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- /*=============================================================================
- Copyright (c) 2001-2014 Joel de Guzman
- Copyright (c) 2001-2011 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(BOOST_SPIRIT_X3_REAL_POLICIES_APRIL_17_2006_1158PM)
- #define BOOST_SPIRIT_X3_REAL_POLICIES_APRIL_17_2006_1158PM
- #include <boost/spirit/home/x3/string/detail/string_parse.hpp>
- #include <boost/spirit/home/x3/support/numeric_utils/extract_int.hpp>
- namespace boost { namespace spirit { namespace x3
- {
- ///////////////////////////////////////////////////////////////////////////
- // 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).
- //
- // 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 != last && *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
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