Introduce a base class for hashers

Chaos/Hashing/Hasher.hpp

@@ -0,0 +1,25 @@
+#ifndef CHAOS_HASHING_HASHER_HPP
+#define CHAOS_HASHING_HASHER_HPP
+
+namespace Chaos::Hashing
+{
+
+template<typename T>
+class Hasher
+{
+public:
+    template<typename InputIt>
+    void Update(InputIt begin, InputIt end)
+    {
+        static_cast<T &>(*this).Update(begin, end);
+    }
+
+    auto Finish()
+    {
+        return static_cast<T &>(*this).Finish();
+    }
+};
+
+} // namespace Chaos::Hashing
+
+#endif

Chaos/Hashing/Md4.hpp

@@ -6,6 +6,7 @@
 #include <string>
 
 #include "Hash.hpp"
+#include "Hasher.hpp"
 
 namespace Chaos::Hashing::Md4
 {
@@ -148,7 +149,7 @@ struct Md4Hash : public Hash<Md4Hash>
     std::array<uint8_t, 16> RawDigest;
 };
 
-class Md4Hasher
+class Md4Hasher : public Hasher<Md4Hasher>
 {
 public:
     Md4Hasher()