/*
 * Copyright 1998-2014 University Corporation for Atmospheric Research/Unidata
 *
 *   Portions of this software were developed by the Unidata Program at the
 *   University Corporation for Atmospheric Research.
 *
 *   Access and use of this software shall impose the following obligations
 *   and understandings on the user. The user is granted the right, without
 *   any fee or cost, to use, copy, modify, alter, enhance and distribute
 *   this software, and any derivative works thereof, and its supporting
 *   documentation for any purpose whatsoever, provided that this entire
 *   notice appears in all copies of the software, derivative works and
 *   supporting documentation.  Further, UCAR requests that the user credit
 *   UCAR/Unidata in any publications that result from the use of this
 *   software or in any product that includes this software. The names UCAR
 *   and/or Unidata, however, may not be used in any advertising or publicity
 *   to endorse or promote any products or commercial entity unless specific
 *   written permission is obtained from UCAR/Unidata. The user also
 *   understands that UCAR/Unidata is not obligated to provide the user with
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 *
 *   THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR
 *   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *   DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
 *   INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
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 *   WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
 */

package ucar.nc2.util.cache;

import net.jcip.annotations.Immutable;
import ucar.nc2.util.Misc;

import java.util.Formatter;

/**
 * Integer arrays that are constant or are sequential can be stored without storing all of the elements.
 * Keeps memory requirements down in PartitionVariable
 *
 * @author caron
 * @since 11/4/2014
 */
@Immutable
public class SmartArrayInt {
  private final int[] raw;
  private final int start;
  private final boolean isOrdered;   // if elem[i] = constant + i;
  private final boolean isConstant;  // if elem[i] = constant
  private final int n;

  public SmartArrayInt(int[] raw) {
    this.n = raw.length;
    if (raw.length == 0) {
      this.start = -1;
      this.isOrdered = false;
      this.isConstant = true;
      this.raw = null;
      return;
    }
    boolean isO = true;
    boolean isC = true;
    this.start = raw[0];
    for (int i=0; i<raw.length; i++) {
      if (raw[i] != start+i) isO = false;
      if (raw[i] != start) isC = false;
    }

    this.raw = (!isO && !isC) ? raw : null;
    this.isOrdered = isO;
    this.isConstant = isC;
  }

  public int get(int idx) {
    if (isConstant) return start;
    if (isOrdered) return start+idx;
    return raw[idx];
  }

  public int getN() {
    return n;
  }

  public void show(Formatter f) {
    if (isConstant) f.format("isConstant="+start);
    else if (isOrdered) f.format("isOrdered start="+start);
    else Misc.showInts(raw, f);
  }

  /**
   * Find the index of the want value
   * @param want  value wanted
   * @return < 0 if not found, else the index. If duplicates, then return any match
   */
  public int findIdx(int want) {
    if (isConstant) return (want == start)  ? 0 : -1;
    if (isOrdered) return want - start;
    for (int i=0; i<raw.length; i++)
      if (raw[i] == want) return i;
    return -1;
  }

}