org.apache.poi.hssf.record.SSTRecord Maven / Gradle / Ivy
/* ==================================================================== Copyright 2002-2004 Apache Software Foundation Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ==================================================================== */ package org.apache.poi.hssf.record; import org.apache.poi.util.BinaryTree; import org.apache.poi.util.LittleEndian; import org.apache.poi.util.LittleEndianConsts; import java.util.Iterator; import java.util.List; /** * Title: Static String Table Record *METHOD AND FORCE 8-BIT ENCODING ON * A STRING THAT SHOULD USE 16-BIT ENCODING, YOU WILL CORRUPT THE * STRING; IF YOU USE THAT METHOD AND FORCE 16-BIT ENCODING, YOU * ARE WASTING SPACE WHEN THE WORKBOOK IS WRITTEN OUT. * * @param string string to be added * * @return the index of that string in the table */ public int addString( final String string ) { int rval; if ( string == null ) { rval = addString( "", false ); } else { // scan for characters greater than 255 ... if any are // present, we have to use 16-bit encoding. Otherwise, we // can use 8-bit encoding boolean useUTF16 = false; int strlen = string.length(); for ( int j = 0; j < strlen; j++ ) { if ( string.charAt( j ) > 255 ) { useUTF16 = true; break; } } rval = addString( string, useUTF16 ); } return rval; } /** * Add a string and assert the encoding (8-bit or 16-bit) to be * used. ** Description: This holds all the strings for LabelSSTRecords. *
* REFERENCE: PG 389 Microsoft Excel 97 Developer's Kit (ISBN: * 1-57231-498-2) *
* @author Andrew C. Oliver (acoliver at apache dot org) * @author Marc Johnson (mjohnson at apache dot org) * @author Glen Stampoultzis (glens at apache.org) * * @see org.apache.poi.hssf.record.LabelSSTRecord * @see org.apache.poi.hssf.record.ContinueRecord */ public class SSTRecord extends Record { /** how big can an SST record be? As big as any record can be: 8228 bytes */ static final int MAX_RECORD_SIZE = 8228; /** standard record overhead: two shorts (record id plus data space size)*/ static final int STD_RECORD_OVERHEAD = 2 * LittleEndianConsts.SHORT_SIZE; /** SST overhead: the standard record overhead, plus the number of strings and the number of unique strings -- two ints */ static final int SST_RECORD_OVERHEAD = ( STD_RECORD_OVERHEAD + ( 2 * LittleEndianConsts.INT_SIZE ) ); /** how much data can we stuff into an SST record? That would be _max minus the standard SST record overhead */ static final int MAX_DATA_SPACE = MAX_RECORD_SIZE - SST_RECORD_OVERHEAD; /** overhead for each string includes the string's character count (a short) and the flag describing its characteristics (a byte) */ static final int STRING_MINIMAL_OVERHEAD = LittleEndianConsts.SHORT_SIZE + LittleEndianConsts.BYTE_SIZE; public static final short sid = 0xfc; /** union of strings in the SST and EXTSST */ private int field_1_num_strings; /** according to docs ONLY SST */ private int field_2_num_unique_strings; private BinaryTree field_3_strings; /** Record lengths for initial SST record and all continue records */ private List _record_lengths = null; private SSTDeserializer deserializer; /** 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; /** * default constructor */ public SSTRecord() { field_1_num_strings = 0; field_2_num_unique_strings = 0; field_3_strings = new BinaryTree(); deserializer = new SSTDeserializer(field_3_strings); } /** * Constructs an SST record and sets its fields appropriately. * * @param id must be 0xfc or an exception will be throw upon * validation * @param size the size of the data area of the record * @param data of the record (should not contain sid/len) */ public SSTRecord( final short id, final short size, final byte[] data ) { super( id, size, data ); } /** * Constructs an SST record and sets its fields appropriately. * * @param id must be 0xfc or an exception will be throw upon * validation * @param size the size of the data area of the record * @param data of the record (should not contain sid/len) * @param offset of the record */ public SSTRecord( final short id, final short size, final byte[] data, int offset ) { super( id, size, data, offset ); } /** * Add a string. Determines whether 8-bit encoding can be used, or * whether 16-bit encoding must be used. *
* THIS IS THE PREFERRED METHOD OF ADDING A STRING. IF YOU USE THE * OTHER ,code>addString
