GZIPInputStream

AI-generated Key Takeaways

• GZIPInputStream provides a way to read data compressed in the GZIP file format.

• It extends InflaterInputStream and uses CRC-32 for data integrity checks.

• Two constructors are available: one with a custom buffer size and one with a default buffer size.

• The read method allows reading uncompressed data into a byte array.

• Closing the stream releases associated system resources using the close method.

public class GZIPInputStream extends InflaterInputStream

This class implements a stream filter for reading compressed data in the GZIP file format.

See Also

• InflaterInputStream

Constant Summary

int

GZIP_MAGIC

GZIP header magic number.

Field Summary

protected CRC32	crc	CRC-32 for uncompressed data.
protected boolean	eos	Indicates end of input stream.

Inherited Field Summary

From class java.util.zip.InflaterInputStream

protected byte[]	buf	Input buffer for decompression.
protected boolean	closed	This field is deprecated. This field will be removed from a future version of Android and should not be used. Subclasses that access this field need to be modified to keep track of their own closed state by overriding close().
protected Inflater	inf	Decompressor for this stream.
protected int	len	Length of input buffer.

From class java.io.FilterInputStream

protected InputStream

in

The input stream to be filtered.

Public Constructor Summary

	GZIPInputStream(InputStream in, int size) Creates a new input stream with the specified buffer size.
	GZIPInputStream(InputStream in) Creates a new input stream with a default buffer size.

Public Method Summary

void	close() Closes this input stream and releases any system resources associated with the stream.
int	read(byte[] buf, int off, int len) Reads uncompressed data into an array of bytes.

Inherited Method Summary

From class java.util.zip.InflaterInputStream

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.
void	fill() Fills input buffer with more data to decompress.
synchronized 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.
synchronized 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.

From class java.io.FilterInputStream

int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
synchronized 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 the next byte of data from this input stream.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from this input stream into an array of bytes.
int	read(byte[] b) Reads up to byte.length bytes of data from this input stream into an array of bytes.
synchronized 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 over and discards n bytes of data from the input stream.

From class java.io.InputStream

int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
synchronized 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.
abstract int	read() Reads the next byte of data from the input stream.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
int	read(byte[] b) Reads some number of bytes from the input stream and stores them into the buffer array b.
synchronized 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 over and discards n bytes of data from this input stream.

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.io.Closeable

abstract void

close() Closes this stream and releases any system resources associated with it.

From interface java.lang.AutoCloseable

abstract void

close() Closes this resource, relinquishing any underlying resources.

Constants

public static final int GZIP_MAGIC

GZIP header magic number.

Constant Value: 35615

Fields

protected CRC32 crc

CRC-32 for uncompressed data.

protected boolean eos

Indicates end of input stream.

Public Constructors

public GZIPInputStream (InputStream in, int size)

Creates a new input stream with the specified buffer size.

Parameters

in	the input stream
size	the input buffer size

Throws

ZipException	if a GZIP format error has occurred or the compression method used is unsupported
IOException	if an I/O error has occurred
IllegalArgumentException	if size <= 0

public GZIPInputStream (InputStream in)

Creates a new input stream with a default buffer size.

Parameters

in	the input stream

Throws

ZipException	if a GZIP format error has occurred or the compression method used is unsupported
IOException	if an I/O error has occurred

Public Methods

public void close ()

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

Throws

IOException	if an I/O error has occurred

public int read (byte[] buf, int off, int len)

Reads uncompressed data into an array of 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.

Parameters

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

Throws

NullPointerException	If buf is null.
IndexOutOfBoundsException	If off is negative, len is negative, or len is greater than buf.length - off
ZipException	if the compressed input data is corrupt.
IOException	if an I/O error has occurred.