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538 lines
21 KiB
538 lines
21 KiB
/* |
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* Copyright 2008-2012 NVIDIA Corporation |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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/*! \file thrust/iterator/iterator_facade.h |
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* \brief A class which exposes a public interface for iterators |
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*/ |
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/* |
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* (C) Copyright David Abrahams 2002. |
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* (C) Copyright Jeremy Siek 2002. |
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* (C) Copyright Thomas Witt 2002. |
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* |
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* Distributed under the Boost Software License, Version 1.0. |
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* (See accompanying NOTICE file for the complete license) |
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* |
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* For more information, see http://www.boost.org |
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*/ |
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#pragma once |
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#include <thrust/detail/config.h> |
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#include <thrust/detail/type_traits.h> |
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#include <thrust/iterator/detail/iterator_facade_category.h> |
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#include <thrust/iterator/detail/distance_from_result.h> |
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namespace thrust |
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{ |
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/*! \addtogroup iterators |
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* \{ |
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*/ |
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/*! \addtogroup fancyiterator Fancy Iterators |
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* \ingroup iterators |
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* \{ |
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*/ |
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// This forward declaration is required for the friend declaration |
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// in iterator_core_access |
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template<typename Derived, typename Value, typename System, typename Traversal, typename Reference, typename Difference> class iterator_facade; |
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/*! \p iterator_core_access is the class which user iterator types derived from \p thrust::iterator_adaptor |
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* or \p thrust::iterator_facade must befriend to allow it to access their private interface. |
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*/ |
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class iterator_core_access |
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{ |
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/*! \cond |
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*/ |
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// declare our friends |
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template<typename Derived, typename Value, typename System, typename Traversal, typename Reference, typename Difference> friend class iterator_facade; |
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// iterator comparisons are our friends |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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friend bool |
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operator ==(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs); |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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friend bool |
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operator !=(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs); |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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friend bool |
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operator <(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs); |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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friend bool |
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operator >(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs); |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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friend bool |
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operator <=(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs); |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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friend bool |
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operator >=(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs); |
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// iterator difference is our friend |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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friend |
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typename thrust::detail::distance_from_result< |
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iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1>, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> |
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>::type |
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operator-(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs); |
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template<typename Facade> |
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__host__ __device__ |
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static typename Facade::reference dereference(Facade const& f) |
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{ |
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return f.dereference(); |
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} |
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template<typename Facade> |
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__host__ __device__ |
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static void increment(Facade& f) |
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{ |
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f.increment(); |
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} |
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template<typename Facade> |
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__host__ __device__ |
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static void decrement(Facade& f) |
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{ |
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f.decrement(); |
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} |
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template <class Facade1, class Facade2> |
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__host__ __device__ |
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static bool equal(Facade1 const& f1, Facade2 const& f2) |
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{ |
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return f1.equal(f2); |
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} |
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// XXX TODO: Investigate whether we need both of these cases |
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//template <class Facade1, class Facade2> |
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//__host__ __device__ |
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//static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::true_) |
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//{ |
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// return f1.equal(f2); |
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//} |
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//template <class Facade1, class Facade2> |
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//__host__ __device__ |
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//static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::false_) |
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//{ |
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// return f2.equal(f1); |
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//} |
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template <class Facade> |
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__host__ __device__ |
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static void advance(Facade& f, typename Facade::difference_type n) |
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{ |
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f.advance(n); |
