1 | // Copyright Kevlin Henney, 2000-2005. |
2 | // Copyright Alexander Nasonov, 2006-2010. |
3 | // Copyright Antony Polukhin, 2011-2020. |
4 | // |
5 | // Distributed under the Boost Software License, Version 1.0. (See |
6 | // accompanying file LICENSE_1_0.txt or copy at |
7 | // http://www.boost.org/LICENSE_1_0.txt) |
8 | // |
9 | // what: lexical_cast custom keyword cast |
10 | // who: contributed by Kevlin Henney, |
11 | // enhanced with contributions from Terje Slettebo, |
12 | // with additional fixes and suggestions from Gennaro Prota, |
13 | // Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov, |
14 | // Alexander Nasonov, Antony Polukhin, Justin Viiret, Michael Hofmann, |
15 | // Cheng Yang, Matthew Bradbury, David W. Birdsall, Pavel Korzh and other Boosters |
16 | // when: November 2000, March 2003, June 2005, June 2006, March 2011 - 2014 |
17 | |
18 | #ifndef BOOST_LEXICAL_CAST_DETAIL_INF_NAN_HPP |
19 | #define BOOST_LEXICAL_CAST_DETAIL_INF_NAN_HPP |
20 | |
21 | #include <boost/config.hpp> |
22 | #ifdef BOOST_HAS_PRAGMA_ONCE |
23 | # pragma once |
24 | #endif |
25 | |
26 | #if defined(BOOST_NO_STRINGSTREAM) || defined(BOOST_NO_STD_WSTRING) |
27 | #define BOOST_LCAST_NO_WCHAR_T |
28 | #endif |
29 | |
30 | #include <cstddef> |
31 | #include <cstring> |
32 | #include <boost/limits.hpp> |
33 | #include <boost/detail/workaround.hpp> |
34 | #include <boost/math/special_functions/sign.hpp> |
35 | #include <boost/math/special_functions/fpclassify.hpp> |
36 | |
37 | #include <boost/lexical_cast/detail/lcast_char_constants.hpp> |
38 | |
39 | namespace boost { |
40 | namespace detail |
41 | { |
42 | template <class CharT> |
43 | bool lc_iequal(const CharT* val, const CharT* lcase, const CharT* ucase, unsigned int len) BOOST_NOEXCEPT { |
44 | for( unsigned int i=0; i < len; ++i ) { |
45 | if ( val[i] != lcase[i] && val[i] != ucase[i] ) return false; |
46 | } |
47 | |
48 | return true; |
49 | } |
50 | |
51 | /* Returns true and sets the correct value if found NaN or Inf. */ |
52 | template <class CharT, class T> |
53 | inline bool parse_inf_nan_impl(const CharT* begin, const CharT* end, T& value |
54 | , const CharT* lc_NAN, const CharT* lc_nan |
55 | , const CharT* lc_INFINITY, const CharT* lc_infinity |
56 | , const CharT opening_brace, const CharT closing_brace) BOOST_NOEXCEPT |
57 | { |
58 | using namespace std; |
59 | if (begin == end) return false; |
60 | const CharT minus = lcast_char_constants<CharT>::minus; |
61 | const CharT plus = lcast_char_constants<CharT>::plus; |
62 | const int inifinity_size = 8; // == sizeof("infinity") - 1 |
63 | |
64 | /* Parsing +/- */ |
65 | bool const has_minus = (*begin == minus); |
66 | if (has_minus || *begin == plus) { |
67 | ++ begin; |
68 | } |
69 | |
70 | if (end - begin < 3) return false; |
71 | if (lc_iequal(begin, lc_nan, lc_NAN, 3)) { |
72 | begin += 3; |
73 | if (end != begin) { |
74 | /* It is 'nan(...)' or some bad input*/ |
75 | |
76 | if (end - begin < 2) return false; // bad input |
77 | -- end; |
78 | if (*begin != opening_brace || *end != closing_brace) return false; // bad input |
79 | } |
80 | |
81 | if( !has_minus ) value = std::numeric_limits<T>::quiet_NaN(); |
82 | else value = (boost::math::changesign) (std::numeric_limits<T>::quiet_NaN()); |
83 | return true; |
84 | } else if ( |
85 | ( /* 'INF' or 'inf' */ |
86 | end - begin == 3 // 3 == sizeof('inf') - 1 |
87 | && lc_iequal(begin, lc_infinity, lc_INFINITY, 3) |
88 | ) |
89 | || |
90 | ( /* 'INFINITY' or 'infinity' */ |
91 | end - begin == inifinity_size |
