/*
* 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.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSBoolean;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSNull;
import org.apache.pdfbox.cos.COSNumber;
import org.apache.pdfbox.cos.COSObject;
import org.apache.pdfbox.cos.COSStream;
import org.apache.pdfbox.pdmodel.common.PDStream;
import org.apache.pdfbox.contentstream.operator.Operator;
/**
* This will parse a PDF byte stream and extract operands and such.
*
* @author Ben Litchfield
*/
public class PDFStreamParser extends BaseParser
{
/**
* Log instance.
*/
private static final Log LOG = LogFactory.getLog(PDFStreamParser.class);
private List<Object> streamObjects = new ArrayList<Object>( 100 );
private final int MAX_BIN_CHAR_TEST_LENGTH = 10;
private final byte[] binCharTestArr = new byte[MAX_BIN_CHAR_TEST_LENGTH];
/**
* Constructor that takes a stream to parse.
*
* @since Apache PDFBox 1.3.0
* @param stream The stream to read data from.
* @param forceParsing flag to skip malformed or otherwise unparseable
* input where possible
* @throws IOException If there is an error reading from the stream.
*/
public PDFStreamParser(InputStream stream, boolean forceParsing)
throws IOException
{
super(stream, forceParsing);
}
/**
* Constructor that takes a stream to parse.
*
* @param stream The stream to read data from.
*
* @throws IOException If there is an error reading from the stream.
*/
public PDFStreamParser(InputStream stream)
throws IOException
{
this(stream, FORCE_PARSING);
}
/**
* Constructor.
*
* @param stream The stream to parse.
*
* @throws IOException If there is an error initializing the stream.
*/
public PDFStreamParser( PDStream stream ) throws IOException
{
this( stream.createInputStream() );
}
/**
* Constructor.
*
* @since Apache PDFBox 1.3.0
* @param stream The stream to parse.
* @param forceParsing flag to skip malformed or otherwise unparseable
* input where possible
* @throws IOException If there is an error initializing the stream.
*/
public PDFStreamParser(COSStream stream, boolean forceParsing)
throws IOException
{
this(stream.getUnfilteredStream(), forceParsing);
}
/**
* Constructor.
*
* @param stream The stream to parse.
*
* @throws IOException If there is an error initializing the stream.
*/
public PDFStreamParser( COSStream stream ) throws IOException
{
this( stream.getUnfilteredStream() );
}
/**
* This will parse the tokens in the stream. This will close the
* stream when it is finished parsing.
*
* @throws IOException If there is an error while parsing the stream.
*/
public void parse() throws IOException
{
try
{
Object token;
while( (token = parseNextToken()) != null )
{
streamObjects.add( token );
}
}
finally
{
pdfSource.close();
}
}
/**
* This will get the tokens that were parsed from the stream.
*
* @return All of the tokens in the stream.
*/
public List<Object> getTokens()
{
return streamObjects;
}
/**
* This will close the underlying pdfSource object.
*
* @throws IOException If there is an error releasing resources.
*/
public void close() throws IOException
{
pdfSource.close();
}
/**
* This will get an iterator which can be used to parse the stream
* one token after the other.
*
* @return an iterator to get one token after the other
*/
public Iterator<Object> getTokenIterator()
{
return new Iterator<Object>()
{
private Object token;
private void tryNext()
{
try
{
if (token == null)
{
token = parseNextToken();
}
}
catch (IOException e)
{
throw new RuntimeException(e);
}
}
/** {@inheritDoc} */
@Override
public boolean hasNext()
{
tryNext();
return token != null;
}
/** {@inheritDoc} */
@Override
public Object next()
{
tryNext();
Object tmp = token;
if (tmp == null)
{
throw new NoSuchElementException();
}
token = null;
return tmp;
}
/** {@inheritDoc} */
@Override
public void remove()
{
throw new UnsupportedOperationException();
}
};
}
/**
* This will parse the next token in the stream.
*
* @return The next token in the stream or null if there are no more tokens in the stream.
*
* @throws IOException If an io error occurs while parsing the stream.
