LevelS C++ support library  3.83
safe_cast.h
Go to the documentation of this file.
1 /*
2  * This file is part of libcxxsupport.
3  *
4  * libcxxsupport is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * libcxxsupport is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with libcxxsupport; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 /*
20  * libcxxsupport is being developed at the Max-Planck-Institut fuer Astrophysik
21  * and financially supported by the Deutsches Zentrum fuer Luft- und Raumfahrt
22  * (DLR).
23  */
24 
25 /*! \file safe_cast.h
26  * Numerical cast operator with additional checks that the value is preserved.
27  *
28  * Copyright (C) 2009 Max-Planck-Society
29  * Author: Martin Reinecke
30  */
31 
32 #ifndef PLANCK_SAFE_CAST_H
33 #define PLANCK_SAFE_CAST_H
34 
35 #include <limits>
36 #include "error_handling.h"
37 
38 template<typename T1, typename T2, bool s1, bool s2> struct safe_cast_helper__
39  {};
40 
41 template<typename T1, typename T2> struct safe_cast_helper__ <T1,T2,true,true>
42  {
43  static T1 cast (const T2 &arg)
44  {
45  T1 res = T1(arg);
46  planck_assert(T2(res)==arg, "safe_cast: value changed during cast");
47  return res;
48  }
49  };
50 
51 template<typename T1, typename T2> struct safe_cast_helper__ <T1,T2,false,false>
52  {
53  static T1 cast (const T2 &arg)
54  {
55  T1 res = T1(arg);
56  planck_assert(T2(res)==arg, "safe_cast: value changed during cast");
57  return res;
58  }
59  };
60 
61 template<typename T1, typename T2> struct safe_cast_helper__ <T1,T2,true,false>
62  {
63  static T1 cast (const T2 &arg)
64  {
65  T1 res = T1(arg);
66  planck_assert((res>=0) && (T2(res)==arg),
67  "safe_cast: value changed during cast");
68  return res;
69  }
70  };
71 
72 template<typename T1, typename T2> struct safe_cast_helper__ <T1,T2,false,true>
73  {
74  static T1 cast (const T2 &arg)
75  {
76  T1 res = T1(arg);
77  planck_assert((arg>=0) && (T2(res)==arg),
78  "safe_cast: value changed during cast");
79  return res;
80  }
81  };
82 
83 /*! Tries to cast \a arg from its type to a variable of type \c T1.
84  If this conversion leads to a change of the actual value (e.g. due to
85  overflow or truncation), an exception is thrown. */
86 template<typename T1, typename T2> inline T1 safe_cast(const T2 &arg)
87  {
88  return safe_cast_helper__<T1,T2,std::numeric_limits<T1>::is_signed,
89  std::numeric_limits<T2>::is_signed>::cast(arg);
90  }
91 
92 #endif
T1 safe_cast(const T2 &arg)
Definition: safe_cast.h:86
#define planck_assert(testval, msg)

Generated on Wed Nov 13 2024 12:18:16 for LevelS C++ support library