Line data Source code
1 : // Copyright Kevlin Henney, 2000-2005.
2 : // Copyright Alexander Nasonov, 2006-2010.
3 : // Copyright Antony Polukhin, 2011-2019.
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 0 : 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 0 : const CharT minus = lcast_char_constants<CharT>::minus;
111 0 : if ((boost::math::isnan)(value)) {
112 0 : if ((boost::math::signbit)(value)) {
113 0 : *begin = minus;
114 0 : ++ begin;
115 : }
116 :
117 0 : memcpy(begin, lc_nan, 3 * sizeof(CharT));
118 0 : end = begin + 3;
119 0 : return true;
120 0 : } else if ((boost::math::isinf)(value)) {
121 0 : if ((boost::math::signbit)(value)) {
122 0 : *begin = minus;
123 0 : ++ begin;
124 : }
125 :
126 0 : memcpy(begin, lc_infinity, 3 * sizeof(CharT));
127 0 : end = begin + 3;
128 0 : 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 0 : bool put_inf_nan(CharT* begin, CharT*& end, const T& value) BOOST_NOEXCEPT {
189 0 : 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 :
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