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} |
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// Facade2 is convertible to Facade1, |
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// so return Facade1's difference_type |
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template <class Facade1, class Facade2> |
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__host__ __device__ |
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static typename Facade1::difference_type |
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distance_from(Facade1 const& f1, Facade2 const& f2, thrust::detail::true_type) |
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{ |
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return -f1.distance_to(f2); |
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} |
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// Facade2 is not convertible to Facade1, |
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// so return Facade2's difference_type |
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template <class Facade1, class Facade2> |
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__host__ __device__ |
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static typename Facade2::difference_type |
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distance_from(Facade1 const& f1, Facade2 const& f2, thrust::detail::false_type) |
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{ |
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return f2.distance_to(f1); |
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} |
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template <class Facade1, class Facade2> |
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__host__ __device__ |
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static typename thrust::detail::distance_from_result<Facade1,Facade2>::type |
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distance_from(Facade1 const& f1, Facade2 const& f2) |
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{ |
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// dispatch the implementation of this method upon whether or not |
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// Facade2 is convertible to Facade1 |
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return distance_from(f1, f2, |
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typename thrust::detail::is_convertible<Facade2,Facade1>::type()); |
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} |
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// |
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// Curiously Recurring Template interface. |
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// |
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template <typename Derived, typename Value, typename System, typename Traversal, typename Reference, typename Difference> |
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__host__ __device__ |
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static Derived& derived(iterator_facade<Derived,Value,System,Traversal,Reference,Difference>& facade) |
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{ |
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return *static_cast<Derived*>(&facade); |
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} |
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template <typename Derived, typename Value, typename System, typename Traversal, typename Reference, typename Difference> |
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__host__ __device__ |
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static Derived const& derived(iterator_facade<Derived,Value,System,Traversal,Reference,Difference> const& facade) |
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{ |
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return *static_cast<Derived const*>(&facade); |
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} |
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/*! \endcond |
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*/ |
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}; // end iterator_core_access |
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/*! \p iterator_facade is a template which allows the programmer to define a novel iterator with a standards-conforming interface |
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* which Thrust can use to reason about algorithm acceleration opportunities. |
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* |
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* Because most of a standard iterator's interface is defined in terms of a small set of core primitives, \p iterator_facade |
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* defines the non-primitive portion mechanically. In principle a novel iterator could explicitly provide the entire interface in |
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* an ad hoc fashion but doing so might be tedious and prone to subtle errors. |
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* |
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* Often \p iterator_facade is too primitive a tool to use for defining novel iterators. In these cases, \p iterator_adaptor |
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* or a specific fancy iterator should be used instead. |
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* |
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* \p iterator_facade's functionality is derived from and generally equivalent to \p boost::iterator_facade. |
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* The exception is Thrust's addition of the template parameter \p System, which is necessary to allow Thrust |
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* to dispatch an algorithm to one of several parallel backend systems. An additional exception is Thrust's omission |
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* of the \c operator-> member function. |
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* |
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* Interested users may refer to <tt>boost::iterator_facade</tt>'s documentation for usage examples. |
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* |
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* \note \p iterator_facade's arithmetic operator free functions exist with the usual meanings but are omitted here for brevity. |
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*/ |
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template<typename Derived, typename Value, typename System, typename Traversal, typename Reference, typename Difference> |
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class iterator_facade |
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{ |
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private: |
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/*! \cond |
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*/ |
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// |
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// Curiously Recurring Template interface. |
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// |
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__host__ __device__ |
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Derived& derived() |
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{ |
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return *static_cast<Derived*>(this); |
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} |
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__host__ __device__ |
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Derived const& derived() const |
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{ |
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return *static_cast<Derived const*>(this); |
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} |
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/*! \endcond |
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*/ |
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public: |
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/*! The type of element pointed to by \p iterator_facade. |
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*/ |
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typedef typename thrust::detail::remove_const<Value>::type value_type; |
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/*! The return type of \p iterator_facade::operator*(). |
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*/ |
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typedef Reference reference; |
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/*! The return type of \p iterator_facade's non-existent \c operator->() |
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* member function. Unlike \c boost::iterator_facade, \p iterator_facade |
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* disallows access to the \p value_type's members through expressions of the |
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* form <tt>iter->member</tt>. \p pointer is defined to \c void to indicate |