* USE THIS METHOD AT YOUR OWN RISK. IF YOU FORCE 8-BIT ENCODING, * YOU MAY CORRUPT YOUR STRING. IF YOU FORCE 16-BIT ENCODING AND * IT ISN'T NECESSARY, YOU WILL WASTE SPACE WHEN THIS RECORD IS * WRITTEN OUT. * * @param string string to be added * @param useUTF16 if true, forces 16-bit encoding. If false, * forces 8-bit encoding * * @return the index of that string in the table */ public int addString( final String string, final boolean useUTF16 ) { field_1_num_strings++; String str = ( string == null ) ? "" : string; int rval; UnicodeString ucs = new UnicodeString(); ucs.setString( str ); ucs.setCharCount( (short) str.length() ); ucs.setOptionFlags( (byte) ( useUTF16 ? 1 : 0 ) ); Integer integer = (Integer) field_3_strings.getKeyForValue( ucs ); if ( integer != null ) { rval = integer.intValue(); } else { // This is a new string -- we didn't see it among the // strings we've already collected rval = field_3_strings.size(); field_2_num_unique_strings++; integer = new Integer( rval ); SSTDeserializer.addToStringTable( field_3_strings, integer, ucs ); // field_3_strings.put( integer, ucs ); } return rval; } /** * @return number of strings */ public int getNumStrings() { return field_1_num_strings; } /** * @return number of unique strings */ public int getNumUniqueStrings() { return field_2_num_unique_strings; } /** * USE THIS METHOD AT YOUR OWN PERIL: THE
addString* METHODS MANIPULATE THE NUMBER OF STRINGS AS A SIDE EFFECT; YOUR * ATTEMPTS AT MANIPULATING THE STRING COUNT IS LIKELY TO BE VERY * WRONG AND WILL RESULT IN BAD BEHAVIOR WHEN THIS RECORD IS * WRITTEN OUT AND ANOTHER PROCESS ATTEMPTS TO READ THE RECORD * * @param count number of strings * */ public void setNumStrings( final int count ) { field_1_num_strings = count; } /** * USE THIS METHOD AT YOUR OWN PERIL: THEaddString* METHODS MANIPULATE THE NUMBER OF UNIQUE STRINGS AS A SIDE * EFFECT; YOUR ATTEMPTS AT MANIPULATING THE UNIQUE STRING COUNT * IS LIKELY TO BE VERY WRONG AND WILL RESULT IN BAD BEHAVIOR WHEN * THIS RECORD IS WRITTEN OUT AND ANOTHER PROCESS ATTEMPTS TO READ * THE RECORD * * @param count number of strings */ public void setNumUniqueStrings( final int count ) { field_2_num_unique_strings = count; } /** * Get a particular string by its index * * @param id index into the array of strings * * @return the desired string */ public String getString( final int id ) { return ( (UnicodeString) field_3_strings.get( new Integer( id ) ) ).getString(); } public boolean isString16bit( final int id ) { UnicodeString unicodeString = ( (UnicodeString) field_3_strings.get( new Integer( id ) ) ); return ( ( unicodeString.getOptionFlags() & 0x01 ) == 1 ); } /** * Return a debugging string representation * * @return string representation */ public String toString() { StringBuffer buffer = new StringBuffer(); buffer.append( "[SST]\n" ); buffer.append( " .numstrings = " ) .append( Integer.toHexString( getNumStrings() ) ).append( "\n" ); buffer.append( " .uniquestrings = " ) .append( Integer.toHexString( getNumUniqueStrings() ) ).append( "\n" ); for ( int k = 0; k < field_3_strings.size(); k++ ) { buffer.append( " .string_" + k + " = " ) .append( ( field_3_strings .get( new Integer( k ) ) ).toString() ).append( "\n" ); } buffer.append( "[/SST]\n" ); return buffer.toString(); } /** * @return sid */ public short getSid() { return sid; } /** * @return hashcode */ public int hashCode() { return field_2_num_unique_strings; } public boolean equals( Object o ) { if ( ( o == null ) || ( o.getClass() != this.getClass() ) ) { return false; } SSTRecord other = (SSTRecord) o; return ( ( field_1_num_strings == other .field_1_num_strings ) && ( field_2_num_unique_strings == other .field_2_num_unique_strings ) && field_3_strings .equals( other.field_3_strings ) ); } /** * validate SID * * @param id the alleged SID * * @exception RecordFormatException if validation fails */ protected void validateSid( final short id ) throws RecordFormatException { if ( id != sid ) { throw new RecordFormatException( "NOT An SST RECORD" ); } } /** * Fill the fields from the data ** The data consists of sets of string data. This string data is * arranged as follows: *
*
** short string_length; // length of string data * byte string_flag; // flag specifying special string * // handling * short run_count; // optional count of formatting runs * int extend_length; // optional extension length * char[] string_data; // string data, can be byte[] or * // short[] (length of array is * // string_length) * int[] formatting_runs; // optional formatting runs (length of * // array is run_count) * byte[] extension; // optional extension (length of array * // is extend_length) ** The string_flag is bit mapped as follows: *
*
