org.apache.pdfbox.io

Class PushBackInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

java.io.PushbackInputStream

org.apache.pdfbox.io.PushBackInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

ByteArrayPushBackInputStream

public class PushBackInputStream
extends PushbackInputStream

A simple subclass that adds a few convience methods.

Version:

$Revision: 1.6 $

Author:

Ben Litchfield

Field Summary

Fields inherited from class java.io.PushbackInputStream

buf, pos

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
PushBackInputStream(InputStream input, int size) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	fillBuffer() This is a method used to fix PDFBox issue 974661, the PDF parsing code needs to know if there is at least x amount of data left in the stream, but the available() method returns how much data will be available without blocking.
long	getOffset() Returns the current byte offset in the file.
boolean	isEOF() A simple test to see if we are at the end of the stream.
int	peek() This will peek at the next byte.
int	read()
int	read(byte[] b)
int	read(byte[] b, int off, int len)
byte[]	readFully(int length) Reads a given number of bytes from the underlying stream.
void	seek(long newOffset) Allows to seek to another position within stream in case the underlying stream implements RandomAccessRead.
void	unread(byte[] b)
void	unread(byte[] b, int off, int len)
void	unread(int b)

Methods inherited from class java.io.PushbackInputStream

available, close, mark, markSupported, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PushBackInputStream

public PushBackInputStream(InputStream input,
                   int size)
                    throws IOException

Constructor.

Parameters:

input - The input stream.

size - The size of the push back buffer.

Throws:

IOException - If there is an error with the stream.

Method Detail

peek

public int peek()
         throws IOException

This will peek at the next byte.

Returns:

The next byte on the stream, leaving it as available to read.

Throws:

IOException - If there is an error reading the next byte.

getOffset

public long getOffset()

Returns the current byte offset in the file.

Returns:

the int byte offset

read

public int read()
         throws IOException

Overrides:

read in class PushbackInputStream

Throws:

IOException

read

public int read(byte[] b)
         throws IOException

Overrides:

read in class FilterInputStream

Throws:

IOException

read

public int read(byte[] b,
       int off,
       int len)
         throws IOException

Overrides:

read in class PushbackInputStream

Throws:

IOException

unread

public void unread(int b)
            throws IOException

Overrides:

unread in class PushbackInputStream

Throws:

IOException

unread

public void unread(byte[] b)
            throws IOException

Overrides:

unread in class PushbackInputStream

Throws:

IOException

unread

public void unread(byte[] b,
          int off,
          int len)
            throws IOException

Overrides:

unread in class PushbackInputStream

Throws:

IOException

isEOF

public boolean isEOF()
              throws IOException

A simple test to see if we are at the end of the stream.

Returns:

true if we are at the end of the stream.

Throws:

IOException - If there is an error reading the next byte.

fillBuffer

public void fillBuffer()
                throws IOException

This is a method used to fix PDFBox issue 974661, the PDF parsing code needs to know if there is at least x amount of data left in the stream, but the available() method returns how much data will be available without blocking. PDFBox is willing to block to read the data, so we will first fill the internal buffer.

Throws:

IOException - If there is an error filling the buffer.

readFully

public byte[] readFully(int length)
                 throws IOException

Reads a given number of bytes from the underlying stream.

Parameters:

length - the number of bytes to be read

Returns:

a byte array containing the bytes just read

Throws:

IOException - if an I/O error occurs while reading data

seek

public void seek(long newOffset)
          throws IOException

Allows to seek to another position within stream in case the underlying stream implements RandomAccessRead. Otherwise an IOException is thrown. Pushback buffer is cleared before seek operation by skipping over all bytes of buffer.

Parameters:

newOffset - new position within stream from which to read next

Throws:

IOException - if underlying stream does not implement RandomAccessRead or seek operation on underlying stream was not successful