mapnik/src/wkb.cpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2011 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/

//$Id: wkb.cpp 19 2005-03-22 13:53:27Z pavlenko $

#include <mapnik/global.hpp>
#include <mapnik/wkb.hpp>
#include <mapnik/geom_util.hpp>
#include <mapnik/feature.hpp>

// boost
#include <boost/utility.hpp>
#include <boost/format.hpp>

namespace mapnik
{
struct wkb_reader : boost::noncopyable
{
private:
    enum wkbByteOrder {
        wkbXDR=0,
        wkbNDR=1
    };

    const char* wkb_;
    unsigned size_;
    unsigned pos_;
    wkbByteOrder byteOrder_;
    bool needSwap_;
    wkbFormat format_;

public:
        
    enum wkbGeometryType {
        wkbPoint=1,
        wkbLineString=2,
        wkbPolygon=3,
        wkbMultiPoint=4,
        wkbMultiLineString=5,
        wkbMultiPolygon=6,
        wkbGeometryCollection=7,
        wkbPointZ=1001,
        wkbLineStringZ=1002,
        wkbPolygonZ=1003,
        wkbMultiPointZ=1004,
        wkbMultiLineStringZ=1005,
        wkbMultiPolygonZ=1006,
        wkbGeometryCollectionZ=1007
    };

    wkb_reader(const char* wkb, unsigned size, wkbFormat format)
        : wkb_(wkb),
          size_(size),
          pos_(0),
          format_(format)
    {
        // try to determine WKB format automatically
        if (format_ == wkbAuto)
        {
            if (size >= 44
                && (unsigned char)(wkb_[0]) == (unsigned char)(0x00)
                && (unsigned char)(wkb_[38]) == (unsigned char)(0x7C))
            {
                format_ = wkbSpatiaLite;
            }
            else
            {
                format_ = wkbGeneric;
            }
        }

        switch (format_)
        {
        case wkbSpatiaLite:
            byteOrder_ = (wkbByteOrder) wkb_[1];
            pos_ = 39;
#ifdef MAPNIK_DEBUG_WKB
            std::clog << "wkb_reader: format is wkbSpatiaLite" << std::endl;
#endif
            break;

        case wkbGeneric:
        default:
            byteOrder_ = (wkbByteOrder) wkb_[0];
            pos_ = 1;
#ifdef MAPNIK_DEBUG_WKB
            std::clog << "wkb_reader: format is wkbGeneric" << std::endl;
#endif
            break;
        }

#ifndef MAPNIK_BIG_ENDIAN
        needSwap_ = byteOrder_ ? wkbXDR : wkbNDR;
#else
        needSwap_ = byteOrder_ ? wkbNDR : wkbXDR;
#endif      
    }
             
    void read(boost::ptr_vector<geometry_type> & paths) 
    {
        int type = read_integer();

#ifdef MAPNIK_DEBUG_WKB
        std::clog << "wkb_reader: read " << wkb_geometry_type_string(type) << " " << type << std::endl;
#endif

        switch (type)
        {
        case wkbPoint:
            read_point(paths);
            break;
        case wkbLineString:
            read_linestring(paths);
            break;
        case wkbPolygon:
            read_polygon(paths);
            break;
        case wkbMultiPoint:
            read_multipoint(paths);
            break;
        case wkbMultiLineString:
            read_multilinestring(paths);
            break;
        case wkbMultiPolygon:
            read_multipolygon(paths);
            break;
        case wkbGeometryCollection:
            read_collection(paths);
            break;
        case wkbPointZ:
            read_point_xyz(paths);
            break;
        case wkbLineStringZ:
            read_linestring_xyz(paths);
            break;
        case wkbPolygonZ:
            read_polygon_xyz(paths);
            break;
        case wkbMultiPointZ:
            read_multipoint_xyz(paths);
            break;
        case wkbMultiLineStringZ:
            read_multilinestring_xyz(paths);
            break;
        case wkbMultiPolygonZ:
            read_multipolygon_xyz(paths);
            break;
        case wkbGeometryCollectionZ:
            read_collection(paths);
            break;
        default:
            break;
        }
    }
          