92 | && lc_iequal(begin, lc_infinity, lc_INFINITY, inifinity_size) |
93 | ) |
94 | ) |
95 | { |
96 | if( !has_minus ) value = std::numeric_limits<T>::infinity(); |
97 | else value = (boost::math::changesign) (std::numeric_limits<T>::infinity()); |
98 | return true; |
99 | } |
100 | |
101 | return false; |
102 | } |
103 | |
104 | template <class CharT, class T> |
105 | bool put_inf_nan_impl(CharT* begin, CharT*& end, const T& value |
106 | , const CharT* lc_nan |
107 | , const CharT* lc_infinity) BOOST_NOEXCEPT |
108 | { |
109 | using namespace std; |
110 | const CharT minus = lcast_char_constants<CharT>::minus; |
111 | if ((boost::math::isnan)(value)) { |
112 | if ((boost::math::signbit)(value)) { |
113 | *begin = minus; |
114 | ++ begin; |
115 | } |
116 | |
117 | memcpy(begin, lc_nan, 3 * sizeof(CharT)); |
118 | end = begin + 3; |
119 | return true; |
120 | } else if ((boost::math::isinf)(value)) { |
121 | if ((boost::math::signbit)(value)) { |
122 | *begin = minus; |
123 | ++ begin; |
124 | } |
125 | |
126 | memcpy(begin, lc_infinity, 3 * sizeof(CharT)); |
127 | end = begin + 3; |
128 | return true; |
129 | } |
130 | |
131 | return false; |
132 | } |
133 | |
134 | |
135 | #ifndef BOOST_LCAST_NO_WCHAR_T |
136 | template <class T> |
137 | bool parse_inf_nan(const wchar_t* begin, const wchar_t* end, T& value) BOOST_NOEXCEPT { |
138 | return parse_inf_nan_impl(begin, end, value |
139 | , L"NAN" , L"nan" |
140 | , L"INFINITY" , L"infinity" |
141 | , L'(', L')'); |
142 | } |
143 | |
144 | template <class T> |
145 | bool put_inf_nan(wchar_t* begin, wchar_t*& end, const T& value) BOOST_NOEXCEPT { |
146 | return put_inf_nan_impl(begin, end, value, L"nan" , L"infinity" ); |
147 | } |
148 | |
149 | #endif |
150 | #if !defined(BOOST_NO_CXX11_CHAR16_T) && !defined(BOOST_NO_CXX11_UNICODE_LITERALS) |
151 | template <class T> |
152 | bool parse_inf_nan(const char16_t* begin, const char16_t* end, T& value) BOOST_NOEXCEPT { |
153 | return parse_inf_nan_impl(begin, end, value |
154 | , u"NAN" , u"nan" |
155 | , u"INFINITY" , u"infinity" |
156 | , u'(', u')'); |
157 | } |
158 | |
159 | template <class T> |
160 | bool put_inf_nan(char16_t* begin, char16_t*& end, const T& value) BOOST_NOEXCEPT { |
161 | return put_inf_nan_impl(begin, end, value, u"nan" , u"infinity" ); |
162 | } |
163 | #endif |
164 | #if !defined(BOOST_NO_CXX11_CHAR32_T) && !defined(BOOST_NO_CXX11_UNICODE_LITERALS) |
165 | template <class T> |
166 | bool parse_inf_nan(const char32_t* begin, const char32_t* end, T& value) BOOST_NOEXCEPT { |
167 | return parse_inf_nan_impl(begin, end, value |
168 | , U"NAN" , U"nan" |
169 | , U"INFINITY" , U"infinity" |
170 | , U'(', U')'); |
171 | } |
172 | |
173 | template <class T> |
174 | bool put_inf_nan(char32_t* begin, char32_t*& end, const T& value) BOOST_NOEXCEPT { |
175 | return put_inf_nan_impl(begin, end, value, U"nan" , U"infinity" ); |
176 | } |
177 | #endif |
178 | |
179 | template <class CharT, class T> |
180 | bool parse_inf_nan(const CharT* begin, const CharT* end, T& value) BOOST_NOEXCEPT { |
181 | return parse_inf_nan_impl(begin, end, value |
182 | , "NAN" , "nan" |
183 | , "INFINITY" , "infinity" |
184 | , '(', ')'); |
185 | } |
186 | |
187 | template <class CharT, class T> |
188 | bool put_inf_nan(CharT* begin, CharT*& end, const T& value) BOOST_NOEXCEPT { |
189 | return put_inf_nan_impl(begin, end, value, "nan" , "infinity" ); |
190 | } |
191 | } |
192 | } // namespace boost |
193 | |
194 | #undef BOOST_LCAST_NO_WCHAR_T |
195 | |
196 | #endif // BOOST_LEXICAL_CAST_DETAIL_INF_NAN_HPP |
197 | |
198 | |