1 // -*- C++ -*- 2 3 // Copyright (C) 2007, 2009 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 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 38 39 // Compile time constants for builtin types. 40 // Sadly std::numeric_limits member functions cannot be used for this. 41 #define __glibcxx_signed(_Tp) ((_Tp)(-1) < 0) 42 #define __glibcxx_digits(_Tp) \ 43 (sizeof(_Tp) * __CHAR_BIT__ - __glibcxx_signed(_Tp)) 44 45 #define __glibcxx_min(_Tp) \ 46 (__glibcxx_signed(_Tp) ? (_Tp)1 << __glibcxx_digits(_Tp) : (_Tp)0) 47 48 #define __glibcxx_max(_Tp) \ 49 (__glibcxx_signed(_Tp) ? \ 50 (((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0) 51 52 template<typename _Value> 53 struct __numeric_traits_integer 54 { 55 // Only integers for initialization of member constant. 56 static const _Value __min = __glibcxx_min(_Value); 57 static const _Value __max = __glibcxx_max(_Value); 58 59 // NB: these two also available in std::numeric_limits as compile 60 // time constants, but <limits> is big and we avoid including it. 61 static const bool __is_signed = __glibcxx_signed(_Value); 62 static const int __digits = __glibcxx_digits(_Value); 63 }; 64 65 template<typename _Value> 66 const _Value __numeric_traits_integer<_Value>::__min; 67 68 template<typename _Value> 69 const _Value __numeric_traits_integer<_Value>::__max; 70 71 template<typename _Value> 72 const bool __numeric_traits_integer<_Value>::__is_signed; 73 74 template<typename _Value> 75 const int __numeric_traits_integer<_Value>::__digits; 76 77 #undef __glibcxx_signed 78 #undef __glibcxx_digits 79 #undef __glibcxx_min 80 #undef __glibcxx_max 81 82 #define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \ 83 (std::__are_same<_Tp, float>::__value ? _Fval \ 84 : std::__are_same<_Tp, double>::__value ? _Dval : _LDval) 85 86 #define __glibcxx_max_digits10(_Tp) \ 87 (2 + __glibcxx_floating(_Tp, __FLT_MANT_DIG__, __DBL_MANT_DIG__, \ 88 __LDBL_MANT_DIG__) * 3010 / 10000) 89 90 #define __glibcxx_digits10(_Tp) \ 91 __glibcxx_floating(_Tp, __FLT_DIG__, __DBL_DIG__, __LDBL_DIG__) 92 93 #define __glibcxx_max_exponent10(_Tp) \ 94 __glibcxx_floating(_Tp, __FLT_MAX_10_EXP__, __DBL_MAX_10_EXP__, \ 95 __LDBL_MAX_10_EXP__) 96 97 template<typename _Value> 98 struct __numeric_traits_floating 99 { 100 // Only floating point types. See N1822. 101 static const int __max_digits10 = __glibcxx_max_digits10(_Value); 102 103 // See above comment... 104 static const bool __is_signed = true; 105 static const int __digits10 = __glibcxx_digits10(_Value); 106 static const int __max_exponent10 = __glibcxx_max_exponent10(_Value); 107 }; 108 109 template<typename _Value> 110 const int __numeric_traits_floating<_Value>::__max_digits10; 111 112 template<typename _Value> 113 const bool __numeric_traits_floating<_Value>::__is_signed; 114 115 template<typename _Value> 116 const int __numeric_traits_floating<_Value>::__digits10; 117 118 template<typename _Value> 119 const int __numeric_traits_floating<_Value>::__max_exponent10; 120 121 template<typename _Value> 122 struct __numeric_traits 123 : public __conditional_type<std::__is_integer<_Value>::__value, 124 __numeric_traits_integer<_Value>, 125 __numeric_traits_floating<_Value> >::__type 126 { }; 127 128 _GLIBCXX_END_NAMESPACE 129 130 #undef __glibcxx_floating 131 #undef __glibcxx_max_digits10 132 #undef __glibcxx_digits10 133 #undef __glibcxx_max_exponent10 134 135 #endif 136
