headerblockwriter.java

Office格式转换代码

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache POI" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache POI", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.poi.poifs.storage;

import java.io.*;

import java.util.*;

import org.apache.poi.poifs.common.POIFSConstants;
import org.apache.poi.util.IntegerField;
import org.apache.poi.util.LittleEndianConsts;
import org.apache.poi.util.LongField;
import org.apache.poi.util.ShortField;

/**
 * The block containing the archive header
 *
 * @author Marc Johnson (mjohnson at apache dot org)
 */

public class HeaderBlockWriter
    extends BigBlock
    implements HeaderBlockConstants
{
    private static final byte _default_value = ( byte ) 0xFF;

    // number of big block allocation table blocks (int)
    private IntegerField      _bat_count;

    // start of the property set block (int index of the property set
    // chain's first big block)
    private IntegerField      _property_start;

    // start of the small block allocation table (int index of small
    // block allocation table's first big block)
    private IntegerField      _sbat_start;

    // number of big blocks holding the small block allocation table
    private IntegerField      _sbat_block_count;

    // big block index for extension to the big block allocation table
    private IntegerField      _xbat_start;
    private IntegerField      _xbat_count;
    private byte[]            _data;

    /**
     * Create a single instance initialized with default values
     */

    public HeaderBlockWriter()
    {
        _data = new byte[ POIFSConstants.BIG_BLOCK_SIZE ];
        Arrays.fill(_data, _default_value);
        new LongField(_signature_offset, _signature, _data);
        new IntegerField(0x08, 0, _data);
        new IntegerField(0x0c, 0, _data);
        new IntegerField(0x10, 0, _data);
        new IntegerField(0x14, 0, _data);
        new ShortField(0x18, ( short ) 0x3b, _data);
        new ShortField(0x1a, ( short ) 0x3, _data);
        new ShortField(0x1c, ( short ) -2, _data);
        new ShortField(0x1e, ( short ) 0x9, _data);
        new IntegerField(0x20, 0x6, _data);
        new IntegerField(0x24, 0, _data);
        new IntegerField(0x28, 0, _data);
        _bat_count      = new IntegerField(_bat_count_offset, 0, _data);
        _property_start = new IntegerField(_property_start_offset,
                                           POIFSConstants.END_OF_CHAIN,
                                           _data);
        new IntegerField(0x34, 0, _data);
        new IntegerField(0x38, 0x1000, _data);
        _sbat_start = new IntegerField(_sbat_start_offset,
                                       POIFSConstants.END_OF_CHAIN, _data);
        _sbat_block_count = new IntegerField(_sbat_block_count_offset, 0,
					     _data);
        _xbat_start = new IntegerField(_xbat_start_offset,
                                       POIFSConstants.END_OF_CHAIN, _data);
        _xbat_count = new IntegerField(_xbat_count_offset, 0, _data);
    }

    /**
     * Set BAT block parameters. Assumes that all BAT blocks are
     * contiguous. Will construct XBAT blocks if necessary and return
     * the array of newly constructed XBAT blocks.
     *
     * @param blockCount count of BAT blocks
     * @param startBlock index of first BAT block
     *
     * @return array of XBAT blocks; may be zero length, will not be
     *         null
     */

    public BATBlock [] setBATBlocks(final int blockCount,
                                    final int startBlock)
    {
        BATBlock[] rvalue;

        _bat_count.set(blockCount, _data);
        int limit  = Math.min(blockCount, _max_bats_in_header);
        int offset = _bat_array_offset;

        for (int j = 0; j < limit; j++)
        {
            new IntegerField(offset, startBlock + j, _data);
            offset += LittleEndianConsts.INT_SIZE;
        }
        if (blockCount > _max_bats_in_header)
        {
            int   excess_blocks      = blockCount - _max_bats_in_header;
            int[] excess_block_array = new int[ excess_blocks ];

            for (int j = 0; j < excess_blocks; j++)
            {
                excess_block_array[ j ] = startBlock + j
                                          + _max_bats_in_header;
            }
            rvalue = BATBlock.createXBATBlocks(excess_block_array,
                                               startBlock + blockCount);
            _xbat_start.set(startBlock + blockCount, _data);
        }
        else
        {
            rvalue = BATBlock.createXBATBlocks(new int[ 0 ], 0);
            _xbat_start.set(POIFSConstants.END_OF_CHAIN, _data);
        }
        _xbat_count.set(rvalue.length, _data);
        return rvalue;
    }

    /**
     * Set start of Property Table
     *
     * @param startBlock the index of the first block of the Property
     *                   Table
     */

    public void setPropertyStart(final int startBlock)
    {
        _property_start.set(startBlock, _data);
    }

    /**
     * Set start of small block allocation table
     *
     * @param startBlock the index of the first big block of the small
     *                   block allocation table
     */

    public void setSBATStart(final int startBlock)
    {
        _sbat_start.set(startBlock, _data);
    }

    /**
     * Set count of SBAT blocks
     *
     * @param count the number of SBAT blocks
     */

    public void setSBATBlockCount(final int count)
    {
	_sbat_block_count.set(count, _data);
    }

    /**
     * For a given number of BAT blocks, calculate how many XBAT
     * blocks will be needed
     *
     * @param blockCount number of BAT blocks
     *
     * @return number of XBAT blocks needed
     */

    static int calculateXBATStorageRequirements(final int blockCount)
    {
        return (blockCount > _max_bats_in_header)
               ? BATBlock.calculateXBATStorageRequirements(blockCount
                   - _max_bats_in_header)
               : 0;
    }

    /* ********** START extension of BigBlock ********** */

    /**
     * Write the block's data to an OutputStream
     *
     * @param stream the OutputStream to which the stored data should
     *               be written
     *
     * @exception IOException on problems writing to the specified
     *            stream
     */

    void writeData(final OutputStream stream)
        throws IOException
    {
        doWriteData(stream, _data);
    }

    /* **********  END  extension of BigBlock ********** */
}   // end public class HeaderBlockWriter