/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2003-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* 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.
*/
package org.geotools.data;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.CharBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import org.geotools.factory.Hints;
import org.geotools.referencing.ReferencingFactoryFinder;
import org.geotools.resources.NIOUtilities;
import org.opengis.referencing.FactoryException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
/**
* @author Simone Giannecchini
* @since 2.3
* @source $URL:
* http://svn.geotools.org/geotools/trunk/gt/module/main/src/org/geotools/data/PrjFileReader.java $
*/
public class PrjFileReader {
ByteBuffer buffer;
ReadableByteChannel channel;
CharBuffer charBuffer;
CharsetDecoder decoder;
CoordinateReferenceSystem crs;
/**
* Load the index file from the given channel.
*
* @param channel
* The channel to read from.
* @throws IOException
* If an error occurs.
*/
public PrjFileReader(ReadableByteChannel channel) throws IOException,
FactoryException {
this(channel, null);
}
/**
* Load the index file from the given channel.
*
* @param channel
* The channel to read from.
* @param hints
*
* @throws IOException
* If an error occurs.
*/
public PrjFileReader(ReadableByteChannel channel, final Hints hints)
throws IOException, FactoryException {
Charset chars = Charset.forName("ISO-8859-1");
decoder = chars.newDecoder();
this.channel = channel;
init();
// ok, everything is ready...
decoder.decode(buffer, charBuffer, true);
buffer.limit(buffer.capacity());
charBuffer.flip();
crs = ReferencingFactoryFinder.getCRSFactory(hints).createFromWKT(charBuffer.toString());
}
/**
* Return the Coordinate Reference System retrieved by this reader.
*
* @deprecated use {@link #getCoordinateReferenceSystem()}.
*/
public CoordinateReferenceSystem getCoodinateSystem() {
return crs;
}
/**
* Return the Coordinate Reference System retrieved by this reader.
*
* @return the Coordinate Reference System
*/
public CoordinateReferenceSystem getCoordinateReferenceSystem() {
return crs;
}
private int fill(ByteBuffer buffer, ReadableByteChannel channel)
throws IOException {
int r = buffer.remaining();
// channel reads return -1 when EOF or other error
// because they a non-blocking reads, 0 is a valid return value!!
while (buffer.remaining() > 0 && r != -1) {
r = channel.read(buffer);
}
if (r == -1) {
buffer.limit(buffer.position());
}
return r;
}
private void init() throws IOException {
// create the ByteBuffer
// if we have a FileChannel, lets map it
if (channel instanceof FileChannel) {
FileChannel fc = (FileChannel) channel;
buffer = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
buffer.position((int) fc.position());
} else {
// Some other type of channel
// start with a 8K buffer, should be more than adequate
int size = 8 * 1024;
// if for some reason its not, resize it
// size = header.getRecordLength() > size ? header.getRecordLength()
// : size;
buffer = ByteBuffer.allocateDirect(size);
// fill it and reset
fill(buffer, channel);
buffer.flip();
}
// The entire file is in little endian
buffer.order(ByteOrder.LITTLE_ENDIAN);
charBuffer = CharBuffer.allocate(8 * 1024);
Charset chars = Charset.forName("ISO-8859-1");
decoder = chars.newDecoder();
}
public void close() throws IOException {
NIOUtilities.clean(buffer); // will close if a MappedByteBuffer
if (channel.isOpen()) {
channel.close();
}
}
}