geometry to wkb initial implementation
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Artem Pavlenko
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1627046943
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4659a4d697
1 changed files with 234 additions and 0 deletions
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include/mapnik/util/geometry_to_wkb.hpp
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include/mapnik/util/geometry_to_wkb.hpp
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/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2011 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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//$Id$
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#ifndef MAPNIK_GEOMETRY_TO_WKB_HPP
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#define MAPNIK_GEOMETRY_TO_WKB_HPP
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// mapnik
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#include <mapnik/global.hpp>
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#include <mapnik/geometry.hpp>
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// boost
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#include <boost/shared_ptr.hpp>
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#include <boost/make_shared.hpp>
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#include <boost/interprocess/streams/bufferstream.hpp>
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#include <boost/foreach.hpp>
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// stl
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#include <vector>
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namespace mapnik { namespace util {
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std::string to_hex(const char* blob, unsigned size)
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{
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std::string buf;
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buf.reserve(size*2);
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std::ostringstream s(buf);
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s.seekp(0);
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char hex[3];
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std::memset(hex,0,3);
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for ( unsigned pos=0; pos < size; ++pos)
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{
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std::sprintf (hex, "%02x", int(blob[pos]) & 0xff);
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s << hex;
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}
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return s.str();
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}
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enum wkbByteOrder {
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wkbXDR=0,
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wkbNDR=1
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};
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inline void reverse_bytes(char size, char *address)
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{
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char * first = address;
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char * last = first + size - 1;
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for(;first < last;++first, --last)
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{
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char x = *last;
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*last = *first;
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*first = x;
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}
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}
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template <typename S, typename T>
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inline void write (S & stream, T val, std::size_t size, wkbByteOrder byte_order)
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{
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#ifdef MAPNIK_BIG_ENDIAN
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bool need_swap = byte_order ? wkbNDR : wkbXDR;
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#else
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bool need_swap = byte_order ? wkbXDR : wkbNDR;
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#endif
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char* buf = reinterpret_cast<char*>(&val);
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if (need_swap)
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{
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reverse_bytes(size,buf);
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}
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stream.write(buf,size);
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}
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struct wkb_buffer
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{
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wkb_buffer(std::size_t size)
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: size_(size),
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data_( (size_!=0) ? static_cast<char*>(::operator new (size_)):0)
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{}
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~wkb_buffer()
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{
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::operator delete(data_);
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}
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inline std::size_t size() const
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{
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return size_;
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}
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inline char* buffer()
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{
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return data_;
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}
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std::size_t size_;
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char * data_;
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};
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typedef boost::shared_ptr<wkb_buffer> wkb_buffer_ptr;
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wkb_buffer_ptr to_point_wkb( geometry_type const& g, wkbByteOrder byte_order)
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{
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assert(g.num_points() == 1);
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std::size_t size = 1 + 4 + 8*2 ; // byteOrder + wkbType + Point
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wkb_buffer_ptr wkb = boost::make_shared<wkb_buffer>(size);
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boost::interprocess::bufferstream ss(wkb->buffer(), wkb->size(), std::ios::out | std::ios::binary);
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ss.write(reinterpret_cast<char*>(&byte_order),1);
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int type = static_cast<int>(g.type());
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write(ss,type,4,byte_order);
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double x,y;
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g.get_vertex(0,&x,&y);
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write(ss,x,8,byte_order);
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write(ss,y,8,byte_order);
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assert(ss.good());
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return wkb;
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}
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wkb_buffer_ptr to_line_string_wkb( geometry_type const& g, wkbByteOrder byte_order)
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{
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unsigned num_points = g.num_points();
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assert(num_points > 1);
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std::size_t size = 1 + 4 + 4 + 8*2*num_points ; // byteOrder + wkbType + numPoints + Point*numPoints
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wkb_buffer_ptr wkb = boost::make_shared<wkb_buffer>(size);
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boost::interprocess::bufferstream ss(wkb->buffer(), wkb->size(), std::ios::out | std::ios::binary);
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ss.write(reinterpret_cast<char*>(&byte_order),1);
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int type = static_cast<int>(g.type());
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write(ss,type,4,byte_order);
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write(ss,num_points,4,byte_order);
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double x,y;
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for (unsigned i=0; i< num_points; ++i)
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{
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g.get_vertex(i,&x,&y);
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write(ss,x,8,byte_order);
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write(ss,y,8,byte_order);
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}
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assert(ss.good());
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return wkb;
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}
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wkb_buffer_ptr to_polygon_wkb( geometry_type const& g, wkbByteOrder byte_order)
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{
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unsigned num_points = g.num_points();
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assert(num_points > 1);
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typedef std::pair<double,double> point_type;
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typedef std::vector<point_type> linear_ring;
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boost::ptr_vector<linear_ring> rings;
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double x,y;
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std::size_t size = 1 + 4 + 4 ; // byteOrder + wkbType + numRings
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for (unsigned i=0; i< num_points; ++i)
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{
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unsigned command = g.get_vertex(i,&x,&y);
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if (command == SEG_MOVETO)
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{
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rings.push_back(new linear_ring); // start new loop
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size += 4; // num_points
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}
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rings.back().push_back(std::make_pair(x,y));
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size += 2 * 8; // point
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}
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unsigned num_rings = rings.size();
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wkb_buffer_ptr wkb = boost::make_shared<wkb_buffer>(size);
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boost::interprocess::bufferstream ss(wkb->buffer(), wkb->size(), std::ios::out | std::ios::binary);
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ss.write(reinterpret_cast<char*>(&byte_order),1);
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int type = static_cast<int>(g.type());
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write(ss,type,4,byte_order);
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write(ss,num_rings,4,byte_order);
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BOOST_FOREACH ( linear_ring const& ring, rings)
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{
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unsigned num_points = ring.size();
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write(ss,num_points,4,byte_order);
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BOOST_FOREACH ( point_type const& pt, ring)
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{
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double x = pt.first;
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double y = pt.second;
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write(ss,x,8,byte_order);
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write(ss,y,8,byte_order);
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}
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}
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assert(ss.good());
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return wkb;
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}
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wkb_buffer_ptr to_wkb(geometry_type const& g, wkbByteOrder byte_order )
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{
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wkb_buffer_ptr wkb;
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switch (g.type())
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{
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case mapnik::Point :
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wkb = to_point_wkb(g, byte_order);
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break;
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case mapnik::LineString:
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wkb = to_line_string_wkb(g, byte_order);
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break;
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case mapnik::Polygon:
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wkb = to_polygon_wkb(g, byte_order);
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break;
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case mapnik::MultiPoint:
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case mapnik::MultiLineString:
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case mapnik::MultiPolygon:
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break;
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default:
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break;
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}
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return wkb;
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}
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}}
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#endif // MAPNIK_GEOMETRY_TO_WKB_HPP
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