*/
private Object parseNextToken() throws IOException
{
Object retval;
skipSpaces();
int nextByte = pdfSource.peek();
if( ((byte)nextByte) == -1 )
{
return null;
}
char c = (char)nextByte;
switch(c)
{
case '<':
{
int leftBracket = pdfSource.read();//pull off first left bracket
c = (char)pdfSource.peek(); //check for second left bracket
pdfSource.unread( leftBracket ); //put back first bracket
if(c == '<')
{
COSDictionary pod = parseCOSDictionary();
skipSpaces();
if((char)pdfSource.peek() == 's')
{
retval = parseCOSStream( pod );
}
else
{
retval = pod;
}
}
else
{
retval = parseCOSString();
}
break;
}
case '[': // array
{
retval = parseCOSArray();
break;
}
case '(': // string
retval = parseCOSString();
break;
case '/': // name
retval = parseCOSName();
break;
case 'n': // null
{
String nullString = readString();
if( nullString.equals( "null") )
{
retval = COSNull.NULL;
}
else
{
retval = Operator.getOperator(nullString);
}
break;
}
case 't':
case 'f':
{
String next = readString();
if( next.equals( "true" ) )
{
retval = COSBoolean.TRUE;
break;
}
else if( next.equals( "false" ) )
{
retval = COSBoolean.FALSE;
}
else
{
retval = Operator.getOperator(next);
}
break;
}
case 'R':
{
String line = readString();
if( line.equals( "R" ) )
{
retval = new COSObject( null );
}
else
{
retval = Operator.getOperator(line);
}
break;
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '-':
case '+':
case '.':
{
/* We will be filling buf with the rest of the number. Only
* allow 1 "." and "-" and "+" at start of number. */
StringBuffer buf = new StringBuffer();
buf.append( c );
pdfSource.read();
boolean dotNotRead = c != '.';
while( Character.isDigit(c = (char)pdfSource.peek()) || dotNotRead && c == '.')
{
buf.append( c );
pdfSource.read();
if (dotNotRead && c == '.')
{
dotNotRead = false;
}
}
retval = COSNumber.get( buf.toString() );
break;
}
case 'B':
{
String next = readString();
retval = Operator.getOperator(next);
if( next.equals( "BI" ) )
{
Operator beginImageOP = (Operator)retval;
COSDictionary imageParams = new COSDictionary();
beginImageOP.setImageParameters( imageParams );
Object nextToken = null;
while( (nextToken = parseNextToken()) instanceof COSName )
{
Object value = parseNextToken();
imageParams.setItem( (COSName)nextToken, (COSBase)value );
}
//final token will be the image data, maybe??
Operator imageData = (Operator)nextToken;
beginImageOP.setImageData( imageData.getImageData() );
}
break;
}
case 'I':
{
//Special case for ID operator
String id = "" + (char)pdfSource.read() + (char)pdfSource.read();
if( !id.equals( "ID" ) )
{
throw new IOException( "Error: Expected operator 'ID' actual='" + id + "'" );
}
ByteArrayOutputStream imageData = new ByteArrayOutputStream();
if( isWhitespace() )
{
//pull off the whitespace character
pdfSource.read();
}
int lastByte = pdfSource.read();
int currentByte = pdfSource.read();
// PDF spec is kinda unclear about this. Should a whitespace
// always appear before EI? Not sure, so that we just read
// until EI<whitespace>.
// Be aware not all kind of whitespaces are allowed here. see PDFBOX-1561
while( !(lastByte == 'E' &&
currentByte == 'I' &&
hasNextSpaceOrReturn() &&
hasNoFollowingBinData( pdfSource )) &&
!pdfSource.isEOF() )
{
imageData.write( lastByte );
lastByte = currentByte;
currentByte = pdfSource.read();
}
// the EI operator isn't unread, as it won't be processed anyway
retval = Operator.getOperator("ID");
// save the image data to the operator, so that it can be accessed later
((Operator)retval).setImageData( imageData.toByteArray() );
break;
}
case ']':
{
// some ']' around without its previous '['
// this means a PDF is somewhat corrupt but we will continue to parse.
