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 parse_signboost::spirit::qi::ureal_policies33 parse_sign(Iterator& /*first*/, Iterator const& /*last*/) 34 { 35 return false; 36 } 37 38 template <typename Iterator, typename Attribute> 39 static bool parse_nboost::spirit::qi::ureal_policies40 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 parse_dotboost::spirit::qi::ureal_policies47 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 parse_frac_nboost::spirit::qi::ureal_policies57 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 parse_expboost::spirit::qi::ureal_policies76 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 parse_exp_nboost::spirit::qi::ureal_policies86 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 parse_nanboost::spirit::qi::ureal_policies120 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 parse_infboost::spirit::qi::ureal_policies151 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 parse_signboost::spirit::qi::real_policies179 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 199