Module java.base
Package java.util.zip

# Class GZIPInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
java.util.zip.InflaterInputStream
java.util.zip.GZIPInputStream

All Implemented Interfaces:
  `Closeable`, `AutoCloseable`

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

Since:
  1.1
See Also:
  - `InflaterInputStream`

## Field Summary

Fields
Modifier and Type
Field
Description
`protected CRC32`
`crc`
CRC-32 for uncompressed data.
`protected boolean`
`eos`
Indicates end of input stream.
`static final int`
`GZIP_MAGIC`
GZIP header magic number.

### Fields declared in class java.util.zip.InflaterInputStream

`buf, inf, len`

### Fields declared in class java.io.FilterInputStream

`in`

## Constructor Summary

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

## Method Summary

Modifier and Type
Method
Description
`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, returning the number of inflated bytes.

### Methods declared in class java.util.zip.InflaterInputStream

`available, fill, mark, markSupported, read, reset, skip`

### Methods declared in class java.io.FilterInputStream

`read`

### Methods declared in class java.io.InputStream

`nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo`

### Methods declared in class java.lang.Object

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

## Field Details

### crc

protected CRC32 crc
CRC-32 for uncompressed data.

### eos

protected boolean eos
Indicates end of input stream.

### GZIP_MAGIC

public static final int GZIP_MAGIC
GZIP header magic number.

See Also:
  - Constant Field Values

## Constructor Details

### GZIPInputStream

public GZIPInputStream(InputStream in, int size) throws IOException
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`

### GZIPInputStream

public GZIPInputStream(InputStream in) throws IOException
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

## Method Details

### read

public int read(byte[] buf, 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 `InflaterInputStream`
Parameters:
  `buf` - the buffer into which the data is read
  `off` - the start offset in the destination array `buf`
  `len` - the maximum number of bytes read
Returns:
  the actual number of bytes inflated, 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.
See Also:
  - `FilterInputStream.in`

### 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 `InflaterInputStream`
Throws:
  `IOException` - if an I/O error has occurred
See Also:
  - `FilterInputStream.in`