]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | /*============================================================================= |
2 | Copyright (c) 2001-2011 Joel de Guzman | |
3 | Copyright (c) 2001-2011 Hartmut Kaiser | |
4 | ||
5 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
6 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
7 | ==============================================================================*/ | |
8 | #if !defined(SPIRIT_REAL_POLICIES_APRIL_17_2006_1158PM) | |
9 | #define SPIRIT_REAL_POLICIES_APRIL_17_2006_1158PM | |
10 | ||
11 | #if defined(_MSC_VER) | |
12 | #pragma once | |
13 | #endif | |
14 | ||
15 | #include <boost/spirit/home/qi/numeric/numeric_utils.hpp> | |
16 | #include <boost/spirit/home/qi/detail/string_parse.hpp> | |
17 | ||
18 | namespace boost { namespace spirit { namespace qi | |
19 | { | |
20 | /////////////////////////////////////////////////////////////////////////// | |
21 | // Default (unsigned) real number policies | |
22 | /////////////////////////////////////////////////////////////////////////// | |
23 | template <typename T> | |
24 | struct ureal_policies | |
25 | { | |
26 | // trailing dot policy suggested by Gustavo Guerra | |
27 | static bool const allow_leading_dot = true; | |
28 | static bool const allow_trailing_dot = true; | |
29 | static bool const expect_dot = false; | |
30 | ||
31 | template <typename Iterator> | |
32 | static bool | |
33 | parse_sign(Iterator& /*first*/, Iterator const& /*last*/) | |
34 | { | |
35 | return false; | |
36 | } | |
37 | ||
38 | template <typename Iterator, typename Attribute> | |
39 | static bool | |
40 | parse_n(Iterator& first, Iterator const& last, Attribute& attr_) | |
41 | { | |
42 | return extract_uint<Attribute, 10, 1, -1>::call(first, last, attr_); | |
43 | } | |
44 | ||
45 | template <typename Iterator> | |
46 | static bool | |
47 | parse_dot(Iterator& first, Iterator const& last) | |
48 | { | |
49 | if (first == last || *first != '.') | |
50 | return false; | |
51 | ++first; | |
52 | return true; | |
53 | } | |
54 | ||
55 | template <typename Iterator, typename Attribute> | |
56 | static bool | |
57 | parse_frac_n(Iterator& first, Iterator const& last, Attribute& attr_, int& frac_digits) | |
58 | { | |
59 | Iterator savef = first; | |
60 | bool r = extract_uint<Attribute, 10, 1, -1, true, true>::call(first, last, attr_); | |
61 | if (r) | |
62 | { | |
63 | // Optimization note: don't compute frac_digits if T is | |
64 | // an unused_type. This should be optimized away by the compiler. | |
65 | if (!is_same<T, unused_type>::value) | |
66 | frac_digits = | |
67 | static_cast<int>(std::distance(savef, first)); | |
68 | // ignore extra (non-significant digits) | |
69 | extract_uint<unused_type, 10, 1, -1>::call(first, last, unused); | |
70 | } | |
71 | return r; | |
72 | } | |
73 | ||
74 | template <typename Iterator> | |
75 | static bool | |
76 | parse_exp(Iterator& first, Iterator const& last) | |
77 | { | |
78 | if (first == last || (*first != 'e' && *first != 'E')) | |
79 | return false; | |
80 | ++first; | |
81 | return true; | |
82 | } | |
83 | ||
84 | template <typename Iterator> | |
85 | static bool | |
86 | parse_exp_n(Iterator& first, Iterator const& last, int& attr_) | |
87 | { | |
88 | return extract_int<int, 10, 1, -1>::call(first, last, attr_); | |
89 | } | |
90 | ||
91 | /////////////////////////////////////////////////////////////////////// | |
92 | // The parse_nan() and parse_inf() functions get called whenever: | |
93 | // | |
94 | // - a number to parse does not start with a digit (after having | |
95 | // successfully parsed an optional sign) | |
96 | // | |
97 | // or | |
