Chris@16: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@16: 
Chris@16: // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
Chris@16: // Copyright (c) 2011-2012 Bruno Lalande, Paris, France.
Chris@16: // Copyright (c) 2011-2012 Mateusz Loskot, London, UK.
Chris@16: 
Chris@16: // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
Chris@16: // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software License,
Chris@16: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_GEOMETRY_UTIL_RATIONAL_HPP
Chris@16: #define BOOST_GEOMETRY_UTIL_RATIONAL_HPP
Chris@16: 
Chris@16: #include <boost/rational.hpp>
Chris@16: #include <boost/numeric/conversion/bounds.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/util/coordinate_cast.hpp>
Chris@16: #include <boost/geometry/util/select_most_precise.hpp>
Chris@16: 
Chris@16: 
Chris@101: namespace boost{ namespace geometry
Chris@101: {
Chris@16: 
Chris@16: 
Chris@101: // Specialize for Boost.Geometry's coordinate cast
Chris@16: // (from string to coordinate type)
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct coordinate_cast<rational<T> >
Chris@16: {
Chris@16:     static inline void split_parts(std::string const& source, std::string::size_type p,
Chris@16:         T& before, T& after, bool& negate, std::string::size_type& len)
Chris@16:     {
Chris@16:         std::string before_part = source.substr(0, p);
Chris@16:         std::string const after_part = source.substr(p + 1);
Chris@16: 
Chris@16:         negate = false;
Chris@16: 
Chris@16:         if (before_part.size() > 0 && before_part[0] == '-')
Chris@16:         {
Chris@16:             negate = true;
Chris@16:             before_part.erase(0, 1);
Chris@16:         }
Chris@16:         before = atol(before_part.c_str());
Chris@16:         after = atol(after_part.c_str());
Chris@16:         len = after_part.length();
Chris@16:     }
Chris@16: 
Chris@16: 
Chris@16:     static inline rational<T> apply(std::string const& source)
Chris@16:     {
Chris@16:         T before, after;
Chris@16:         bool negate;
Chris@16:         std::string::size_type len;
Chris@16: 
Chris@16:         // Note: decimal comma is not (yet) supported, it does (and should) not
Chris@16:         // occur in a WKT, where points are comma separated.
Chris@16:         std::string::size_type p = source.find(".");
Chris@16:         if (p == std::string::npos)
Chris@16:         {
Chris@16:             p = source.find("/");
Chris@16:             if (p == std::string::npos)
Chris@16:             {
Chris@16:                 return rational<T>(atol(source.c_str()));
Chris@16:             }
Chris@16:             split_parts(source, p, before, after, negate, len);
Chris@16: 
Chris@101:             return negate
Chris@16:                 ? -rational<T>(before, after)
Chris@16:                 : rational<T>(before, after)
Chris@16:                 ;
Chris@16: 
Chris@16:         }
Chris@16: 
Chris@16:         split_parts(source, p, before, after, negate, len);
Chris@16: 
Chris@16:         T den = 1;
Chris@16:         for (std::string::size_type i = 0; i < len; i++)
Chris@16:         {
Chris@16:             den *= 10;
Chris@16:         }
Chris@16: 
Chris@101:         return negate
Chris@16:             ? -rational<T>(before) - rational<T>(after, den)
Chris@16:             : rational<T>(before) + rational<T>(after, den)
Chris@16:             ;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: // Specialize for Boost.Geometry's select_most_precise
Chris@16: template <typename T1, typename T2>
Chris@16: struct select_most_precise<boost::rational<T1>, boost::rational<T2> >
Chris@16: {
Chris@16:     typedef typename boost::rational
Chris@16:         <
Chris@16:             typename select_most_precise<T1, T2>::type
Chris@16:         > type;
Chris@16: };
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct select_most_precise<boost::rational<T>, double>
Chris@16: {
Chris@16:     typedef typename boost::rational<T> type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: }} // namespace boost::geometry
Chris@16: 
Chris@16: 
Chris@16: // Specializes boost::rational to boost::numeric::bounds
Chris@101: namespace boost { namespace numeric
Chris@16: {
Chris@16: 
Chris@16: template<class T>
Chris@16: struct bounds<rational<T> >
Chris@16: {
Chris@101:     static inline rational<T> lowest()
Chris@101:     {
Chris@101:         return rational<T>(bounds<T>::lowest(), 1);
Chris@16:     }
Chris@101:     static inline rational<T> highest()
Chris@101:     {
Chris@101:         return rational<T>(bounds<T>::highest(), 1);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: }} // namespace boost::numeric
Chris@16: 
Chris@16: 
Chris@16: // Support for boost::numeric_cast to int and to double (necessary for SVG-mapper)
Chris@16: namespace boost { namespace numeric
Chris@16: {
Chris@16: 
Chris@16: template
Chris@16: <
Chris@16:     typename T,
Chris@16:     typename Traits,
Chris@16:     typename OverflowHandler,
Chris@16:     typename Float2IntRounder,
Chris@16:     typename RawConverter,
Chris@16:     typename UserRangeChecker
Chris@16: >
Chris@16: struct converter<int, rational<T>, Traits, OverflowHandler, Float2IntRounder, RawConverter, UserRangeChecker>
Chris@16: {
Chris@16:     static inline int convert(rational<T> const& arg)
Chris@16:     {
Chris@16:         return int(rational_cast<double>(arg));
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template
Chris@16: <
Chris@16:     typename T,
Chris@16:     typename Traits,
Chris@16:     typename OverflowHandler,
Chris@16:     typename Float2IntRounder,
Chris@16:     typename RawConverter,
Chris@16:     typename UserRangeChecker
Chris@16: >
Chris@16: struct converter<double, rational<T>, Traits, OverflowHandler, Float2IntRounder, RawConverter, UserRangeChecker>
Chris@16: {
Chris@16:     static inline double convert(rational<T> const& arg)
Chris@16:     {
Chris@16:         return rational_cast<double>(arg);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: 
Chris@16: #endif // BOOST_GEOMETRY_UTIL_RATIONAL_HPP