poi/src/java/org/apache/poi/hssf/record/SSTSerializer.java

276 lines
10 KiB
Java

/* ====================================================================
* 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 apache@apache.org.
*
* 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.hssf.record;
import org.apache.poi.util.BinaryTree;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
/**
* This class handles serialization of SST records. It utilizes the record processor
* class write individual records. This has been refactored from the SSTRecord class.
*
* @author Glen Stampoultzis (glens at apache.org)
*/
class SSTSerializer
{
// todo: make private again
private List recordLengths;
private BinaryTree strings;
private int numStrings;
private int numUniqueStrings;
private SSTRecordHeader sstRecordHeader;
/** Offsets from the beginning of the SST record (even across continuations) */
int[] bucketAbsoluteOffsets;
/** Offsets relative the start of the current SST or continue record */
int[] bucketRelativeOffsets;
int startOfSST, startOfRecord;
/** The default bucket size (this is used for ExternSST) */
final static int DEFAULT_BUCKET_SIZE = 8;
public SSTSerializer( List recordLengths, BinaryTree strings, int numStrings, int numUniqueStrings )
{
this.recordLengths = recordLengths;
this.strings = strings;
this.numStrings = numStrings;
this.numUniqueStrings = numUniqueStrings;
this.sstRecordHeader = new SSTRecordHeader( numStrings, numUniqueStrings );
int infoRecs = (strings.size() / SSTSerializer.DEFAULT_BUCKET_SIZE);
if ((strings.size() % SSTSerializer.DEFAULT_BUCKET_SIZE) != 0)
infoRecs ++;
this.bucketAbsoluteOffsets = new int[infoRecs];
this.bucketRelativeOffsets = new int[infoRecs];
}
/**
* Create a byte array consisting of an SST record and any
* required Continue records, ready to be written out.
* <p>
* If an SST record and any subsequent Continue records are read
* in to create this instance, this method should produce a byte
* array that is identical to the byte array produced by
* concatenating the input records' data.
*
* @return the byte array
*/
public int serialize( int record_size, int offset, byte[] data )
{
int record_length_index = 0;
if ( calculateUnicodeSize() > SSTRecord.MAX_DATA_SPACE )
serializeLargeRecord( record_size, record_length_index, data, offset );
else
serializeSingleSSTRecord( data, offset, record_length_index );
return record_size;
}
/**
* Calculates the total unicode size for all the strings.
*
* @return the total size.
*/
public static int calculateUnicodeSize(Map strings)
{
int retval = 0;
for ( int k = 0; k < strings.size(); k++ )
{
retval += getUnicodeString( strings, k ).getRecordSize();
}
return retval;
}
public int calculateUnicodeSize()
{
return calculateUnicodeSize(strings);
}
/**
* This case is chosen when an SST record does not span over to a continue record.
*/
private void serializeSingleSSTRecord( byte[] data, int offset, int record_length_index )
{
int len = ( (Integer) recordLengths.get( record_length_index ) ).intValue();
int recordSize = SSTRecord.SST_RECORD_OVERHEAD + len - SSTRecord.STD_RECORD_OVERHEAD;
sstRecordHeader.writeSSTHeader( data, 0 + offset, recordSize );
int pos = SSTRecord.SST_RECORD_OVERHEAD;
for ( int k = 0; k < strings.size(); k++ )
{
if (k % DEFAULT_BUCKET_SIZE == 0)
{
bucketAbsoluteOffsets[k / DEFAULT_BUCKET_SIZE] = pos;
bucketRelativeOffsets[k / DEFAULT_BUCKET_SIZE] = pos;
}
System.arraycopy( getUnicodeString( k ).serialize(), 0, data, pos + offset, getUnicodeString( k ).getRecordSize() );
pos += getUnicodeString( k ).getRecordSize();
}
}
/**
* Large records are serialized to an SST and to one or more CONTINUE records. Joy. They have the special
* characteristic that they can change the option field when a single string is split across to a
* CONTINUE record.
*/
private void serializeLargeRecord( int record_size, int record_length_index, byte[] buffer, int offset )
{
startOfSST = offset;
byte[] stringReminant = null;
int stringIndex = 0;
boolean lastneedcontinue = false;
boolean first_record = true;
int totalWritten = 0;
while ( totalWritten != record_size )
{
int recordLength = ( (Integer) recordLengths.get( record_length_index++ ) ).intValue();
RecordProcessor recordProcessor = new RecordProcessor( buffer,
recordLength, numStrings, numUniqueStrings );
// write the appropriate header
startOfRecord = offset + totalWritten;
recordProcessor.writeRecordHeader( offset, totalWritten, recordLength, first_record );
first_record = false;
// now, write the rest of the data into the current
// record space
if ( lastneedcontinue )
{
lastneedcontinue = stringReminant.length > recordProcessor.getAvailable();
// the last string in the previous record was not written out completely
stringReminant = recordProcessor.writeStringRemainder( lastneedcontinue,
stringReminant, offset, totalWritten );
}
// last string's remnant, if any, is cleaned up as best as can be done ... now let's try and write
// some more strings
for ( ; stringIndex < strings.size(); stringIndex++ )
{
UnicodeString unistr = getUnicodeString( stringIndex );
if (stringIndex % DEFAULT_BUCKET_SIZE == 0)
{
bucketAbsoluteOffsets[stringIndex / DEFAULT_BUCKET_SIZE] = offset + totalWritten + recordProcessor.getRecordOffset() - startOfSST;
bucketRelativeOffsets[stringIndex / DEFAULT_BUCKET_SIZE] = offset + totalWritten + recordProcessor.getRecordOffset() - startOfRecord;
}
if ( unistr.getRecordSize() <= recordProcessor.getAvailable() )
{
recordProcessor.writeWholeString( unistr, offset, totalWritten );
}
else
{
// can't write the entire string out
if ( recordProcessor.getAvailable() >= SSTRecord.STRING_MINIMAL_OVERHEAD )
{
// we can write some of it
stringReminant = recordProcessor.writePartString( unistr, offset, totalWritten );
lastneedcontinue = true;
stringIndex++;
}
break;
}
}
totalWritten += recordLength + SSTRecord.STD_RECORD_OVERHEAD;
}
}
private UnicodeString getUnicodeString( int index )
{
return getUnicodeString(strings, index);
}
private static UnicodeString getUnicodeString( Map strings, int index )
{
Integer intunipos = new Integer( index );
return ( (UnicodeString) strings.get( intunipos ) );
}
public int getRecordSize()
{
SSTRecordSizeCalculator calculator = new SSTRecordSizeCalculator(strings);
int recordSize = calculator.getRecordSize();
recordLengths = calculator.getRecordLengths();
return recordSize;
}
public List getRecordLengths()
{
return recordLengths;
}
public int[] getBucketAbsoluteOffsets()
{
return bucketAbsoluteOffsets;
}
public int[] getBucketRelativeOffsets()
{
return bucketRelativeOffsets;
}
}