49 lines
1.4 KiB
C
49 lines
1.4 KiB
C
|
// Copyright 2018 The Abseil Authors.
|
||
|
|
//
|
||
|
|
// 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 ABSL_CONTAINER_INTERNAL_CONTAINER_H_
|
||
|
|
#define ABSL_CONTAINER_INTERNAL_CONTAINER_H_
|
||
|
|
|
||
|
|
#include <type_traits>
|
||
|
|
|
||
|
|
#include "absl/meta/type_traits.h"
|
||
|
|
|
||
|
|
namespace absl {
|
||
|
|
namespace container_internal {
|
||
|
|
|
||
|
|
template <class, class = void>
|
||
|
|
struct IsTransparent : std::false_type {};
|
||
|
|
template <class T>
|
||
|
|
struct IsTransparent<T, absl::void_t<typename T::is_transparent>>
|
||
|
|
: std::true_type {};
|
||
|
|
|
||
|
|
template <bool is_transparent>
|
||
|
|
struct KeyArg {
|
||
|
|
// Transparent. Forward `K`.
|
||
|
|
template <typename K, typename key_type>
|
||
|
|
using type = K;
|
||
|
|
};
|
||
|
|
|
||
|
|
template <>
|
||
|
|
struct KeyArg<false> {
|
||
|
|
// Not transparent. Always use `key_type`.
|
||
|
|
template <typename K, typename key_type>
|
||
|
|
using type = key_type;
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace container_internal
|
||
|
|
} // namespace absl
|
||
|
|
|
||
|
|
#endif // ABSL_CONTAINER_INTERNAL_CONTAINER_H_
|