Example usage for javax.crypto CipherOutputStream flush

Introduction

In this page you can find the example usage for javax.crypto CipherOutputStream flush.

Prototype

public void flush() throws IOException 

Source Link

Document

Flushes this output stream by forcing any buffered output bytes that have already been processed by the encapsulated cipher object to be written out.

Usage

From source file:com.microsoft.azure.storage.core.Utility.java

/**
 * Encrypts an input stream up to a given length.
 * Exits early if the encrypted data is longer than the abandon length.
 * //from w  w  w.jav  a 2  s.  com
 * @param sourceStream
 *            A <code>InputStream</code> object that represents the stream to measure.
 * @param targetStream
 *            A <code>ByteArrayOutputStream</code> object that represents the stream to write the encrypted data.
 * @param cipher
 *            The <code>Cipher</code> to use to encrypt the data. 
 * @param writeLength
 *            The number of bytes to read and encrypt from the sourceStream.
 * @param abandonLength
 *            The number of bytes to read before the analysis is abandoned. Set this value to <code>-1</code> to
 *            force the entire stream to be read. This parameter is provided to support upload thresholds.
 * @return
 *            The size of the encrypted stream, or -1 if the encrypted stream would be over the abandonLength.
 * @throws IOException
 *            If an I/O error occurs.
 */
public static long encryptStreamIfUnderThreshold(final InputStream sourceStream,
        final ByteArrayOutputStream targetStream, Cipher cipher, long writeLength, long abandonLength)
        throws IOException {
    if (abandonLength < 0) {
        abandonLength = Long.MAX_VALUE;
    }

    if (!sourceStream.markSupported()) {
        throw new IllegalArgumentException(SR.INPUT_STREAM_SHOULD_BE_MARKABLE);
    }

    sourceStream.mark(Constants.MAX_MARK_LENGTH);

    if (writeLength < 0) {
        writeLength = Long.MAX_VALUE;
    }

    CipherOutputStream encryptStream = new CipherOutputStream(targetStream, cipher);

    int count = -1;
    long totalEncryptedLength = targetStream.size();
    final byte[] retrievedBuff = new byte[Constants.BUFFER_COPY_LENGTH];

    int nextCopy = (int) Math.min(retrievedBuff.length, writeLength - totalEncryptedLength);
    count = sourceStream.read(retrievedBuff, 0, nextCopy);

    while (nextCopy > 0 && count != -1) {

        // Note: We are flushing the CryptoStream on every write here.  This way, we don't end up encrypting more data than we intend here, if
        // we go over the abandonLength.
        encryptStream.write(retrievedBuff, 0, count);
        encryptStream.flush();
        totalEncryptedLength = targetStream.size();

        if (totalEncryptedLength > abandonLength) {
            // Abandon operation
            break;
        }

        nextCopy = (int) Math.min(retrievedBuff.length, writeLength - totalEncryptedLength);
        count = sourceStream.read(retrievedBuff, 0, nextCopy);
    }

    sourceStream.reset();
    sourceStream.mark(Constants.MAX_MARK_LENGTH);

    encryptStream.close();
    totalEncryptedLength = targetStream.size();
    if (totalEncryptedLength > abandonLength) {
        totalEncryptedLength = -1;
    }

    return totalEncryptedLength;
}

---

From source file:com.zacwolf.commons.crypto._CRYPTOfactory.java

public final void encryptToOutputStream(final byte[] bytes, final OutputStream outputStream)
        throws InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException,
        InvalidAlgorithmParameterException, IOException {
    ready();//  ww  w . j  av  a2s  . c o  m
    activecrypts++;
    try {
        final Cipher ecipher = crypter.getEcipher();
        final byte[] salt = ecipher.getIV();
        if (salt == null) {
            outputStream.write(0);
        } else {
            outputStream.write(salt.length);
            outputStream.write(salt);
        }
        outputStream.flush();
        CipherOutputStream cop = null;
        try {
            cop = new CipherOutputStream(outputStream, ecipher) {
                /*
                 * WebSphere 7 has a known bug with it's implementation of ibmjceprovider.jar
                 * concerning writing byte-arrays in a serialized object when the byte-array length
                 * is zero.
                 * see: http://www.ibm.com/developerworks/forums/thread.jspa?messageID=14597510
                 * 
                 * Added an override of the CipherOutputStream write method so that it is only called when
                 * the byte array has length > 0
                 */
                @Override
                public void write(final byte[] b, final int off, final int len) throws IOException {
                    if (len > 0) {
                        super.write(b, off, len);
                        //super.flush(); Do NOT flush here, as it slows the process down exponentially
                    }
                }
            };
            cop.write(bytes);
            cop.flush();
        } finally {
            if (cop != null) {
                cop.flush();
                cop.close();
            }
            outputStream.flush();
            outputStream.close();
        }
    } finally {
        activecrypts--;
    }
}

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