Reversed
(src/utils/py-like/reversed.hpp)

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• Last update: 2021-11-30 17:55:32+09:00
• Include: #include "src/utils/py-like/reversed.hpp"

Required by

• Enumerate (src/utils/py-like/enumerate.hpp)
• Range (src/utils/py-like/range.hpp)

Code

#pragma once

/**
 * @file reversed.hpp
 * @brief Reversed
 */

#include <vector>

#include "lib/cxx17"

namespace workspace {

// Reversed container.
template <class _Container> class reversed {
  _Container __c;

 public:
  template <class _Tp>
  constexpr reversed(_Tp &&__x) noexcept : __c(std::forward<_Container>(__x)) {}

  template <class _Tp>
  constexpr reversed(std::initializer_list<_Tp> __x) noexcept : __c(__x) {}

  constexpr decltype(auto) begin() noexcept { return std::rbegin(__c); }
  constexpr decltype(auto) begin() const noexcept { return std::rbegin(__c); }

  constexpr decltype(auto) end() noexcept { return std::rend(__c); }
  constexpr decltype(auto) end() const noexcept { return std::rend(__c); }

  constexpr bool empty() const noexcept { return std::empty(__c); }

  constexpr decltype(auto) size() const noexcept { return std::size(__c); }

  using iterator = decltype(std::rbegin(__c));
  using const_iterator = decltype(std::crbegin(__c));

  using size_type = decltype(std::size(__c));
  using difference_type =
      typename std::iterator_traits<iterator>::difference_type;
  using value_type = typename std::iterator_traits<iterator>::value_type;

  using reference = typename std::iterator_traits<iterator>::reference;
  using const_reference =
      typename std::iterator_traits<const_iterator>::reference;
};

#if __cpp_deduction_guides >= 201606L

template <class _Tp> reversed(_Tp &&) -> reversed<_Tp>;

template <class _Tp>
reversed(std::initializer_list<_Tp>) -> reversed<std::initializer_list<_Tp>>;

#endif

}  // namespace workspace

#line 2 "src/utils/py-like/reversed.hpp"

/**
 * @file reversed.hpp
 * @brief Reversed
 */

#include <vector>

#line 2 "lib/cxx17"

#line 2 "lib/cxx14"

#ifndef _CXX14_CONSTEXPR
#if __cplusplus >= 201402L
#define _CXX14_CONSTEXPR constexpr
#else
#define _CXX14_CONSTEXPR
#endif
#endif
#line 4 "lib/cxx17"

#ifndef _CXX17_CONSTEXPR
#if __cplusplus >= 201703L
#define _CXX17_CONSTEXPR constexpr
#else
#define _CXX17_CONSTEXPR
#endif
#endif

#ifndef _CXX17_STATIC_ASSERT
#if __cplusplus >= 201703L
#define _CXX17_STATIC_ASSERT static_assert
#else
#define _CXX17_STATIC_ASSERT assert
#endif
#endif

#include <iterator>

#if __cplusplus < 201703L

namespace std {

/**
 *  @brief  Return the size of a container.
 *  @param  __cont  Container.
 */
template <typename _Container>
constexpr auto size(const _Container& __cont) noexcept(noexcept(__cont.size()))
    -> decltype(__cont.size()) {
  return __cont.size();
}

/**
 *  @brief  Return the size of an array.
 */
template <typename _Tp, size_t _Nm>
constexpr size_t size(const _Tp (&)[_Nm]) noexcept {
  return _Nm;
}

/**
 *  @brief  Return whether a container is empty.
 *  @param  __cont  Container.
 */
template <typename _Container>
[[nodiscard]] constexpr auto empty(const _Container& __cont) noexcept(
    noexcept(__cont.empty())) -> decltype(__cont.empty()) {
  return __cont.empty();
}

/**
 *  @brief  Return whether an array is empty (always false).
 */
template <typename _Tp, size_t _Nm>
[[nodiscard]] constexpr bool empty(const _Tp (&)[_Nm]) noexcept {
  return false;
}

/**
 *  @brief  Return whether an initializer_list is empty.
 *  @param  __il  Initializer list.
 */
template <typename _Tp>
[[nodiscard]] constexpr bool empty(initializer_list<_Tp> __il) noexcept {
  return __il.size() == 0;
}

struct monostate {};

}  // namespace std

#else

#include <variant>

#endif
#line 11 "src/utils/py-like/reversed.hpp"

namespace workspace {

// Reversed container.
template <class _Container> class reversed {
  _Container __c;

 public:
  template <class _Tp>
  constexpr reversed(_Tp &&__x) noexcept : __c(std::forward<_Container>(__x)) {}

  template <class _Tp>
  constexpr reversed(std::initializer_list<_Tp> __x) noexcept : __c(__x) {}

  constexpr decltype(auto) begin() noexcept { return std::rbegin(__c); }
  constexpr decltype(auto) begin() const noexcept { return std::rbegin(__c); }

  constexpr decltype(auto) end() noexcept { return std::rend(__c); }
  constexpr decltype(auto) end() const noexcept { return std::rend(__c); }

  constexpr bool empty() const noexcept { return std::empty(__c); }

  constexpr decltype(auto) size() const noexcept { return std::size(__c); }

  using iterator = decltype(std::rbegin(__c));
  using const_iterator = decltype(std::crbegin(__c));

  using size_type = decltype(std::size(__c));
  using difference_type =
      typename std::iterator_traits<iterator>::difference_type;
  using value_type = typename std::iterator_traits<iterator>::value_type;

  using reference = typename std::iterator_traits<iterator>::reference;
  using const_reference =
      typename std::iterator_traits<const_iterator>::reference;
};

#if __cpp_deduction_guides >= 201606L

template <class _Tp> reversed(_Tp &&) -> reversed<_Tp>;

template <class _Tp>
reversed(std::initializer_list<_Tp>) -> reversed<std::initializer_list<_Tp>>;

#endif

}  // namespace workspace

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