Package 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:

java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

ByteArrayPushBackInputStream

public class PushBackInputStream
extends java.io.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.FilterInputStream

in

Fields inherited from class java.io.PushbackInputStream

buf, pos

Constructor Summary

Constructors

Constructor	Description
PushBackInputStream(java.io.InputStream input, int size)	Constructor.

Method Summary

Modifier and Type	Method	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.InputStream

readAllBytes, readNBytes, transferTo

Methods inherited from class java.lang.Object

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

Methods inherited from class java.io.PushbackInputStream

available, close, mark, markSupported, reset, skip

Constructor Detail

PushBackInputStream

public PushBackInputStream(java.io.InputStream input,
                           int size)
                    throws java.io.IOException

Constructor.

Parameters:

input - The input stream.

size - The size of the push back buffer.

Throws:

java.io.IOException - If there is an error with the stream.

Method Detail

peek

public int peek()
         throws java.io.IOException

This will peek at the next byte.

Returns:

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

Throws:

java.io.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 java.io.IOException

Overrides:

read in class java.io.PushbackInputStream

Throws:

java.io.IOException

read

public int read(byte[] b)
         throws java.io.IOException

Overrides:

read in class java.io.FilterInputStream

Throws:

java.io.IOException

read

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

Overrides:

read in class java.io.PushbackInputStream

Throws:

java.io.IOException

unread

public void unread(int b)
            throws java.io.IOException

Overrides:

unread in class java.io.PushbackInputStream

Throws:

java.io.IOException

unread

public void unread(byte[] b)
            throws java.io.IOException

Overrides:

unread in class java.io.PushbackInputStream

Throws:

java.io.IOException

unread

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

Overrides:

unread in class java.io.PushbackInputStream

Throws:

java.io.IOException

isEOF

public boolean isEOF()
              throws java.io.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:

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

fillBuffer

public void fillBuffer()
                throws java.io.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:

java.io.IOException - If there is an error filling the buffer.

readFully

public byte[] readFully(int length)
                 throws java.io.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:

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

seek

public void seek(long newOffset)
          throws java.io.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:

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