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* that these expressions are not allowed. This limitation may be relaxed in a |
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* future version of Thrust. |
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*/ |
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typedef void pointer; |
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/*! The type of expressions of the form <tt>x - y</tt> where <tt>x</tt> and <tt>y</tt> |
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* are of type \p iterator_facade. |
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*/ |
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typedef Difference difference_type; |
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/*! The type of iterator category of \p iterator_facade. |
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*/ |
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typedef typename thrust::detail::iterator_facade_category< |
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System, Traversal, Value, Reference |
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>::type iterator_category; |
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/*! \p operator*() dereferences this \p iterator_facade. |
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* \return A reference to the element pointed to by this \p iterator_facade. |
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*/ |
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__host__ __device__ |
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reference operator*() const |
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{ |
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return iterator_core_access::dereference(this->derived()); |
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} |
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// XXX unimplemented for now, consider implementing it later |
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//pointer operator->() const |
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//{ |
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// return; |
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//} |
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// XXX investigate whether or not we need to go to the lengths |
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// boost does to determine the return type |
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/*! \p operator[] performs indexed dereference. |
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* \return A reference to the element \p n distance away from this \p iterator_facade. |
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*/ |
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__host__ __device__ |
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reference operator[](difference_type n) const |
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{ |
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return *(this->derived() + n); |
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} |
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/*! \p operator++ pre-increments this \p iterator_facade to refer to the element in the next position. |
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* \return <tt>*this</tt> |
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*/ |
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__host__ __device__ |
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Derived& operator++() |
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{ |
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iterator_core_access::increment(this->derived()); |
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return this->derived(); |
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} |
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/*! \p operator++ post-increments this \p iterator_facade and returns a new \p iterator_facade referring to the element in the next position. |
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* \return A copy of <tt>*this</tt> before increment. |
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*/ |
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__host__ __device__ |
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Derived operator++(int) |
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{ |
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Derived tmp(this->derived()); |
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++*this; |
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return tmp; |
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} |
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/*! \p operator-- pre-decrements this \p iterator_facade to refer to the element in the previous position. |
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* \return <tt>*this</tt> |
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*/ |
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__host__ __device__ |
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Derived& operator--() |
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{ |
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iterator_core_access::decrement(this->derived()); |
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return this->derived(); |
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} |
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/*! \p operator-- post-decrements this \p iterator_facade and returns a new \p iterator_facade referring to the element in the previous position. |
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* \return A copy of <tt>*this</tt> before decrement. |
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*/ |
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__host__ __device__ |
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Derived operator--(int) |
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{ |
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Derived tmp(this->derived()); |
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--*this; |
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return tmp; |
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} |
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/*! \p operator+= increments this \p iterator_facade to refer to an element a given distance after its current position. |
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* \param n The quantity to increment. |
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* \return <tt>*this</tt> |
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*/ |
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__host__ __device__ |
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Derived& operator+=(difference_type n) |
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{ |
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iterator_core_access::advance(this->derived(), n); |
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return this->derived(); |
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} |
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/*! \p operator-= decrements this \p iterator_facade to refer to an element a given distance before its current postition. |
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* \param n The quantity to decrement. |
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* \return <tt>*this</tt> |
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*/ |
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__host__ __device__ |
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Derived& operator-=(difference_type n) |
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{ |
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iterator_core_access::advance(this->derived(), -n); |
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return this->derived(); |
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} |
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/*! \p operator- subtracts a given quantity from this \p iterator_facade and returns a new \p iterator_facade referring to the element at the given position before this \p iterator_facade. |
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* \param n The quantity to decrement |
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* \return An \p iterator_facade pointing \p n elements before this \p iterator_facade. |
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*/ |
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__host__ __device__ |
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Derived operator-(difference_type n) const |
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{ |
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Derived result(this->derived()); |
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return result -= n; |
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} |
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}; // end iterator_facade |
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/*! \cond |
