Add swap() and support std::hash

include/rcp.h

@@ -23,6 +23,7 @@
 #pragma once
 
 #include <atomic>
+#include <functional>
 #include <type_traits>
 
 /**
@@ -118,6 +119,13 @@ public:
         other.ptr = nullptr;
     }
 
+    void swap(rcp & other) noexcept
+    {
+        T * tmp = ptr;
+        ptr = other.ptr;
+        other.ptr = tmp;
+    }
+
     void reset()
     {
         if (ptr)
@@ -179,6 +187,18 @@ public:
     friend rcp<V> rcp_dynamic_cast(rcp<W> && other);
 };
 
+namespace std
+{
+    template <typename T>
+    struct hash<rcp<T>>
+    {
+        size_t operator()(const rcp<T> & p) const noexcept
+        {
+            return hash<const void *>()(static_cast<const void *>(p.get_raw()));
+        }
+    };
+}
+
 template <typename T, typename U>
 rcp<T> rcp_dynamic_cast(const rcp<U> & other)
 {