/*=============================================================================
    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
