HillIndexGraphStorage.java

/*  This file is part of Openrouteservice.
 *
 *  Openrouteservice 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, see <https://www.gnu.org/licenses/>.
 */
package org.heigit.ors.routing.graphhopper.extensions.storages;

import com.graphhopper.storage.DataAccess;
import com.graphhopper.storage.Directory;
import com.graphhopper.storage.Graph;
import com.graphhopper.storage.GraphExtension;

import java.util.Map;

public class HillIndexGraphStorage implements GraphExtension {
    private final int efHillIndex;

    private DataAccess orsEdges;
    protected int edgeEntryIndex = 0;
    protected int edgeEntryBytes;
    protected int edgesCount; // number of edges with custom values

    private int maxHillIndex = 15;

    private final byte[] byteValues;

    public HillIndexGraphStorage(Map<String, String> parameters) {
        efHillIndex = 0;

        if (parameters.containsKey("maximum_slope"))
            maxHillIndex = (int) Double.parseDouble(parameters.get("maximum_slope"));

        edgeEntryBytes = edgeEntryIndex + (maxHillIndex > 15 ? 2 : 1);
        edgesCount = 0;
        byteValues = new byte[2];
    }

    public void init(Graph graph, Directory dir) {
        if (edgesCount > 0)
            throw new AssertionError("The ORS storage must be initialized only once.");

        this.orsEdges = dir.find("ext_hillindex");
    }

    public HillIndexGraphStorage create(long initBytes) {
        orsEdges.create(initBytes * edgeEntryBytes);
        return this;
    }

    public void flush() {
        orsEdges.setHeader(0, edgeEntryBytes);
        orsEdges.setHeader(4, edgesCount);
        orsEdges.flush();
    }

    @Override
    public long getCapacity() {
        return orsEdges.getCapacity();
    }

    public void close() {
        orsEdges.close();
    }

    public int entries() {
        return edgesCount;
    }

    public boolean loadExisting() {
        if (!orsEdges.loadExisting())
            throw new IllegalStateException("Unable to load storage 'ext_hillindex'. corrupt file or directory?");

        edgeEntryBytes = orsEdges.getHeader(0);
        edgesCount = orsEdges.getHeader(4);
        return true;
    }

    private void ensureEdgesIndex(int edgeIndex) {
        orsEdges.ensureCapacity(((long) edgeIndex + 1) * edgeEntryBytes);
    }

    private int getHillIndex(int value) {
        return Math.min(value, maxHillIndex);
    }

    public void setEdgeValue(int edgeId, int hillIndex, int reverseHillIndex) {
        edgesCount++;
        ensureEdgesIndex(edgeId);

        if (hillIndex != 0 || reverseHillIndex != 0) {
            // add entry
            long edgePointer = (long) edgeId * edgeEntryBytes;
            if (maxHillIndex <= 15) {
                byteValues[0] = (byte) (getHillIndex(hillIndex) << 4 | (0x0F & getHillIndex(reverseHillIndex))); //hillIndex | (reverseHillIndex << 4))
                orsEdges.setBytes(edgePointer + efHillIndex, byteValues, 1);
            } else {
                byteValues[0] = (byte) getHillIndex(hillIndex);
                byteValues[1] = (byte) getHillIndex(reverseHillIndex);
                orsEdges.setBytes(edgePointer + efHillIndex, byteValues, 2);
            }
        }
    }

    public int getEdgeValue(int edgeId, boolean reverse, byte[] buffer) {
        long edgePointer = (long) edgeId * edgeEntryBytes;

        if (maxHillIndex <= 15) {
            orsEdges.getBytes(edgePointer + efHillIndex, buffer, 1);

            int value = buffer[0];
            if (value < 0)
                value = 256 + value;

            if (reverse)
                return (value >> 4) & 0xF;
            else
                return value & 0xF;
        } else {
            orsEdges.getBytes(edgePointer + efHillIndex, buffer, 2);

            return reverse ? buffer[1] : buffer[0];
        }
    }

    @Override
    public boolean isClosed() {
        return false;
    }
}