numerics.hpp

来自「CGAL is a collaborative effort of severa」· HPP 代码 · 共 284 行

/*=============================================================================
    Copyright (c) 1998-2003 Joel de Guzman
    Copyright (c) 2001-2003 Hartmut Kaiser
    http://spirit.sourceforge.net/

    Use, modification and distribution is subject to 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_NUMERICS_HPP
#define BOOST_SPIRIT_NUMERICS_HPP

#include <boost/config.hpp>
#include <boost/spirit/core/parser.hpp>
#include <boost/spirit/core/composite/directives.hpp>
#include <boost/spirit/core/primitives/impl/numerics.ipp>

namespace boost { namespace spirit 
{
    ///////////////////////////////////////////////////////////////////////////
    //
    //  uint_parser class
    //
    ///////////////////////////////////////////////////////////////////////////
    template <
        typename T = unsigned,
        int Radix = 10,
        unsigned MinDigits = 1,
        int MaxDigits = -1
    >
    struct uint_parser : parser<uint_parser<T, Radix, MinDigits, MaxDigits> >
    {
        typedef uint_parser<T, Radix, MinDigits, MaxDigits> self_t;
    
        template <typename ScannerT>
        struct result
        {
            typedef typename match_result<ScannerT, T>::type type;
        };
        
        template <typename ScannerT>
        typename parser_result<self_t, ScannerT>::type
        parse(ScannerT const& scan) const
        {
            typedef impl::uint_parser_impl<T, Radix, MinDigits, MaxDigits> impl_t;
            typedef typename parser_result<impl_t, ScannerT>::type result_t;
            return impl::contiguous_parser_parse<result_t>(impl_t(), scan, scan);
        }
    };
    
    ///////////////////////////////////////////////////////////////////////////
    //
    //  int_parser class
    //
    ///////////////////////////////////////////////////////////////////////////
    template <
        typename T = unsigned,
        int Radix = 10,
        unsigned MinDigits = 1,
        int MaxDigits = -1
    >
    struct int_parser : parser<int_parser<T, Radix, MinDigits, MaxDigits> >
    {
        typedef int_parser<T, Radix, MinDigits, MaxDigits> self_t;
    
        template <typename ScannerT>
        struct result
        {
            typedef typename match_result<ScannerT, T>::type type;
        };
        
        template <typename ScannerT>
        typename parser_result<self_t, ScannerT>::type
        parse(ScannerT const& scan) const
        {
            typedef impl::int_parser_impl<T, Radix, MinDigits, MaxDigits> impl_t;
            typedef typename parser_result<impl_t, ScannerT>::type result_t;
            return impl::contiguous_parser_parse<result_t>(impl_t(), scan, scan);
        }
    };
    
    ///////////////////////////////////////////////////////////////////////////
    //
    //  uint_parser/int_parser instantiations
    //
    ///////////////////////////////////////////////////////////////////////////
    int_parser<int> const
        int_p   = int_parser<int>();
    
    uint_parser<unsigned> const
        uint_p  = uint_parser<unsigned>();
    
    uint_parser<unsigned, 2> const
        bin_p   = uint_parser<unsigned, 2>();
    
    uint_parser<unsigned, 8> const
        oct_p   = uint_parser<unsigned, 8>();
    
    uint_parser<unsigned, 16> const
        hex_p   = uint_parser<unsigned, 16>();
    
    ///////////////////////////////////////////////////////////////////////////
    //
    //  sign_parser class
    //
    ///////////////////////////////////////////////////////////////////////////
    namespace impl
    {
        //  Utility to extract the prefix sign ('-' | '+')
        template <typename ScannerT>
        bool extract_sign(ScannerT const& scan, std::size_t& count);
    }
    
    struct sign_parser : public parser<sign_parser>
    {
        typedef sign_parser self_t;

        template <typename ScannerT>
        struct result 
        {
            typedef typename match_result<ScannerT, bool>::type type;
        };

        sign_parser() {}
    
        template <typename ScannerT>
        typename parser_result<self_t, ScannerT>::type
        parse(ScannerT const& scan) const
        {
            if (!scan.at_end())
            {
                std::size_t length;
                typename ScannerT::iterator_t save(scan.first);
                bool neg = impl::extract_sign(scan, length);
                if (length)
                    return scan.create_match(1, neg, save, scan.first);
            }
            return scan.no_match();
        }
    };
    
    sign_parser const sign_p = sign_parser();
    
