org.kalypso.grid.BinaryGeoGridReader.java Source code

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Here is the source code for org.kalypso.grid.BinaryGeoGridReader.java

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/*----------------    FILE HEADER KALYPSO ------------------------------------------
 *
 *  This file is part of kalypso.
 *  Copyright (C) 2004 by:
 * 
 *  Technical University Hamburg-Harburg (TUHH)
 *  Institute of River and coastal engineering
 *  Denickestrae 22
 *  21073 Hamburg, Germany
 *  http://www.tuhh.de/wb
 * 
 *  and
 *  
 *  Bjoernsen Consulting Engineers (BCE)
 *  Maria Trost 3
 *  56070 Koblenz, Germany
 *  http://www.bjoernsen.de
 * 
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 *  Contact:
 * 
 *  E-Mail:
 *  belger@bjoernsen.de
 *  schlienger@bjoernsen.de
 *  v.doemming@tuhh.de
 *   
 *  ---------------------------------------------------------------------------*/
package org.kalypso.grid;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.net.URL;

import org.apache.commons.io.FileUtils;
import org.kalypso.contribs.eclipse.core.resources.ResourceUtilities;
import org.kalypsodeegree.model.geometry.ByteUtils;

import com.vividsolutions.jts.geom.Coordinate;

/**
 * @author barbarins
 */
public class BinaryGeoGridReader extends AbstractDelegatingGeoGrid {
    private static Integer BLOCK_SIZE = 1024 * 1024 / 2;

    protected byte[] m_blockData;

    protected BufferedInputStream m_gridStream;

    protected int m_scale;

    private int m_linesTotal;

    private int m_lineLen;

    private int m_blockStart;

    private int m_blockEnd;

    private int m_linesInBlock;

    public BinaryGeoGridReader(final IGeoGrid inputGrid, final URL pUrl) throws IOException {
        super(inputGrid);

        File fileFromUrl = ResourceUtilities.findJavaFileFromURL(pUrl);
        /* Tries to find a file from the given url. */
        if (fileFromUrl == null)
            fileFromUrl = FileUtils.toFile(pUrl);

        m_gridStream = new BufferedInputStream(new FileInputStream(fileFromUrl));

        // skip header
        /* Read header */
        m_gridStream.skip(12);
        final byte[] lScaleBuff = new byte[4];
        read(lScaleBuff, 1);
        m_scale = ByteUtils.readBEInt(lScaleBuff, 0);

        try {
            m_linesTotal = getSizeY();
            m_lineLen = getSizeX() * 4;
        } catch (final GeoGridException e) {
            e.printStackTrace();
        }

        // block_size is set to "optimal" size of the buffer from start on
        m_linesInBlock = BLOCK_SIZE / m_lineLen;

        if (m_linesInBlock >= m_linesTotal)
            m_linesInBlock = m_linesTotal;

        if (m_linesInBlock == 0)
            m_linesInBlock = 1;

        BLOCK_SIZE = m_linesInBlock * m_lineLen;

        m_blockData = new byte[BLOCK_SIZE];

        readNextBlock();
        m_blockStart = 0;
        m_blockEnd = m_linesInBlock - 1;
    }

    public int getScale() {
        return m_scale;
    }

    @Override
    public void close() {
        try {
            m_gridStream.close();
        } catch (final IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void dispose() {
        super.dispose();
        close();
    }

    private void read(final byte[] blockData, final int items) throws IOException {
        m_gridStream.read(blockData, 0, items * 4);
    }

    private void readNextBlock() {
        try {
            m_gridStream.read(m_blockData, 0, BLOCK_SIZE);
        } catch (final IOException e) {
            e.printStackTrace();
        }

        m_blockStart += m_linesInBlock;
        m_blockEnd += m_linesInBlock;
    }

    @Override
    public double getValue(final int x, final int y) {
        if (y < m_blockStart)
            return Double.NaN;

        while (y > m_blockEnd) {
            readNextBlock();
        }

        final int index = (y - m_blockStart) * (m_lineLen / 4) + x;
        final int z = ByteUtils.readBEInt(m_blockData, index * 4);

        if (z == Integer.MIN_VALUE /* NO_DATA */)
            return Double.NaN;

        final BigDecimal decimal = new BigDecimal(BigInteger.valueOf(z), m_scale);
        final double value = decimal.doubleValue();

        return value;
    }

    @Override
    public IGeoWalkingStrategy getWalkingStrategy() {
        return new OptimizedGeoGridWalkingStrategy();
    }

    @Override
    public double getValue(final Coordinate crd) throws GeoGridException {
        final GeoGridCell cell = GeoGridUtilities.cellFromPosition(this, crd);
        return getValue(cell.x, cell.y);
    }

}