From e761afc18ef4a82c365a78e761066dabcb801be3 Mon Sep 17 00:00:00 2001
From: Kenneth Moreland <kmorel@sandia.gov>
Date: Thu, 17 Sep 2015 22:31:58 -0600
Subject: [PATCH] Add new version of DynamicArrayHandle::CastToArrayHandle

This takes a reference to an array handle and fills it. This removes a
lot of the pain of determining template arguments.
---
 vtkm/cont/DynamicArrayHandle.h                | 18 +++++++-
 .../testing/UnitTestDynamicArrayHandle.cxx    | 41 +++++++++++++++++++
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/vtkm/cont/DynamicArrayHandle.h b/vtkm/cont/DynamicArrayHandle.h
index db0e02fa8..2e2526765 100644
--- a/vtkm/cont/DynamicArrayHandle.h
+++ b/vtkm/cont/DynamicArrayHandle.h
@@ -193,8 +193,8 @@ public:
   }
 
   /// Returns this array cast to an ArrayHandle object of the given type and
-  /// storage. Throws ErrorControlBadValue if the cast does not work. Use
-  /// IsTypeAndStorage to check if the cast can happen.
+  /// storage. Throws \c ErrorControlBadValue if the cast does not work. Use
+  /// \c IsTypeAndStorage to check if the cast can happen.
   ///
   template<typename Type, typename Storage>
   VTKM_CONT_EXPORT
@@ -209,6 +209,20 @@ public:
     return container->Array;
   }
 
+  /// Given a refernce to an ArrayHandle object, casts this array to the
+  /// ArrayHandle's type and sets the given ArrayHandle to this array. Throws
+  /// \c ErrorControlBadValue if the cast does not work. Use \c
+  /// IsTypeAndStorage to check if the cast can happen.
+  ///
+  template<typename ArrayHandleType>
+  VTKM_CONT_EXPORT
+  void CastToArrayHandle(ArrayHandleType &array) const {
+    VTKM_IS_ARRAY_HANDLE(ArrayHandleType);
+    typedef typename ArrayHandleType::ValueType ValueType;
+    typedef typename ArrayHandleType::StorageTag StorageTag;
+    array = this->CastToArrayHandle(ValueType(), StorageTag());
+  }
+
   /// Changes the types to try casting to when resolving this dynamic array,
   /// which is specified with a list tag like those in TypeListTag.h. Since C++
   /// does not allow you to actually change the template arguments, this method
diff --git a/vtkm/cont/testing/UnitTestDynamicArrayHandle.cxx b/vtkm/cont/testing/UnitTestDynamicArrayHandle.cxx
index b2fe88d6f..0e5ee6614 100644
--- a/vtkm/cont/testing/UnitTestDynamicArrayHandle.cxx
+++ b/vtkm/cont/testing/UnitTestDynamicArrayHandle.cxx
@@ -153,6 +153,33 @@ vtkm::cont::DynamicArrayHandle CreateDynamicArray(T)
         vtkm::cont::make_ArrayHandle(buffer, ARRAY_SIZE));
 }
 
+template<typename ArrayHandleType>
+void CheckCastToArrayHandle(const ArrayHandleType &array)
+{
+  VTKM_IS_ARRAY_HANDLE(ArrayHandleType);
+
+  vtkm::cont::DynamicArrayHandle dynamicArray = array;
+
+  ArrayHandleType castArray1;
+  dynamicArray.CastToArrayHandle(castArray1);
+  for (vtkm::Id index = 0; index < array.GetNumberOfValues(); index++)
+  {
+    VTKM_TEST_ASSERT(test_equal(array.GetPortalConstControl().Get(index),
+                                castArray1.GetPortalConstControl().Get(index)),
+                     "Cast array has bad value.");
+  }
+
+  ArrayHandleType castArray2 =
+      dynamicArray.CastToArrayHandle(typename ArrayHandleType::ValueType(),
+                                     typename ArrayHandleType::StorageTag());
+  for (vtkm::Id index = 0; index < array.GetNumberOfValues(); index++)
+  {
+    VTKM_TEST_ASSERT(test_equal(array.GetPortalConstControl().Get(index),
+                                castArray2.GetPortalConstControl().Get(index)),
+                     "Cast array has bad value.");
+  }
+}
+
 template<typename T, typename DynamicArrayType>
 void TryNewInstance(T, DynamicArrayType originalArray)
 {
@@ -306,6 +333,17 @@ void TryUnusualTypeAndStorage()
   std::cout << "  Found instance when storage and type lists were reset." << std:: endl;
 }
 
+void TryCastToArrayHandle()
+{
+  std::cout << "  Normal array handle." << std::endl;
+  vtkm::FloatDefault buffer[ARRAY_SIZE];
+  for (vtkm::Id index = 0; index < ARRAY_SIZE; index++)
+  {
+    buffer[index] = TestValue(index, vtkm::FloatDefault());
+  }
+  CheckCastToArrayHandle(vtkm::cont::make_ArrayHandle(buffer, ARRAY_SIZE));
+}
+
 void TestDynamicArrayHandle()
 {
   std::cout << "Try common types with default type lists." << std::endl;
@@ -333,6 +371,9 @@ void TestDynamicArrayHandle()
 
   std::cout << "Try unusual type in unusual storage." << std::endl;
   TryUnusualTypeAndStorage();
+
+  std::cout << "Try CastToArrayHandle" << std::endl;
+  TryCastToArrayHandle();
 }
 
 } // anonymous namespace