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regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
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    http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.crypto.cipher;

import java.nio.ByteBuffer;
import java.security.NoSuchAlgorithmException;
import java.util.StringTokenizer;
import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.ShortBufferException;

import org.apache.commons.crypto.Crypto;
import org.apache.commons.crypto.utils.Utils;

OpenSSL cryptographic wrapper using JNI. Currently only AES-CTR is supported.
It's flexible to add other crypto algorithms/modes.
/**
 * OpenSSL cryptographic wrapper using JNI. Currently only AES-CTR is supported.
 * It's flexible to add other crypto algorithms/modes.
 */
final class OpenSsl {

    // Mode constant defined by OpenSsl JNI
    public static final int ENCRYPT_MODE = 1;
    public static final int DECRYPT_MODE = 0;

    
Currently only support AES/CTR/NoPadding. /** Currently only support AES/CTR/NoPadding. */
    private static enum AlgorithmMode {
        AES_CTR, AES_CBC;

        
Gets the mode.
Params:
algorithm – the algorithm.
mode – the mode.
Throws:
NoSuchAlgorithmException – if the algorithm is not available.
Returns:
the Algorithm mode./**
         * Gets the mode.
         *
         * @param algorithm the algorithm.
         * @param mode the mode.
         * @return the Algorithm mode.
         * @throws NoSuchAlgorithmException if the algorithm is not available.
         */
        static int get(String algorithm, String mode)
                throws NoSuchAlgorithmException {
            try {
                return AlgorithmMode.valueOf(algorithm + "_" + mode).ordinal();
            } catch (Exception e) {
                throw new NoSuchAlgorithmException(
                        "Doesn't support algorithm: " + algorithm
                                + " and mode: " + mode);
            }
        }
    }

    private static enum Padding {
        NoPadding, PKCS5Padding;

        
Gets the Padding instance.
Params:
padding – the padding.
Throws:
NoSuchPaddingException – if the padding is not available.
Returns:
the value of Padding./**
         * Gets the Padding instance.
         *
         * @param padding the padding.
         * @return the value of Padding.
         * @throws NoSuchPaddingException if the padding is not available.
         */
        static int get(String padding) throws NoSuchPaddingException {
            try {
                return Padding.valueOf(padding).ordinal();
            } catch (Exception e) {
                throw new NoSuchPaddingException("Doesn't support padding: "
                        + padding);
            }
        }
    }

    private long context = 0;
    private final int algorithm;
    private final int padding;

    private static final Throwable loadingFailureReason;

    static {
        Throwable loadingFailure = null;
        try {
            if (Crypto.isNativeCodeLoaded()) {
                OpenSslNative.initIDs();
            } else {
                loadingFailure = Crypto.getLoadingError();
            }
        } catch (Exception t) {
            loadingFailure = t;
        } catch (UnsatisfiedLinkError t) {
            loadingFailure = t;            
        } finally {
            loadingFailureReason = loadingFailure;
        }
    }

    
Gets the failure reason when loading OpenSsl native.
Returns:
the failure reason; null if it was loaded and initialised successfully/**
     * Gets the failure reason when loading OpenSsl native.
     *
     * @return the failure reason; null if it was loaded and initialised successfully
     */
    public static Throwable getLoadingFailureReason() {
        return loadingFailureReason;
    }

    
Constructs a OpenSsl instance based on context, algorithm and padding. 
Params:
context – the context.
algorithm – the algorithm.
padding – the padding./**
     * Constructs a {@link OpenSsl} instance based on context, algorithm and padding.
     *
     * @param context the context.
     * @param algorithm the algorithm.
     * @param padding the padding.
     */
    private OpenSsl(long context, int algorithm, int padding) {
        this.context = context;
        this.algorithm = algorithm;
        this.padding = padding;
    }

