GEOS  3.10.3
util.h
1 /**********************************************************************
2  *
3  * GEOS - Geometry Engine Open Source
4  * http://geos.osgeo.org
5  *
6  * Copyright (C) 2001-2002 Vivid Solutions Inc.
7  * Copyright (C) 2006 Refractions Research Inc.
8  *
9  * This is free software; you can redistribute and/or modify it under
10  * the terms of the GNU Lesser General Public Licence as published
11  * by the Free Software Foundation.
12  * See the COPYING file for more information.
13  *
14  **********************************************************************
15  *
16  * Utility header to retain a bit of backward compatibility.
17  * Try to avoid including this header directly.
18  *
19  **********************************************************************/
20 
21 #ifndef GEOS_UTIL_H
22 #define GEOS_UTIL_H
23 
24 #include <geos/util/GEOSException.h>
25 #include <geos/util/IllegalArgumentException.h>
26 #include <geos/util/TopologyException.h>
27 #include <geos/util/GeometricShapeFactory.h>
28 
29 #include <memory>
30 #include <type_traits>
31 
32 //
33 // Private macros definition
34 //
35 
36 namespace geos {
37 template<class T>
38 void
39 ignore_unused_variable_warning(T const &) {}
40 
41 namespace detail {
42 #if __cplusplus >= 201402L
43 using std::make_unique;
44 #else
45 // Backport of std::make_unique to C++11
46 // Source: https://stackoverflow.com/a/19472607
47 template<class T>
48 struct _Unique_if {
49  typedef std::unique_ptr<T> _Single_object;
50 };
51 
52 template<class T>
53 struct _Unique_if<T[]> {
54  typedef std::unique_ptr<T[]> _Unknown_bound;
55 };
56 
57 template<class T, std::size_t N>
58 struct _Unique_if<T[N]> {
59  typedef void _Known_bound;
60 };
61 
62 template<class T, class... Args>
63 typename _Unique_if<T>::_Single_object
64 make_unique(Args &&... args) {
65  return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
66 }
67 
68 template<class T>
69 typename _Unique_if<T>::_Unknown_bound
70 make_unique(std::size_t n) {
71  typedef typename std::remove_extent<T>::type U;
72  return std::unique_ptr<T>(new U[n]());
73 }
74 
75 template<class T, class... Args>
76 typename _Unique_if<T>::_Known_bound
77 make_unique(Args &&...) = delete;
78 
79 #endif
80 
90 template<typename To, typename From> inline To down_cast(From* f)
91 {
92  static_assert(
93  (std::is_base_of<From,
94  typename std::remove_pointer<To>::type>::value),
95  "target type not derived from source type");
96 #if GEOS_DEBUG
97  assert(f == nullptr || dynamic_cast<To>(f) != nullptr);
98 #endif
99  return static_cast<To>(f);
100 }
101 
102 // Avoid "redundant move" warning when calling std::move() to return
103 // unique_ptr<Derived> from a function with return type unique_ptr<Base>
104 // The std::move is required for the gcc 4.9 series, which has not addressed
105 // CWG defect 1579 ("return by converting move constructor")
106 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1579
107 #if __GNUC__ > 0 && __GNUC__ < 5
108 #define RETURN_UNIQUE_PTR(x) (std::move(x))
109 #else
110 #define RETURN_UNIQUE_PTR(x) (x)
111 #endif
112 
113 } // namespace detail
114 } // namespace geos
115 
116 #endif // GEOS_UTIL_H
Basic namespace for all GEOS functionalities.
Definition: Angle.h:26