/*
* 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.pdfbox.pdfparser;
import java.io.IOException;
import java.io.InputStream;
import java.util.regex.Pattern;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSDocument;
import org.apache.pdfbox.cos.COSObject;
import org.apache.pdfbox.pdfwriter.COSWriter;
import org.apache.pdfbox.persistence.util.COSObjectKey;
public class VisualSignatureParser extends BaseParser {
/**
* Log instance.
*/
private static final Log log = LogFactory.getLog(PDFParser.class);
public VisualSignatureParser(InputStream input) throws IOException {
super(input);
}
public void parse() throws IOException {
document = new COSDocument();
skipToNextObj();
boolean wasLastParsedObjectEOF = false;
try {
while(!wasLastParsedObjectEOF) {
if(pdfSource.isEOF()) {
break;
}
try {
wasLastParsedObjectEOF = parseObject();
} catch(IOException e) {
/*
* Warning is sent to the PDFBox.log and to the Console that
* we skipped over an object
*/
log.warn("Parsing Error, Skipping Object", e);
skipToNextObj();
}
skipSpaces();
}
} catch(IOException e) {
/*
* PDF files may have random data after the EOF marker. Ignore errors if
* last object processed is EOF.
*/
if(!wasLastParsedObjectEOF) {
throw e;
}
}
}
private void skipToNextObj() throws IOException {
byte[] b = new byte[16];
Pattern p = Pattern.compile("\\d+\\s+\\d+\\s+obj.*", Pattern.DOTALL);
/* Read a buffer of data each time to see if it starts with a
* known keyword. This is not the most efficient design, but we should
* rarely be needing this function. We could update this to use the
* circular buffer, like in readUntilEndStream().
*/
while(!pdfSource.isEOF()) {
int l = pdfSource.read(b);
if(l < 1) {
break;
}
String s = new String(b, "US-ASCII");
if(s.startsWith("trailer")
|| s.startsWith("xref")
|| s.startsWith("startxref")
|| s.startsWith("stream")
|| p.matcher(s).matches()) {
pdfSource.unread(b);
break;
} else {
pdfSource.unread(b, 1, l - 1);
}
}
}
private boolean parseObject() throws IOException {
boolean isEndOfFile = false;
skipSpaces();
//peek at the next character to determine the type of object we are parsing
char peekedChar = (char) pdfSource.peek();
//ignore endobj and endstream sections.
while(peekedChar == 'e') {
//there are times when there are multiple endobj, so lets
//just read them and move on.
readString();
skipSpaces();
peekedChar = (char) pdfSource.peek();
}
if(pdfSource.isEOF()) {
// end of file we will return a false and call it a day.
} else if(peekedChar == 'x') {
//xref table. Note: The contents of the Xref table are currently ignored
return true;
} else if(peekedChar == 't' || peekedChar == 's') {
// Note: startxref can occur in either a trailer section or by itself
if(peekedChar == 't') {
return true;
}
if(peekedChar == 's') {
skipToNextObj();
//verify that EOF exists
String eof = readExpectedString("%%EOF");
if(eof.indexOf("%%EOF") == -1 && !pdfSource.isEOF()) {
throw new IOException("expected='%%EOF' actual='" + eof + "' next=" + readString()
+ " next=" + readString());
}
isEndOfFile = true;
}
} else {
//we are going to parse an normal object
int number = -1;
int genNum = -1;
String objectKey = null;
boolean missingObjectNumber = false;
try {
char peeked = (char) pdfSource.peek();
if(peeked == '<') {
missingObjectNumber = true;
} else {
number = readInt();
}
} catch(IOException e) {
//ok for some reason "GNU Ghostscript 5.10" puts two endobj
//statements after an object, of course this is nonsense
//but because we want to support as many PDFs as possible
//we will simply try again
number = readInt();
}
if(!missingObjectNumber) {
skipSpaces();
genNum = readInt();
objectKey = readString(3);
//System.out.println( "parseObject() num=" + number +
//" genNumber=" + genNum + " key='" + objectKey + "'" );
if(!objectKey.equals("obj")) {
throw new IOException("expected='obj' actual='" + objectKey + "' " + pdfSource);
}
} else {
number = -1;
genNum = -1;
}
skipSpaces();
COSBase pb = parseDirObject();
String endObjectKey = readString();
if(endObjectKey.equals("stream")) {
pdfSource.unread(endObjectKey.getBytes());
pdfSource.unread(' ');
if(pb instanceof COSDictionary) {
pb = parseCOSStream((COSDictionary) pb, getDocument().getScratchFile());
} else {
// this is not legal
// the combination of a dict and the stream/endstream forms a complete stream object
throw new IOException("stream not preceded by dictionary");
}
endObjectKey = readString();
}
COSObjectKey key = new COSObjectKey(number, genNum);
COSObject pdfObject = document.getObjectFromPool(key);
pb.setNeedToBeUpdate(true);
pdfObject.setObject(pb);
if(!endObjectKey.equals("endobj")) {
if(endObjectKey.startsWith("endobj")) {
/*
* Some PDF files don't contain a new line after endobj so we
* need to make sure that the next object number is getting read separately
* and not part of the endobj keyword. Ex. Some files would have "endobj28"
* instead of "endobj"
*/
pdfSource.unread(endObjectKey.substring(6).getBytes());
} else if(!pdfSource.isEOF()) {
try {
//It is possible that the endobj is missing, there
//are several PDFs out there that do that so skip it and move on.
Float.parseFloat(endObjectKey);
pdfSource.unread(COSWriter.SPACE);
pdfSource.unread(endObjectKey.getBytes());
} catch(NumberFormatException e) {
//we will try again incase there was some garbage which
//some writers will leave behind.
String secondEndObjectKey = readString();
if(!secondEndObjectKey.equals("endobj")) {
if(isClosing()) {
//found a case with 17506.pdf object 41 that was like this
//41 0 obj [/Pattern /DeviceGray] ] endobj
//notice the second array close, here we are reading it
//and ignoring and attempting to continue
pdfSource.read();
}
skipSpaces();
String thirdPossibleEndObj = readString();
if(!thirdPossibleEndObj.equals("endobj")) {
throw new IOException("expected='endobj' firstReadAttempt='" + endObjectKey + "' "
+ "secondReadAttempt='" + secondEndObjectKey + "' " + pdfSource);
}
}
}
}
}
skipSpaces();
}
return isEndOfFile;
}
public COSDocument getDocument() throws IOException {
if(document == null) {
throw new IOException("You must call parse() before calling getDocument()");
}
return document;
}
}