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*/ |
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// Comparison operators |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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// XXX it might be nice to implement this at some point |
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//typename enable_if_interoperable<Dr1,Dr2,bool>::type // exposition |
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bool |
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operator ==(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs) |
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{ |
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return iterator_core_access |
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::equal(*static_cast<Derived1 const*>(&lhs), |
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*static_cast<Derived2 const*>(&rhs)); |
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} |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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// XXX it might be nice to implement this at some point |
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//typename enable_if_interoperable<Dr1,Dr2,bool>::type // exposition |
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bool |
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operator !=(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs) |
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{ |
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return !iterator_core_access |
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::equal(*static_cast<Derived1 const*>(&lhs), |
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*static_cast<Derived2 const*>(&rhs)); |
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} |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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// XXX it might be nice to implement this at some point |
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//typename enable_if_interoperable<Dr1,Dr2,bool>::type // exposition |
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bool |
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operator <(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs) |
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{ |
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return 0 > iterator_core_access |
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::distance_from(*static_cast<Derived1 const*>(&lhs), |
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*static_cast<Derived2 const*>(&rhs)); |
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} |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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// XXX it might be nice to implement this at some point |
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//typename enable_if_interoperable<Dr1,Dr2,bool>::type // exposition |
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bool |
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operator >(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs) |
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{ |
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return 0 < iterator_core_access |
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::distance_from(*static_cast<Derived1 const*>(&lhs), |
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*static_cast<Derived2 const*>(&rhs)); |
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} |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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// XXX it might be nice to implement this at some point |
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//typename enable_if_interoperable<Dr1,Dr2,bool>::type // exposition |
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bool |
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operator <=(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs) |
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{ |
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return 0 >= iterator_core_access |
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::distance_from(*static_cast<Derived1 const*>(&lhs), |
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*static_cast<Derived2 const*>(&rhs)); |
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} |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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// XXX it might be nice to implement this at some point |
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//typename enable_if_interoperable<Dr1,Dr2,bool>::type // exposition |
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bool |
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operator >=(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs) |
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{ |
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return 0 <= iterator_core_access |
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::distance_from(*static_cast<Derived1 const*>(&lhs), |
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*static_cast<Derived2 const*>(&rhs)); |
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} |
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// Iterator difference |
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template <typename Derived1, typename Value1, typename System1, typename Traversal1, typename Reference1, typename Difference1, |
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typename Derived2, typename Value2, typename System2, typename Traversal2, typename Reference2, typename Difference2> |
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inline __host__ __device__ |
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|
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// divine the type this operator returns |
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typename thrust::detail::distance_from_result< |
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iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1>, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> |
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>::type |
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|
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operator-(iterator_facade<Derived1,Value1,System1,Traversal1,Reference1,Difference1> const& lhs, |
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iterator_facade<Derived2,Value2,System2,Traversal2,Reference2,Difference2> const& rhs) |
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{ |
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return iterator_core_access |
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::distance_from(*static_cast<Derived1 const*>(&lhs), |
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*static_cast<Derived2 const*>(&rhs)); |
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} |
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// Iterator addition |
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template <typename Derived, typename Value, typename System, typename Traversal, typename Reference, typename Difference> |
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inline __host__ __device__ |
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Derived operator+ (iterator_facade<Derived,Value,System,Traversal,Reference,Difference> const& i, |
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typename Derived::difference_type n) |
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{ |
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Derived tmp(static_cast<Derived const&>(i)); |
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return tmp += n; |
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} |
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template <typename Derived, typename Value, typename System, typename Traversal, typename Reference, typename Difference> |
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inline __host__ __device__ |
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Derived operator+ (typename Derived::difference_type n, |
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iterator_facade<Derived,Value,System,Traversal,Reference,Difference> const& i) |
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{ |
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Derived tmp(static_cast<Derived const&>(i)); |
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return tmp += n; |
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} |
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/*! \endcond |
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*/ |
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/*! \} // end fancyiterators |
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*/ |
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/*! \} // end iterators |
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*/ |
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} // end thrust |
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