1 | // -*- C++ -*- |
2 | |
3 | // Copyright (C) 2007-2017 Free Software Foundation, Inc. |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free |
6 | // software; you can redistribute it and/or modify it under the terms |
7 | // of the GNU General Public License as published by the Free Software |
8 | // Foundation; either version 3, or (at your option) any later |
9 | // version. |
10 | |
11 | // This library is distributed in the hope that it will be useful, but |
12 | // WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | // General Public License for more details. |
15 | |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version |
18 | // 3.1, as published by the Free Software Foundation. |
19 | |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
23 | // <http://www.gnu.org/licenses/>. |
24 | |
25 | /** @file ext/numeric_traits.h |
26 | * This file is a GNU extension to the Standard C++ Library. |
27 | */ |
28 | |
29 | #ifndef _EXT_NUMERIC_TRAITS |
30 | #define _EXT_NUMERIC_TRAITS 1 |
31 | |
32 | #pragma GCC system_header |
33 | |
34 | #include <bits/cpp_type_traits.h> |
35 | #include <ext/type_traits.h> |
36 | |
37 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
38 | { |
39 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
40 | |
41 | // Compile time constants for builtin types. |
42 | // Sadly std::numeric_limits member functions cannot be used for this. |
43 | #define __glibcxx_signed(_Tp) ((_Tp)(-1) < 0) |
44 | #define __glibcxx_digits(_Tp) \ |
45 | (sizeof(_Tp) * __CHAR_BIT__ - __glibcxx_signed(_Tp)) |
46 | |
47 | #define __glibcxx_min(_Tp) \ |
48 | (__glibcxx_signed(_Tp) ? (_Tp)1 << __glibcxx_digits(_Tp) : (_Tp)0) |
49 | |
50 | #define __glibcxx_max(_Tp) \ |
51 | (__glibcxx_signed(_Tp) ? \ |
52 | (((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0) |
53 | |
54 | template<typename _Value> |
55 | struct __numeric_traits_integer |
56 | { |
57 | // Only integers for initialization of member constant. |
58 | static const _Value __min = __glibcxx_min(_Value); |
59 | static const _Value __max = __glibcxx_max(_Value); |
60 | |
61 | // NB: these two also available in std::numeric_limits as compile |
62 | // time constants, but <limits> is big and we avoid including it. |
63 | static const bool __is_signed = __glibcxx_signed(_Value); |
64 | static const int __digits = __glibcxx_digits(_Value); |
65 | }; |
66 | |
67 | template<typename _Value> |
68 | const _Value __numeric_traits_integer<_Value>::__min; |
69 | |
70 | template<typename _Value> |
71 | const _Value __numeric_traits_integer<_Value>::__max; |
72 | |
73 | template<typename _Value> |
74 | const bool __numeric_traits_integer<_Value>::__is_signed; |
75 | |
76 | template<typename _Value> |
77 | const int __numeric_traits_integer<_Value>::__digits; |
78 | |
79 | #undef __glibcxx_signed |
80 | #undef __glibcxx_digits |
81 | #undef __glibcxx_min |
82 | #undef __glibcxx_max |
83 | |
84 | #define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \ |
85 | (std::__are_same<_Tp, float>::__value ? _Fval \ |
86 | : std::__are_same<_Tp, double>::__value ? _Dval : _LDval) |
87 | |
88 | #define __glibcxx_max_digits10(_Tp) \ |
89 | (2 + __glibcxx_floating(_Tp, __FLT_MANT_DIG__, __DBL_MANT_DIG__, \ |
90 | __LDBL_MANT_DIG__) * 643L / 2136) |
91 | |
92 | #define __glibcxx_digits10(_Tp) \ |
93 | __glibcxx_floating(_Tp, __FLT_DIG__, __DBL_DIG__, __LDBL_DIG__) |
94 | |
95 | #define __glibcxx_max_exponent10(_Tp) \ |
96 | __glibcxx_floating(_Tp, __FLT_MAX_10_EXP__, __DBL_MAX_10_EXP__, \ |
97 | __LDBL_MAX_10_EXP__) |
98 | |
99 | template<typename _Value> |
100 | struct __numeric_traits_floating |
101 | { |
102 | // Only floating point types. See N1822. |
103 | static const int __max_digits10 = __glibcxx_max_digits10(_Value); |
104 | |
105 | // See above comment... |
106 | static const bool __is_signed = true; |
107 | static const int __digits10 = __glibcxx_digits10(_Value); |
108 | static const int __max_exponent10 = __glibcxx_max_exponent10(_Value); |
109 | }; |
110 | |
111 | template<typename _Value> |
112 | const int __numeric_traits_floating<_Value>::__max_digits10; |
113 | |
114 | template<typename _Value> |
115 | const bool __numeric_traits_floating<_Value>::__is_signed; |
116 | |
117 | template<typename _Value> |
118 | const int __numeric_traits_floating<_Value>::__digits10; |
119 | |
120 | template<typename _Value> |
121 | const int __numeric_traits_floating<_Value>::__max_exponent10; |
122 | |
123 | template<typename _Value> |
124 | struct __numeric_traits |
125 | : public __conditional_type<std::__is_integer<_Value>::__value, |
126 | __numeric_traits_integer<_Value>, |
127 | __numeric_traits_floating<_Value> >::__type |
128 | { }; |
129 | |
130 | _GLIBCXX_END_NAMESPACE_VERSION |
131 | } // namespace |
132 | |
133 | #undef __glibcxx_floating |
134 | #undef __glibcxx_max_digits10 |
135 | #undef __glibcxx_digits10 |
136 | #undef __glibcxx_max_exponent10 |
137 | |
138 | #endif |
139 | |