compoundfile.java

jxtl API Java中Excel的生成与导入解析参考文档

/*********************************************************************
*
*      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.read.biff;

import java.util.ArrayList;
import java.util.Iterator;

import common.Logger;

import jxl.WorkbookSettings;
import jxl.biff.BaseCompoundFile;
import jxl.biff.IntegerHelper;

/**
 * Reads in and defrags an OLE compound compound file
 * (Made public only for the PropertySets demo)
 */
public final class CompoundFile extends BaseCompoundFile
{
  /**
   * The logger
   */
  private static Logger logger = Logger.getLogger(CompoundFile.class);

  /**
   * The original OLE stream, organized into blocks, which can
   * appear at any physical location in the file
   */
  private byte[] data;
  /**
   * The number of blocks it takes to store the big block depot
   */
  private int numBigBlockDepotBlocks;
  /**
   * The start block of the small block depot
   */
  private int sbdStartBlock;
  /**
   * The start block of the root entry
   */
  private int rootStartBlock;
  /**
   * The header extension block
   */
  private int extensionBlock;
  /**
   * The number of header extension blocks
   */
  private int numExtensionBlocks;
  /**
   * The root entry
   */
  private byte[] rootEntry;
  /**
   * The sequence of blocks which comprise the big block chain
   */
  private int[] bigBlockChain;
  /**
   * The sequence of blocks which comprise the small block chain
   */
  private int[] smallBlockChain;
  /**
   * The chain of blocks which comprise the big block depot
   */
  private int[] bigBlockDepotBlocks;
  /**
   * The list of property sets
   */
  private ArrayList propertySets;

  /**
   * The workbook settings
   */
  private WorkbookSettings settings;

  /** 
   * The property storage root entry
   */
  private PropertyStorage rootEntryPropertyStorage;

  /**
   * Initializes the compound file
   *
   * @param d the raw data of the ole stream
   * @param ws the workbook settings
   * @exception BiffException
   */
  public CompoundFile(byte[] d, WorkbookSettings ws) throws BiffException
  {
    super();
    data = d;
    settings = ws;

    // First verify the OLE identifier
    for (int i = 0; i < IDENTIFIER.length; i++)
    {
      if (data[i] != IDENTIFIER[i])
      {
        throw new BiffException(BiffException.unrecognizedOLEFile);
      }
    }

    propertySets = new ArrayList();
    numBigBlockDepotBlocks = IntegerHelper.getInt
      (data[NUM_BIG_BLOCK_DEPOT_BLOCKS_POS],
       data[NUM_BIG_BLOCK_DEPOT_BLOCKS_POS + 1],
       data[NUM_BIG_BLOCK_DEPOT_BLOCKS_POS + 2],
       data[NUM_BIG_BLOCK_DEPOT_BLOCKS_POS + 3]);
    sbdStartBlock = IntegerHelper.getInt
      (data[SMALL_BLOCK_DEPOT_BLOCK_POS],
       data[SMALL_BLOCK_DEPOT_BLOCK_POS + 1],
       data[SMALL_BLOCK_DEPOT_BLOCK_POS + 2],
       data[SMALL_BLOCK_DEPOT_BLOCK_POS + 3]);
    rootStartBlock = IntegerHelper.getInt
      (data[ROOT_START_BLOCK_POS],
       data[ROOT_START_BLOCK_POS + 1],
       data[ROOT_START_BLOCK_POS + 2],
       data[ROOT_START_BLOCK_POS + 3]);
    extensionBlock = IntegerHelper.getInt
      (data[EXTENSION_BLOCK_POS],
       data[EXTENSION_BLOCK_POS + 1],
       data[EXTENSION_BLOCK_POS + 2],
       data[EXTENSION_BLOCK_POS + 3]);
    numExtensionBlocks = IntegerHelper.getInt
      (data[NUM_EXTENSION_BLOCK_POS],
       data[NUM_EXTENSION_BLOCK_POS + 1],
       data[NUM_EXTENSION_BLOCK_POS + 2],
       data[NUM_EXTENSION_BLOCK_POS + 3]);

    bigBlockDepotBlocks = new int[numBigBlockDepotBlocks];

    int pos = BIG_BLOCK_DEPOT_BLOCKS_POS;

    int bbdBlocks = numBigBlockDepotBlocks;

    if (numExtensionBlocks != 0)
    {
      bbdBlocks = (BIG_BLOCK_SIZE - BIG_BLOCK_DEPOT_BLOCKS_POS) / 4;
    }

