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// Copyright 2020 Google LLC
//
// 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
//
// https://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.
#ifndef PLATFORM_BASE_TYPES_H_
#define PLATFORM_BASE_TYPES_H_
#include <type_traits>
namespace location {
namespace nearby {
// Similar to static_cast, but will assert that Derived is a derived type of
// Base.
// Usage:
// class A {};
// class B : public A {};
// class C {};
// B b;
// A* a = &b;
// B* b2 = down_cast<B*>(a); // This is OK.
// C* c = down_cast<C*>(a); // This will fail to compile.
template <typename Derived, typename Base>
inline Derived down_cast(Base* value) {
using DerivedType = typename std::remove_pointer<Derived>::type;
static_assert(std::is_base_of<Base, DerivedType>::value,
"incompatible casting");
return static_cast<Derived>(value);
}
} // namespace nearby
} // namespace location
#endif // PLATFORM_BASE_TYPES_H_
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