ogrpolygon.cpp

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/******************************************************************************
 * $Id: ogrpolygon.cpp,v 1.21 2003/06/09 13:48:54 warmerda Exp $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  The OGRPolygon geometry class.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 1999, Frank Warmerdam
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ******************************************************************************
 *
 * $Log: ogrpolygon.cpp,v $
 * Revision 1.21  2003/06/09 13:48:54  warmerda
 * added DB2 V7.2 byte order hack
 *
 * Revision 1.20  2003/05/28 19:16:43  warmerda
 * fixed up argument names and stuff for docs
 *
 * Revision 1.19  2003/03/07 21:28:56  warmerda
 * support 0x8000 style 3D WKB flags
 *
 * Revision 1.18  2002/09/11 13:47:17  warmerda
 * preliminary set of fixes for 3D WKB enum
 *
 * Revision 1.17  2002/05/02 19:44:53  warmerda
 * fixed 3D binary support for polygon/linearring
 *
 * Revision 1.16  2002/03/05 14:25:14  warmerda
 * expand tabs
 *
 * Revision 1.15  2001/11/01 17:20:33  warmerda
 * added DISABLE_OGRGEOM_TRANSFORM macro
 *
 * Revision 1.14  2001/09/21 16:24:20  warmerda
 * added transform() and transformTo() methods
 *
 * Revision 1.13  2001/07/18 05:03:05  warmerda
 * added CPL_CVSID
 *
 * Revision 1.12  1999/11/18 19:02:19  warmerda
 * expanded tabs
 *
 * Revision 1.11  1999/09/22 13:18:55  warmerda
 * Added the addRingDirectly() method.
 *
 * Revision 1.10  1999/09/13 02:27:33  warmerda
 * incorporated limited 2.5d support
 *
 * Revision 1.9  1999/07/27 00:48:12  warmerda
 * Added Equal() support
 *
 * Revision 1.8  1999/07/06 21:36:47  warmerda
 * tenatively added getEnvelope() and Intersect()
 *
 * Revision 1.7  1999/06/25 20:44:43  warmerda
 * implemented assignSpatialReference, carry properly
 *
 * Revision 1.6  1999/05/31 20:43:55  warmerda
 * added empty() method
 *
 * Revision 1.5  1999/05/31 14:59:06  warmerda
 * added documentation
 *
 * Revision 1.4  1999/05/23 05:34:41  warmerda
 * added support for clone(), multipolygons and geometry collections
 *
 * Revision 1.3  1999/05/20 14:35:44  warmerda
 * added support for well known text format
 *
 * Revision 1.2  1999/05/17 14:38:11  warmerda
 * Added new IPolygon style methods.
 *
 * Revision 1.1  1999/03/30 21:21:05  warmerda
 * New
 *
 */

#include "ogr_geometry.h"
#include "ogr_p.h"

CPL_CVSID("$Id: ogrpolygon.cpp,v 1.21 2003/06/09 13:48:54 warmerda Exp $");

/************************************************************************/
/*                             OGRPolygon()                             */
/************************************************************************/

/**
 * Create an empty polygon.
 */

OGRPolygon::OGRPolygon()

{
    nRingCount = 0;
    papoRings = NULL;
}

/************************************************************************/
/*                            ~OGRPolygon()                             */
/************************************************************************/

OGRPolygon::~OGRPolygon()

{
    empty();
}

/************************************************************************/
/*                               clone()                                */
/************************************************************************/

OGRGeometry *OGRPolygon::clone()

{
    OGRPolygon  *poNewPolygon;

    poNewPolygon = new OGRPolygon;
    poNewPolygon->assignSpatialReference( getSpatialReference() );

    for( int i = 0; i < nRingCount; i++ )
    {
        poNewPolygon->addRing( papoRings[i] );
    }

    return poNewPolygon;
}

/************************************************************************/
/*                               empty()                                */
/************************************************************************/

void OGRPolygon::empty()

{
    if( papoRings != NULL )
    {
        for( int i = 0; i < nRingCount; i++ )
        {
            delete papoRings[i];
        }
        OGRFree( papoRings );
    }

    papoRings = NULL;
    nRingCount = 0;
}

/************************************************************************/
/*                          getGeometryType()                           */
/************************************************************************/

OGRwkbGeometryType OGRPolygon::getGeometryType()

{
    if( getCoordinateDimension() == 3 )
        return wkbPolygon25D;
    else
        return wkbPolygon;
}

/************************************************************************/
/*                            getDimension()                            */
/************************************************************************/

int OGRPolygon::getDimension()

{
    return 2;
}

/************************************************************************/
/*                       getCoordinateDimension()                       */
/************************************************************************/

int OGRPolygon::getCoordinateDimension()

{
    for( int iRing = 0; iRing < nRingCount; iRing++ )
    {
        if( papoRings[iRing]->getCoordinateDimension() == 3 )
            return 3;
    }

    return 2;
}

/************************************************************************/
/*                            flattenTo2D()                             */
/************************************************************************/

void OGRPolygon::flattenTo2D()

{
    for( int iRing = 0; iRing < nRingCount; iRing++ )
        papoRings[iRing]->flattenTo2D();
}

/************************************************************************/
/*                          getGeometryName()                           */
/************************************************************************/

const char * OGRPolygon::getGeometryName()

{
    return "POLYGON";
}

/************************************************************************/
/*                          getExteriorRing()                           */
/************************************************************************/

