ogrfeature.cpp

用于读取TAB、MIF、SHP文件的类

 *
 * This method updates the features geometry, and operate exactly as
 * SetGeometryDirectly(), except that this method does not assume ownership
 * of the passed geometry, but instead makes a copy of it. 
 *
 * This method is the same as the C function OGR_F_SetGeometry().
 *
 * @param poGeomIn new geometry to apply to feature. Passing NULL value here
 * is correct and it will result in deallocation of currently assigned geometry
 * without assigning new one.
 *
 * @return OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if
 * the geometry type is illegal for the OGRFeatureDefn (checking not yet
 * implemented). 
 */ 

OGRErr OGRFeature::SetGeometry( OGRGeometry * poGeomIn )

{
    delete poGeometry;

    if( poGeomIn != NULL )
        poGeometry = poGeomIn->clone();
    else
        poGeometry = NULL;

    // I should be verifying that the geometry matches the defn's type.
    
    return OGRERR_NONE;
}

/************************************************************************/
/*                         OGR_F_SetGeometry()                          */
/************************************************************************/

/**
 * Set feature geometry.
 *
 * This function updates the features geometry, and operate exactly as
 * SetGeometryDirectly(), except that this function does not assume ownership
 * of the passed geometry, but instead makes a copy of it. 
 *
 * This function is the same as the C++ OGRFeature::SetGeometry().
 *
 * @param hFeat handle to the feature on which new geometry is applied to.
 * @param hGeom handle to the new geometry to apply to feature.
 *
 * @return OGRERR_NONE if successful, or OGR_UNSUPPORTED_GEOMETRY_TYPE if
 * the geometry type is illegal for the OGRFeatureDefn (checking not yet
 * implemented). 
 */ 

OGRErr OGR_F_SetGeometry( OGRFeatureH hFeat, OGRGeometryH hGeom )

{
    return ((OGRFeature *) hFeat)->SetGeometry((OGRGeometry *) hGeom);
}

/************************************************************************/
/*                           StealGeometry()                            */
/************************************************************************/

/**
 * Take away ownership of geometry.
 *
 * Fetch the geometry from this feature, and clear the reference to the
 * geometry on the feature.  This is a mechanism for the application to
 * take over ownship of the geometry from the feature without copying. 
 * Sort of an inverse to SetGeometryDirectly().
 *
 * After this call the OGRFeature will have a NULL geometry.
 *
 * @return the pointer to the geometry.
 */

OGRGeometry *OGRFeature::StealGeometry()

{
    OGRGeometry *poReturn = poGeometry;
    poGeometry = NULL;
    return poReturn;
}

/************************************************************************/
/*                           GetGeometryRef()                           */
/************************************************************************/

/**
 * \fn OGRGeometry *OGRFeature::GetGeometryRef();
 *
 * Fetch pointer to feature geometry.
 *
 * This method is the same as the C function OGR_F_GetGeometryRef().
 *
 * @return pointer to internal feature geometry.  This object should
 * not be modified.
 */

/************************************************************************/
/*                        OGR_F_GetGeometryRef()                        */
/************************************************************************/

/**
 * Fetch an handle to feature geometry.
 *
 * This function is the same as the C++ method OGRFeature::GetGeometryRef().
 *
 * @param hFeat handle to the feature to get geometry from.
 * @return an handle to internal feature geometry.  This object should
 * not be modified.
 */

OGRGeometryH OGR_F_GetGeometryRef( OGRFeatureH hFeat )

{
    return ((OGRFeature *) hFeat)->GetGeometryRef();
}

/************************************************************************/
/*                               Clone()                                */
/************************************************************************/

/**
 * Duplicate feature.
 *
 * The newly created feature is owned by the caller, and will have it's own
 * reference to the OGRFeatureDefn.
 *
 * This method is the same as the C function OGR_F_Clone().
 *
 * @return new feature, exactly matching this feature.
 */

OGRFeature *OGRFeature::Clone()

{
    OGRFeature  *poNew = new OGRFeature( poDefn );

    poNew->SetGeometry( poGeometry );

    for( int i = 0; i < poDefn->GetFieldCount(); i++ )
    {
        poNew->SetField( i, pauFields + i );
    }

    if( GetStyleString() != NULL )
        poNew->SetStyleString(GetStyleString());

    poNew->SetFID( GetFID() );

    return poNew;
}

/************************************************************************/
/*                            OGR_F_Clone()                             */
/************************************************************************/

/**
 * Duplicate feature.
 *
 * The newly created feature is owned by the caller, and will have it's own
 * reference to the OGRFeatureDefn.
 *
 * This function is the same as the C++ method OGRFeature::Clone().
 *
 * @param hFeat handle to the feature to clone.
 * @return an handle to the new feature, exactly matching this feature.
 */

OGRFeatureH OGR_F_Clone( OGRFeatureH hFeat )

{
    return (OGRFeatureH) ((OGRFeature *) hFeat)->Clone();
}

/************************************************************************/
/*                           GetFieldCount()                            */
/************************************************************************/

/**
 * \fn int OGRFeature::GetFieldCount();
 *
 * Fetch number of fields on this feature.  This will always be the same
 * as the field count for the OGRFeatureDefn.
 *
 * This method is the same as the C function OGR_F_GetFieldCount().
 *
 * @return count of fields.
 */

/************************************************************************/
/*                        OGR_F_GetFieldCount()                         */
/************************************************************************/

/**
 * Fetch number of fields on this feature.  This will always be the same
 * as the field count for the OGRFeatureDefn.
 *
 * This function is the same as the C++ method OGRFeature::GetFieldCount().
 *
 * @param hFeat handle to the feature to get the fields count from.
 * @return count of fields.
 */

int OGR_F_GetFieldCount( OGRFeatureH hFeat )

