1// Copyright Kevlin Henney, 2000-2005.
2// Copyright Alexander Nasonov, 2006-2010.
3// Copyright Antony Polukhin, 2011-2023.
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 <boost/limits.hpp>
31#include <boost/detail/workaround.hpp>
32#include <boost/core/cmath.hpp>
33#include <cstddef>
34#include <cstring>
35
36#include <boost/lexical_cast/detail/lcast_char_constants.hpp>
37
38namespace boost {
39 namespace detail
40 {
41 template <class CharT>
42 bool lc_iequal(const CharT* val, const CharT* lcase, const CharT* ucase, unsigned int len) BOOST_NOEXCEPT {
43 for( unsigned int i=0; i < len; ++i ) {
44 if ( val[i] != lcase[i] && val[i] != ucase[i] ) return false;
45 }
46
47 return true;
48 }
49
50 /* Returns true and sets the correct value if found NaN or Inf. */
51 template <class CharT, class T>
52 inline bool parse_inf_nan_impl(const CharT* begin, const CharT* end, T& value
53 , const CharT* lc_NAN, const CharT* lc_nan
54 , const CharT* lc_INFINITY, const CharT* lc_infinity
55 , const CharT opening_brace, const CharT closing_brace) BOOST_NOEXCEPT
56 {
57 if (begin == end) return false;
58 const CharT minus = lcast_char_constants<CharT>::minus;
59 const CharT plus = lcast_char_constants<CharT>::plus;
60 const int inifinity_size = 8; // == sizeof("infinity") - 1
61
62 /* Parsing +/- */
63 bool const has_minus = (*begin == minus);
64 if (has_minus || *begin == plus) {
65 ++ begin;
66 }
67
68 if (end - begin < 3) return false;
69 if (lc_iequal(begin, lc_nan, lc_NAN, 3)) {
70 begin += 3;
71 if (end != begin) {
72 /* It is 'nan(...)' or some bad input*/
73
74 if (end - begin < 2) return false; // bad input
75 -- end;
76 if (*begin != opening_brace || *end != closing_brace) return false; // bad input
77 }
78
79 if( !has_minus ) value = std::numeric_limits<T>::quiet_NaN();
80 else value = boost::core::copysign(std::numeric_limits<T>::quiet_NaN(), static_cast<T>(-1));
81 return true;
82 } else if (
83 ( /* 'INF' or 'inf' */
84 end - begin == 3 // 3 == sizeof('inf') - 1
85 && lc_iequal(begin, lc_infinity, lc_INFINITY, 3)
86 )
87 ||
88 ( /* 'INFINITY' or 'infinity' */
89 end - begin == inifinity_size
90 && lc_iequal(begin, lc_infinity, lc_INFINITY, inifinity_size)
91 )
92 )
93 {
94 if( !has_minus ) value = std::numeric_limits<T>::infinity();
95 else value = -std::numeric_limits<T>::infinity();
96 return true;
97 }
98
99 return false;
100 }
101
102 template <class CharT, class T>
103 bool put_inf_nan_impl(CharT* begin, CharT*& end, const T& value
104 , const CharT* lc_nan
105 , const CharT* lc_infinity) BOOST_NOEXCEPT
106 {
107 const CharT minus = lcast_char_constants<CharT>::minus;
108 if (boost::core::isnan(value)) {
109 if (boost::core::signbit(value)) {
110 *begin = minus;
111 ++ begin;
112 }
113
114 std::memcpy(dest: begin, src: lc_nan, n: 3 * sizeof(CharT));
115 end = begin + 3;
116 return true;
117 } else if (boost::core::isinf(value)) {
118 if (boost::core::signbit(value)) {
119 *begin = minus;
120 ++ begin;
121 }
122
123 std::memcpy(dest: begin, src: lc_infinity, n: 3 * sizeof(CharT));
124 end = begin + 3;
125 return true;
126 }
127
128 return false;
129 }
130
131
132#ifndef BOOST_LCAST_NO_WCHAR_T
133 template <class T>
134 bool parse_inf_nan(const wchar_t* begin, const wchar_t* end, T& value) BOOST_NOEXCEPT {
135 return parse_inf_nan_impl(begin, end, value
136 , L"NAN", L"nan"
137 , L"INFINITY", L"infinity"
138 , L'(', L')');
139 }
140
141 template <class T>
142 bool put_inf_nan(wchar_t* begin, wchar_t*& end, const T& value) BOOST_NOEXCEPT {
143 return put_inf_nan_impl(begin, end, value, L"nan", L"infinity");
144 }
145
146#endif
147#if !defined(BOOST_NO_CXX11_CHAR16_T) && !defined(BOOST_NO_CXX11_UNICODE_LITERALS)
148 template <class T>
149 bool parse_inf_nan(const char16_t* begin, const char16_t* end, T& value) BOOST_NOEXCEPT {
150 return parse_inf_nan_impl(begin, end, value
151 , u"NAN", u"nan"
152 , u"INFINITY", u"infinity"
153 , u'(', u')');
154 }
155
156 template <class T>
157 bool put_inf_nan(char16_t* begin, char16_t*& end, const T& value) BOOST_NOEXCEPT {
158 return put_inf_nan_impl(begin, end, value, u"nan", u"infinity");
159 }
160#endif
161#if !defined(BOOST_NO_CXX11_CHAR32_T) && !defined(BOOST_NO_CXX11_UNICODE_LITERALS)
162 template <class T>
163 bool parse_inf_nan(const char32_t* begin, const char32_t* end, T& value) BOOST_NOEXCEPT {
164 return parse_inf_nan_impl(begin, end, value
165 , U"NAN", U"nan"
166 , U"INFINITY", U"infinity"
167 , U'(', U')');
168 }
169
170 template <class T>
171 bool put_inf_nan(char32_t* begin, char32_t*& end, const T& value) BOOST_NOEXCEPT {
172 return put_inf_nan_impl(begin, end, value, U"nan", U"infinity");
173 }
174#endif
175
176 template <class CharT, class T>
177 bool parse_inf_nan(const CharT* begin, const CharT* end, T& value) BOOST_NOEXCEPT {
178 return parse_inf_nan_impl(begin, end, value
179 , "NAN", "nan"
180 , "INFINITY", "infinity"
181 , '(', ')');
182 }
183
184 template <class CharT, class T>
185 bool put_inf_nan(CharT* begin, CharT*& end, const T& value) BOOST_NOEXCEPT {
186 return put_inf_nan_impl(begin, end, value, "nan", "infinity");
187 }
188 }
189} // namespace boost
190
191#undef BOOST_LCAST_NO_WCHAR_T
192
193#endif // BOOST_LEXICAL_CAST_DETAIL_INF_NAN_HPP
194
195