private:
        
    int read_integer() 
    {
        boost::int32_t n;
        if (needSwap_)
        {
            read_int32_xdr(wkb_ + pos_, n);
        } 
        else 
        {
            read_int32_ndr(wkb_ + pos_, n);
        }
        pos_ += 4;
            
        return n;
    }
        
    double read_double()
    {
        double d;
        if (needSwap_)
        {
            read_double_xdr(wkb_ + pos_, d);
        }
        else 
        {
            read_double_ndr(wkb_ + pos_, d);
        }
        pos_ += 8;
            
        return d;
    }
        
    void read_coords(CoordinateArray& ar)
    {
        if (! needSwap_)
        {
            for (unsigned i = 0; i < ar.size(); ++i)
            {
                read_double_ndr(wkb_ + pos_, ar[i].x);
                read_double_ndr(wkb_ + pos_ + 8, ar[i].y);
                pos_ += 16; // skip XY
            }
        }
        else 
        {
            for (unsigned i=0;i<ar.size();++i)
            {
                read_double_xdr(wkb_ + pos_, ar[i].x);
                read_double_xdr(wkb_ + pos_ + 8, ar[i].y);
                pos_ += 16; // skip XY
            }
        }
    }

    void read_coords_xyz(CoordinateArray& ar)
    {
        if (! needSwap_)
        {
            for (unsigned i = 0; i < ar.size(); ++i)
            {
                read_double_ndr(wkb_ + pos_, ar[i].x);
                read_double_ndr(wkb_ + pos_ + 8, ar[i].y);
                pos_ += 24; // skip XYZ
            }
        }
        else
        {
            for (unsigned i = 0; i < ar.size(); ++i)
            {
                read_double_xdr(wkb_ + pos_, ar[i].x);
                read_double_xdr(wkb_ + pos_ + 8, ar[i].y);
                pos_ += 24; // skip XYZ
            }
        }
    }


    void read_point(boost::ptr_vector<geometry_type> & paths)
    {
        geometry_type* pt = new geometry_type(Point);
        double x = read_double();
        double y = read_double();
        pt->move_to(x, y);
        paths.push_back(pt);
    }
         
    void read_multipoint(boost::ptr_vector<geometry_type> & paths)
    {
        int num_points = read_integer();
        for (int i = 0; i < num_points; ++i)
        {
            pos_ += 5;
            read_point(paths);
        }
    }
    
    void read_point_xyz(boost::ptr_vector<geometry_type> & paths)
    {
        geometry_type* pt = new geometry_type(Point);
        double x = read_double();
        double y = read_double();
        pos_ += 8; // double z = read_double();
        pt->move_to(x, y);
        paths.push_back(pt);
    }

    void read_multipoint_xyz(boost::ptr_vector<geometry_type> & paths)
    {
        int num_points = read_integer();
        for (int i = 0; i < num_points; ++i)
        {
            pos_ += 5;
            read_point_xyz(paths);
        }
    }

    void read_linestring(boost::ptr_vector<geometry_type> & paths)
    {
        geometry_type* line = new geometry_type(LineString);
        int num_points = read_integer();
        CoordinateArray ar(num_points);
        read_coords(ar);
        line->set_capacity(num_points);
        line->move_to(ar[0].x, ar[0].y);
        for (int i = 1; i < num_points; ++i)
        {
            line->line_to(ar[i].x, ar[i].y);
        }
        paths.push_back(line);
    }
         
    void read_multilinestring(boost::ptr_vector<geometry_type> & paths)
    {
        int num_lines = read_integer();
        for (int i = 0; i < num_lines; ++i)
        {
            pos_ += 5;
            read_linestring(paths);
        }
    }
    
    void read_linestring_xyz(boost::ptr_vector<geometry_type> & paths)
    {
        geometry_type* line = new geometry_type(LineString);
        int num_points = read_integer();
        CoordinateArray ar(num_points);
        read_coords_xyz(ar);
        line->set_capacity(num_points);
        line->move_to(ar[0].x, ar[0].y);
        for (int i = 1; i < num_points; ++i)
        {
            line->line_to(ar[i].x, ar[i].y);
        }
        paths.push_back(line);
    }

