// SPDX-FileCopyrightText: Copyright (c) 2008-2013, NVIDIA Corporation. All rights reserved.
// SPDX-License-Identifier: Apache-2.0

#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/allocator/tagged_allocator.h>
#include <thrust/detail/type_traits/pointer_traits.h>
#include <thrust/iterator/iterator_traits.h>

#include <cuda/std/limits>

THRUST_NAMESPACE_BEGIN
namespace detail
{
template <typename T, typename Tag, typename Pointer>
class tagged_allocator;

template <typename Tag, typename Pointer>
class tagged_allocator<void, Tag, Pointer>
{
public:
  using value_type      = void;
  using pointer         = typename ::cuda::std::pointer_traits<Pointer>::template rebind<void>;
  using const_pointer   = typename ::cuda::std::pointer_traits<Pointer>::template rebind<const void>;
  using size_type       = std::size_t;
  using difference_type = typename ::cuda::std::pointer_traits<Pointer>::difference_type;
  using system_type     = Tag;

  template <typename U>
  struct rebind
  {
    using other = tagged_allocator<U, Tag, Pointer>;
  }; // end rebind
};

template <typename T, typename Tag, typename Pointer>
class tagged_allocator
{
public:
  using value_type      = T;
  using pointer         = typename ::cuda::std::pointer_traits<Pointer>::template rebind<T>;
  using const_pointer   = typename ::cuda::std::pointer_traits<Pointer>::template rebind<const T>;
  using reference       = thrust::detail::it_reference_t<pointer>;
  using const_reference = thrust::detail::it_reference_t<const_pointer>;
  using size_type       = std::size_t;
  using difference_type = typename ::cuda::std::pointer_traits<pointer>::difference_type;
  using system_type     = Tag;

  template <typename U>
  struct rebind
  {
    using other = tagged_allocator<U, Tag, Pointer>;
  }; // end rebind

  tagged_allocator() = default;

  tagged_allocator(const tagged_allocator&) = default;

  template <typename U, typename OtherPointer>
  _CCCL_HOST_DEVICE tagged_allocator(const tagged_allocator<U, Tag, OtherPointer>&)
  {}

  ~tagged_allocator() = default;

  _CCCL_HOST_DEVICE pointer address(reference x) const
  {
    return &x;
  }

  _CCCL_HOST_DEVICE const_pointer address(const_reference x) const
  {
    return &x;
  }

  size_type max_size() const
  {
    return (::cuda::std::numeric_limits<size_type>::max)() / sizeof(T);
  }

  _CCCL_HOST_DEVICE friend bool operator==(const tagged_allocator&, const tagged_allocator&)
  {
    return true;
  }

  _CCCL_HOST_DEVICE friend bool operator!=(const tagged_allocator&, const tagged_allocator&)
  {
    return false;
  }
};
} // namespace detail
THRUST_NAMESPACE_END