| Bit number | *Meaning if 0 | *Meaning if 1 | *
|---|---|---|
| 0 | *string_data is byte[] | *string_data is short[] * |
| 1 | *Should always be 0 | *string_flag is defective * |
| 2 | *extension is not included | *extension is included * |
| 3 | *formatting run data is not included | *formatting run data is included * |
| 4 | *Should always be 0 | *string_flag is defective * |
| 5 | *Should always be 0 | *string_flag is defective * |
| 6 | *Should always be 0 | *string_flag is defective * |
| 7 | *Should always be 0 | *string_flag is defective * |
* We can handle eating the overhead associated with bits 2 or 3 * (or both) being set, but we have no idea what to do with the * associated data. The UnicodeString class can handle the byte[] * vs short[] nature of the actual string data * * @param data raw data * @param size size of the raw data */ protected void fillFields( final byte[] data, final short size, int offset ) { // this method is ALWAYS called after construction -- using // the nontrivial constructor, of course -- so this is where // we initialize our fields field_1_num_strings = LittleEndian.getInt( data, 0 + offset ); field_2_num_unique_strings = LittleEndian.getInt( data, 4 + offset ); field_3_strings = new BinaryTree(); deserializer = new SSTDeserializer(field_3_strings); deserializer.manufactureStrings( data, 8 + offset); } /** * @return an iterator of the strings we hold. All instances are * UnicodeStrings */ Iterator getStrings() { return field_3_strings.values().iterator(); } /** * @return count of the strings we hold. */ int countStrings() { return field_3_strings.size(); } /** * called by the class that is responsible for writing this sucker. * Subclasses should implement this so that their data is passed back in a * byte array. * * @return size */ public int serialize( int offset, byte[] data ) { SSTSerializer serializer = new SSTSerializer( _record_lengths, field_3_strings, getNumStrings(), getNumUniqueStrings() ); int bytes = serializer.serialize( getRecordSize(), offset, data ); bucketAbsoluteOffsets = serializer.getBucketAbsoluteOffsets(); bucketRelativeOffsets = serializer.getBucketRelativeOffsets(); // for ( int i = 0; i < bucketAbsoluteOffsets.length; i++ ) // { // System.out.println( "bucketAbsoluteOffset = " + bucketAbsoluteOffsets[i] ); // System.out.println( "bucketRelativeOffset = " + bucketRelativeOffsets[i] ); // } return bytes; } public int getRecordSize() { SSTRecordSizeCalculator calculator = new SSTRecordSizeCalculator(field_3_strings); int recordSize = calculator.getRecordSize(); _record_lengths = calculator.getRecordLengths(); return recordSize; } SSTDeserializer getDeserializer() { return deserializer; } /** * Strange to handle continue records this way. Is it a smell? */ public void processContinueRecord( byte[] record ) { deserializer.processContinueRecord( record ); } /** * Creates an extended string record based on the current contents of * the current SST record. The offset within the stream to the SST record * is required because the extended string record points directly to the * strings in the SST record. *
* NOTE: THIS FUNCTION MUST ONLY BE CALLED AFTER THE SST RECORD HAS BEEN
* SERIALIZED.
*
* @param sstOffset The offset in the stream to the start of the
* SST record.
* @return The new SST record.
*/
public ExtSSTRecord createExtSSTRecord(int sstOffset)
{
if (bucketAbsoluteOffsets == null || bucketAbsoluteOffsets == null)
throw new IllegalStateException("SST record has not yet been serialized.");
ExtSSTRecord extSST = new ExtSSTRecord();
extSST.setNumStringsPerBucket((short)8);
int[] absoluteOffsets = (int[]) bucketAbsoluteOffsets.clone();
int[] relativeOffsets = (int[]) bucketRelativeOffsets.clone();
for ( int i = 0; i < absoluteOffsets.length; i++ )
absoluteOffsets[i] += sstOffset;
extSST.setBucketOffsets(absoluteOffsets, relativeOffsets);
return extSST;
}
/**
* Calculates the size in bytes of the EXTSST record as it would be if the
* record was serialized.
*
* @return The size of the ExtSST record in bytes.
*/
public int calcExtSSTRecordSize()
{
return ExtSSTRecord.getRecordSizeForStrings(field_3_strings.size());
}
}