Package org.bouncycastle.crypto.io

Class CipherInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
org.bouncycastle.crypto.io.CipherInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
public class CipherInputStream
extends FilterInputStream
A CipherInputStream is composed of an InputStream and a BufferedBlockCipher 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.

  • Field Summary

    Fields inherited from class java.io.FilterInputStream

    in

  • Constructor Summary

    Constructors
    Constructor Description
    CipherInputStream​(InputStream is, BufferedBlockCipher cipher)
    Constructs a CipherInputStream from an InputStream and a BufferedBlockCipher.
    CipherInputStream​(InputStream is, StreamCipher cipher)  

  • Method Summary

    Modifier and Type Method Description
    int available()
    Returns an estimated number of bytes that can be read or skipped without blocking for more input.
    void close()
    Closes this stream.
    boolean markSupported()
    Indicates whether this stream supports mark() and reset().
    int read()
    Reads a single byte from the filtered stream and returns it as an integer in the range from 0 to 255.
    int read​(byte[] b)
    Equivalent to read(buffer, 0, buffer.length).
    int read​(byte[] b, int off, int len)
    Reads up to byteCount bytes from this stream and stores them in the byte array buffer starting at byteOffset.
    long skip​(long n)
    Skips byteCount bytes in this stream.

    Methods inherited from class java.io.FilterInputStream

    mark, reset

    Methods inherited from class java.lang.Object

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

  • Constructor Details

  • Method Details

    • read

      public int read() throws IOException
      Description copied from class: FilterInputStream
      Reads a single byte from the filtered stream and returns it as an integer in the range from 0 to 255. Returns -1 if the end of this stream has been reached.
      Overrides:
      read in class FilterInputStream
      Returns:
      the byte read or -1 if the end of the filtered stream has been reached.
      Throws:
      IOException - if the stream is closed or another IOException occurs.

    • read

      public int read​(byte[] b) throws IOException
      Description copied from class: InputStream
      Equivalent to read(buffer, 0, buffer.length).
      Overrides:
      read in class InputStream
      Throws:
      IOException

    • read

      public int read​(byte[] b, int off, int len) throws IOException
      Description copied from class: InputStream
      Reads up to byteCount bytes from this stream and stores them in the byte array buffer starting at byteOffset. Returns the number of bytes actually read or -1 if the end of the stream has been reached.
      Overrides:
      read in class FilterInputStream
      Throws:
      IOException - if the stream is closed or another IOException occurs.

    • skip

      public long skip​(long n) throws IOException
      Description copied from class: FilterInputStream
      Skips byteCount bytes in this stream. Subsequent calls to read will not return these bytes unless reset is used. This implementation skips byteCount bytes in the filtered stream.
      Overrides:
      skip in class FilterInputStream
      Parameters:
      n - the number of bytes to skip.
      Returns:
      the number of bytes actually skipped.
      Throws:
      IOException - if this stream is closed or another IOException occurs.
      See Also:
      FilterInputStream.mark(int), FilterInputStream.reset()

    • available

      public int available() throws IOException
      Description copied from class: InputStream
      Returns an estimated number of bytes that can be read or skipped without blocking for more input.

      Note that this method provides such a weak guarantee that it is not very useful in practice.

      Firstly, the guarantee is "without blocking for more input" rather than "without blocking": a read may still block waiting for I/O to complete — the guarantee is merely that it won't have to wait indefinitely for data to be written. The result of this method should not be used as a license to do I/O on a thread that shouldn't be blocked.

      Secondly, the result is a conservative estimate and may be significantly smaller than the actual number of bytes available. In particular, an implementation that always returns 0 would be correct. In general, callers should only use this method if they'd be satisfied with treating the result as a boolean yes or no answer to the question "is there definitely data ready?".

      Thirdly, the fact that a given number of bytes is "available" does not guarantee that a read or skip will actually read or skip that many bytes: they may read or skip fewer.

      It is particularly important to realize that you must not use this method to size a container and assume that you can read the entirety of the stream without needing to resize the container. Such callers should probably write everything they read to a ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're reading from a file, File.length() returns the current length of the file (though assuming the file's length can't change may be incorrect, reading a file is inherently racy).

      The default implementation of this method in InputStream always returns 0. Subclasses should override this method if they are able to indicate the number of bytes available.

      Overrides:
      available in class FilterInputStream
      Returns:
      the estimated number of bytes available
      Throws:
      IOException - if this stream is closed or an error occurs

    • close

      public void close() throws IOException
      Description copied from class: FilterInputStream
      Closes this stream. This implementation closes the filtered stream.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class FilterInputStream
      Throws:
      IOException - if an error occurs while closing this stream.

    • markSupported

      public boolean markSupported()
      Description copied from class: FilterInputStream
      Indicates whether this stream supports mark() and reset(). This implementation returns whether or not the filtered stream supports marking.
      Overrides:
      markSupported in class FilterInputStream
      Returns:
      true if mark() and reset() are supported, false otherwise.
      See Also:
      FilterInputStream.mark(int), FilterInputStream.reset(), FilterInputStream.skip(long)