thrust/iterator/reverse_iterator.h

File members: thrust/iterator/reverse_iterator.h

/*
 *  Copyright 2008-2013 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.
 */

/*
 * (C) Copyright David Abrahams 2002.
 * (C) Copyright Jeremy Siek    2002.
 * (C) Copyright Thomas Witt    2002.
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying NOTICE file for the complete license)
 *
 * For more information, see http://www.boost.org
 */

#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.h>
#include <thrust/iterator/iterator_adaptor.h>
#include <thrust/iterator/iterator_traits.h>

THRUST_NAMESPACE_BEGIN

template <typename>
class reverse_iterator;

namespace detail
{
template <typename BidirectionalIterator>
struct make_reverse_iterator_base
{
  using type = iterator_adaptor<reverse_iterator<BidirectionalIterator>, BidirectionalIterator>;
};
} // namespace detail

template <typename BidirectionalIterator>
class reverse_iterator : public detail::make_reverse_iterator_base<BidirectionalIterator>::type
{

private:
  using super_t = typename detail::make_reverse_iterator_base<BidirectionalIterator>::type;

  friend class iterator_core_access;

public:
  reverse_iterator() = default;

  _CCCL_HOST_DEVICE explicit reverse_iterator(BidirectionalIterator x)
      : super_t(x)
  {}

  template <typename OtherBidirectionalIterator,
            detail::enable_if_convertible_t<OtherBidirectionalIterator, BidirectionalIterator, int> = 0>
  _CCCL_HOST_DEVICE reverse_iterator(reverse_iterator<OtherBidirectionalIterator> const& rhs)
      : super_t(rhs.base())
  {}

private:
  _CCCL_EXEC_CHECK_DISABLE
  _CCCL_HOST_DEVICE typename super_t::reference dereference() const
  {
    auto b = this->base();
    return *--b;
  }

  _CCCL_HOST_DEVICE void increment()
  {
    --this->base_reference();
  }

  _CCCL_HOST_DEVICE void decrement()
  {
    ++this->base_reference();
  }

  _CCCL_HOST_DEVICE void advance(typename super_t::difference_type n)
  {
    this->base_reference() += -n;
  }

  template <typename OtherBidirectionalIterator>
  _CCCL_HOST_DEVICE typename super_t::difference_type
  distance_to(reverse_iterator<OtherBidirectionalIterator> const& y) const
  {
    return this->base_reference() - y.base();
  }
};

template <typename BidirectionalIterator>
_CCCL_HOST_DEVICE reverse_iterator<BidirectionalIterator> make_reverse_iterator(BidirectionalIterator x)
{
  return reverse_iterator<BidirectionalIterator>(x);
}

THRUST_NAMESPACE_END