IlvShapeFileIndex Class Reference

This class allows applications to take advantage of ESRI Shapefile index files (.shx files).
More...

#include <ilviews/maps/format/shapefile/shpindex.h>

Public Member Functions
	IlvShapeFileIndex (const char *shxFileName)
	Initializes an IlvShapeFileIndex from the .shx file specified. More...
	IlvShapeFileIndex (istream &istr)
	Initializes an IlvShapeFileIndex from an istream. More...
IlvMapsError	getInitStatus () const
	Checks the initialization status of this reader. More...
IlBoolean	getLowerRightCorner (IlvCoordinate &result) const
	Returns the lower right corner of the rectangle containing all the map features of the shape file corresponding to this index reader. More...
IlInt	getRecordCount () const
	Returns the number of objects in this index. More...
IlvMapsError	getRecordLength (IlInt index, IlInt &length)
	Retrieves the record length of the object at the specified index. More...
IlvMapsError	getRecordOffset (IlInt index, IlInt &offset)
	Retrieves the file offset of the object at the specified index. More...
IlBoolean	getUpperLeftCorner (IlvCoordinate &result) const
	Returns the upper left corner of the rectangle containing all the map features of the shape file corresponding to this index reader. More...

Protected Member Functions
const IlvMapInput &	getInput () const
	Returns the map input of this reader. More...
virtual void	setInitStatus (IlvMapsError status)
	Sets the initialization status of this reader. More...

Detailed Description

This class allows applications to take advantage of ESRI Shapefile index files (.shx files).

Library: ilvmaps
Index files allow direct access to geometries in the main Shapefile (.shp file). Index files map record indexes to file offsets.

Index files are typically used to load geometries on demand.

Constructor & Destructor Documentation

IlvShapeFileIndex() [1/2]

IlvShapeFileIndex::IlvShapeFileIndex

(

const char *

shxFileName

)

Initializes an IlvShapeFileIndex from the .shx file specified.

Parameters

shxFileName

The file name of the .shx file.

IlvShapeFileIndex() [2/2]

IlvShapeFileIndex::IlvShapeFileIndex

(

istream &

istr

)

Initializes an IlvShapeFileIndex from an istream.

Parameters

istr	The input stream opened on the shape data.

Member Function Documentation

getInitStatus()

IlvMapsError IlvShapeFileIndex::getInitStatus

(

)

const

Checks the initialization status of this reader.

Returns

IlvMaps::NoError() if the initialization of this reader is successful, or an error if an error occurred during the initialization.

getInput()

const IlvMapInput& IlvShapeFileIndex::getInput ( ) const

protected

Returns the map input of this reader.

Returns

A reference to the IlvMapInput of the reader.

getLowerRightCorner()

IlBoolean IlvShapeFileIndex::getLowerRightCorner

(

IlvCoordinate &

result

)

const

Returns the lower right corner of the rectangle containing all the map features of the shape file corresponding to this index reader.

Parameters

result

Set to the result on return.

Returns

IlFalse if the lower right corner is unknown.

getRecordCount()

IlInt IlvShapeFileIndex::getRecordCount

(

)

const

Returns the number of objects in this index.

Returns

The number of objects in this index.

getRecordLength()

IlvMapsError IlvShapeFileIndex::getRecordLength	(	IlInt	index,
		IlInt &	length
	)

Retrieves the record length of the object at the specified index.

The index of objects is in the range [0, getRecordCount()].

Note

The length is specified as the content length of the record. It does not include the 4 byte header.

Parameters

index	The index of objects.
length	The returned length, in bytes.

Returns

IlvMaps::NoError() if no error occurs.

getRecordOffset()

IlvMapsError IlvShapeFileIndex::getRecordOffset	(	IlInt	index,
		IlInt &	offset
	)

Retrieves the file offset of the object at the specified index.

The index of objects is in the range [0, getRecordCount()].

The file offset is expressed in bytes, from the start of the files. As there is a 100 bytes header in the .shx file, the index of the first object is at offset 100.

Parameters

index	The index of the objects.
offset	The returned offset.

getUpperLeftCorner()

IlBoolean IlvShapeFileIndex::getUpperLeftCorner

(

IlvCoordinate &

result

)

const

Returns the upper left corner of the rectangle containing all the map features of the shape file corresponding to this index reader.

Parameters

result

Set to the result on return.

Returns

IlFalse if the upper left corner is unknown.

setInitStatus()

virtual void IlvShapeFileIndex::setInitStatus ( IlvMapsError  status )

protectedvirtual

Sets the initialization status of this reader.

Parameters

status

The new initialization status.