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Java library to automate the analysis of Android heap dumps.

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/**
 * ****************************************************************************
 * Copyright (c) 2008 SAP AG.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * SAP AG - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.mat.collect;

import java.io.Serializable;

/**
 * This class manages huge bit fields. It is much faster than
 * {@link java.util.BitSet} and was specifically developed to be used with huge
 * bit sets in ISnapshot (e.g. needed in virtual GC traces). Out of performance
 * reasons no method does any parameter checking, i.e. only valid values are
 * expected.
 */
public final class BitField implements Serializable {
  private static final long serialVersionUID = 1L;

  private int[] bits;

  /**
   * Creates a bit field with the given number of bits. Size is expected to be
   * positive - out of performance reasons no checks are done!
   */
  public BitField(int size) {
    bits = new int[(((size) - 1) >>> 0x5) + 1];
  }

  /**
   * Sets the bit on the given index. Index is expected to be in range - out
   * of performance reasons no checks are done!
   */
  public final void set(int index) {
    bits[index >>> 0x5] |= (1 << (index & 0x1f));
  }

  /**
   * Clears the bit on the given index. Index is expected to be in range - out
   * of performance reasons no checks are done!
   */
  public final void clear(int index) {
    bits[index >>> 0x5] &= ~(1 << (index & 0x1f));
  }

  /**
   * Gets the bit on the given index. Index is expected to be in range - out
   * of performance reasons no checks are done!
   */
  public final boolean get(int index) {
    return (bits[index >>> 0x5] & (1 << (index & 0x1f))) != 0;
  }
}