From 6da2dc0cda7c640468c84738c9b668be223ac96f Mon Sep 17 00:00:00 2001
From: Robert Maynard <robert.maynard@kitware.com>
Date: Thu, 26 May 2016 08:23:27 -0400
Subject: [PATCH] ArrayPortalFromIterators now can be explicitly instantiated.

Template instantiation is useful because when you are creating object files, as
uninstantiated template definitions are not are not added. Fully supporting
explicit instantiation like ITK does will require more code changes, but
this is a very minor step towards that goal.
---
 vtkm/cont/internal/ArrayPortalFromIterators.h | 88 ++++++++++++++++++-
 1 file changed, 86 insertions(+), 2 deletions(-)

diff --git a/vtkm/cont/internal/ArrayPortalFromIterators.h b/vtkm/cont/internal/ArrayPortalFromIterators.h
index c12a32092..00a90536a 100644
--- a/vtkm/cont/internal/ArrayPortalFromIterators.h
+++ b/vtkm/cont/internal/ArrayPortalFromIterators.h
@@ -29,15 +29,22 @@
 #include <iterator>
 #include <limits>
 
+#include <boost/type_traits.hpp>
+
 namespace vtkm {
 namespace cont {
 namespace internal {
 
+template<typename IteratorT, typename Enable= void>
+class ArrayPortalFromIterators;
+
 /// This templated implementation of an ArrayPortal allows you to adapt a pair
 /// of begin/end iterators to an ArrayPortal interface.
 ///
 template<class IteratorT>
-class ArrayPortalFromIterators
+class ArrayPortalFromIterators<IteratorT,
+                               typename boost::disable_if<
+                                boost::is_const< typename boost::remove_pointer<IteratorT>::type > >::type>
 {
 public:
   typedef typename std::iterator_traits<IteratorT>::value_type ValueType;
@@ -94,7 +101,84 @@ public:
   VTKM_EXEC_CONT_EXPORT
   void Set(vtkm::Id index, const ValueType& value) const
   {
-    *this->IteratorAt(index) = value;
+    *(this->BeginIterator + index) = value;
+  }
+
+  VTKM_SUPPRESS_EXEC_WARNINGS
+  VTKM_EXEC_CONT_EXPORT
+  IteratorT GetIteratorBegin() const {
+    return this->BeginIterator;
+  }
+
+private:
+  IteratorT BeginIterator;
+  vtkm::Id NumberOfValues;
+
+  VTKM_SUPPRESS_EXEC_WARNINGS
+  VTKM_EXEC_CONT_EXPORT
+  IteratorT IteratorAt(vtkm::Id index) const
+  {
+    VTKM_ASSERT(index >= 0);
+    VTKM_ASSERT(index < this->GetNumberOfValues());
+
+    return this->BeginIterator + index;
+  }
+};
+
+template<class IteratorT>
+class ArrayPortalFromIterators<IteratorT,
+                               typename boost::enable_if<
+                                boost::is_const< typename boost::remove_pointer<IteratorT>::type > >::type>
+{
+public:
+  typedef typename std::iterator_traits<IteratorT>::value_type ValueType;
+  typedef IteratorT IteratorType;
+
+  VTKM_SUPPRESS_EXEC_WARNINGS
+  VTKM_CONT_EXPORT
+  ArrayPortalFromIterators() {  }
+
+  VTKM_SUPPRESS_EXEC_WARNINGS
+  VTKM_CONT_EXPORT
+  ArrayPortalFromIterators(IteratorT begin, IteratorT end)
+    : BeginIterator(begin)
+  {
+    typename std::iterator_traits<IteratorT>::difference_type numberOfValues =
+      std::distance(begin, end);
+    VTKM_ASSERT(numberOfValues >= 0);
+#ifndef VTKM_USE_64BIT_IDS
+    if (numberOfValues > std::numeric_limits<vtkm::Id>::max())
+    {
+      throw vtkm::cont::ErrorControlBadAllocation(
+        "Distance of iterators larger than maximum array size. "
+        "To support larger arrays, try turning on VTKM_USE_64BIT_IDS.");
+    }
+#endif // !VTKM_USE_64BIT_IDS
+    this->NumberOfValues = static_cast<vtkm::Id>(numberOfValues);
+  }
+
+  /// Copy constructor for any other ArrayPortalFromIterators with an iterator
+  /// type that can be copied to this iterator type. This allows us to do any
+  /// type casting that the iterators do (like the non-const to const cast).
+  ///
+  template<class OtherIteratorT>
+  VTKM_CONT_EXPORT
+  ArrayPortalFromIterators(const ArrayPortalFromIterators<OtherIteratorT> &src)
+    : BeginIterator(src.GetIteratorBegin()), NumberOfValues(src.GetNumberOfValues())
+  {  }
+
+  VTKM_SUPPRESS_EXEC_WARNINGS
+  VTKM_EXEC_CONT_EXPORT
+  vtkm::Id GetNumberOfValues() const
+  {
+    return this->NumberOfValues;
+  }
+
+  VTKM_SUPPRESS_EXEC_WARNINGS
+  VTKM_EXEC_CONT_EXPORT
+  ValueType Get(vtkm::Id index) const
+  {
+    return *this->IteratorAt(index);
   }
 
   VTKM_SUPPRESS_EXEC_WARNINGS