/* Copyright (c) 2012-2021 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

#pragma once

#include <cassert>
#include <memory>
#include <type_traits>

namespace antlrcpp {

  template <typename To, typename From>
  To downCast(From* from) {
    static_assert(std::is_pointer_v<To>, "Target type not a pointer.");
    static_assert(std::is_base_of_v<From, std::remove_pointer_t<To>>, "Target type not derived from source type.");
  #if !defined(__GNUC__) || defined(__GXX_RTTI)
    assert(from == nullptr || dynamic_cast<To>(from) != nullptr);
  #endif
    return static_cast<To>(from);
  }

  template <typename To, typename From>
  To downCast(From& from) {
    static_assert(std::is_lvalue_reference_v<To>, "Target type not a lvalue reference.");
    static_assert(std::is_base_of_v<From, std::remove_reference_t<To>>, "Target type not derived from source type.");
  #if !defined(__GNUC__) || defined(__GXX_RTTI)
    assert(dynamic_cast<std::add_pointer_t<std::remove_reference_t<To>>>(std::addressof(from)) != nullptr);
  #endif
    return static_cast<To>(from);
  }

}