Added in API level 1

CipherInputStream

open class CipherInputStream : FilterInputStream

kotlin.Any
↳	java.io.InputStream
	↳	java.io.FilterInputStream
		↳	javax.crypto.CipherInputStream

A CipherInputStream is composed of an InputStream and a Cipher so that read() methods return data that are read in from the underlying InputStream but have been additionally processed by the Cipher. The Cipher must be fully initialized before being used by a CipherInputStream.

For example, if the Cipher is initialized for decryption, the CipherInputStream will attempt to read in data and decrypt them, before returning the decrypted data.

This class adheres strictly to the semantics, especially the failure semantics, of its ancestor classes java.io.FilterInputStream and java.io.InputStream. This class has exactly those methods specified in its ancestor classes, and overrides them all. Moreover, this class catches all exceptions that are not thrown by its ancestor classes. In particular, the skip method skips, and the available method counts only data that have been processed by the encapsulated Cipher.

It is crucial for a programmer using this class not to use methods that are not defined or overriden in this class (such as a new method or constructor that is later added to one of the super classes), because the design and implementation of those methods are unlikely to have considered security impact with regard to CipherInputStream.

Summary

Public constructors
CipherInputStream(is: InputStream!, c: Cipher!) Constructs a CipherInputStream from an InputStream and a Cipher.

Protected constructors
CipherInputStream(is: InputStream!) Constructs a CipherInputStream from an InputStream without specifying a Cipher.

Public methods
open Int	available() Returns the number of bytes that can be read from this input stream without blocking.
open Unit	close() Closes this input stream and releases any system resources associated with the stream.
open Boolean	markSupported() Tests if this input stream supports the mark and reset methods, which it does not.
open Int	read() Reads the next byte of data from this input stream.
open Int	read(b: ByteArray!) Reads up to b.length bytes of data from this input stream into an array of bytes.
open Int	read(b: ByteArray!, off: Int, len: Int) Reads up to len bytes of data from this input stream into an array of bytes.
open Long	skip(n: Long) Skips n bytes of input from the bytes that can be read from this input stream without blocking.

Inherited functions
From class FilterInputStream Unit mark(readlimit: Int) Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes. The readlimit argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated. This method simply performs in.mark(readlimit). Unit reset() Repositions this stream to the position at the time the mark method was last called on this input stream. This method simply performs in.reset(). Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.
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. 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.

Inherited properties
From class FilterInputStream InputStream! in The input stream to be filtered.

Public constructors

CipherInputStream

Added in API level 1

CipherInputStream(
    is: InputStream!, 
    c: Cipher!)

Constructs a CipherInputStream from an InputStream and a Cipher.
Note: if the specified input stream or cipher is null, a NullPointerException may be thrown later when they are used.

Parameters
is	InputStream!: the to-be-processed input stream
c	Cipher!: an initialized Cipher object

Protected constructors

CipherInputStream

Added in API level 1

protected CipherInputStream(is: InputStream!)

Constructs a CipherInputStream from an InputStream without specifying a Cipher. This has the effect of constructing a CipherInputStream using a NullCipher.
Note: if the specified input stream is null, a NullPointerException may be thrown later when it is used.

Parameters
is	InputStream!: the to-be-processed input stream

Public methods

available

Added in API level 1

open fun available(): Int

Returns the number of bytes that can be read from this input stream without blocking. The available method of InputStream returns 0. This method should be overridden by subclasses.

Return
Int	the number of bytes that can be read from this input stream without blocking.

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

The close method of CipherInputStream calls the close method of its underlying input stream.

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

markSupported

Added in API level 1

open fun markSupported(): Boolean

Tests if this input stream supports the mark and reset methods, which it does not.

Return
Boolean	false, since this class does not support the mark and reset methods.

See Also

• java.io.InputStream#mark(int)
• java.io.InputStream#reset()

read

Added in API level 1

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 method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

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

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

read

Added in API level 1

open fun read(b: ByteArray!): Int

Reads up to b.length bytes of data from this input stream into an array of bytes.

The read method of InputStream calls the read method of three arguments with the arguments b, 0, and b.length.

Parameters
b	ByteArray!: the buffer into which the data is read.

Return
Int	the total number of bytes read into the buffer, or -1 is 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 the end of the file, if the input stream has been closed, or if some other I/O error occurs.
java.lang.NullPointerException	if b is null.
java.io.IOException	if an I/O error occurs.

See Also

• java.io.InputStream#read(byte[], int, int)

read

Added in API level 1

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

Reads up to len bytes of data from this input stream into an array of bytes. This method blocks until some input is available. If the first argument is null, up to len bytes are read and discarded.

Parameters
b	ByteArray!: the buffer into which the data is read.
off	Int: the start offset in the destination array buf
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
java.io.IOException	if an I/O error occurs.

See Also

• java.io.InputStream#read()

skip

Added in API level 1

open fun skip(n: Long): Long

Skips n bytes of input from the bytes that can be read from this input stream without blocking.

Fewer bytes than requested might be skipped. The actual number of bytes skipped is equal to n or the result of a call to #available(), whichever is smaller. If n is less than zero, no bytes are skipped.

The actual number of bytes skipped 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 in.skip(n) throws an IOException.
java.io.IOException	if an I/O error occurs.