Added in API level 1

BufferedInputStream

open class BufferedInputStream : FilterInputStream

A BufferedInputStream adds functionality to another input stream-namely, the ability to buffer the input and to support the mark and reset methods. When the BufferedInputStream is created, an internal buffer array is created. As bytes from the stream are read or skipped, the internal buffer is refilled as necessary from the contained input stream, many bytes at a time. The mark operation remembers a point in the input stream and the reset operation causes all the bytes read since the most recent mark operation to be reread before new bytes are taken from the contained input stream.

Summary

Public constructors

Creates a BufferedInputStream and saves its argument, the input stream in, for later use.

Creates a BufferedInputStream with the specified buffer size, and saves its argument, the input stream in, for later use.

Public methods
open Int

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.

open Unit

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

open Unit
mark(readlimit: Int)

See the general contract of the mark method of InputStream.

open Boolean

Tests if this input stream supports the mark and reset methods.

open Int

See the general contract of the read method of InputStream.

open Int
read(b: ByteArray!, off: Int, len: Int)

Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.

open Unit

See the general contract of the reset method of InputStream.

open Long
skip(n: Long)

See the general contract of the skip method of InputStream.

Inherited functions
InputStream! nullInputStream()

Returns a new InputStream that reads no bytes. The returned stream is initially open. The stream is closed by calling the close() method. Subsequent calls to close() have no effect.

While the stream is open, the available(), read(), read(byte[]), read(byte[], int, int), readAllBytes(), readNBytes(byte[], int, int), readNBytes(int), skip(long), skipNBytes(long), and transferTo() methods all behave as if end of stream has been reached. After the stream has been closed, these methods all throw IOException.

The markSupported() method returns false. The mark() method does nothing, and the reset() method throws IOException.

ByteArray! readAllBytes()

Reads all remaining bytes from the input stream. This method blocks until all remaining bytes have been read and end of stream is detected, or an exception is thrown. This method does not close the input stream.

When this stream reaches end of stream, further invocations of this method will return an empty byte array.

Note that this method is intended for simple cases where it is convenient to read all bytes into a byte array. It is not intended for reading input streams with large amounts of data.

The behavior for the case where the input stream is asynchronously closed, or the thread interrupted during the read, is highly input stream specific, and therefore not specified.

If an I/O error occurs reading from the input stream, then it may do so after some, but not all, bytes have been read. Consequently the input stream may not be at end of stream and may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

Int readNBytes(b: ByteArray!, off: Int, len: Int)

Reads the requested number of bytes from the input stream into the given byte array. This method blocks until len bytes of input data have been read, end of stream is detected, or an exception is thrown. The number of bytes actually read, possibly zero, is returned. This method does not close the input stream.

In the case where end of stream is reached before len bytes have been read, then the actual number of bytes read will be returned. When this stream reaches end of stream, further invocations of this method will return zero.

If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read up to len bytes.

The first byte read is stored into element b[off], the next one in to b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k ] through b[off+len-1] unaffected.

The behavior for the case where the input stream is asynchronously closed, or the thread interrupted during the read, is highly input stream specific, and therefore not specified.

If an I/O error occurs reading from the input stream, then it may do so after some, but not all, bytes of b have been updated with data from the input stream. Consequently the input stream and b may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

ByteArray! readNBytes(len: Int)

Reads up to a specified number of bytes from the input stream. This method blocks until the requested number of bytes has been read, end of stream is detected, or an exception is thrown. This method does not close the input stream.

The length of the returned array equals the number of bytes read from the stream. If len is zero, then no bytes are read and an empty byte array is returned. Otherwise, up to len bytes are read from the stream. Fewer than len bytes may be read if end of stream is encountered.

When this stream reaches end of stream, further invocations of this method will return an empty byte array.

Note that this method is intended for simple cases where it is convenient to read the specified number of bytes into a byte array. The total amount of memory allocated by this method is proportional to the number of bytes read from the stream which is bounded by len. Therefore, the method may be safely called with very large values of len provided sufficient memory is available.

The behavior for the case where the input stream is asynchronously closed, or the thread interrupted during the read, is highly input stream specific, and therefore not specified.

If an I/O error occurs reading from the input stream, then it may do so after some, but not all, bytes have been read. Consequently the input stream may not be at end of stream and may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

Unit skipNBytes(n: Long)

Skips over and discards exactly n bytes of data from this input stream. If n is zero, then no bytes are skipped. If n is negative, then no bytes are skipped. Subclasses may handle the negative value differently.

This method blocks until the requested number of bytes has been skipped, end of file is reached, or an exception is thrown.

If end of stream is reached before the stream is at the desired position, then an EOFException is thrown.

If an I/O error occurs, then the input stream may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

Long transferTo(out: OutputStream!)

Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read. On return, this input stream will be at end of stream. This method does not close either stream.

This method may block indefinitely reading from the input stream, or writing to the output stream. The behavior for the case where the input and/or output stream is asynchronously closed, or the thread interrupted during the transfer, is highly input and output stream specific, and therefore not specified.

If an I/O error occurs reading from the input stream or writing to the output stream, then it may do so after some bytes have been read or written. Consequently the input stream may not be at end of stream and one, or both, streams may be in an inconsistent state. It is strongly recommended that both streams be promptly closed if an I/O error occurs.

Int read(b: ByteArray!)

Reads up to b.length bytes of data from this input stream into an array of bytes. This method blocks until some input is available.

This method simply performs the call read(b, 0, b.length) and returns the result. It is important that it does not do in.read(b) instead; certain subclasses of FilterInputStream depend on the implementation strategy actually used.

Properties
ByteArray!

The internal buffer array where the data is stored.

Int

The index one greater than the index of the last valid byte in the buffer.

