| // -*- C++ -*- |
| |
| // Copyright (C) 2007-2020 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the terms |
| // of the GNU General Public License as published by the Free Software |
| // Foundation; either version 3, or (at your option) any later |
| // version. |
| |
| // This library is distributed in the hope that it will be useful, but |
| // WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| // General Public License for more details. |
| |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| /** @file ext/numeric_traits.h |
| * This file is a GNU extension to the Standard C++ Library. |
| */ |
| |
| #ifndef _EXT_NUMERIC_TRAITS |
| #define _EXT_NUMERIC_TRAITS 1 |
| |
| #pragma GCC system_header |
| |
| #include <bits/cpp_type_traits.h> |
| #include <ext/type_traits.h> |
| |
| namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| // Compile time constants for builtin types. |
| // In C++98 std::numeric_limits member functions are not constant expressions |
| // (that changed in C++11 with the addition of 'constexpr'). |
| // Even for C++11, this header is smaller than <limits> and can be used |
| // when only is_signed, digits, min, or max values are needed for integers, |
| // or is_signed, digits10, max_digits10, or max_exponent10 for floats. |
| |
| // Unlike __is_integer (and std::is_integral) this trait is true for |
| // non-standard built-in integer types such as __int128 and __int20. |
| template<typename _Tp> |
| struct __is_integer_nonstrict |
| : public std::__is_integer<_Tp> |
| { |
| using std::__is_integer<_Tp>::__value; |
| |
| // The number of bits in the value representation. |
| enum { __width = __value ? sizeof(_Tp) * __CHAR_BIT__ : 0 }; |
| }; |
| |
| template<typename _Value> |
| struct __numeric_traits_integer |
| { |
| #if __cplusplus >= 201103L |
| static_assert(__is_integer_nonstrict<_Value>::__value, |
| "invalid specialization"); |
| #endif |
| |
| // NB: these two are also available in std::numeric_limits as compile |
| // time constants, but <limits> is big and we can avoid including it. |
| static const bool __is_signed = (_Value)(-1) < 0; |
| static const int __digits |
| = __is_integer_nonstrict<_Value>::__width - __is_signed; |
| |
| // The initializers must be constants so that __max and __min are too. |
| static const _Value __max = __is_signed |
| ? (((((_Value)1 << (__digits - 1)) - 1) << 1) + 1) |
| : ~(_Value)0; |
| static const _Value __min = __is_signed ? -__max - 1 : (_Value)0; |
| }; |
| |
| template<typename _Value> |
| const _Value __numeric_traits_integer<_Value>::__min; |
| |
| template<typename _Value> |
| const _Value __numeric_traits_integer<_Value>::__max; |
| |
| template<typename _Value> |
| const bool __numeric_traits_integer<_Value>::__is_signed; |
| |
| template<typename _Value> |
| const int __numeric_traits_integer<_Value>::__digits; |
| |
| // Enable __numeric_traits_integer for types where the __is_integer_nonstrict |
| // primary template doesn't give the right answer. |
| #define _GLIBCXX_INT_N_TRAITS(T, WIDTH) \ |
| template<> struct __is_integer_nonstrict<T> \ |
| { \ |
| enum { __value = 1 }; \ |
| typedef std::__true_type __type; \ |
| enum { __width = WIDTH }; \ |
| }; \ |
| template<> struct __is_integer_nonstrict<unsigned T> \ |
| { \ |
| enum { __value = 1 }; \ |
| typedef std::__true_type __type; \ |
