You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
42 lines
1.4 KiB
42 lines
1.4 KiB
4 months ago
|
/*
|
||
|
|
* 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_LIBARTBASE_BASE_STL_UTIL_IDENTITY_H_
|
||
|
|
#define ART_LIBARTBASE_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_LIBARTBASE_BASE_STL_UTIL_IDENTITY_H_
|