com.yahoo.sketches.theta.HeapUpdateSketch Maven / Gradle / Ivy

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/*
 * Copyright 2015-16, Yahoo! Inc.
 * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms.
 */

package com.yahoo.sketches.theta;

import static com.yahoo.sketches.Util.MIN_LG_NOM_LONGS;
import static com.yahoo.sketches.theta.PreambleUtil.EMPTY_FLAG_MASK;
import static com.yahoo.sketches.theta.PreambleUtil.SER_VER;
import static com.yahoo.sketches.theta.PreambleUtil.insertCurCount;
import static com.yahoo.sketches.theta.PreambleUtil.insertFamilyID;
import static com.yahoo.sketches.theta.PreambleUtil.insertFlags;
import static com.yahoo.sketches.theta.PreambleUtil.insertLgArrLongs;
import static com.yahoo.sketches.theta.PreambleUtil.insertLgNomLongs;
import static com.yahoo.sketches.theta.PreambleUtil.insertP;
import static com.yahoo.sketches.theta.PreambleUtil.insertPreLongs;
import static com.yahoo.sketches.theta.PreambleUtil.insertSeedHash;
import static com.yahoo.sketches.theta.PreambleUtil.insertSerVer;
import static com.yahoo.sketches.theta.PreambleUtil.insertThetaLong;

import com.yahoo.memory.NativeMemory;
import com.yahoo.sketches.ResizeFactor;
import com.yahoo.sketches.Util;

/**
 * The parent class for Heap Updatable Theta Sketches.
 *
 * @author Lee Rhodes
 */
abstract class HeapUpdateSketch extends UpdateSketch {
  final int lgNomLongs_;
  private final long seed_;
  private final float p_;
  private final ResizeFactor rf_;

  HeapUpdateSketch(final int lgNomLongs, final long seed, final float p, final ResizeFactor rf) {
    lgNomLongs_ = Math.max(lgNomLongs, MIN_LG_NOM_LONGS);
    seed_ = seed;
    p_ = p;
    rf_ = rf;
  }

  //Sketch

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

  @Override
  public ResizeFactor getResizeFactor() {
    return rf_;
  }

  //restricted methods

  @Override
  int getLgNomLongs() {
    return lgNomLongs_;
  }

  @Override
  long getSeed() {
    return seed_;
  }

  @Override
  float getP() {
    return p_;
  }

  @Override
  short getSeedHash() {
    return Util.computeSeedHash(getSeed());
  }

  byte[] toByteArray(final int preLongs, final byte familyID) {
    if (isDirty()) { rebuild(); }
    final int preBytes = (preLongs << 3) & 0X3F;
    final int dataBytes = getCurrentDataLongs(false) << 3;
    final byte[] byteArrOut = new byte[preBytes + dataBytes];
    final NativeMemory memOut = new NativeMemory(byteArrOut);
    final Object memObj = memOut.array(); //may be null
    final long memAdd = memOut.getCumulativeOffset(0L);

    //preamble first 8 bytes. Note: only compact can be reduced to 8 bytes.
    final int lgRf = this.getResizeFactor().lg() & 3;
    final byte byte0 = (byte) ((lgRf << 6) | preLongs);
    insertPreLongs(memObj, memAdd, byte0);
    insertSerVer(memObj, memAdd, SER_VER);
    insertFamilyID(memObj, memAdd, familyID);
    insertLgNomLongs(memObj, memAdd, this.getLgNomLongs());
    insertLgArrLongs(memObj, memAdd, this.getLgArrLongs());
    insertSeedHash(memObj, memAdd, this.getSeedHash());

    insertCurCount(memObj, memAdd, this.getRetainedEntries(true));
    insertP(memObj, memAdd, this.getP());
    insertThetaLong(memObj, memAdd, this.getThetaLong());

    //Flags: BigEnd=0, ReadOnly=0, Empty=X, compact=0, ordered=0
    final byte flags = this.isEmpty() ? (byte) EMPTY_FLAG_MASK : 0;
    insertFlags(memObj, memAdd, flags);

    //Data
    final int arrLongs = 1 << this.getLgArrLongs();
    final long[] cache = this.getCache();
    memOut.putLongArray(preBytes, cache, 0, arrLongs); //load byteArrOut

    return byteArrOut;
  }

}