| enum { __width = WIDTH }; \ |
| }; |
| |
| // We need to specify the width for some __intNN types because they |
| // have padding bits, e.g. the object representation of __int20 has 32 bits, |
| // but its width (number of bits in the value representation) is only 20. |
| #if defined __GLIBCXX_TYPE_INT_N_0 && __GLIBCXX_BITSIZE_INT_N_0 % __CHAR_BIT__ |
| _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_0, __GLIBCXX_BITSIZE_INT_N_0) |
| #endif |
| #if defined __GLIBCXX_TYPE_INT_N_1 && __GLIBCXX_BITSIZE_INT_N_1 % __CHAR_BIT__ |
| _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_1, __GLIBCXX_BITSIZE_INT_N_1) |
| #endif |
| #if defined __GLIBCXX_TYPE_INT_N_2 && __GLIBCXX_BITSIZE_INT_N_2 % __CHAR_BIT__ |
| _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_2, __GLIBCXX_BITSIZE_INT_N_2) |
| #endif |
| #if defined __GLIBCXX_TYPE_INT_N_3 && __GLIBCXX_BITSIZE_INT_N_3 % __CHAR_BIT__ |
| _GLIBCXX_INT_N_TRAITS(__GLIBCXX_TYPE_INT_N_3, __GLIBCXX_BITSIZE_INT_N_3) |
| #endif |
| |
| #if defined __STRICT_ANSI__ && defined __SIZEOF_INT128__ |
| // In strict modes __is_integer<__int128> is false, |
| // but we still want to define __numeric_traits_integer<__int128>. |
| _GLIBCXX_INT_N_TRAITS(__int128, 128) |
| #endif |
| |
| #undef _GLIBCXX_INT_N_TRAITS |
| |
| #if __cplusplus >= 201103L |
| /// Convenience alias for __numeric_traits<integer-type>. |
| template<typename _Tp> |
| using __int_traits = __numeric_traits_integer<_Tp>; |
| #endif |
| |
| #define __glibcxx_floating(_Tp, _Fval, _Dval, _LDval) \ |
| (std::__are_same<_Tp, float>::__value ? _Fval \ |
| : std::__are_same<_Tp, double>::__value ? _Dval : _LDval) |
| |
| #define __glibcxx_max_digits10(_Tp) \ |
| (2 + __glibcxx_floating(_Tp, __FLT_MANT_DIG__, __DBL_MANT_DIG__, \ |
| __LDBL_MANT_DIG__) * 643L / 2136) |
| |
| #define __glibcxx_digits10(_Tp) \ |
| __glibcxx_floating(_Tp, __FLT_DIG__, __DBL_DIG__, __LDBL_DIG__) |
| |
| #define __glibcxx_max_exponent10(_Tp) \ |
| __glibcxx_floating(_Tp, __FLT_MAX_10_EXP__, __DBL_MAX_10_EXP__, \ |
| __LDBL_MAX_10_EXP__) |
| |
| // N.B. this only supports float, double and long double (no __float128 etc.) |
| template<typename _Value> |
| struct __numeric_traits_floating |
| { |
| // Only floating point types. See N1822. |
| static const int __max_digits10 = __glibcxx_max_digits10(_Value); |
| |
| // See above comment... |
| static const bool __is_signed = true; |
| static const int __digits10 = __glibcxx_digits10(_Value); |
| static const int __max_exponent10 = __glibcxx_max_exponent10(_Value); |
| }; |
| |
| template<typename _Value> |
| const int __numeric_traits_floating<_Value>::__max_digits10; |
| |
| template<typename _Value> |
| const bool __numeric_traits_floating<_Value>::__is_signed; |
| |
| template<typename _Value> |
| const int __numeric_traits_floating<_Value>::__digits10; |
| |
| template<typename _Value> |
| const int __numeric_traits_floating<_Value>::__max_exponent10; |
| |
| template<typename _Value> |
| struct __numeric_traits |
| : public __conditional_type<__is_integer_nonstrict<_Value>::__value, |
| __numeric_traits_integer<_Value>, |
| __numeric_traits_floating<_Value> >::__type |
| { }; |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| |
| #undef __glibcxx_floating |
| #undef __glibcxx_max_digits10 |
| #undef __glibcxx_digits10 |
| #undef __glibcxx_max_exponent10 |
| |
| #endif |