Ref<EVP_PKEY, EVP_PKEY_free>;