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Diffstat (limited to 'boost/spirit/home/x3/numeric/real_policies.hpp')
| -rw-r--r-- | boost/spirit/home/x3/numeric/real_policies.hpp | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/boost/spirit/home/x3/numeric/real_policies.hpp b/boost/spirit/home/x3/numeric/real_policies.hpp new file mode 100644 index 0000000000..4e02b266c5 --- /dev/null +++ b/boost/spirit/home/x3/numeric/real_policies.hpp @@ -0,0 +1,186 @@ +/*============================================================================= + 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(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/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) + // + // 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 |