| // Minimal replacement for numeric_limits of integers. -*- C++ -*- |
| |
| // Copyright (C) 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 bits/int_limits.h |
| * This is an internal header file, included by other library headers. |
| * Do not attempt to use it directly. @headername{limits} |
| */ |
| |
| #ifndef _GLIBCXX_INT_LIMITS_H |
| #define _GLIBCXX_INT_LIMITS_H 1 |
| |
| #pragma GCC system_header |
| |
| #if __cplusplus >= 201103L |
| #include <bits/c++config.h> |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| namespace __detail |
| { |
| // This template is used for arbitrary signed and unsigned integer types |
| // (by headers <bit> and <charconv>) and for specific integer types |
| // (by <memory_resource> and <string_view>) but also for char (<charconv>). |
| // For simplicity's sake, all integral types except bool are supported. |
| |
| // Lightweight alternative to numeric_limits<signed integer type>. |
| template<typename _Tp, bool = is_signed<_Tp>::value> |
| struct __int_limits |
| { |
| static_assert(is_integral<_Tp>::value, "unsupported specialization"); |
| using _Up = typename make_unsigned<_Tp>::type; |
| static constexpr int digits = sizeof(_Tp) * __CHAR_BIT__ - 1; |
| static constexpr _Tp min() noexcept { return _Tp(_Up(1) << digits); } |
| static constexpr _Tp max() noexcept { return _Tp(_Up(~_Up(0)) >> 1); } |
| }; |
| |
| // Lightweight alternative to numeric_limits<unsigned integer type>. |
| template<typename _Tp> |
| struct __int_limits<_Tp, false> |
| { |
| static_assert(is_integral<_Tp>::value, "unsupported specialization"); |
| static constexpr int digits = sizeof(_Tp) * __CHAR_BIT__; |
| static constexpr _Tp min() noexcept { return 0; } |
| static constexpr _Tp max() noexcept { return _Tp(-1); } |
| }; |
| |
| template<> struct __int_limits<bool>; // not defined |
| } |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| #endif // C++11 |
| #endif // _GLIBCXX_INT_LIMITS_H |