webrtc/rtc_base/containers/identity.h
Victor Boivie fd954fcec7 Import flat_map and flat_set from chromium/base/
These implementations have been copied from Chromium and adapted to
build and run in WebRTC's environment.

Bug: webrtc:12689
Change-Id: Id8ff5d86b00827102a6be9d613fad7864130d013
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/224661
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34425}
2021-07-06 19:57:18 +00:00

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/*
* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
// This implementation is borrowed from Chromium.
#ifndef RTC_BASE_CONTAINERS_IDENTITY_H_
#define RTC_BASE_CONTAINERS_IDENTITY_H_
#include <utility>
namespace webrtc {
// Implementation of C++20's std::identity.
//
// Reference:
// - https://en.cppreference.com/w/cpp/utility/functional/identity
// - https://wg21.link/func.identity
struct identity {
template <typename T>
constexpr T&& operator()(T&& t) const noexcept {
return std::forward<T>(t);
}
using is_transparent = void;
};
} // namespace webrtc
#endif // RTC_BASE_CONTAINERS_IDENTITY_H_