// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

#pragma once
#include <type_traits>
#include <utility>

namespace Microsoft::Common::Utilities {

  // A simple wrapper for reinterpret_casting from TOriginalTypePtr to
  // TResultTypePtr that does a static_assert before performing the cast. The
  // usage syntax for this function is the same as the syntax for doing a regular
  // reinterpret_cast. For example:
  //
  //   uint32_t* i;
  //   auto p = CheckedReinterpretCast<char32_t*>(i);
  //
  template <typename TResultTypePtr, typename TOriginalTypePtr>
  inline TResultTypePtr CheckedReinterpretCast(TOriginalTypePtr p) noexcept {
    using TResultType = typename std::remove_pointer<TResultTypePtr>::type;
    using TOriginalType = typename std::remove_pointer<TOriginalTypePtr>::type;

    static_assert(
      std::is_pointer<TResultTypePtr>::value && std::is_pointer<TOriginalTypePtr>::value &&
      std::is_integral<TResultType>::value && std::is_integral<TOriginalType>::value &&
      sizeof(TResultType) == sizeof(TOriginalType),
      "CheckedReinterpretCast can only be used to cast from T1* to T2*, where "
      "T1 and T2 are integral types of the same size.");

    return reinterpret_cast<TResultTypePtr>(p);
  }

  // A compile time function that deduces the size of an array.
  template <typename T, std::size_t N>
  constexpr std::size_t ArraySize(T(&)[N]) noexcept {
    return N;
  }

} // namespace Microsoft::Common::Utilities