GZIPInputStream (Java SE 23 & JDK 23)
Description: declaration: module: java.base, package: java.util.zip, class: GZIPInputStream
Keywords: java.util.zip.GZIPInputStream class

# 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
      `NullPointerException` - if `in` is null
      `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
      `NullPointerException` - if `in` is null
      `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`