mapnik/src/wkb.cpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 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>

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
    };
        
    wkb_reader(const char* wkb,unsigned size,wkbFormat format)
        : wkb_(wkb),
          size_(size),
          pos_(0),
          format_(format)
    {
        switch (format_)
        {
        case wkbSpatiaLite:
            byteOrder_ = (wkbByteOrder) wkb_[1];
            pos_ = 39;
            break;

        case wkbGeneric:
        default:
            byteOrder_ = (wkbByteOrder) wkb_[0];
            pos_ = 1;
            break;
        }

#ifndef MAPNIK_BIG_ENDIAN
        needSwap_=byteOrder_?wkbXDR:wkbNDR;
#else
        needSwap_=byteOrder_?wkbNDR:wkbXDR;     
#endif      
    }

    ~wkb_reader() {}

    void read_multi(Feature & feature) 
    {
        int type=read_integer();
        switch (type)
        {
        case wkbPoint:
            read_point(feature);
            break;
        case wkbLineString:
            read_linestring(feature);
            break;
        case wkbPolygon:
            read_polygon(feature);
            break;
        case wkbMultiPoint:
            read_multipoint(feature);
            break;
        case wkbMultiLineString:
            read_multilinestring(feature);
            break;
        case wkbMultiPolygon:
            read_multipolygon(feature);
            break;
        case wkbGeometryCollection:
            break;
        default:
            break;
        }
    }
         
    void read(Feature & feature) 
    {
        int type=read_integer();
        switch (type)
        {
        case wkbPoint:
            read_point(feature);
            break;
        case wkbLineString:
            read_linestring(feature);
            break;
        case wkbPolygon:
            read_polygon(feature);
            break;
        case wkbMultiPoint:
            read_multipoint_2(feature);
            break;
        case wkbMultiLineString:
            read_multilinestring_2(feature);
            break;
        case wkbMultiPolygon:
            read_multipolygon_2(feature);
            break;
        case wkbGeometryCollection:
            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)
    {
        int size=sizeof(coord<double,2>)*ar.size();
        if (!needSwap_)
        {
            std::memcpy(&ar[0],wkb_+pos_,size);
            pos_+=size;
        }
        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;
            }
        }
            
    }
        
    void read_point(Feature & feature)
    {
        geometry_type * pt = new geometry_type(Point);
        double x = read_double();
        double y = read_double();
        pt->move_to(x,y);
        feature.add_geometry(pt);
    }
         
    void read_multipoint(Feature & feature)
    {
        int num_points = read_integer();
        for (int i=0;i<num_points;++i) 
        {
            pos_+=5;
            read_point(feature);
        }
    }
         
    void read_multipoint_2(Feature & feature)
    {
        geometry_type * pt = new geometry_type(Point);
        int num_points = read_integer(); 
        for (int i=0;i<num_points;++i) 
        {
            pos_+=5;
            double x = read_double();
            double y = read_double();
            pt->move_to(x,y);
        }
        feature.add_geometry(pt);
    }
         
    void read_linestring(Feature & feature)
    {
        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);
        }
        feature.add_geometry(line);
    }
         
    void read_multilinestring(Feature & feature)
    {
        int num_lines=read_integer();
        for (int i=0;i<num_lines;++i)
        {
            pos_+=5;
            read_linestring(feature);
        }
    }

    void read_multilinestring_2(Feature & feature)
    {
        geometry_type * line = new geometry_type(LineString);
        int num_lines=read_integer();
        unsigned capacity = 0;
        for (int i=0;i<num_lines;++i)
        {
            pos_+=5;
            int num_points=read_integer();
            capacity+=num_points;
            CoordinateArray ar(num_points); 
            read_coords(ar);
            line->set_capacity(capacity);
            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); 
            } 
        }
        feature.add_geometry(line);
    }
         
    void read_polygon(Feature & feature) 
    {
        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);
            }
        }
        feature.add_geometry(poly);
    }
        
    void read_multipolygon(Feature & feature)
    {
        int num_polys=read_integer();
        for (int i=0;i<num_polys;++i)
        {
            pos_+=5;
            read_polygon(feature);
        }
    }

    void read_multipolygon_2(Feature & feature)
    {
        geometry_type * poly = new geometry_type(Polygon);
        int num_polys=read_integer();
        unsigned capacity = 0;
        for (int i=0;i<num_polys;++i)
        {
            pos_+=5;
            int num_rings=read_integer();
            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);
                }
                poly->line_to(ar[0].x,ar[0].y);
            }
        }
        feature.add_geometry(poly);
    }
};
    
void geometry_utils::from_wkb (Feature & feature,
                               const char* wkb,
                               unsigned size,
                               bool multiple_geometries,
                               wkbFormat format) 
{
    wkb_reader reader(wkb,size,format);
    if (multiple_geometries)
        return reader.read_multi(feature);
    else
        return reader.read(feature);
}    
}