98 | // | |
99 | // - after a floating point number of the value 1 (having no | |
100 | // exponential part and a fractional part value of 0) has been | |
101 | // parsed. | |
102 | // | |
103 | // The first call allows to recognize representations of NaN or Inf | |
104 | // starting with a non-digit character (such as NaN, Inf, QNaN etc.). | |
105 | // | |
106 | // The second call allows to recognize representation formats starting | |
107 | // with a 1.0 (such as 1.0#NAN or 1.0#INF etc.). | |
108 | // | |
109 | // The functions should return true if a Nan or Inf has been found. In | |
110 | // this case the attr should be set to the matched value (NaN or | |
111 | // Inf). The optional sign will be automatically applied afterwards. | |
112 | // | |
113 | // The default implementation below recognizes representations of NaN | |
114 | // and Inf as mandated by the C99 Standard and as proposed for | |
115 | // inclusion into the C++0x Standard: nan, nan(...), inf and infinity | |
116 | // (the matching is performed case-insensitively). | |
117 | /////////////////////////////////////////////////////////////////////// | |
118 | template <typename Iterator, typename Attribute> | |
119 | static bool | |
120 | parse_nan(Iterator& first, Iterator const& last, Attribute& attr_) | |
121 | { | |
122 | if (first == last) | |
123 | return false; // end of input reached | |
124 | ||
125 | if (*first != 'n' && *first != 'N') | |
126 | return false; // not "nan" | |
127 | ||
128 | // nan[(...)] ? | |
129 | if (detail::string_parse("nan", "NAN", first, last, unused)) | |
130 | { | |
131 | if (first != last && *first == '(') | |
132 | { | |
133 | // skip trailing (...) part | |
134 | Iterator i = first; | |
135 | ||
136 | while (++i != last && *i != ')') | |
137 | ; | |
138 | if (i == last) | |
139 | return false; // no trailing ')' found, give up | |
140 | ||
141 | first = ++i; | |
142 | } | |
143 | attr_ = std::numeric_limits<T>::quiet_NaN(); | |
144 | return true; | |
145 | } | |
146 | return false; | |
147 | } | |
148 | ||
149 | template <typename Iterator, typename Attribute> | |
150 | static bool | |
151 | parse_inf(Iterator& first, Iterator const& last, Attribute& attr_) | |
152 | { | |
153 | if (first == last) | |
154 | return false; // end of input reached | |
155 | ||
156 | if (*first != 'i' && *first != 'I') | |
157 | return false; // not "inf" | |
158 | ||
159 | // inf or infinity ? | |
160 | if (detail::string_parse("inf", "INF", first, last, unused)) | |
161 | { | |
162 | // skip allowed 'inity' part of infinity | |
163 | detail::string_parse("inity", "INITY", first, last, unused); | |
164 | attr_ = std::numeric_limits<T>::infinity(); | |
165 | return true; | |
166 | } | |
167 | return false; | |
168 | } | |
169 | }; | |
170 | ||
171 | /////////////////////////////////////////////////////////////////////////// | |
172 | // Default (signed) real number policies | |
173 | /////////////////////////////////////////////////////////////////////////// | |
174 | template <typename T> | |
175 | struct real_policies : ureal_policies<T> | |
176 | { | |
177 | template <typename Iterator> | |
178 | static bool | |
179 | parse_sign(Iterator& first, Iterator const& last) | |
180 | { | |
181 | return extract_sign(first, last); | |
182 | } | |
183 | }; | |
184 | ||
185 | template <typename T> | |
186 | struct strict_ureal_policies : ureal_policies<T> | |
187 | { | |
188 | static bool const expect_dot = true; | |
189 | }; | |
190 | ||
191 | template <typename T> | |
192 | struct strict_real_policies : real_policies<T> | |
193 | { | |
194 | static bool const expect_dot = true; | |
195 | }; | |
196 | }}} | |
197 | ||
198 | #endif |