/**
 * Fetch reference to external polygon ring.
 *
 * Note that the returned ring pointer is to an internal data object of
 * the OGRPolygon.  It should not be modified or deleted by the application,
 * and the pointer is only valid till the polygon is next modified.  Use
 * the OGRGeometry::clone() method to make a separate copy within the
 * application.
 *
 * Relates to the SFCOM IPolygon::get_ExteriorRing() method.
 *
 * @return pointer to external ring.  May be NULL if the OGRPolygon is empty.
 */

OGRLinearRing *OGRPolygon::getExteriorRing()

{
    if( nRingCount > 0 )
        return papoRings[0];
    else
        return NULL;
}

/************************************************************************/
/*                        getNumInteriorRings()                         */
/************************************************************************/

/**
 * Fetch the number of internal rings.
 *
 * Relates to the SFCOM IPolygon::get_NumInteriorRings() method.
 *
 * @return count of internal rings, zero or more.
 */


int OGRPolygon::getNumInteriorRings()

{
    if( nRingCount > 0 )
        return nRingCount-1;
    else
        return 0;
}

/************************************************************************/
/*                          getInteriorRing()                           */
/************************************************************************/

/**
 * Fetch reference to indicated internal ring.
 *
 * Note that the returned ring pointer is to an internal data object of
 * the OGRPolygon.  It should not be modified or deleted by the application,
 * and the pointer is only valid till the polygon is next modified.  Use
 * the OGRGeometry::clone() method to make a separate copy within the
 * application.
 *
 * Relates to the SFCOM IPolygon::get_InternalRing() method.
 *
 * @param iRing internal ring index from 0 to getNumInternalRings() - 1.
 *
 * @return pointer to external ring.  May be NULL if the OGRPolygon is empty.
 */

OGRLinearRing *OGRPolygon::getInteriorRing( int iRing )

{
    if( iRing < 0 || iRing >= nRingCount-1 )
        return NULL;
    else
        return papoRings[iRing+1];
}

/************************************************************************/
/*                              addRing()                               */
/************************************************************************/

/**
 * Add a ring to a polygon.
 *
 * If the polygon has no external ring (it is empty) this will be used as
 * the external ring, otherwise it is used as an internal ring.  The passed
 * OGRLinearRing remains the responsibility of the caller (an internal copy
 * is made).
 *
 * This method has no SFCOM analog.
 *
 * @param poNewRing ring to be added to the polygon.
 */

void OGRPolygon::addRing( OGRLinearRing * poNewRing )

{
    papoRings = (OGRLinearRing **) OGRRealloc( papoRings,
                                               sizeof(void*) * (nRingCount+1));

    papoRings[nRingCount] = new OGRLinearRing( poNewRing );

    nRingCount++;
}

/************************************************************************/
/*                          addRingDirectly()                           */
/************************************************************************/

/**
 * Add a ring to a polygon.
 *
 * If the polygon has no external ring (it is empty) this will be used as
 * the external ring, otherwise it is used as an internal ring.  Ownership
 * of the passed ring is assumed by the OGRPolygon, but otherwise this
 * method operates the same as OGRPolygon::AddRing().
 *
 * This method has no SFCOM analog.
 *
 * @param poNewRing ring to be added to the polygon.
 */

void OGRPolygon::addRingDirectly( OGRLinearRing * poNewRing )

{
    papoRings = (OGRLinearRing **) OGRRealloc( papoRings,
                                               sizeof(void*) * (nRingCount+1));

    papoRings[nRingCount] = poNewRing;

    nRingCount++;
}

/************************************************************************/
/*                              WkbSize()                               */
/*                                                                      */
/*      Return the size of this object in well known binary             */
/*      representation including the byte order, and type information.  */
/************************************************************************/

int OGRPolygon::WkbSize()

{
    int         nSize = 9;
    int         b3D = getCoordinateDimension() == 3;

    for( int i = 0; i < nRingCount; i++ )
    {
        nSize += papoRings[i]->_WkbSize( b3D );
    }

    return nSize;
}

/************************************************************************/
/*                           importFromWkb()                            */
/*                                                                      */
/*      Initialize from serialized stream in well known binary          */
/*      format.                                                         */
/************************************************************************/

OGRErr OGRPolygon::importFromWkb( unsigned char * pabyData,
                                  int nSize )

{
    OGRwkbByteOrder     eByteOrder;
    int                 nDataOffset, b3D;
    
    if( nSize < 21 && nSize != -1 )
        return OGRERR_NOT_ENOUGH_DATA;

/* -------------------------------------------------------------------- */
/*      Get the byte order byte.                                        */
/* -------------------------------------------------------------------- */
    eByteOrder = DB2_V72_FIX_BYTE_ORDER((OGRwkbByteOrder) *pabyData);
    CPLAssert( eByteOrder == wkbXDR || eByteOrder == wkbNDR );

/* -------------------------------------------------------------------- */
/*      Get the geometry feature type.  For now we assume that          */
/*      geometry type is between 0 and 255 so we only have to fetch     */
/*      one byte.                                                       */
/* -------------------------------------------------------------------- */
#ifdef DEBUG
    OGRwkbGeometryType eGeometryType;
    
    if( eByteOrder == wkbNDR )
        eGeometryType = (OGRwkbGeometryType) pabyData[1];
    else
        eGeometryType = (OGRwkbGeometryType) pabyData[4];

    CPLAssert( eGeometryType == wkbPolygon );
#endif