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.
82 lines
1.8 KiB
82 lines
1.8 KiB
/*
|
|
* Copyright (C) 2018 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 LIBTEXTCLASSIFIER_UTILS_OPTIONAL_H_
|
|
#define LIBTEXTCLASSIFIER_UTILS_OPTIONAL_H_
|
|
|
|
#include "utils/base/logging.h"
|
|
|
|
namespace libtextclassifier3 {
|
|
|
|
// Holds an optional value.
|
|
template <class T>
|
|
class Optional {
|
|
public:
|
|
Optional() : init_(false) {}
|
|
|
|
Optional(const Optional& other) {
|
|
init_ = other.init_;
|
|
if (other.init_) {
|
|
value_ = other.value_;
|
|
}
|
|
}
|
|
|
|
explicit Optional(T value) : init_(true), value_(value) {}
|
|
|
|
Optional& operator=(Optional&& other) {
|
|
init_ = other.init_;
|
|
if (other.init_) {
|
|
value_ = std::move(other);
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
Optional& operator=(T&& other) {
|
|
init_ = true;
|
|
value_ = std::move(other);
|
|
return *this;
|
|
}
|
|
|
|
constexpr bool has_value() const { return init_; }
|
|
|
|
T const* operator->() const {
|
|
TC3_CHECK(init_) << "Bad optional access.";
|
|
return value_;
|
|
}
|
|
|
|
T const& value() const& {
|
|
TC3_CHECK(init_) << "Bad optional access.";
|
|
return value_;
|
|
}
|
|
|
|
T const& value_or(T&& default_value) const& {
|
|
return (init_ ? value_ : default_value);
|
|
}
|
|
|
|
void set(const T& value) {
|
|
init_ = true;
|
|
value_ = value;
|
|
}
|
|
|
|
private:
|
|
bool init_;
|
|
T value_;
|
|
};
|
|
|
|
} // namespace libtextclassifier3
|
|
|
|
#endif // LIBTEXTCLASSIFIER_UTILS_OPTIONAL_H_
|