Ticket #6249: make_relative_append_example.cpp

#include "boost/filesystem.hpp"
#include "boost/version.hpp"

namespace boost { namespace filesystem3 {
        template < >
        path& path::append< typename path::iterator >( typename path::iterator begin, typename path::iterator end, const codecvt_type& cvt)
        {
                for( ; begin != end ; ++begin )
                        *this /= *begin;
                return *this;
        }
        // Return path when appended to a_From will resolve to same as a_To
        boost::filesystem::path make_relative( boost::filesystem::path a_From, boost::filesystem::path a_To )
        {
                a_From = boost::filesystem::absolute( a_From ); a_To = boost::filesystem::absolute( a_To );
                boost::filesystem::path ret;
                boost::filesystem::path::const_iterator itrFrom( a_From.begin() ), itrTo( a_To.begin() );
                // Find common base
                for( boost::filesystem::path::const_iterator toEnd( a_To.end() ), fromEnd( a_From.end() ) ; itrFrom != fromEnd && itrTo != toEnd && *itrFrom == *itrTo; ++itrFrom, ++itrTo );
                // Navigate backwards in directory to reach previously found base
                for( boost::filesystem::path::const_iterator fromEnd( a_From.end() ); itrFrom != fromEnd; ++itrFrom )
                {
                        if( (*itrFrom) != "." )
                                ret /= "..";
                }
                // Now navigate down the directory branch
                ret.append( itrTo, a_To.end() );
                return ret;
        }
} }
namespace boost { namespace filesystem { using filesystem3::make_relative; } }


int main()
{
        boost::filesystem::path a("foo/bar"), b("foo/test/korv.txt");
        std::cout << boost::filesystem::make_relative( a, b ).string() << std::endl;
        return 0;
}