/**
* Read data from underlying stream and process with cipher until end of stream or some data is
* available after cipher processing.
*
* @return -1 to indicate end of stream, or the number of bytes (> 0) available.
*/
private int nextChunk() throws IOException {
if (finalized) {
return -1;
}
bufOff = 0;
maxBuf = 0;
// Keep reading until EOF or cipher processing produces data
while (maxBuf == 0) {
int read = in.read(inBuf);
if (read == -1) {
finaliseCipher();
if (maxBuf == 0) {
return -1;
}
return maxBuf;
}
try {
if (bufferedBlockCipher != null) {
maxBuf = bufferedBlockCipher.processBytes(inBuf, 0, read, buf, 0);
} else if (aeadBlockCipher != null) {
maxBuf = aeadBlockCipher.processBytes(inBuf, 0, read, buf, 0);
} else {
streamCipher.processBytes(inBuf, 0, read, buf, 0);
maxBuf = read;
}
} catch (Exception e) {
throw new IOException("Error processing stream " + e);
}
}
return maxBuf;
}
/** Constructs a CipherInputStream from an InputStream and an AEADBlockCipher. */
public CipherInputStream(InputStream is, AEADBlockCipher cipher) {
super(is);
this.aeadBlockCipher = cipher;
buf = new byte[cipher.getOutputSize(INPUT_BUF_SIZE)];
inBuf = new byte[INPUT_BUF_SIZE];
}
private void finaliseCipher() throws IOException {
try {
finalized = true;
if (bufferedBlockCipher != null) {
maxBuf = bufferedBlockCipher.doFinal(buf, 0);
} else if (aeadBlockCipher != null) {
maxBuf = aeadBlockCipher.doFinal(buf, 0);
} else {
maxBuf = 0; // a stream cipher
}
} catch (final InvalidCipherTextException e) {
throw new InvalidCipherTextIOException("Error finalising cipher", e);
} catch (Exception e) {
throw new IOException("Error finalising cipher " + e);
}
}