1 | // Special functions -*- C++ -*- |
2 | |
3 | // Copyright (C) 2006-2021 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 |
7 | // terms of the GNU General Public License as published by the |
8 | // Free Software Foundation; either version 3, or (at your option) |
9 | // any later version. |
10 | |
11 | // This library is distributed in the hope that it will be useful, |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | // GNU General Public License for more details. |
15 | |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version |
18 | // 3.1, as published by the Free Software Foundation. |
19 | |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
23 | // <http://www.gnu.org/licenses/>. |
24 | |
25 | /** @file tr1/special_function_util.h |
26 | * This is an internal header file, included by other library headers. |
27 | * Do not attempt to use it directly. @headername{tr1/cmath} |
28 | */ |
29 | |
30 | // |
31 | // ISO C++ 14882 TR1: 5.2 Special functions |
32 | // |
33 | |
34 | // Written by Edward Smith-Rowland based on numerous mathematics books. |
35 | |
36 | #ifndef _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H |
37 | #define _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H 1 |
38 | |
39 | namespace std _GLIBCXX_VISIBILITY(default) |
40 | { |
41 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
42 | |
43 | #if _GLIBCXX_USE_STD_SPEC_FUNCS |
44 | #elif defined(_GLIBCXX_TR1_CMATH) |
45 | namespace tr1 |
46 | { |
47 | #else |
48 | # error do not include this header directly, use <cmath> or <tr1/cmath> |
49 | #endif |
50 | namespace __detail |
51 | { |
52 | /// A class to encapsulate type dependent floating point |
53 | /// constants. Not everything will be able to be expressed as |
54 | /// type logic. |
55 | template<typename _Tp> |
56 | struct __floating_point_constant |
57 | { |
58 | static const _Tp __value; |
59 | }; |
60 | |
61 | |
62 | /// A structure for numeric constants. |
63 | template<typename _Tp> |
64 | struct __numeric_constants |
65 | { |
66 | /// Constant @f$ \pi @f$. |
67 | static _Tp __pi() throw() |
68 | { return static_cast<_Tp>(3.1415926535897932384626433832795029L); } |
69 | /// Constant @f$ \pi / 2 @f$. |
70 | static _Tp __pi_2() throw() |
71 | { return static_cast<_Tp>(1.5707963267948966192313216916397514L); } |
72 | /// Constant @f$ \pi / 3 @f$. |
73 | static _Tp __pi_3() throw() |
74 | { return static_cast<_Tp>(1.0471975511965977461542144610931676L); } |
75 | /// Constant @f$ \pi / 4 @f$. |
76 | static _Tp __pi_4() throw() |
77 | { return static_cast<_Tp>(0.7853981633974483096156608458198757L); } |
78 | /// Constant @f$ 1 / \pi @f$. |
79 | static _Tp __1_pi() throw() |
80 | { return static_cast<_Tp>(0.3183098861837906715377675267450287L); } |
81 | /// Constant @f$ 2 / \sqrt(\pi) @f$. |
82 | static _Tp __2_sqrtpi() throw() |
83 | { return static_cast<_Tp>(1.1283791670955125738961589031215452L); } |
84 | /// Constant @f$ \sqrt(2) @f$. |
85 | static _Tp __sqrt2() throw() |
86 | { return static_cast<_Tp>(1.4142135623730950488016887242096981L); } |
87 | /// Constant @f$ \sqrt(3) @f$. |
88 | static _Tp __sqrt3() throw() |
89 | { return static_cast<_Tp>(1.7320508075688772935274463415058723L); } |
90 | /// Constant @f$ \sqrt(\pi/2) @f$. |
91 | static _Tp __sqrtpio2() throw() |
92 | { return static_cast<_Tp>(1.2533141373155002512078826424055226L); } |
93 | /// Constant @f$ 1 / sqrt(2) @f$. |
94 | static _Tp __sqrt1_2() throw() |
95 | { return static_cast<_Tp>(0.7071067811865475244008443621048490L); } |
96 | /// Constant @f$ \log(\pi) @f$. |
97 | static _Tp __lnpi() throw() |
98 | { return static_cast<_Tp>(1.1447298858494001741434273513530587L); } |
99 | /// Constant Euler's constant @f$ \gamma_E @f$. |
100 | static _Tp __gamma_e() throw() |
101 | { return static_cast<_Tp>(0.5772156649015328606065120900824024L); } |
102 | /// Constant Euler-Mascheroni @f$ e @f$ |
103 | static _Tp __euler() throw() |
104 | { return static_cast<_Tp>(2.7182818284590452353602874713526625L); } |
105 | }; |
106 | |
107 | |
108 | #if _GLIBCXX_USE_C99_MATH && !_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC |
109 | |
110 | /// This is a wrapper for the isnan function. Otherwise, for NaN, |
111 | /// all comparisons result in false. If/when we build a std::isnan |
112 | /// out of intrinsics, this will disappear completely in favor of |
113 | /// std::isnan. |
114 | template<typename _Tp> |
115 | inline bool __isnan(_Tp __x) |
116 | { return std::isnan(__x); } |
117 | |
118 | #else |
119 | |
120 | template<typename _Tp> |
121 | inline bool __isnan(const _Tp __x) |
122 | { return __builtin_isnan(__x); } |
123 | |
124 | template<> |
125 | inline bool __isnan<float>(float __x) |
126 | { return __builtin_isnanf(__x); } |
127 | |
128 | template<> |
129 | inline bool __isnan<long double>(long double __x) |
130 | { return __builtin_isnanl(__x); } |
131 | |
132 | #endif |
133 | } // namespace __detail |
134 | #if ! _GLIBCXX_USE_STD_SPEC_FUNCS && defined(_GLIBCXX_TR1_CMATH) |
135 | } // namespace tr1 |
136 | #endif |
137 | |
138 | _GLIBCXX_END_NAMESPACE_VERSION |
139 | } |
140 | |
141 | #endif // _GLIBCXX_TR1_SPECIAL_FUNCTION_UTIL_H |
142 | |
143 | |