pdfSource.read();
retval = COSNull.NULL; // must be a better solution than null...
break;
}
default:
{
//we must be an operator
String operator = readOperator();
if( operator.trim().length() == 0 )
{
//we have a corrupt stream, stop reading here
retval = null;
}
else
{
retval = Operator.getOperator(operator);
}
}
}
return retval;
}
/**
* Looks up an amount of bytes if they contain only ASCII characters (no
* control sequences etc.), and that these ASCII characters begin with a
* sequence of 1-3 non-blank characters between blanks
*
* @return <code>true</code> if next bytes are probably printable ASCII
* characters starting with a PDF operator, otherwise <code>false</code>
*/
private boolean hasNoFollowingBinData(final PushbackInputStream pdfSource)
throws IOException
{
// as suggested in PDFBOX-1164
final int readBytes = pdfSource.read(binCharTestArr, 0, MAX_BIN_CHAR_TEST_LENGTH);
boolean noBinData = true;
int startOpIdx = -1;
int endOpIdx = -1;
if (readBytes > 0)
{
for (int bIdx = 0; bIdx < readBytes; bIdx++)
{
final byte b = binCharTestArr[bIdx];
if (b < 0x09 || b > 0x0a && b < 0x20 && b != 0x0d)
{
// control character or > 0x7f -> we have binary data
noBinData = false;
break;
}
// find the start of a PDF operator
if (startOpIdx == -1 && !(b == 9 || b == 0x20 || b == 0x0a || b == 0x0d))
{
startOpIdx = bIdx;
}
else if (startOpIdx != -1 && endOpIdx == -1 &&
(b == 9 || b == 0x20 || b == 0x0a || b == 0x0d))
{
endOpIdx = bIdx;
}
}
if (readBytes == MAX_BIN_CHAR_TEST_LENGTH) // only if not close to eof
{
// a PDF operator is 1-3 bytes long
if (startOpIdx != -1 && endOpIdx == -1)
{
endOpIdx = MAX_BIN_CHAR_TEST_LENGTH;
}
if (endOpIdx != -1 && startOpIdx != -1 && endOpIdx - startOpIdx > 3)
{
noBinData = false;
}
}
pdfSource.unread(binCharTestArr, 0, readBytes);
}
if (!noBinData)
{
LOG.warn("ignoring 'EI' assumed to be in the middle of inline image");
}
return noBinData;
}
/**
* This will read an operator from the stream.
*
* @return The operator that was read from the stream.
*
* @throws IOException If there is an error reading from the stream.
*/
protected String readOperator() throws IOException
{
skipSpaces();
//average string size is around 2 and the normal string buffer size is
//about 16 so lets save some space.
StringBuffer buffer = new StringBuffer(4);
int nextChar = pdfSource.peek();
while(
nextChar != -1 && // EOF
!isWhitespace(nextChar) &&
!isClosing(nextChar) &&
nextChar != '[' &&
nextChar != '<' &&
nextChar != '(' &&
nextChar != '/' &&
(nextChar < '0' ||
nextChar > '9' ) )
{
char currentChar = (char)pdfSource.read();
nextChar = pdfSource.peek();
buffer.append( currentChar );
// Type3 Glyph description has operators with a number in the name
if (currentChar == 'd' && (nextChar == '0' || nextChar == '1') )
{
buffer.append( (char)pdfSource.read() );
nextChar = pdfSource.peek();
}
}
return buffer.toString();
}
private boolean isSpaceOrReturn( int c )
{
return c == 10 || c == 13 || c == 32;
}
/**
* Checks if the next char is a space or a return.
*
* @return true if the next char is a space or a return
* @throws IOException if something went wrong
*/
private boolean hasNextSpaceOrReturn() throws IOException
{
return isSpaceOrReturn( pdfSource.peek() );
}
/**
* {@inheritDoc}
*/
@Override
public void clearResources()
{
super.clearResources();
if (streamObjects != null)
{
streamObjects.clear();
streamObjects = null;
}
}
}