freebsd-dev/contrib/libstdc++/include/ext/numeric_traits.h

99 lines
3.2 KiB
C++

// -*- C++ -*-
// Copyright (C) 2007 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 2, 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.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING. If not, write to the Free
// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
// USA.
// As a special exception, you may use this file as part of a free
// software library without restriction. Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to
// produce an executable, this file does not by itself cause the
// resulting executable to be covered by the GNU General Public
// License. This exception does not however invalidate any other
// reasons why the executable file might be covered by the GNU General
// Public License.
/** @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 <limits>
#include <bits/cpp_type_traits.h>
#include <ext/type_traits.h>
_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
// Compile time constants for builtin types.
// Sadly std::numeric_limits member functions cannot be used for this.
#define __glibcxx_signed(_Tp) ((_Tp)(-1) < 0)
#define __glibcxx_digits(_Tp) \
(sizeof(_Tp) * __CHAR_BIT__ - __glibcxx_signed(_Tp))
#define __glibcxx_min(_Tp) \
(__glibcxx_signed(_Tp) ? (_Tp)1 << __glibcxx_digits(_Tp) : (_Tp)0)
#define __glibcxx_max(_Tp) \
(__glibcxx_signed(_Tp) ? \
(((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0)
template<typename _Value>
struct __numeric_traits_integer
{
// Only integers for initialization of member constant.
static const _Value __min = __glibcxx_min(_Value);
static const _Value __max = __glibcxx_max(_Value);
};
template<typename _Value>
const _Value __numeric_traits_integer<_Value>::__min;
template<typename _Value>
const _Value __numeric_traits_integer<_Value>::__max;
template<typename _Value>
struct __numeric_traits_floating
{
// Only floating point types. See N1822.
static const int __max_digits10 =
2 + std::numeric_limits<_Value>::digits * 3010/10000;
};
template<typename _Value>
const int __numeric_traits_floating<_Value>::__max_digits10;
template<typename _Value>
struct __numeric_traits
: public __conditional_type<std::__is_integer<_Value>::__value,
__numeric_traits_integer<_Value>,
__numeric_traits_floating<_Value> >::__type
{ };
_GLIBCXX_END_NAMESPACE
#undef __glibcxx_signed
#undef __glibcxx_min
#undef __glibcxx_max
#undef __glibcxx_digits
#endif