{
    return ((OGRFeature *) hFeat)->GetFieldCount();
}

/************************************************************************/
/*                          GetFieldDefnRef()                           */
/************************************************************************/

/**
 * \fn OGRFieldDefn *OGRFeature::GetFieldDefnRef( int iField );
 *
 * Fetch definition for this field.
 *
 * This method is the same as the C function OGR_F_GetFieldDefnRef().
 *
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the field definition (from the OGRFeatureDefn).  This is an
 * internal reference, and should not be deleted or modified.
 */

/************************************************************************/
/*                       OGR_F_GetFieldDefnRef()                        */
/************************************************************************/

/**
 * Fetch definition for this field.
 *
 * This function is the same as the C++ method OGRFeature::GetFieldDefnRef().
 *
 * @param hFeat handle to the feature on which the field is found.
 * @param i the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return an handle to the field definition (from the OGRFeatureDefn).
 * This is an internal reference, and should not be deleted or modified.
 */

OGRFieldDefnH OGR_F_GetFieldDefnRef( OGRFeatureH hFeat, int i )

{
    return (OGRFieldDefnH) ((OGRFeature *) hFeat)->GetFieldDefnRef(i);
}

/************************************************************************/
/*                           GetFieldIndex()                            */
/************************************************************************/

/**
 * \fn int OGRFeature::GetFieldIndex( const char * pszName );
 * 
 * Fetch the field index given field name.
 *
 * This is a cover for the OGRFeatureDefn::GetFieldIndex() method. 
 *
 * This method is the same as the C function OGR_F_GetFieldIndex().
 *
 * @param pszName the name of the field to search for. 
 *
 * @return the field index, or -1 if no matching field is found.
 */

/************************************************************************/
/*                        OGR_F_GetFieldIndex()                         */
/************************************************************************/

/**
 * Fetch the field index given field name.
 *
 * This is a cover for the OGRFeatureDefn::GetFieldIndex() method. 
 *
 * This function is the same as the C++ method OGRFeature::GetFieldIndex().
 *
 * @param hFeat handle to the feature on which the field is found.
 * @param pszName the name of the field to search for. 
 *
 * @return the field index, or -1 if no matching field is found.
 */

int OGR_F_GetFieldIndex( OGRFeatureH hFeat, const char *pszName )

{
    return ((OGRFeature *) hFeat)->GetFieldIndex( pszName );
}

/************************************************************************/
/*                             IsFieldSet()                             */
/************************************************************************/

/**
 * \fn int OGRFeature::IsFieldSet( int iField );
 *
 * Test if a field has ever been assigned a value or not.
 *
 * This method is the same as the C function OGR_F_IsFieldSet().
 *
 * @param iField the field to test.
 *
 * @return TRUE if the field has been set, otherwise false.
 */

/************************************************************************/
/*                          OGR_F_IsFieldSet()                          */
/************************************************************************/

/**
 * Test if a field has ever been assigned a value or not.
 *
 * This function is the same as the C++ method OGRFeature::IsFieldSet().
 *
 * @param hFeat handle to the feature on which the field is.
 * @param iField the field to test.
 *
 * @return TRUE if the field has been set, otherwise false.
 */

int OGR_F_IsFieldSet( OGRFeatureH hFeat, int iField )

{
    return ((OGRFeature *)hFeat)->IsFieldSet( iField );
}

/************************************************************************/
/*                             UnsetField()                             */
/************************************************************************/

/**
 * Clear a field, marking it as unset.
 *
 * This method is the same as the C function OGR_F_UnsetField().
 *
 * @param iField the field to unset.
 */

void OGRFeature::UnsetField( int iField )

{
    OGRFieldDefn        *poFDefn = poDefn->GetFieldDefn( iField );

    CPLAssert( poFDefn != NULL || iField == -1 );
    if( poFDefn == NULL || !IsFieldSet(iField) )
        return;
    
    switch( poFDefn->GetType() )
    {
      case OFTRealList:
      case OFTIntegerList:
        CPLFree( pauFields[iField].IntegerList.paList );
        break;

      case OFTStringList:
        CSLDestroy( pauFields[iField].StringList.paList );
        break;

      case OFTString:
        CPLFree( pauFields[iField].String );
        break;

      case OFTBinary:
        CPLFree( pauFields[iField].Binary.paData );
        break;

      default:
        break;
    }

    pauFields[iField].Set.nMarker1 = OGRUnsetMarker;
    pauFields[iField].Set.nMarker2 = OGRUnsetMarker;
}

/************************************************************************/
/*                          OGR_F_UnsetField()                          */
/************************************************************************/

/**
 * Clear a field, marking it as unset.
 *
 * This function is the same as the C++ method OGRFeature::UnsetField().
 *
 * @param hFeat handle to the feature on which the field is.
 * @param iField the field to unset.
 */

void OGR_F_UnsetField( OGRFeatureH hFeat, int iField )

{
    ((OGRFeature *) hFeat)->UnsetField( iField );
}

/************************************************************************/
/*                           GetRawFieldRef()                           */
/************************************************************************/

/**
 * \fn OGRField *OGRFeature::GetRawFieldRef( int iField );
 *
 * Fetch a pointer to the internal field value given the index.  
 *
 * This method is the same as the C function OGR_F_GetRawFieldRef().
 *
 * @param iField the field to fetch, from 0 to GetFieldCount()-1.
 *
 * @return the returned pointer is to an internal data structure, and should
 * not be freed, or modified. 
 */