org.locationtech.geowave.adapter.raster.stats.HistogramConfig Maven / Gradle / Ivy

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/**
 * Copyright (c) 2013-2020 Contributors to the Eclipse Foundation
 *
 *  See the NOTICE file distributed with this work for additional information regarding copyright
 * ownership. All rights reserved. This program and the accompanying materials are made available
 * under the terms of the Apache License, Version 2.0 which accompanies this distribution and is
 * available at http://www.apache.org/licenses/LICENSE-2.0.txt
 */
package org.locationtech.geowave.adapter.raster.stats;

import java.awt.image.SampleModel;
import java.nio.ByteBuffer;
import org.geotools.coverage.TypeMap;
import org.geotools.util.NumberRange;
import org.locationtech.geowave.core.index.VarintUtils;
import org.locationtech.geowave.core.index.persist.Persistable;

public class HistogramConfig implements Persistable {
  private static final int MAX_DEFAULT_NUM_BINS = 65536;
  private double[] highValues;
  private double[] lowValues;
  private int[] numBins;

  public HistogramConfig() {}

  public HistogramConfig(final SampleModel sampleModel) {
    final int numBands = sampleModel.getNumBands();
    highValues = new double[numBands];
    lowValues = new double[numBands];
    numBins = new int[numBands];
    for (int b = 0; b < numBands; b++) {
      final NumberRange range = TypeMap.getRange(TypeMap.getSampleDimensionType(sampleModel, b));
      int bins;
      double min = range.getMinimum(true);
      double max = range.getMaximum(true);
      if (Double.isInfinite(min)
          || Double.isInfinite(max)
          || Double.isNaN(min)
          || Double.isNaN(max)) {
        // in this case there is no reasonable default, just use a range
        // of 0 to 1 as a placeholder
        min = 0;
        max = 1;
        bins = MAX_DEFAULT_NUM_BINS;
      } else {
        bins = (int) Math.min(MAX_DEFAULT_NUM_BINS, (max - min) + 1);
      }
      lowValues[b] = min;
      highValues[b] = max;
      numBins[b] = bins;
    }
  }

  public HistogramConfig(final double[] highValues, final double[] lowValues, final int[] numBins) {
    this.highValues = highValues;
    this.lowValues = lowValues;
    this.numBins = numBins;
  }

  @Override
  public byte[] toBinary() {
    int byteLength = 0;
    for (int b = 0; b < highValues.length; b++) {
      byteLength += 16 + VarintUtils.unsignedIntByteLength(numBins[b]);
    }
    byteLength += VarintUtils.unsignedIntByteLength(highValues.length);
    // constant number of bands, 8 + 8 + 4 bytes per band (high,low, and
    // numBins), and 4 more for the total bands
    final ByteBuffer buf = ByteBuffer.allocate(byteLength);
    VarintUtils.writeUnsignedInt(highValues.length, buf);
    for (int b = 0; b < highValues.length; b++) {
      buf.putDouble(lowValues[b]);
      buf.putDouble(highValues[b]);
      VarintUtils.writeUnsignedInt(numBins[b], buf);
    }
    return buf.array();
  }

  public double[] getHighValues() {
    return highValues;
  }

  public double[] getLowValues() {
    return lowValues;
  }

  public int[] getNumBins() {
    return numBins;
  }

  @Override
  public void fromBinary(final byte[] bytes) {
    final ByteBuffer buf = ByteBuffer.wrap(bytes);
    final int numBands = VarintUtils.readUnsignedInt(buf);
    highValues = new double[numBands];
    lowValues = new double[numBands];
    numBins = new int[numBands];
    for (int b = 0; b < numBands; b++) {
      lowValues[b] = buf.getDouble();
      highValues[b] = buf.getDouble();
      numBins[b] = VarintUtils.readUnsignedInt(buf);
    }
  }
}