CipherInputStream

Creates a new CipherInputStream instance for an InputStream and a cipher.

Warning: passing a null source creates an invalid CipherInputStream. All read operations on such a stream will fail.

Creates a new CipherInputStream instance for an InputStream without a cipher.

A NullCipher is created and used to process the data.

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, 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.

Closes this CipherInputStream, also closes the underlying input stream and call doFinal on the cipher object.

Returns whether this input stream supports mark and reset, which it does not.

Reads the next byte from this cipher input stream.

Reads the next len bytes from this input stream into buffer buf starting at offset off.

if buf is null, the next len bytes are read and discarded.

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.