suballocatedintvector.java

来自「JAVA 所有包」· Java 代码 · 共 556 行 · 第 1/2 页

      int offset=at&m_MASK;
      int push;
      
      // ***** Easier to work down from top?
      while(index<=maxindex)
      {
        int copylen=m_blocksize-offset-1;
        int[] block=m_map[index];
        if(null==block)
        {
          push=0;
          block=m_map[index]=new int[m_blocksize];
        }
        else
        {
          push=block[m_blocksize-1];
          System.arraycopy(block, offset , block, offset+1, copylen);
        }
        block[offset]=value;
        value=push;
        offset=0;
        ++index;
      }
    }
  }

  /**
   * Wipe it out. Currently defined as equivalent to setSize(0).
   */
  public void removeAllElements()
  {
    m_firstFree = 0;
    m_buildCache = m_map0;
    m_buildCacheStartIndex = 0;
  }

  /**
   * Removes the first occurrence of the argument from this vector.
   * If the object is found in this vector, each component in the vector
   * with an index greater or equal to the object's index is shifted
   * downward to have an index one smaller than the value it had
   * previously.
   *
   * @param s Int to remove from array
   *
   * @return True if the int was removed, false if it was not found
   */
  private  boolean removeElement(int s)
  {
    int at=indexOf(s,0);
    if(at<0)
      return false;
    removeElementAt(at);
    return true;
  }

  /**
   * Deletes the component at the specified index. Each component in
   * this vector with an index greater or equal to the specified
   * index is shifted downward to have an index one smaller than
   * the value it had previously.
   *
   * @param at index of where to remove and int
   */
  private  void removeElementAt(int at)
  {
        // No point in removing elements that "don't exist"...  
    if(at<m_firstFree)
    {
      int index=at>>>m_SHIFT;
      int maxindex=m_firstFree>>>m_SHIFT;
      int offset=at&m_MASK;
      
      while(index<=maxindex)
      {
        int copylen=m_blocksize-offset-1;
        int[] block=m_map[index];
        if(null==block)
          block=m_map[index]=new int[m_blocksize];
        else
          System.arraycopy(block, offset+1, block, offset, copylen);
        if(index<maxindex)
        {
          int[] next=m_map[index+1];
          if(next!=null)
            block[m_blocksize-1]=(next!=null) ? next[0] : 0;
        }
        else
          block[m_blocksize-1]=0;
        offset=0;
        ++index;
      }
    }
    --m_firstFree;
  }

  /**
   * Sets the component at the specified index of this vector to be the
   * specified object. The previous component at that position is discarded.
   *
   * The index must be a value greater than or equal to 0 and less
   * than the current size of the vector.
   *
   * @param value object to set
   * @param at    Index of where to set the object
   */
  public void setElementAt(int value, int at)
  {
    if(at<m_blocksize)
      m_map0[at]=value;
    else
    {
      int index=at>>>m_SHIFT;
      int offset=at&m_MASK;
        
      if(index>=m_map.length)
      {
	int newsize=index+m_numblocks;
	int[][] newMap=new int[newsize][];
	System.arraycopy(m_map, 0, newMap, 0, m_map.length);
	m_map=newMap;
      }

      int[] block=m_map[index];
      if(null==block)
	block=m_map[index]=new int[m_blocksize];
      block[offset]=value;
    }

    if(at>=m_firstFree)
      m_firstFree=at+1;
  }
  

  /**
   * Get the nth element. This is often at the innermost loop of an
   * application, so performance is critical.
   *
   * @param i index of value to get
   *
   * @return value at given index. If that value wasn't previously set,
   * the result is undefined for performance reasons. It may throw an
   * exception (see below), may return zero, or (if setSize has previously
   * been used) may return stale data.
   *
   * @throws ArrayIndexOutOfBoundsException if the index was _clearly_
   * unreasonable (negative, or past the highest block).
   *
   * @throws NullPointerException if the index points to a block that could
   * have existed (based on the highest index used) but has never had anything
   * set into it.
   * %REVIEW% Could add a catch to create the block in that case, or return 0.
   * Try/Catch is _supposed_ to be nearly free when not thrown to. Do we
   * believe that? Should we have a separate safeElementAt?
   */
  public int elementAt(int i)
  {
    // This is actually a significant optimization!
    if(i<m_blocksize)
      return m_map0[i];

    return m_map[i>>>m_SHIFT][i&m_MASK];
  }

  /**
   * Tell if the table contains the given node.
   *
   * @param s object to look for
   *
   * @return true if the object is in the list
   */
  private  boolean contains(int s)
  {
    return (indexOf(s,0) >= 0);
  }

  /**
   * Searches for the first occurence of the given argument,
   * beginning the search at index, and testing for equality
   * using the equals method.
   *
   * @param elem object to look for
   * @param index Index of where to begin search
   * @return the index of the first occurrence of the object
   * argument in this vector at position index or later in the
   * vector; returns -1 if the object is not found.
   */
  public int indexOf(int elem, int index)
  {
        if(index>=m_firstFree)
                return -1;
          
    int bindex=index>>>m_SHIFT;
    int boffset=index&m_MASK;
    int maxindex=m_firstFree>>>m_SHIFT;
    int[] block;
    
    for(;bindex<maxindex;++bindex)
    {
      block=m_map[bindex];
      if(block!=null)
        for(int offset=boffset;offset<m_blocksize;++offset)
          if(block[offset]==elem)
            return offset+bindex*m_blocksize;
      boffset=0; // after first
    }
    // Last block may need to stop before end
    int maxoffset=m_firstFree&m_MASK;
    block=m_map[maxindex];
    for(int offset=boffset;offset<maxoffset;++offset)
      if(block[offset]==elem)
        return offset+maxindex*m_blocksize;

    return -1;    
  }

  /**
   * Searches for the first occurence of the given argument,
   * beginning the search at index, and testing for equality
   * using the equals method.
   *
   * @param elem object to look for
   * @return the index of the first occurrence of the object
   * argument in this vector at position index or later in the
   * vector; returns -1 if the object is not found.
   */
  public int indexOf(int elem)
  {
    return indexOf(elem,0);
  }

  /**
   * Searches for the first occurence of the given argument,
   * beginning the search at index, and testing for equality
   * using the equals method.
   *
   * @param elem Object to look for
   * @return the index of the first occurrence of the object
   * argument in this vector at position index or later in the
   * vector; returns -1 if the object is not found.
   */
  private  int lastIndexOf(int elem)
  {
    int boffset=m_firstFree&m_MASK;
    for(int index=m_firstFree>>>m_SHIFT;
        index>=0;
        --index)
    {
      int[] block=m_map[index];
      if(block!=null)
        for(int offset=boffset; offset>=0; --offset)
          if(block[offset]==elem)
            return offset+index*m_blocksize;
      boffset=0; // after first
    }
    return -1;
  }
  
  /**
   * Return the internal m_map0 array
   * @return the m_map0 array
   */
  public final int[] getMap0()
  {
    return m_map0;
  }
  
  /**
   * Return the m_map double array
   * @return the internal map of array of arrays 
   */
  public final int[][] getMap()
  {
    return m_map;
  }
  
}