Open Chinese Convert 1.1.5
A project for conversion between Traditional and Simplified Chinese
Optional.hpp
1/*
2 * Open Chinese Convert
3 *
4 * Copyright 2010-2014 Carbo Kuo <byvoid@byvoid.com>
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19#pragma once
20
21namespace opencc {
26template <typename T> class Optional {
27public:
31 Optional(T actual) : isNull(false), data(actual) {}
32
36 bool IsNull() const { return isNull; }
37
41 const T& Get() const { return data; }
42
46 static Optional<T> Null() { return Optional(); }
47
48private:
49 Optional() : isNull(true) {}
50
51 bool isNull;
52 T data;
53};
54
60template <typename T> class Optional<T*> {
61private:
62 Optional() : data(nullptr) {}
63
64 typedef T* TPtr;
65 TPtr data;
66
67public:
68 Optional(TPtr actual) : data(actual) {}
69
70 bool IsNull() const { return data == nullptr; }
71
72 const TPtr& Get() const { return data; }
73
74 static Optional<TPtr> Null() { return Optional(); }
75};
76} // namespace opencc
A class that wraps type T into a nullable type.
Definition: Optional.hpp:26
const T & Get() const
Returns the containing data of the instance.
Definition: Optional.hpp:41
bool IsNull() const
Returns true if the instance is null.
Definition: Optional.hpp:36
static Optional< T > Null()
Constructs a null instance.
Definition: Optional.hpp:46
Optional(T actual)
The constructor of Optional.
Definition: Optional.hpp:31