Class InflaterInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

java.util.zip.InflaterInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

GZIPInputStream, ZipInputStream

public class InflaterInputStream
extends FilterInputStream

This class implements a stream filter for uncompressing data in the "deflate" compression format. It is also used as the basis for other decompression filters, such as GZIPInputStream.

Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown.

Decompressor Usage

An InflaterInputStream created without specifying a decompressor will create a decompressor at construction time, and close the decompressor when the input stream is closed.

If a decompressor is specified when creating a InflaterInputStream, it is the responsibility of the caller to close the decompressor after closing the input stream.

API Note:

The close() method should be called to release resources used by this stream, either directly, or with the try-with-resources statement.

Since:

1.1

See Also:

• Inflater

Field Summary

Fields

Modifier and Type	Field	Description
protected byte[]	buf	Input buffer for decompression.
protected Inflater	inf	Decompressor for this stream.
protected int	len	The total number of bytes read into the input buffer.

Fields declared in class FilterInputStream

in

Modifier and Type	Field	Description
protected InputStream	in	The input stream to be filtered.

Constructor Summary

Constructors

Constructor	Description
InflaterInputStream(InputStream in)	Creates a new input stream and decompressor with a default buffer size.
InflaterInputStream(InputStream in, Inflater inf)	Creates a new input stream with the specified decompressor and a default buffer size.
InflaterInputStream(InputStream in, Inflater inf, int size)	Creates a new input stream with the specified decompressor and buffer size.

Method Summary

Modifier and Type	Method	Description
int	available()	Returns 0 after EOF has been reached, otherwise always return 1.
void	close()	Closes this input stream and releases any system resources associated with the stream.
protected void	fill()	Fills input buffer with more data to decompress.
void	mark(int readlimit)	Marks the current position in this input stream.
boolean	markSupported()	Tests if this input stream supports the mark and reset methods.
int	read()	Reads a byte of uncompressed data.
int	read(byte[] b, int off, int len)	Reads uncompressed data into an array of bytes, returning the number of inflated bytes.
void	reset()	Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n)	Skips specified number of bytes of uncompressed data.

Methods declared in class FilterInputStream

read

Modifier and Type	Method	Description
int	read(byte[] b)	Reads up to b.length bytes of data from this input stream into an array of bytes.

Methods declared in class InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Modifier and Type	Method	Description
static InputStream	nullInputStream()	Returns a new InputStream that reads no bytes.
byte[]	readAllBytes()	Reads all remaining bytes from the input stream.
int	readNBytes(byte[] b, int off, int len)	Reads the requested number of bytes from the input stream into the given byte array.
byte[]	readNBytes(int len)	Reads up to a specified number of bytes from the input stream.
void	skipNBytes(long n)	Skips over and discards exactly n bytes of data from this input stream.
long	transferTo(OutputStream out)	Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Field Details

inf

protected Inflater inf

Decompressor for this stream.

buf

protected byte[] buf

Input buffer for decompression.

len

protected int len

The total number of bytes read into the input buffer.

Constructor Details

InflaterInputStream

public InflaterInputStream(InputStream in,
 Inflater inf,
 int size)

Creates a new input stream with the specified decompressor and buffer size.

Closing this input stream will not close the given decompressor.

Parameters:

in - the input stream

inf - the decompressor ("inflater")

size - the input buffer size

Throws:

IllegalArgumentException - if size <= 0

InflaterInputStream

public InflaterInputStream(InputStream in,
 Inflater inf)

Creates a new input stream with the specified decompressor and a default buffer size.

Closing this input stream will not close the given decompressor.

Parameters:

in - the input stream

inf - the decompressor ("inflater")

InflaterInputStream

public InflaterInputStream(InputStream in)

Creates a new input stream and decompressor with a default buffer size.

The decompressor will be closed when this input stream is closed.

Parameters:

in - the input stream

Method Details

read

public int read()
         throws IOException

Reads a byte of uncompressed data. This method will block until enough input is available for decompression.

Overrides:

read in class FilterInputStream

Returns:

the byte read, or -1 if end of compressed input is reached

Throws:

IOException - if an I/O error has occurred

See Also:

• FilterInputStream.in

read

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

Reads uncompressed data into an array of bytes, returning the number of inflated bytes. If len is not zero, the method will block until some input can be decompressed; otherwise, no bytes are read and 0 is returned.

If this method returns a nonzero integer n then buf[off] through buf[off+n-1] contain the uncompressed data. The content of elements buf[off+n] through buf[off+len-1] is undefined, contrary to the specification of the InputStream superclass, so an implementation is free to modify these elements during the inflate operation. If this method returns -1 or throws an exception then the content of buf[off] through buf[off+len -1] is undefined.

Overrides:

read in class FilterInputStream

Parameters:

b - the buffer into which the data is read

off - the start offset in the destination array b

len - the maximum number of bytes read

Returns:

the actual number of bytes inflated, or -1 if the end of the compressed input is reached or a preset dictionary is needed

Throws:

IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off

ZipException - if a ZIP format error has occurred

IOException - if an I/O error has occurred

See Also:

• FilterInputStream.in

available

public int available()
              throws IOException

Returns 0 after EOF has been reached, otherwise always return 1.

Programs should not count on this method to return the actual number of bytes that could be read without blocking.

Overrides:

available in class FilterInputStream

Returns:

1 before EOF and 0 after EOF.

Throws:

IOException - if an I/O error occurs.

skip

public long skip(long n)
          throws IOException

Skips specified number of bytes of uncompressed data. This method may block until the specified number of bytes are skipped or end of stream is reached.

Overrides:

skip in class FilterInputStream

Implementation Note:

This method skips at most Integer.MAX_VALUE bytes.

Parameters:

n - the number of bytes to skip. If n is zero then no bytes are skipped.

Returns:

the actual number of bytes skipped, which might be zero

Throws:

IOException - if an I/O error occurs or if this stream is already closed

IllegalArgumentException - if n < 0

See Also:

• InputStream.skipNBytes(long)

close

public void close()
           throws IOException

Closes this input stream and releases any system resources associated with the stream.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class FilterInputStream

Throws:

IOException - if an I/O error has occurred

See Also:

• FilterInputStream.in

fill

protected void fill()
             throws IOException

Fills input buffer with more data to decompress.

Implementation Requirements:

This method will read up to buf.length bytes into the input buffer, buf, starting at element 0. The len field will be set to the number of bytes read.

Throws:

IOException - if an I/O error has occurred

EOFException - if the end of input stream has been reached unexpectedly

markSupported

public boolean markSupported()

Tests if this input stream supports the mark and reset methods. The markSupported method of InflaterInputStream returns false.

Overrides:

markSupported in class FilterInputStream

Returns:

a boolean indicating if this stream type supports the mark and reset methods.

See Also:

• InputStream.mark(int)
• InputStream.reset()

mark

public void mark(int readlimit)

Marks the current position in this input stream.

Overrides:

mark in class FilterInputStream

Implementation Requirements:

The mark method of InflaterInputStream does nothing.

Parameters:

readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

See Also:

• InputStream.reset()

reset

public void reset()
           throws IOException

Repositions this stream to the position at the time the mark method was last called on this input stream.

Overrides:

reset in class FilterInputStream

Implementation Requirements:

The method reset for class InflaterInputStream does nothing except throw an IOException.

Throws:

IOException - if this method is invoked.

See Also:

• InputStream.mark(int)
• IOException