org.apache.poi.hdgf.chunks.ChunkFactory Maven / Gradle / Ivy
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this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
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http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.poi.hdgf.chunks;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.StringTokenizer;
import org.apache.poi.util.LocaleUtil;
import org.apache.poi.util.POILogFactory;
import org.apache.poi.util.POILogger;
/**
* Factor class to create the appropriate chunks, which
* needs the version of the file to process the chunk header
* and trailer areas.
* Makes use of chunks_parse_cmds.tbl from vsdump to be able
* to process the chunk value area
*/
public final class ChunkFactory {
/** The version of the currently open document */
private int version;
/**
* Key is a Chunk's type, value is an array of its CommandDefinitions
*/
private Hashtable chunkCommandDefinitions =
new Hashtable();
/**
* What the name is of the chunk table definitions file?
* This file comes from the scratchpad resources directory.
*/
private static String chunkTableName =
"/org/apache/poi/hdgf/chunks_parse_cmds.tbl";
/** For logging problems we spot with the file */
private static POILogger logger = POILogFactory.getLogger(ChunkFactory.class);
public ChunkFactory(int version) throws IOException {
this.version = version;
processChunkParseCommands();
}
/**
* Open chunks_parse_cmds.tbl and process it, to get the definitions
* of all the different possible chunk commands.
*/
private void processChunkParseCommands() throws IOException {
String line;
InputStream cpd = null;
BufferedReader inp = null;
try {
cpd = ChunkFactory.class.getResourceAsStream(chunkTableName);
if(cpd == null) {
throw new IllegalStateException("Unable to find HDGF chunk definition on the classpath - " + chunkTableName);
}
inp = new BufferedReader(new InputStreamReader(cpd, LocaleUtil.CHARSET_1252));
while( (line = inp.readLine()) != null ) {
if(line.startsWith("#")) continue;
if(line.startsWith(" ")) continue;
if(line.startsWith("\t")) continue;
if(line.length() == 0) continue;
// Start xxx
if(!line.startsWith("start")) {
throw new IllegalStateException("Expecting start xxx, found " + line);
}
int chunkType = Integer.parseInt(line.substring(6));
ArrayList defsL = new ArrayList();
// Data entries
while( ! (line = inp.readLine()).startsWith("end") ) {
StringTokenizer st = new StringTokenizer(line, " ");
int defType = Integer.parseInt(st.nextToken());
int offset = Integer.parseInt(st.nextToken());
String name = st.nextToken("\uffff").substring(1);
CommandDefinition def = new CommandDefinition(defType,offset,name);
defsL.add(def);
}
CommandDefinition[] defs = defsL.toArray(new CommandDefinition[defsL.size()]);
// Add to the hashtable
chunkCommandDefinitions.put(Integer.valueOf(chunkType), defs);
}
} finally {
if (inp != null) inp.close();
if (cpd != null) cpd.close();
}
}
public int getVersion() { return version; }
/**
* Creates the appropriate chunk at the given location.
* @param data
* @param offset
*/
public Chunk createChunk(byte[] data, int offset) {
// Create the header
ChunkHeader header =
ChunkHeader.createChunkHeader(version, data, offset);
// Sanity check
if(header.length < 0) {
throw new IllegalArgumentException("Found a chunk with a negative length, which isn't allowed");
}
// How far up to look
int endOfDataPos = offset + header.getLength() + header.getSizeInBytes();
// Check we have enough data, and tweak the header size
// as required
if(endOfDataPos > data.length) {
logger.log(POILogger.WARN,
"Header called for " + header.getLength() +" bytes, but that would take us past the end of the data!");
endOfDataPos = data.length;
header.length = data.length - offset - header.getSizeInBytes();
if(header.hasTrailer()) {
header.length -= 8;
endOfDataPos -= 8;
}
if(header.hasSeparator()) {
header.length -= 4;
endOfDataPos -= 4;
}
}
// Create the trailer and separator, if required
ChunkTrailer trailer = null;
ChunkSeparator separator = null;
if(header.hasTrailer()) {
if(endOfDataPos <= data.length-8) {
trailer = new ChunkTrailer(
data, endOfDataPos);
endOfDataPos += 8;
} else {
logger.log(POILogger.ERROR, "Header claims a length to " + endOfDataPos + " there's then no space for the trailer in the data (" + data.length + ")");
}
}
if(header.hasSeparator()) {
if(endOfDataPos <= data.length-4) {
separator = new ChunkSeparator(
data, endOfDataPos);
} else {
logger.log(POILogger.ERROR, "Header claims a length to " + endOfDataPos + " there's then no space for the separator in the data (" + data.length + ")");
}
}
// Now, create the chunk
byte[] contents = new byte[header.getLength()];
System.arraycopy(data, offset+header.getSizeInBytes(), contents, 0, contents.length);
Chunk chunk = new Chunk(header, trailer, separator, contents);
// Feed in the stuff from chunks_parse_cmds.tbl
CommandDefinition[] defs = chunkCommandDefinitions.get(Integer.valueOf(header.getType()));
if(defs == null) defs = new CommandDefinition[0];
chunk.commandDefinitions = defs;
// Now get the chunk to process its commands
chunk.processCommands();
// All done
return chunk;
}
/**
* The definition of a Command, which a chunk may hold.
* The Command holds the value, this describes it.
*/
public static class CommandDefinition {
private int type;
private int offset;
private String name;
public CommandDefinition(int type, int offset, String name) {
this.type = type;
this.offset = offset;
this.name = name;
}
public String getName() {
return name;
}
public int getOffset() {
return offset;
}
public int getType() {
return type;
}
}
}
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