From 76bc728bc1681ed216ffe6f7720f3f57b5137fab Mon Sep 17 00:00:00 2001
From: Jan Eilers <jan.eilers@arm.com>
Date: Fri, 10 Apr 2020 12:40:24 +0100
Subject: IVGCVSW-4483 Introduce PolymorphicPointerDowncast

 * as replacement for boost::polymorphic_pointer_downcast
 * added PolymorphicPointerDowncast
 * added related unit test
 * added description to PolymorphicDowncast

Signed-off-by: Jan Eilers <jan.eilers@arm.com>
Change-Id: I47e94344c1c21941865549a5632cfb7cad804d35
---
 include/armnn/utility/PolymorphicDowncast.hpp | 58 +++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

(limited to 'include')

diff --git a/include/armnn/utility/PolymorphicDowncast.hpp b/include/armnn/utility/PolymorphicDowncast.hpp
index b4a5cad314..8f052370e5 100644
--- a/include/armnn/utility/PolymorphicDowncast.hpp
+++ b/include/armnn/utility/PolymorphicDowncast.hpp
@@ -9,6 +9,7 @@
 
 #include <armnn/Exceptions.hpp>
 
+#include <memory>
 #include <type_traits>
 
 namespace armnn
@@ -29,6 +30,46 @@ namespace armnn
 #endif
 
 
+namespace utility
+{
+// static_pointer_cast overload for std::shared_ptr
+template <class T1, class T2>
+std::shared_ptr<T1> StaticPointerCast (const std::shared_ptr<T2>& sp)
+{
+    return std::static_pointer_cast<T1>(sp);
+}
+
+// dynamic_pointer_cast overload for std::shared_ptr
+template <class T1, class T2>
+std::shared_ptr<T1> DynamicPointerCast (const std::shared_ptr<T2>& sp)
+{
+    return std::dynamic_pointer_cast<T1>(sp);
+}
+
+// static_pointer_cast overload for raw pointers
+template<class T1, class T2>
+inline T1* StaticPointerCast(T2 *ptr)
+{
+    return static_cast<T1*>(ptr);
+}
+
+// dynamic_pointer_cast overload for raw pointers
+template<class T1, class T2>
+inline T1* DynamicPointerCast(T2 *ptr)
+{
+    return dynamic_cast<T1*>(ptr);
+}
+
+} // namespace utility
+
+/// Polymorphic downcast for build in pointers only
+///
+/// Usage: Child* pChild = PolymorphicDowncast<Child*>(pBase);
+///
+/// \tparam DestType    Pointer type to the target object (Child pointer type)
+/// \tparam SourceType  Pointer type to the source object (Base pointer type)
+/// \param value        Pointer to the source object
+/// \return             Pointer of type DestType (Pointer of type child)
 template<typename DestType, typename SourceType>
 DestType PolymorphicDowncast(SourceType value)
 {
@@ -40,4 +81,21 @@ DestType PolymorphicDowncast(SourceType value)
     return static_cast<DestType>(value);
 }
 
+
+/// Polymorphic downcast for shared pointers and build in pointers
+///
+/// Usage: auto pChild = PolymorphicPointerDowncast<Child>(pBase)
+///
+/// \tparam DestType    Type of the target object (Child type)
+/// \tparam SourceType  Pointer type to the source object (Base (shared) pointer type)
+/// \param value        Pointer to the source object
+/// \return             Pointer of type DestType ((Shared) pointer of type child)
+template<typename DestType, typename SourceType>
+auto PolymorphicPointerDowncast(const SourceType& value)
+{
+    ARMNN_POLYMORPHIC_CAST_CHECK(utility::DynamicPointerCast<DestType>(value)
+                                 == utility::StaticPointerCast<DestType>(value));
+    return utility::StaticPointerCast<DestType>(value);
+}
+
 } //namespace armnn
\ No newline at end of file
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