/*
 *  Copyright 2008-2016 NVIDIA Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
#pragma once

#include <thrust/detail/config.h>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header

#include <thrust/detail/type_traits/pointer_traits.h>
#include <thrust/execution_policy.h>
#include <thrust/iterator/iterator_traits.h>
#include <thrust/system/detail/generic/memory.h> // for get_value()

THRUST_NAMESPACE_BEGIN

namespace detail
{

// get_iterator_value specialization on iterators
// --------------------------------------------------
// it is okay to dereference iterator in the usual way
template <typename DerivedPolicy, typename Iterator>
_CCCL_HOST_DEVICE typename thrust::iterator_traits<Iterator>::value_type
get_iterator_value(thrust::execution_policy<DerivedPolicy>&, Iterator it)
{
  return *it;
} // get_iterator_value(exec,Iterator);

// get_iterator_value specialization on pointer
// ----------------------------------------------
// we can't just dereference a pointer in the usual way, because
// it may point to a location in the device memory.
// we use get_value(exec,pointer*) function
// to perform a dereferencing consistent with the execution policy
template <typename DerivedPolicy, typename Pointer>
_CCCL_HOST_DEVICE typename thrust::detail::pointer_traits<Pointer*>::element_type
get_iterator_value(thrust::execution_policy<DerivedPolicy>& exec, Pointer* ptr)
{
  return get_value(derived_cast(exec), ptr);
} // get_iterator_value(exec,Pointer*)

} // namespace detail

THRUST_NAMESPACE_END