ByteArrayInputStream | API reference | Android Developers (original) (raw)

open class ByteArrayInputStream : 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.

Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

Summary

Public constructors
ByteArrayInputStream(buf: ByteArray!) Creates a ByteArrayInputStream so that it uses buf as its buffer array.
ByteArrayInputStream(buf: ByteArray!, offset: Int, length: Int) Creates ByteArrayInputStream that uses buf as its buffer array.

Public methods
open Int	available() Returns the number of remaining bytes that can be read (or skipped over) from this input stream.
open Unit	close() Closing a ByteArrayInputStream has no effect.
open Unit	mark(readAheadLimit: Int) Set the current marked position in the stream.
open Boolean	markSupported() Tests if this InputStream supports mark/reset.
open Int	read() Reads the next byte of data from this input stream.
open Int	read(b: ByteArray!, off: Int, len: Int) Reads up to len bytes of data into an array of bytes from this input stream.
open ByteArray!	readAllBytes()
open Int	readNBytes(b: ByteArray!, off: Int, len: Int)
open Unit	reset() Resets the buffer to the marked position.
open Long	skip(n: Long) Skips n bytes of input from this input stream.
open Long	transferTo(out: OutputStream!)

Inherited functions

Inherited functions
From class InputStream 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. Int read(b: ByteArray!) Reads some number of bytes from the input stream and stores them into the buffer array b. The number of bytes actually read is returned as an integer. This method blocks until input data is available, end of file is detected, or an exception is thrown. If the length of b is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at the end of the file, the value -1 is returned; otherwise, at least one byte is read and stored into b. The first byte read is stored into element b[0], the next one into b[1], and so on. The number of bytes read is, at most, equal to the length of b. Let k be the number of bytes actually read; these bytes will be stored in elements b[0] through b[_k_-1], leaving elements b[_k_] through b[b.length-1] unaffected. The read(b) method for class InputStream has the same effect as: read(b, 0, b.length) 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.

From class InputStream 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. Int read(b: ByteArray!) Reads some number of bytes from the input stream and stores them into the buffer array b. The number of bytes actually read is returned as an integer. This method blocks until input data is available, end of file is detected, or an exception is thrown. If the length of b is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at the end of the file, the value -1 is returned; otherwise, at least one byte is read and stored into b. The first byte read is stored into element b[0], the next one into b[1], and so on. The number of bytes read is, at most, equal to the length of b. Let k be the number of bytes actually read; these bytes will be stored in elements b[0] through b[_k_-1], leaving elements b[_k_] through b[b.length-1] unaffected. The read(b) method for class InputStream has the same effect as:

read(b, 0, b.length) 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.

Properties
ByteArray!	buf An array of bytes that was provided by the creator of the stream.
Int	count The index one greater than the last valid character in the input stream buffer.
Int	mark The currently marked position in the stream.
Int	pos The index of the next character to read from the input stream buffer.

Public constructors

ByteArrayInputStream

ByteArrayInputStream(buf: ByteArray!)

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.

Parameters
buf	ByteArray!: the input buffer.

ByteArrayInputStream

ByteArrayInputStream(
    buf: ByteArray!,
    offset: Int,
    length: Int)

Creates ByteArrayInputStream that uses buf as its buffer array. The initial value of pos is offset and the initial value of count is the minimum of offset+length and buf.length. The buffer array is not copied. The buffer's mark is set to the specified offset.

Parameters
buf	ByteArray!: the input buffer.
offset	Int: the offset in the buffer of the first byte to read.
length	Int: the maximum number of bytes to read from the buffer.

Public methods

available

open fun available(): Int

Returns the number of remaining bytes that can be read (or skipped over) from this input stream.

The value returned is count - pos, which is the number of bytes remaining to be read from the input buffer.

Return
Int	the number of remaining bytes that can be read (or skipped over) from this input stream without blocking.

Exceptions
java.io.IOException	if an I/O error occurs.

close

open fun close(): Unit

Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

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

mark

open fun mark(readAheadLimit: Int): Unit

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.

If no mark has been set, then the value of the mark is the offset passed to the constructor (or 0 if the offset was not supplied).

Note: The readAheadLimit for this class has no meaning.

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

markSupported

open fun markSupported(): Boolean

Tests if this InputStream supports mark/reset. The markSupported method of ByteArrayInputStream always returns true.

Return
Boolean	true if this stream instance supports the mark and reset methods; false otherwise.

read

open fun read(): Int

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.

Return
Int	the next byte of data, or -1 if the end of the stream has been reached.

Exceptions
java.io.IOException	if an I/O error occurs.

read

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

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[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.

Parameters
b	ByteArray!: the buffer into which the data is read.
off	Int: the start offset in the destination array b
len	Int: the maximum number of bytes read.

Return
Int	the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Exceptions
java.io.IOException	If the first byte cannot be read for any reason other than end of file, or if the input stream has been closed, or if some other 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

readAllBytes

open fun readAllBytes(): ByteArray!

Return
ByteArray!	a byte array containing the bytes read from this input stream

Exceptions
java.io.IOException	if an I/O error occurs
java.lang.OutOfMemoryError	if an array of the required size cannot be allocated.

readNBytes

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

Parameters
b	ByteArray!: the byte array into which the data is read
off	Int: the start offset in b at which the data is written
len	Int: the maximum number of bytes to read

Return
Int	the actual number of bytes read into the buffer

Exceptions
java.io.IOException	if 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

open fun reset(): Unit

Resets the buffer to the marked position. The marked position is 0 unless another position was marked or an offset was specified in the constructor.

Exceptions
java.io.IOException	if this stream has not been marked or if the mark has been invalidated.

skip

open fun skip(n: Long): Long

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.

Parameters
n	Long: the number of bytes to be skipped.

Return
Long	the actual number of bytes skipped.

Exceptions
java.io.IOException	if an I/O error occurs.

transferTo

open fun transferTo(out: OutputStream!): Long

Parameters
out	OutputStream!: the output stream, non-null

Return
Long	the number of bytes transferred

Exceptions
java.io.IOException	if an I/O error occurs when reading or writing
java.lang.NullPointerException	if out is null

Properties

buf

protected var buf: ByteArray!

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 var count: Int

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 var mark: Int

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.

If no mark has been set, then the value of mark is the offset passed to the constructor (or 0 if the offset was not supplied).

pos

protected var pos: Int

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].