| /*============================================================================= |
| Copyright (c) 2001-2010 Joel de Guzman |
| Copyright (c) 2001-2010 Hartmut Kaiser |
| |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| ==============================================================================*/ |
| #if !defined(SPIRIT_REAL_POLICIES_APRIL_17_2006_1158PM) |
| #define SPIRIT_REAL_POLICIES_APRIL_17_2006_1158PM |
| |
| #if defined(_MSC_VER) |
| #pragma once |
| #endif |
| |
| #include <boost/spirit/home/qi/numeric/numeric_utils.hpp> |
| #include <boost/spirit/home/qi/detail/string_parse.hpp> |
| |
| namespace boost { namespace spirit { namespace qi |
| { |
| /////////////////////////////////////////////////////////////////////////// |
| // Default (unsigned) real number policies |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename T> |
| struct ureal_policies |
| { |
| // trailing dot policy suggested by Gustavo Guerra |
| static bool const allow_leading_dot = true; |
| static bool const allow_trailing_dot = true; |
| static bool const expect_dot = false; |
| |
| template <typename Iterator> |
| static bool |
| parse_sign(Iterator& /*first*/, Iterator const& /*last*/) |
| { |
| return false; |
| } |
| |
| template <typename Iterator, typename Attribute> |
| static bool |
| parse_n(Iterator& first, Iterator const& last, Attribute& attr) |
| { |
| return extract_uint<T, 10, 1, -1>::call(first, last, attr); |
| } |
| |
| template <typename Iterator> |
| static bool |
| parse_dot(Iterator& first, Iterator const& last) |
| { |
| if (first == last || *first != '.') |
| return false; |
| ++first; |
| return true; |
| } |
| |
| template <typename Iterator, typename Attribute> |
| static bool |
| parse_frac_n(Iterator& first, Iterator const& last, Attribute& attr) |
| { |
| return extract_uint<T, 10, 1, -1, true>::call(first, last, attr); |
| } |
| |
| template <typename Iterator> |
| static bool |
| parse_exp(Iterator& first, Iterator const& last) |
| { |
| if (first == last || (*first != 'e' && *first != 'E')) |
| return false; |
| ++first; |
| return true; |
| } |
| |
| template <typename Iterator> |
| static bool |
| parse_exp_n(Iterator& first, Iterator const& last, int& attr) |
| { |
| return extract_int<int, 10, 1, -1>::call(first, last, attr); |
| } |
| |
| /////////////////////////////////////////////////////////////////////// |
| // The parse_nan() and parse_inf() functions get called whenever: |
| // |
| // - a number to parse does not start with a digit (after having |
| // successfully parsed an optional sign) |
| // |
| // or |
| // |
| // - after a floating point number of the value 1 (having no |
| // exponential part and a fractional part value of 0) has been |
| // parsed. |
| // |
| // The first call allows to recognize representations of NaN or Inf |
| // starting with a non-digit character (such as NaN, Inf, QNaN etc.). |
| // |
| // The second call allows to recognize representation formats starting |
| // with a 1.0 (such as 1.0#NAN or 1.0#INF etc.). |
| // |
| // The functions should return true if a Nan or Inf has been found. In |
| // this case the attr should be set to the matched value (NaN or |
| // Inf). The optional sign will be automatically applied afterwards. |
| // |
| // The default implementation below recognizes representations of NaN |
| // and Inf as mandated by the C99 Standard and as proposed for |
| // inclusion into the C++0x Standard: nan, nan(...), inf and infinity |
| // (the matching is performed case-insensitively). |
| /////////////////////////////////////////////////////////////////////// |
| template <typename Iterator, typename Attribute> |
| static bool |
| parse_nan(Iterator& first, Iterator const& last, Attribute& attr) |
| { |
| if (first == last) |
| return false; // end of input reached |
| |
| if (*first != 'n' && *first != 'N') |
| return false; // not "nan" |
| |
| // nan[(...)] ? |
| if (detail::string_parse("nan", "NAN", first, last, unused)) |
| { |
| if (*first == '(') |
| { |
| // skip trailing (...) part |
| Iterator i = first; |
| |
| while (++i != last && *i != ')') |
| ; |
| if (i == last) |
| return false; // no trailing ')' found, give up |
| |
| first = ++i; |
| } |
| attr = std::numeric_limits<T>::quiet_NaN(); |
| return true; |
| } |
| return false; |
| } |
| |
| template <typename Iterator, typename Attribute> |
| static bool |
| parse_inf(Iterator& first, Iterator const& last, Attribute& attr) |
| { |
| if (first == last) |
| return false; // end of input reached |
| |
| if (*first != 'i' && *first != 'I') |
| return false; // not "inf" |
| |
| // inf or infinity ? |
| if (detail::string_parse("inf", "INF", first, last, unused)) |
| { |
| // skip allowed 'inity' part of infinity |
| detail::string_parse("inity", "INITY", first, last, unused); |
| attr = std::numeric_limits<T>::infinity(); |
| return true; |
| } |
| return false; |
| } |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Default (signed) real number policies |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename T> |
| struct real_policies : ureal_policies<T> |
| { |
| template <typename Iterator> |
| static bool |
| parse_sign(Iterator& first, Iterator const& last) |
| { |
| return extract_sign(first, last); |
| } |
| }; |
| |
| template <typename T> |
| struct strict_ureal_policies : ureal_policies<T> |
| { |
| static bool const expect_dot = true; |
| }; |
| |
| template <typename T> |
| struct strict_real_policies : real_policies<T> |
| { |
| static bool const expect_dot = true; |
| }; |
| }}} |
| |
| #endif |