    for (int i = 0; i < bbdBlocks; i++)
    {
      bigBlockDepotBlocks[i] = IntegerHelper.getInt
        (d[pos], d[pos + 1], d[pos + 2], d[pos + 3]);
      pos += 4;
    }

    for (int j = 0; j < numExtensionBlocks; j++)
    {
      pos = (extensionBlock + 1) * BIG_BLOCK_SIZE;
      int blocksToRead = Math.min(numBigBlockDepotBlocks - bbdBlocks,
                                  BIG_BLOCK_SIZE / 4 - 1);

      for (int i = bbdBlocks; i < bbdBlocks + blocksToRead; i++)
      {
        bigBlockDepotBlocks[i] = IntegerHelper.getInt
          (d[pos], d[pos + 1], d[pos + 2], d[pos + 3]);
        pos += 4;
      }

      bbdBlocks += blocksToRead;
      if (bbdBlocks < numBigBlockDepotBlocks)
      {
        extensionBlock = IntegerHelper.getInt
          (d[pos], d[pos + 1], d[pos + 2], d[pos + 3]);
      }
    }

    readBigBlockDepot();
    readSmallBlockDepot();

    rootEntry = readData(rootStartBlock);
    readPropertySets();
  }

  /**
   * Reads the big block depot entries
   */
  private void readBigBlockDepot()
  {
    int pos = 0;
    int index = 0;
    bigBlockChain = new int[numBigBlockDepotBlocks * BIG_BLOCK_SIZE / 4];

    for (int i = 0; i < numBigBlockDepotBlocks; i++)
    {
      pos = (bigBlockDepotBlocks[i] + 1) * BIG_BLOCK_SIZE;

      for (int j = 0; j < BIG_BLOCK_SIZE / 4; j++)
      {
        bigBlockChain[index] = IntegerHelper.getInt
          (data[pos], data[pos + 1], data[pos + 2], data[pos + 3]);
        pos += 4;
        index++;
      }
    }
  }

  /**
   * Reads the small block chain's depot entries
   */
  private void readSmallBlockDepot()
  {
    int pos = 0;
    int index = 0;
    int sbdBlock = sbdStartBlock;
    smallBlockChain = new int[0];

    // Some non-excel generators specify -1 for an empty small block depot
    // simply warn and return
    if (sbdBlock == -1)
    {
      logger.warn("invalid small block depot number");
      return;
    }

    while (sbdBlock != -2)
    {
      // Allocate some more space to the small block chain
      int[] oldChain = smallBlockChain;
      smallBlockChain = new int[smallBlockChain.length + BIG_BLOCK_SIZE / 4];
      System.arraycopy(oldChain, 0, smallBlockChain, 0, oldChain.length);

      pos = (sbdBlock + 1) * BIG_BLOCK_SIZE;

      for (int j = 0; j < BIG_BLOCK_SIZE / 4; j++)
      {
        smallBlockChain[index] = IntegerHelper.getInt
          (data[pos], data[pos + 1], data[pos + 2], data[pos + 3]);
        pos += 4;
        index++;
      }

      sbdBlock = bigBlockChain[sbdBlock];
    }
  }

  /**
   * Reads all the property sets
   */
  private void readPropertySets()
  {
    int offset = 0;
    byte[] d = null;

    while (offset < rootEntry.length)
    {
      d = new byte[PROPERTY_STORAGE_BLOCK_SIZE];
      System.arraycopy(rootEntry, offset, d, 0, d.length);
      PropertyStorage ps = new PropertyStorage(d);

      // sometimes the MAC Operating system leaves some property storage
      // names blank.  Contributed by Jacky
      if (ps.name == null || ps.name.length() == 0)
      {
        if (ps.type == ROOT_ENTRY_PS_TYPE)
        {
          ps.name = ROOT_ENTRY_NAME;
          logger.warn("Property storage name for " + ps.type + 
                      " is empty - setting to " + ROOT_ENTRY_NAME);
        } 
        else
        {
          if (ps.size != 0)
          {
            logger.warn("Property storage type " + ps.type + 
                        " is non-empty and has no associated name");
          }
        }
      }
      propertySets.add(ps);
      if (ps.name.equalsIgnoreCase(ROOT_ENTRY_NAME))
      {
        rootEntryPropertyStorage = ps;
      }
      offset += PROPERTY_STORAGE_BLOCK_SIZE;
    }

    if (rootEntryPropertyStorage == null)
    {
      rootEntryPropertyStorage = (PropertyStorage) propertySets.get(0);
    }
  }

  /**
   * Gets the defragmented stream from this ole compound file
   *
   * @param streamName the stream name to get