Add Padder<>. A CRTP base for padding algorithms.

Chaos/Padding/Padder.hpp

@@ -0,0 +1,34 @@
+#ifndef CHAOS_PADDING_PADDER_HPP
+#define CHAOS_PADDING_PADDER_HPP
+
+namespace Chaos::Padding
+{
+
+template<typename T>
+class Padder
+{
+public:
+    template<typename OutputIt>
+    void Pad(OutputIt begin, OutputIt end) const
+    {
+        Impl().Pad(begin, end);
+    }
+
+protected:
+    Padder() = default;
+
+private:
+    const T & Impl() const
+    {
+        return static_cast<const T &>(*this);
+    }
+
+    T & Impl()
+    {
+        return static_cast<T &>(*this);
+    }
+};
+
+} // namespace Chaos::Padding
+
+#endif // CHAOS_PADDING_PADDER_HPP

Chaos/Padding/PadderPkcs7.hpp

@@ -5,12 +5,13 @@
 #include <iterator>
 #include <limits>
 
+#include "Padding/Padder.hpp"
 #include "Service/ChaosException.hpp"
 
 namespace Chaos::Padding
 {
 
-class PadderPkcs7
+class PadderPkcs7 : public Padder<PadderPkcs7>
 {
 public:
     template<typename OutputIt>

ChaosTests/Padding/PadderPkcs7Tests.cpp

@@ -119,3 +119,25 @@ TEST(PadPkcs7Tests, PadOutIteratorUsageTest)
         ASSERT_EQ(expected, fact);
     }
 }
+
+template<typename Impl, typename OutputIt>
+void PadThroughBase(const Padder<Impl> & padder, OutputIt begin, OutputIt end)
+{
+    padder.Pad(begin, end);
+}
+
+TEST(PadPkcs7Tests, PadThroughBaseTest)
+{
+    {
+        std::array<uint8_t, 5> fact = {};
+        std::array<uint8_t, 5> expected =
+        {
+            0x05, 0x05, 0x05, 0x05, 0x05
+        };
+
+        const PadderPkcs7 padder;
+        PadThroughBase(padder, fact.begin(), fact.end());
+
+        ASSERT_EQ(expected, fact);
+    }
+}