# Class ByteArrayInputStream

java.lang.Object
java.io.InputStream
java.io.ByteArrayInputStream

All Implemented Interfaces:
  `java.lang.AutoCloseable`

public class ByteArrayInputStream extends InputStream
A ByteArrayInputStream contains an internal buffer that contains bytes that may be read from the stream. An internal counter keeps track of the next byte to be supplied by the read method. Since: JDK1.0, CLDC 1.0

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected byte[]`
  `buf`
  An array of bytes that was provided by the creator of the stream.
  `protected int`
  `count`
  The index one greater than the last valid character in the input stream buffer.
  `protected int`
  `mark`
  The currently marked position in the stream.
  `protected int`
  `pos`
  The index of the next character to read from the input stream buffer.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `ByteArrayInputStream(byte[] buf)`
  Creates a ByteArrayInputStream so that it uses buf as its buffer array.
  `ByteArrayInputStream(byte[] buf, int offset, int length)`
  Creates ByteArrayInputStream that uses buf as its buffer array.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `int`
  `available()`
  Returns the number of bytes that can be read from this input stream without blocking.
  `void`
  `close()`
  Closes this input stream and releases any system resources associated with the stream.
  `void`
  `mark(int readAheadLimit)`
  Set the current marked position in the stream.
  `boolean`
  `markSupported()`
  Tests if ByteArrayInputStream supports mark/reset.
  `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 into an array of bytes from this input stream.
  `void`
  `reset()`
  Resets the buffer to the marked position.
  `long`
  `skip(long n)`
  Skips n bytes of input from this input stream.

  ### Methods inherited from class InputStream

  `read`

  ### Methods inherited from class java.lang.Object

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

- ## Field Details

  - ### buf

    protected byte[] buf
    An array of bytes that was provided by the creator of the stream. Elements buf[0] through buf[count-1] are the only bytes that can ever be read from the stream; element buf`pos` is the next byte to be read.

  - ### count

    protected int count
    The index one greater than the last valid character in the input stream buffer. This value should always be nonnegative and not larger than the length of buf. It is one greater than the position of the last byte within buf that can ever be read from the input stream buffer.

  - ### mark

    protected int mark
    The currently marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by the mark() method. The current buffer position is set to this point by the reset() method. Since: JDK1.1

  - ### pos

    protected int pos
    The index of the next character to read from the input stream buffer. This value should always be nonnegative and not larger than the value of count. The next byte to be read from the input stream buffer will be buf`pos`.

- ## Constructor Details

  - ### ByteArrayInputStream

    public ByteArrayInputStream(byte[] buf)
    Creates a ByteArrayInputStream so that it uses buf as its buffer array. The buffer array is not copied. The initial value of pos is 0 and the initial value of count is the length of buf. buf - the input buffer.

  - ### ByteArrayInputStream

    public ByteArrayInputStream(byte[] buf, int offset, int length)
    Creates ByteArrayInputStream that uses buf as its buffer array. The initial value of pos is offset and the initial value of count is offset+length. The buffer array is not copied. Note that if bytes are simply read from the resulting input stream, elements buf`pos` through buf[pos+len-1] will be read; however, if a reset operation is performed, then bytes buf[0] through buf[pos-1] will then become available for input. buf - the input buffer.offset - the offset in the buffer of the first byte to read.length - the maximum number of bytes to read from the buffer.

- ## Method Details

  - ### available

    public int available()

    Returns the number of bytes that can be read from this input stream without blocking. The value returned is count

    - pos, which is the number of bytes remaining to be read from the input buffer.
    Overrides:
      `available` in class `InputStream`

  - ### close

    public void close() throws IOException
    Closes this input stream and releases any system resources associated with the stream.
    Specified by:
      `close` in interface `java.lang.AutoCloseable`
    Overrides:
      `close` in class `InputStream`
    Throws:
      `IOException`

  - ### mark

    public void mark(int readAheadLimit)
    Set the current marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by this method.
    Overrides:
      `mark` in class `InputStream`

  - ### markSupported

    public boolean markSupported()
    Tests if ByteArrayInputStream supports mark/reset.
    Overrides:
      `markSupported` in class `InputStream`

  - ### read

    public int read()
    Reads the next byte of data from this input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This read method cannot block.
    Specified by:
      `read` in class `InputStream`

  - ### read

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

    Reads up to len bytes of data into an array of bytes from this input stream. If pos equals count, then -1 is returned to indicate end of file. Otherwise, the number k of bytes read is equal to the smaller of len and count-pos. If k is positive, then bytes buf`pos` through buf[pos+k-1] are copied into b

    invalid reference

        off

    through b[off+k-1] in the manner performed by System.arraycopy. The value k is added into pos and k is returned.

    This read method cannot block.

    Overrides:
      `read` in class `InputStream`

  - ### reset

    public void reset()
    Resets the buffer to the marked position. The marked position is the beginning unless another position was marked. The value of pos is set to 0.
    Overrides:
      `reset` in class `InputStream`

  - ### skip

    public long skip(long n)
    Skips n bytes of input from this input stream. Fewer bytes might be skipped if the end of the input stream is reached. The actual number k of bytes to be skipped is equal to the smaller of n and count-pos. The value k is added into pos and k is returned.
    Overrides:
      `skip` in class `InputStream`