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package com.googlecode.javaewah;

/*
 * Copyright 2009-2013, Daniel Lemire, Cliff Moon, David McIntosh, Robert Becho, Google Inc., Veronika Zenz and Owen Kaser
 * Licensed under the Apache License, Version 2.0.
 */
/**
 * BitCounter is a fake bitset data structure. Instead of storing the actual
 * data, it only records the number of set bits.
 * 
 * @since 0.4.0
 * @author David McIntosh
 */

public final class BitCounter implements BitmapStorage {

  /**
   * Virtually add words directly to the bitmap
   * 
   * @param newdata
   *          the word
   */
  @Override
  public void add(final long newdata) {
    this.oneBits += Long.bitCount(newdata);
    return;
  }

  /**
   * virtually add several literal words.
   * 
   * @param data
   *          the literal words
   * @param start
   *          the starting point in the array
   * @param number
   *          the number of literal words to add
   */
  @Override 
  public void addStreamOfLiteralWords(long[] data, int start, int number) {
    for (int i = start; i < start + number; i++) {
      add(data[i]);
    }
    return;
  }

  /**
   * virtually add many zeroes or ones.
   * 
   * @param v
   *          zeros or ones
   * @param number
   *          how many to words add
   */
  @Override
public void addStreamOfEmptyWords(boolean v, long number) {
    if (v) {
      this.oneBits += number * EWAHCompressedBitmap.wordinbits;
    }
    return;
  }

  /**
   * virtually add several negated literal words.
   * 
   * @param data
   *          the literal words
   * @param start
   *          the starting point in the array
   * @param number
   *          the number of literal words to add
   */
  // @Override : causes problems with Java 1.5
  @Override
public void addStreamOfNegatedLiteralWords(long[] data, int start, int number) {
    for (int i = start; i < start + number; i++) {
      add(~data[i]);
    }
    return;
  }

  /**
   * As you act on this class, it records the number of set (true) bits.
   * 
   * @return number of set bits
   */
  public int getCount() {
    return this.oneBits;
  }

  /**
   * should directly set the sizeinbits field, but is effectively ignored in
   * this class.
   * 
   * @param bits
   *          number of bits
   */
  // @Override : causes problems with Java 1.5
  @Override
public void setSizeInBits(int bits) {
    // no action
  }

  private int oneBits;

}