memfunc.java

一个非常有用的操作MCRSOFT EXCEL文件的工具。可以用JAVA方便的新建

/*********************************************************************
 *
 *      Copyright (C) 2002 Andrew Khan
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.biff.formula;

import java.util.Stack;

import common.Assert;
import jxl.WorkbookSettings;
import jxl.Sheet;
import jxl.biff.IntegerHelper;
/**
 * Indicates that the function doesn't evaluate to a constant reference
 */

class MemFunc extends Operand implements ParsedThing
{
  /**
   * The number of bytes in the subexpression
   */
  private int length;

  /**
   * The sub expression
   */
  private ParseItem[] subExpression;

  /**
   * Constructor
   */
  public MemFunc()
  {
  }

  /** 
   * Reads the ptg data from the array starting at the specified position
   *
   * @param data the RPN array
   * @param pos the current position in the array, excluding the ptg identifier
   * @return the number of bytes read
   */
  public int read(byte[] data, int pos)
  {
    length = IntegerHelper.getInt(data[pos], data[pos+1]);
    return 2;
  }

  /** 
   * Gets the operands for this operator from the stack
   */
  public void getOperands(Stack s)
  {
  }

  public void getString(StringBuffer buf)
  {
    if (subExpression.length == 1)
    {
      subExpression[0].getString(buf);
    }
    else if (subExpression.length == 2)
    {
      subExpression[1].getString(buf);
      buf.append(':');
      subExpression[0].getString(buf);
    }
  }

  /**
   * Gets the token representation of this item in RPN.  The Attribute
   * token is a special case, which overrides anything useful we could do
   * in the base class
   *
   * @return the bytes applicable to this formula
   */
  byte[] getBytes()
  {
    return null;
  }


  /**
   * Gets the precedence for this operator.  Operator precedents run from 
   * 1 to 5, one being the highest, 5 being the lowest
   *
   * @return the operator precedence
   */
  int getPrecedence()
  {
    return 5;
  }

  /**
   * Accessor for the length
   *
   * @return the length of the subexpression
   */
  public int getLength()
  {
    return length;
  }

  public void setSubExpression(ParseItem[] pi)
  {
    subExpression = pi;
  }
}