    ///////////////////////////////////////////////////////////////////////////
    //
    //  default real number policies
    //
    ///////////////////////////////////////////////////////////////////////////
    template <typename T>
    struct ureal_parser_policies
    {
        // trailing dot policy suggested suggested by Gustavo Guerra
        BOOST_STATIC_CONSTANT(bool, allow_leading_dot = true);
        BOOST_STATIC_CONSTANT(bool, allow_trailing_dot = true);
        BOOST_STATIC_CONSTANT(bool, expect_dot = false);
    
        typedef uint_parser<T, 10, 1, -1>   uint_parser_t;
        typedef int_parser<T, 10, 1, -1>    int_parser_t;
    
        template <typename ScannerT>
        static typename match_result<ScannerT, nil_t>::type
        parse_sign(ScannerT& scan)
        { 
            return scan.no_match(); 
        }
    
        template <typename ScannerT>
        static typename parser_result<uint_parser_t, ScannerT>::type
        parse_n(ScannerT& scan)
        { 
            return uint_parser_t().parse(scan); 
        }
    
        template <typename ScannerT>
        static typename parser_result<chlit<>, ScannerT>::type
        parse_dot(ScannerT& scan)
        { 
            return ch_p('.').parse(scan); 
        }
    
        template <typename ScannerT>
        static typename parser_result<uint_parser_t, ScannerT>::type
        parse_frac_n(ScannerT& scan)
        { 
            return uint_parser_t().parse(scan); 
        }
    
        template <typename ScannerT>
        static typename parser_result<chlit<>, ScannerT>::type
        parse_exp(ScannerT& scan)
        { 
            return as_lower_d['e'].parse(scan); 
        }
    
        template <typename ScannerT>
        static typename parser_result<int_parser_t, ScannerT>::type
        parse_exp_n(ScannerT& scan)
        { 
            return int_parser_t().parse(scan); 
        }
    };
    
    template <typename T>
    struct real_parser_policies : public ureal_parser_policies<T>
    {
        template <typename ScannerT>
        static typename parser_result<sign_parser, ScannerT>::type
        parse_sign(ScannerT& scan)
        { 
            return sign_p.parse(scan); 
        }
    };
    
    ///////////////////////////////////////////////////////////////////////////
    //
    //  real_parser class
    //
    ///////////////////////////////////////////////////////////////////////////
    template <
        typename T = double,
        typename RealPoliciesT = ureal_parser_policies<T>
    >
    struct real_parser
    :   public parser<real_parser<T, RealPoliciesT> >
    {
        typedef real_parser<T, RealPoliciesT> self_t;
    
        template <typename ScannerT>
        struct result
        {
            typedef typename match_result<ScannerT, T>::type type;
        };
    
        real_parser() {}
    
        template <typename ScannerT>
        typename parser_result<self_t, ScannerT>::type
        parse(ScannerT const& scan) const
        {
            typedef typename parser_result<self_t, ScannerT>::type result_t;
            return impl::real_parser_impl<result_t, T, RealPoliciesT>::parse(scan);
        }
    };
    
    ///////////////////////////////////////////////////////////////////////////
    //
    //  real_parser instantiations
    //
    ///////////////////////////////////////////////////////////////////////////
    real_parser<double, ureal_parser_policies<double> > const
        ureal_p     = real_parser<double, ureal_parser_policies<double> >();
    
    real_parser<double, real_parser_policies<double> > const
        real_p      = real_parser<double, real_parser_policies<double> >();
    
    ///////////////////////////////////////////////////////////////////////////
    //
    //  strict reals (do not allow plain integers (no decimal point))
    //
    ///////////////////////////////////////////////////////////////////////////
    template <typename T>
    struct strict_ureal_parser_policies : public ureal_parser_policies<T>
    {
        BOOST_STATIC_CONSTANT(bool, expect_dot = true);
    };
    
    template <typename T>
    struct strict_real_parser_policies : public real_parser_policies<T>
    {
        BOOST_STATIC_CONSTANT(bool, expect_dot = true);
    };
    
    real_parser<double, strict_ureal_parser_policies<double> > const
        strict_ureal_p
            = real_parser<double, strict_ureal_parser_policies<double> >();
    
    real_parser<double, strict_real_parser_policies<double> > const
        strict_real_p
            = real_parser<double, strict_real_parser_policies<double> >();
    
}} // namespace boost::spirit

#endif