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/*
* Copyright (C) 2011 The Android Open Source Project
*
* 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
*
* http://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 ART_RUNTIME_BASE_STL_UTIL_IDENTITY_H_
#define ART_RUNTIME_BASE_STL_UTIL_IDENTITY_H_
namespace art {
// Use to suppress type deduction for a function argument.
// See std::identity<> for more background:
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1856.html#20.2.2 - move/forward helpers
//
// e.g. "template <typename X> void bar(identity<X>::type foo);
// bar(5); // compilation error
// bar<int>(5); // ok
// or "template <typename T> void foo(T* x, typename Identity<T*>::type y);
// Base b;
// Derived d;
// foo(&b, &d); // Use implicit Derived* -> Base* conversion.
// If T was deduced from both &b and &d, there would be a mismatch, i.e. deduction failure.
template <typename T>
struct Identity {
using type = T;
};
} // namespace art
#endif // ART_RUNTIME_BASE_STL_UTIL_IDENTITY_H_