1// -*- C++ -*-
2
3// Copyright (C) 2007 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 2, 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// You should have received a copy of the GNU General Public License along
17// with this library; see the file COPYING.  If not, write to the Free
18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19// USA.
20
21// As a special exception, you may use this file as part of a free
22// software library without restriction.  Specifically, if other files
23// instantiate templates or use macros or inline functions from this
24// file, or you compile this file and link it with other files to
25// produce an executable, this file does not by itself cause the
26// resulting executable to be covered by the GNU General Public
27// License.  This exception does not however invalidate any other
28// reasons why the executable file might be covered by the GNU General
29// Public License.
30
31/** @file ext/numeric_traits.h
32 *  This file is a GNU extension to the Standard C++ Library.
33 */
34
35#ifndef _EXT_NUMERIC_TRAITS
36#define _EXT_NUMERIC_TRAITS 1
37
38#pragma GCC system_header
39
40#include <limits>
41#include <bits/cpp_type_traits.h>
42#include <ext/type_traits.h>
43
44_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
45
46  // Compile time constants for builtin types.
47  // Sadly std::numeric_limits member functions cannot be used for this.
48#define __glibcxx_signed(_Tp) ((_Tp)(-1) < 0)
49#define __glibcxx_digits(_Tp) \
50  (sizeof(_Tp) * __CHAR_BIT__ - __glibcxx_signed(_Tp))
51
52#define __glibcxx_min(_Tp) \
53  (__glibcxx_signed(_Tp) ? (_Tp)1 << __glibcxx_digits(_Tp) : (_Tp)0)
54
55#define __glibcxx_max(_Tp) \
56  (__glibcxx_signed(_Tp) ? \
57   (((((_Tp)1 << (__glibcxx_digits(_Tp) - 1)) - 1) << 1) + 1) : ~(_Tp)0)
58
59  template<typename _Value>
60    struct __numeric_traits_integer
61    {
62      // Only integers for initialization of member constant.
63      static const _Value __min = __glibcxx_min(_Value);
64      static const _Value __max = __glibcxx_max(_Value);
65    };
66
67  template<typename _Value>
68    const _Value __numeric_traits_integer<_Value>::__min;
69
70  template<typename _Value>
71    const _Value __numeric_traits_integer<_Value>::__max;
72
73  template<typename _Value>
74    struct __numeric_traits_floating
75    {
76      // Only floating point types. See N1822.
77      static const int __max_digits10 =
78	2 + std::numeric_limits<_Value>::digits * 3010/10000;
79    };
80
81  template<typename _Value>
82    const int __numeric_traits_floating<_Value>::__max_digits10;
83
84  template<typename _Value>
85    struct __numeric_traits
86    : public __conditional_type<std::__is_integer<_Value>::__value,
87				__numeric_traits_integer<_Value>,
88				__numeric_traits_floating<_Value> >::__type
89    { };
90
91_GLIBCXX_END_NAMESPACE
92
93#undef __glibcxx_signed
94#undef __glibcxx_min
95#undef __glibcxx_max
96#undef __glibcxx_digits
97
98#endif
99