TGUI  0.9.1
Optional.hpp
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24 
25 #ifndef TGUI_OPTIONAL_HPP
26 #define TGUI_OPTIONAL_HPP
27 
28 #include <TGUI/Config.hpp>
29 
30 #if TGUI_COMPILED_WITH_CPP_VER >= 17
31  #include <optional>
32 #else
33  #include <memory>
34 #endif
35 
36 namespace tgui
37 {
38 #if TGUI_COMPILED_WITH_CPP_VER >= 17
39  template<typename T>
40  using Optional = std::optional<T>;
41 #else
42  template<typename T>
43  class Optional
44  {
45  public:
46  Optional() noexcept = default;
47 
48  Optional(const T& val) noexcept :
49  m_ptr(std::make_unique<T>(val))
50  {
51  }
52 
53  Optional(T&& val) noexcept :
54  m_ptr(std::make_unique<T>(std::move(val)))
55  {
56  }
57 
58  Optional(const Optional& other) :
59  m_ptr(other.m_ptr ? std::make_unique<T>(*other.m_ptr) : nullptr)
60  {
61  }
62 
63  Optional(Optional&& other) noexcept = default;
64 
65  template<typename... Args>
66  void emplace(Args&&... args)
67  {
68  m_ptr = std::make_unique<T>(args...);
69  }
70 
71  void reset() noexcept
72  {
73  m_ptr = nullptr;
74  }
75 
76  T& operator*()
77  {
78  return *m_ptr;
79  }
80 
81  const T& operator*() const
82  {
83  return *m_ptr;
84  }
85 
86  T* operator->() noexcept
87  {
88  return m_ptr.get();
89  }
90 
91  const T* operator->() const noexcept
92  {
93  return m_ptr.get();
94  }
95 
96  Optional& operator=(std::nullptr_t) noexcept
97  {
98  m_ptr = nullptr;
99  return *this;
100  }
101 
102  Optional& operator=(const T& val) noexcept
103  {
104  m_ptr = std::make_unique<T>(val);
105  return *this;
106  }
107 
108  Optional& operator=(T&& val) noexcept
109  {
110  m_ptr = std::make_unique<T>(std::move(val));
111  return *this;
112  }
113 
114  Optional& operator=(const Optional& other) noexcept
115  {
116  m_ptr = other.m_ptr ? std::make_unique<T>(*other.m_ptr) : nullptr;
117  return *this;
118  }
119 
120  Optional& operator=(Optional&& val) noexcept = default;
121 
122  bool operator==(std::nullptr_t) const noexcept
123  {
124  return m_ptr == nullptr;
125  }
126 
127  bool operator!=(std::nullptr_t) const noexcept
128  {
129  return m_ptr != nullptr;
130  }
131 
132  explicit operator bool() const noexcept
133  {
134  return m_ptr != nullptr;
135  }
136 
137  const T& value() const
138  {
139  return *m_ptr;
140  }
141 
142  T& value()
143  {
144  return *m_ptr;
145  }
146 
147  private:
148  std::unique_ptr<T> m_ptr;
149  };
150 #endif
151 }
152 
153 #endif // TGUI_OPTIONAL_HPP
Namespace that contains all TGUI functions and classes.
Definition: AbsoluteOrRelativeValue.hpp:36