org.apache.tika.parser.chm.accessor.ChmPmgiHeader Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* 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
* 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.tika.parser.chm.accessor;
import java.util.Arrays;
import org.apache.tika.exception.TikaException;
import org.apache.tika.parser.chm.assertion.ChmAssert;
import org.apache.tika.parser.chm.core.ChmCommons;
import org.apache.tika.parser.chm.core.ChmConstants;
import org.apache.tika.parser.chm.exception.ChmParsingException;
import static java.nio.charset.StandardCharsets.UTF_8;
/**
* Description Note: not always exists An index chunk has the following format:
* 0000: char[4] 'PMGI' 0004: DWORD Length of quickref/free area at end of
* directory chunk 0008: Directory index entries (to quickref/free area) The
* quickref area in an PMGI is the same as in an PMGL The format of a directory
* index entry is as follows: BYTE: length of name BYTEs: name (UTF-8 encoded)
* ENCINT: directory listing chunk which starts with name Encoded Integers aka
* ENCINT An ENCINT is a variable-length integer. The high bit of each byte
* indicates "continued to the next byte". Bytes are stored most significant to
* least significant. So, for example, $EA $15 is (((0xEA&0x7F)<<7)|0x15) =
* 0x3515.
*
*
* Note: This class is not in use
*
* {@link http://translated.by/you/microsoft-s-html-help-chm-format-incomplete/original/?show-translation-form=1 }
*
*
*/
public class ChmPmgiHeader implements ChmAccessor {
private static final long serialVersionUID = -2092282339894303701L;
private byte[] signature;
private long free_space; /* 4 */
/* local usage */
private int dataRemained;
private int currentPlace = 0;
public ChmPmgiHeader() {
signature = ChmConstants.CHM_PMGI_MARKER.getBytes(UTF_8); /* 0 (PMGI) */
}
private int getDataRemained() {
return dataRemained;
}
private void setDataRemained(int dataRemained) {
this.dataRemained = dataRemained;
}
private int getCurrentPlace() {
return currentPlace;
}
private void setCurrentPlace(int currentPlace) {
this.currentPlace = currentPlace;
}
private void unmarshalCharArray(byte[] data, ChmPmgiHeader chmPmgiHeader,
int count) throws ChmParsingException {
int index = -1;
ChmAssert.assertByteArrayNotNull(data);
ChmAssert.assertChmAccessorNotNull(chmPmgiHeader);
ChmAssert.assertPositiveInt(count);
this.setDataRemained(data.length);
index = ChmCommons.indexOf(data,
ChmConstants.CHM_PMGI_MARKER.getBytes(UTF_8));
if (index >= 0)
System.arraycopy(data, index, chmPmgiHeader.getSignature(), 0, count);
else{
//Some chm documents (actually most of them) do not contain
//PMGI header, in this case, we just notice about it.
}
this.setCurrentPlace(this.getCurrentPlace() + count);
this.setDataRemained(this.getDataRemained() - count);
}
private long unmarshalUInt32(byte[] data, long dest) throws ChmParsingException {
ChmAssert.assertByteArrayNotNull(data);
if (4 > getDataRemained())
throw new ChmParsingException("4 > dataLenght");
dest = (data[this.getCurrentPlace()] & 0xff)
| (data[this.getCurrentPlace() + 1] & 0xff) << 8
| (data[this.getCurrentPlace() + 2] & 0xff) << 16
| (data[this.getCurrentPlace() + 3] & 0xff) << 24;
setDataRemained(this.getDataRemained() - 4);
this.setCurrentPlace(this.getCurrentPlace() + 4);
return dest;
}
/**
* Returns pmgi signature if exists
*
* @return signature
*/
public byte[] getSignature() {
return signature;
}
/**
* Sets pmgi signature
*
* @param signature
*/
protected void setSignature(byte[] signature) {
this.signature = signature;
}
/**
* Returns pmgi free space
*
* @return free_space
*/
public long getFreeSpace() {
return free_space;
}
/**
* Sets pmgi free space
*
* @param free_space
*/
protected void setFreeSpace(long free_space) {
this.free_space = free_space;
}
/**
* Returns textual representation of the pmgi header
*/
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("signature:=" + new String(getSignature(), UTF_8) + ", ");
sb.append("free space:=" + getFreeSpace()
+ System.getProperty("line.separator"));
return sb.toString();
}
// @Override
public void parse(byte[] data, ChmPmgiHeader chmPmgiHeader) throws TikaException {
/* we only know how to deal with a 0x8 byte structures */
if (data.length < ChmConstants.CHM_PMGI_LEN)
throw new TikaException("we only know how to deal with a 0x8 byte structures");
/* unmarshal fields */
chmPmgiHeader.unmarshalCharArray(data, chmPmgiHeader, ChmConstants.CHM_SIGNATURE_LEN);
chmPmgiHeader.setFreeSpace(chmPmgiHeader.unmarshalUInt32(data, chmPmgiHeader.getFreeSpace()));
/* check structure */
if (!Arrays.equals(chmPmgiHeader.getSignature(),
ChmConstants.CHM_PMGI_MARKER.getBytes(UTF_8)))
throw new TikaException(
"it does not seem to be valid a PMGI signature, check ChmItsp index_root if it was -1, means no PMGI, use PMGL insted");
}
}