Int

The maximum read ahead allowed after a call to the mark method before subsequent calls to the reset method fail.

Int

The value of the pos field at the time the last mark method was called.

Int

The current position in the buffer.

Inherited properties
InputStream! in

The input stream to be filtered.

Public constructors

BufferedInputStream

Added in API level 1
BufferedInputStream(in: InputStream!)

Creates a BufferedInputStream and saves its argument, the input stream in, for later use. An internal buffer array is created and stored in buf.

Parameters
in InputStream!: the underlying input stream.

BufferedInputStream

Added in API level 1
BufferedInputStream(
    in: InputStream!,
    size: Int)

Creates a BufferedInputStream with the specified buffer size, and saves its argument, the input stream in, for later use. An internal buffer array of length size is created and stored in buf.

Parameters
in InputStream!: the underlying input stream.
size Int: the buffer size.
Exceptions
java.lang.IllegalArgumentException if size <= 0.

Public methods

available

Added in API level 1
open fun available(): Int

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. The next invocation might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

This method returns the sum of the number of bytes remaining to be read in the buffer (count - pos) and the result of calling the in.available().

Return
Int an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking.
Exceptions
java.io.IOException if this input stream has been closed by invoking its #close() method, or an I/O error occurs.

close

Added in API level 1
open fun close(): Unit

Closes this input stream and releases any system resources associated with the stream. Once the stream has been closed, further read(), available(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.

Exceptions
java.lang.Exception if this resource cannot be closed
java.io.IOException if an I/O error occurs.

mark

Added in API level 1
open fun mark(readlimit: Int): Unit

See the general contract of the mark method of InputStream.

Parameters
readlimit Int: the maximum limit of bytes that can be read before the mark position becomes invalid.

See Also

    markSupported

    Added in API level 1
    open fun markSupported(): Boolean

    Tests if this input stream supports the mark and reset methods. The markSupported method of BufferedInputStream returns true.

    Return
    Boolean a boolean indicating if this stream type supports the mark and reset methods.

    read

    Added in API level 1
    open fun read(): Int

    See the general contract of the read method of InputStream.

    Return
    Int the next byte of data, or -1 if the end of the stream is reached.
    Exceptions
    java.io.IOException if this input stream has been closed by invoking its #close() method, or an I/O error occurs.

    read

    Added in API level 1
    open fun read(
        b: ByteArray!,
        off: Int,
        len: Int
    ): Int

    Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.

    This method implements the general contract of the corresponding read method of the InputStream class. As an additional convenience, it attempts to read as many bytes as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

    • The specified number of bytes have been read,
    • The read method of the underlying stream returns -1, indicating end-of-file, or
    • The available method of the underlying stream returns zero, indicating that further input requests would block.
    If the first read on the underlying stream returns -1 to indicate end-of-file then this method returns -1. Otherwise this method returns the number of bytes actually read.

    Subclasses of this class are encouraged, but not required, to attempt to read as many bytes as possible in the same fashion.

    Parameters
    b ByteArray!: destination buffer.
    off Int: offset at which to start storing bytes.
    len Int: maximum number of bytes to read.
    Return
    Int the number of bytes read, or -1 if the end of the stream has been reached.
    Exceptions
    java.io.IOException if this input stream has been closed by invoking its #close() method, or an I/O error occurs.
    java.lang.NullPointerException If b is null.
    java.lang.IndexOutOfBoundsException If off is negative, len is negative, or len is greater than b.length - off

    reset

    Added in API level 1
    open fun reset(): Unit

    See the general contract of the reset method of InputStream.

    If markpos is -1 (no mark has been set or the mark has been invalidated), an IOException is thrown. Otherwise, pos is set equal to markpos.

    Exceptions
    java.io.IOException if this stream has not been marked or, if the mark has been invalidated, or the stream has been closed by invoking its #close() method, or an I/O error occurs.

    See Also

      skip

      Added in API level 1
      open fun skip(n: Long): Long

      See the general contract of the skip method of InputStream.

      Parameters
      n Long: the number of bytes to be skipped.
      Return
      Long the actual number of bytes skipped.
      Exceptions
      java.io.IOException if this input stream has been closed by invoking its #close() method, in.skip(n) throws an IOException, or an I/O error occurs.

      Properties

      buf

      Added in API level 1
      protected var buf: ByteArray!

      The internal buffer array where the data is stored. When necessary, it may be replaced by another array of a different size.

      count

      Added in API level 1
      protected var count: Int

      The index one greater than the index of the last valid byte in the buffer. This value is always in the range 0 through buf.length; elements buf[0] through buf[count-1] contain buffered input data obtained from the underlying input stream.

      marklimit

      Added in API level 1
      protected var marklimit: Int

      The maximum read ahead allowed after a call to the mark method before subsequent calls to the reset method fail. Whenever the difference between pos and markpos exceeds marklimit, then the mark may be dropped by setting markpos to -1.

      See Also

        markpos

        Added in API level 1
        protected var markpos: Int

        The value of the pos field at the time the last mark method was called.

        This value is always in the range -1 through pos. If there is no marked position in the input stream, this field is -1. If there is a marked position in the input stream, then buf[markpos] is the first byte to be supplied as input after a reset operation. If markpos is not -1, then all bytes from positions buf[markpos] through buf[pos-1] must remain in the buffer array (though they may be moved to another place in the buffer array, with suitable adjustments to the values of count, pos, and markpos); they may not be discarded unless and until the difference between pos and markpos exceeds marklimit.

        pos

        Added in API level 1
        protected var pos: Int

        The current position in the buffer. This is the index of the next character to be read from the buf array.

        This value is always in the range 0 through count. If it is less than count, then buf[pos] is the next byte to be supplied as input; if it is equal to count, then the next read or skip operation will require more bytes to be read from the contained input stream.