| /*============================================================================= |
| Copyright (c) 2001-2019 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) |
| ==============================================================================*/ |
| #ifndef BOOST_SPIRIT_QI_NUMERIC_REAL_POLICIES_HPP |
| #define BOOST_SPIRIT_QI_NUMERIC_REAL_POLICIES_HPP |
| |
| #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> |
| #include <boost/type_traits/is_floating_point.hpp> |
| |
| namespace boost { namespace spirit { namespace traits |
| { |
| // So that we won't exceed the capacity of the underlying type T, |
| // we limit the number of digits parsed to its max_digits10. |
| // By default, the value is -1 which tells spirit to parse an |
| // unbounded number of digits. |
| |
| template <typename T, typename Enable = void> |
| struct max_digits10 |
| { |
| static int const value = -1; // unbounded |
| }; |
| |
| template <typename T> |
| struct max_digits10<T |
| , typename enable_if_c<(is_floating_point<T>::value)>::type> |
| { |
| static int const digits = std::numeric_limits<T>::digits; |
| static int const value = 2 + (digits * 30103l) / 100000l; |
| }; |
| }}} |
| |
| namespace boost { namespace spirit { namespace qi |
| { |
| /////////////////////////////////////////////////////////////////////////// |
| // Default (unsigned) real number policies |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename T> |
| struct ureal_policies |
| { |
| // Versioning |
| typedef mpl::int_<2> version; |
| |
| // 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_) |
| { |
| typedef extract_uint<Attribute, 10, 1 |
| , traits::max_digits10<T>::value // See notes on max_digits10 above |
| , false, true> |
| extract_uint; |
| return extract_uint::call(first, last, attr_); |
| } |
| |
| // ignore_excess_digits (required for version > 1 API) |
| template <typename Iterator> |
| static std::size_t |
| ignore_excess_digits(Iterator& first, Iterator const& last) |
| { |
| Iterator save = first; |
| if (extract_uint<unused_type, 10, 1, -1>::call(first, last, unused)) |
| return static_cast<std::size_t>(std::distance(save, first)); |
| return 0; |
| } |
| |
| 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_, int& frac_digits) |
| { |
| Iterator savef = first; |
| bool r = extract_uint<Attribute, 10, 1, -1, true, true>::call(first, last, attr_); |
| if (r) |
| { |
| #if defined(_MSC_VER) && _MSC_VER < 1900 |
| # pragma warning(push) |
| # pragma warning(disable: 4127) // conditional expression is constant |
| #endif |
| // Optimization note: don't compute frac_digits if T is |
| // an unused_type. This should be optimized away by the compiler. |
| if (!is_same<T, unused_type>::value) |
| frac_digits = |
| static_cast<int>(std::distance(savef, first)); |
| #if defined(_MSC_VER) && _MSC_VER < 1900 |
| # pragma warning(pop) |
| #endif |
| // ignore extra (non-significant digits) |
| extract_uint<unused_type, 10, 1, -1>::call(first, last, unused); |
| } |
| return r; |
| } |
| |
| 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 |