InflaterInputStream (Java SE 25 & JDK 25)
Description: declaration: module: java.base, package: java.util.zip, class: InflaterInputStream
Keywords: java.util.zip.InflaterInputStream class

# 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`

- ## 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`

  ### Methods declared in class InputStream

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

  ### Methods declared in class Object

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

- ## 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`