    void read_multilinestring_xyz(boost::ptr_vector<geometry_type> & paths)
    {
        int num_lines = read_integer();
        for (int i = 0; i < num_lines; ++i)
        {
            pos_ += 5;
            read_linestring_xyz(paths);
        }
    }

    
    void read_polygon(boost::ptr_vector<geometry_type> & paths) 
    {
        geometry_type* poly = new geometry_type(Polygon);
        int num_rings = read_integer();
        unsigned capacity = 0;
        for (int i = 0; i < num_rings; ++i)
        {
            int num_points = read_integer();
            capacity += num_points;
            CoordinateArray ar(num_points);
            read_coords(ar);
            poly->set_capacity(capacity);
            poly->move_to(ar[0].x, ar[0].y);
            for (int j = 1; j < num_points; ++j)
            {
                poly->line_to(ar[j].x, ar[j].y);
            }
        }
        paths.push_back(poly);
    }
        
    void read_multipolygon(boost::ptr_vector<geometry_type> & paths)
    {
        int num_polys = read_integer();
        for (int i = 0; i < num_polys; ++i)
        {
            pos_ += 5;
            read_polygon(paths);
        }
    }
    
    void read_polygon_xyz(boost::ptr_vector<geometry_type> & paths)
    {
        geometry_type* poly = new geometry_type(Polygon);
        int num_rings = read_integer();
        unsigned capacity = 0;
        for (int i = 0; i < num_rings; ++i)
        {
            int num_points = read_integer();
            capacity += num_points;
            CoordinateArray ar(num_points);
            read_coords_xyz(ar);
            poly->set_capacity(capacity);
            poly->move_to(ar[0].x, ar[0].y);
            for (int j = 1; j < num_points; ++j)
            {
                poly->line_to(ar[j].x, ar[j].y);
            }
        }
        paths.push_back(poly);
    }

    void read_multipolygon_xyz(boost::ptr_vector<geometry_type> & paths)
    {
        int num_polys = read_integer();
        for (int i = 0; i < num_polys; ++i)
        {
            pos_ += 5;
            read_polygon_xyz(paths);
        }
    }

    void read_collection(boost::ptr_vector<geometry_type> & paths)
    {
        int num_geometries = read_integer();
        for (int i = 0; i < num_geometries; ++i)
        {
            pos_ += 1; // skip byte order
            read(paths);
        }
    }
    
#ifdef MAPNIK_DEBUG_WKB
    std::string wkb_geometry_type_string(int type)
    {
        std::stringstream s;

        switch (type)
        {
        case wkbPoint:               s << "wkbPoint"; break;
        case wkbLineString:          s << "wkbLineString"; break;
        case wkbPolygon:             s << "wkbPolygon"; break;
        case wkbMultiPoint:          s << "wkbMultiPoint"; break;
        case wkbMultiLineString:     s << "wkbMultiLineString"; break;
        case wkbMultiPolygon:        s << "wkbMultiPolygon"; break;
        case wkbGeometryCollection:  s << "wkbGeometryCollection"; break;
        case wkbPointZ:              s << "wkbPointZ"; break;
        case wkbLineStringZ:         s << "wkbLineStringZ"; break;
        case wkbPolygonZ:            s << "wkbPolygonZ"; break;
        case wkbMultiPointZ:         s << "wkbMultiPointZ"; break;
        case wkbMultiLineStringZ:    s << "wkbMultiLineStringZ"; break;
        case wkbMultiPolygonZ:       s << "wkbMultiPolygonZ"; break;
        case wkbGeometryCollectionZ: s << "wkbGeometryCollectionZ"; break;
        default:                     s << "wkbUknown"; break;
        }

        return s.str();
    }
#endif

};

void geometry_utils::from_wkb (boost::ptr_vector<geometry_type>& paths,
                               const char* wkb,
                               unsigned size,
                               wkbFormat format) 
{
    wkb_reader reader(wkb, size, format);
    return reader.read(paths);
}    

}