libstdc++
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00001 // -*- C++ -*- 00002 00003 // Copyright (C) 2007, 2008, 2009, 2010 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the terms 00007 // of the GNU General Public License as published by the Free Software 00008 // Foundation; either version 3, or (at your option) any later 00009 // version. 00010 00011 // This library is distributed in the hope that it will be useful, but 00012 // WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00014 // General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file ext/numeric_traits.h 00026 * This file is a GNU extension to the Standard C++ Library. 00027 */ 00028 00029 #ifndef _EXT_NUMERIC_TRAITS 00030 #define _EXT_NUMERIC_TRAITS 1 00031 00032 #pragma GCC system_header 00033 00034 #include <bits/cpp_type_traits.h> 00035 #include <ext/type_traits.h> 00036 00037 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 00038 { 00039 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00040 00041 // Compile time constants for builtin types. 00042 // Sadly std::numeric_limits member functions cannot be used for this. 00043 #define __glibcxx_signed(_Tp) ((_Tp)(-1) < 0) 00044 #define __glibcxx_digits(_Tp) \ 00045 (sizeof(_Tp) * __CHAR_BIT__ - __glibcxx_signed(_Tp)) 00046 00047 #define __glibcxx_min(_Tp) \ 00048 (__glibcxx_signed(_Tp) ? (_Tp)1 << __glibcxx_digits(_Tp) : (_Tp)0) 00049 00050 #define __glibcxx_max(_Tp) \ 00051 (__glibcxx_signed(_Tp) ? \ 00052 (((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0) 00053 00054 template<typename _Value> 00055 struct __numeric_traits_integer 00056 { 00057 // Only integers for initialization of member constant. 00058 static const _Value __min = __glibcxx_min(_Value); 00059 static const _Value __max = __glibcxx_max(_Value); 00060 00061 // NB: these two also available in std::numeric_limits as compile 00062 // time constants, but <limits> is big and we avoid including it. 00063 static const bool __is_signed = __glibcxx_signed(_Value); 00064 static const int __digits = __glibcxx_digits(_Value); 00065 }; 00066 00067 template<typename _Value> 00068 const _Value __numeric_traits_integer<_Value>::__min; 00069 00070 template<typename _Value> 00071 const _Value __numeric_traits_integer<_Value>::__max; 00072 00073 template<typename _Value> 00074 const bool __numeric_traits_integer<_Value>::__is_signed; 00075 00076 template<typename _Value> 00077 const int __numeric_traits_integer<_Value>::__digits; 00078 00079 #undef __glibcxx_signed 00080 #undef __glibcxx_digits 00081 #undef __glibcxx_min 00082 #undef __glibcxx_max 00083 00084 #define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \ 00085 (std::__are_same<_Tp, float>::__value ? _Fval \ 00086 : std::__are_same<_Tp, double>::__value ? _Dval : _LDval) 00087 00088 #define __glibcxx_max_digits10(_Tp) \ 00089 (2 + __glibcxx_floating(_Tp, __FLT_MANT_DIG__, __DBL_MANT_DIG__, \ 00090 __LDBL_MANT_DIG__) * 643L / 2136) 00091 00092 #define __glibcxx_digits10(_Tp) \ 00093 __glibcxx_floating(_Tp, __FLT_DIG__, __DBL_DIG__, __LDBL_DIG__) 00094 00095 #define __glibcxx_max_exponent10(_Tp) \ 00096 __glibcxx_floating(_Tp, __FLT_MAX_10_EXP__, __DBL_MAX_10_EXP__, \ 00097 __LDBL_MAX_10_EXP__) 00098 00099 template<typename _Value> 00100 struct __numeric_traits_floating 00101 { 00102 // Only floating point types. See N1822. 00103 static const int __max_digits10 = __glibcxx_max_digits10(_Value); 00104 00105 // See above comment... 00106 static const bool __is_signed = true; 00107 static const int __digits10 = __glibcxx_digits10(_Value); 00108 static const int __max_exponent10 = __glibcxx_max_exponent10(_Value); 00109 }; 00110 00111 template<typename _Value> 00112 const int __numeric_traits_floating<_Value>::__max_digits10; 00113 00114 template<typename _Value> 00115 const bool __numeric_traits_floating<_Value>::__is_signed; 00116 00117 template<typename _Value> 00118 const int __numeric_traits_floating<_Value>::__digits10; 00119 00120 template<typename _Value> 00121 const int __numeric_traits_floating<_Value>::__max_exponent10; 00122 00123 template<typename _Value> 00124 struct __numeric_traits 00125 : public __conditional_type<std::__is_integer<_Value>::__value, 00126 __numeric_traits_integer<_Value>, 00127 __numeric_traits_floating<_Value> >::__type 00128 { }; 00129 00130 _GLIBCXX_END_NAMESPACE_VERSION 00131 } // namespace 00132 00133 #undef __glibcxx_floating 00134 #undef __glibcxx_max_digits10 00135 #undef __glibcxx_digits10 00136 #undef __glibcxx_max_exponent10 00137 00138 #endif