PCL
Optional.h
Go to the documentation of this file.
1 // ____ ______ __
2 // / __ \ / ____// /
3 // / /_/ // / / /
4 // / ____// /___ / /___ PixInsight Class Library
5 // /_/ \____//_____/ PCL 2.1.19
6 // ----------------------------------------------------------------------------
7 // pcl/Optional.h - Released 2019-11-07T10:59:34Z
8 // ----------------------------------------------------------------------------
9 // This file is part of the PixInsight Class Library (PCL).
10 // PCL is a multiplatform C++ framework for development of PixInsight modules.
11 //
12 // Copyright (c) 2003-2019 Pleiades Astrophoto S.L. All Rights Reserved.
13 //
14 // Redistribution and use in both source and binary forms, with or without
15 // modification, is permitted provided that the following conditions are met:
16 //
17 // 1. All redistributions of source code must retain the above copyright
18 // notice, this list of conditions and the following disclaimer.
19 //
20 // 2. All redistributions in binary form must reproduce the above copyright
21 // notice, this list of conditions and the following disclaimer in the
22 // documentation and/or other materials provided with the distribution.
23 //
24 // 3. Neither the names "PixInsight" and "Pleiades Astrophoto", nor the names
25 // of their contributors, may be used to endorse or promote products derived
26 // from this software without specific prior written permission. For written
27 // permission, please contact info@pixinsight.com.
28 //
29 // 4. All products derived from this software, in any form whatsoever, must
30 // reproduce the following acknowledgment in the end-user documentation
31 // and/or other materials provided with the product:
32 //
33 // "This product is based on software from the PixInsight project, developed
34 // by Pleiades Astrophoto and its contributors (http://pixinsight.com/)."
35 //
36 // Alternatively, if that is where third-party acknowledgments normally
37 // appear, this acknowledgment must be reproduced in the product itself.
38 //
39 // THIS SOFTWARE IS PROVIDED BY PLEIADES ASTROPHOTO AND ITS CONTRIBUTORS
40 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
41 // TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL PLEIADES ASTROPHOTO OR ITS
43 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
44 // EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, BUSINESS
45 // INTERRUPTION; PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; AND LOSS OF USE,
46 // DATA OR PROFITS) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
47 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
48 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
49 // POSSIBILITY OF SUCH DAMAGE.
50 // ----------------------------------------------------------------------------
51 
52 #ifndef __PCL_Optional_h
53 #define __PCL_Optional_h
54 
56 
57 #include <pcl/Defs.h>
58 #include <pcl/Diagnostics.h>
59 
60 #include <pcl/Exception.h>
61 
62 namespace pcl
63 {
64 
65 // ----------------------------------------------------------------------------
66 
80 template <class T>
81 class PCL_CLASS Optional
82 {
83 public:
84 
91  Optional() : m_value() // N.B: this initialization prevents warnings like
92  { // 'Optional<>::m_value may be used uninitialized...'
93  }
94 
102  Optional( const Optional& ) = default;
103 
104  /*
105  * Move constructor.
106  */
107  Optional( Optional&& ) = default;
108 
112  Optional( const T& value ) :
113  m_value( value ),
114  m_defined( true )
115  {
116  }
117 
121  Optional& operator =( const Optional& x )
122  {
123  if ( bool( m_defined = x.m_defined ) )
124  m_value = x.m_value;
125  return *this;
126  }
127 
131  Optional& operator =( Optional&& x )
132  {
133  if ( bool( m_defined = x.m_defined ) )
134  m_value = std::move( x.m_value );
135  return *this;
136  }
137 
143  Optional& operator =( const T& value )
144  {
145  m_value = value;
146  m_defined = true;
147  return *this;
148  }
149 
157  operator const T&() const
158  {
159  return m_value;
160  }
161 
171  const T& operator ()() const
172  {
173  return m_value;
174  }
175 
179  bool IsDefined() const
180  {
181  return m_defined;
182  }
183 
189  void Undefine()
190  {
191  m_value = T();
192  m_defined = false;
193  }
194 
199  const T& OrElse( const T& value ) const
200  {
201  return m_defined ? m_value : value;
202  }
203 
208  template <class E>
209  const T& OrElseThrow( const Exception& exception ) const
210  {
211  if ( m_defined )
212  return m_value;
213  throw exception;
214  }
215 
220  const T& OrElseThrow( const String& message ) const
221  {
222  if ( m_defined )
223  return m_value;
224  throw Error( message );
225  }
226 
235  bool operator ==( const Optional& x ) const
236  {
237  return m_defined ? (x.m_defined ? m_value == x.m_value : false) : !x.m_defined;
238  }
239 
244  bool operator ==( const T& value ) const
245  {
246  return m_defined && m_value == value;
247  }
248 
255  bool operator <( const Optional& x ) const
256  {
257  return m_defined && (!x.m_defined || m_value < x.m_value);
258  }
259 
264  bool operator <( const T& value ) const
265  {
266  return m_defined && m_value < value;
267  }
268 
269 private:
270 
271  T m_value;
272  bool m_defined = false;
273 };
274 
275 // ----------------------------------------------------------------------------
276 
277 } // pcl
278 
279 #endif // __PCL_Optional_h
280 
281 // ----------------------------------------------------------------------------
282 // EOF pcl/Optional.h - Released 2019-11-07T10:59:34Z
bool IsDefined() const
Definition: Optional.h:179
void Undefine()
Definition: Optional.h:189
Root base class for all PCL exception classes.
Definition: Exception.h:81
PCL root namespace.
Definition: AbstractImage.h:76
An object that can be in a defined or undefined state.
Definition: Optional.h:81
Unicode (UTF-16) string.
Definition: String.h:7911
bool operator<(const Array< T, A > &x1, const Array< T, A > &x2)
Definition: Array.h:2086
A simple exception with an associated error message.
Definition: Exception.h:213
Optional(const T &value)
Definition: Optional.h:112
bool operator==(const Array< T, A > &x1, const Array< T, A > &x2)
Definition: Array.h:2075