    
Return an OpenSslCipher object that implements the specified
transformation.
Params:
transformation – the name of the transformation, e.g.,
       AES/CTR/NoPadding.
Throws:
NoSuchAlgorithmException – if transformation is null,
        empty, in an invalid format, or if OpenSsl doesn't implement the
        specified algorithm.
NoSuchPaddingException – if transformation contains a
        padding scheme that is not available.
IllegalStateException – if native code cannot be initialised
Returns:
OpenSslCipher an OpenSslCipher object/**
     * Return an <code>OpenSslCipher</code> object that implements the specified
     * transformation.
     *
     * @param transformation the name of the transformation, e.g.,
     *        AES/CTR/NoPadding.
     * @return OpenSslCipher an <code>OpenSslCipher</code> object
     * @throws NoSuchAlgorithmException if <code>transformation</code> is null,
     *         empty, in an invalid format, or if OpenSsl doesn't implement the
     *         specified algorithm.
     * @throws NoSuchPaddingException if <code>transformation</code> contains a
     *         padding scheme that is not available.
     * @throws IllegalStateException if native code cannot be initialised
     */
    public static OpenSsl getInstance(String transformation)
            throws NoSuchAlgorithmException, NoSuchPaddingException {
        if (loadingFailureReason != null) {
            throw new IllegalStateException(loadingFailureReason);
        }
        Transform transform = tokenizeTransformation(transformation);
        int algorithmMode = AlgorithmMode.get(transform.algorithm,
                transform.mode);
        int padding = Padding.get(transform.padding);
        long context = OpenSslNative.initContext(algorithmMode, padding);
        return new OpenSsl(context, algorithmMode, padding);
    }

    
Nested class for algorithm, mode and padding. /** Nested class for algorithm, mode and padding. */
    private static class Transform {
        final String algorithm;
        final String mode;
        final String padding;

        
Constructs a Transform based on the algorithm, mode and padding. 
Params:
algorithm – the algorithm
mode – the mode.
padding – the padding./**
         * Constructs a {@link Transform} based on the algorithm, mode and padding.
         *
         * @param algorithm the algorithm
         * @param mode the mode.
         * @param padding the padding.
         */
        public Transform(String algorithm, String mode, String padding) {
            this.algorithm = algorithm;
            this.mode = mode;
            this.padding = padding;
        }
    }

    
Gets the tokens of transformation.
Params:
transformation – the transformation.
Throws:
NoSuchAlgorithmException – if the transformation is null.
Returns:
the Transform instance./**
     * Gets the tokens of transformation.
     *
     * @param transformation the transformation.
     * @return the {@link Transform} instance.
     * @throws NoSuchAlgorithmException if the transformation is null.
     */
    private static Transform tokenizeTransformation(String transformation)
            throws NoSuchAlgorithmException {
        if (transformation == null) {
            throw new NoSuchAlgorithmException("No transformation given.");
        }

        /*
         * Array containing the components of a Cipher transformation: index 0:
         * algorithm (e.g., AES) index 1: mode (e.g., CTR) index 2: padding
         * (e.g., NoPadding)
         */
        String[] parts = new String[3];
        int count = 0;
        StringTokenizer parser = new StringTokenizer(transformation, "/");
        while (parser.hasMoreTokens() && count < 3) {
            parts[count++] = parser.nextToken().trim();
        }
        if (count != 3 || parser.hasMoreTokens()) {
            throw new NoSuchAlgorithmException(
                    "Invalid transformation format: " + transformation);
        }
        return new Transform(parts[0], parts[1], parts[2]);
    }

    
Initialize this cipher with a key and IV.
Params:
mode – ENCRYPT_MODE or DECRYPT_MODE
key – crypto key
iv – crypto iv/**
     * Initialize this cipher with a key and IV.
     *
     * @param mode {@link #ENCRYPT_MODE} or {@link #DECRYPT_MODE}
     * @param key crypto key
     * @param iv crypto iv
     */
    public void init(int mode, byte[] key, byte[] iv) {
        context = OpenSslNative
                .init(context, mode, algorithm, padding, key, iv);
    }

    

Continues a multiple-part encryption or decryption operation. The data is
encrypted or decrypted, depending on how this cipher was initialized.


All input.remaining() bytes starting at
input.position() are processed. The result is stored in the
output buffer.


Upon return, the input buffer's position will be equal to its limit; its
limit will not have changed. The output buffer's position will have
advanced by n, when n is the value returned by this method; the output
buffer's limit will not have changed.

If output.remaining() bytes are insufficient to hold the
result, a ShortBufferException is thrown.
Params:
input – the input ByteBuffer
output – the output ByteBuffer
Throws:
ShortBufferException – if there is insufficient space in the output
        buffer
Returns:
int number of bytes stored in output/**
     * <p>
     * Continues a multiple-part encryption or decryption operation. The data is
     * encrypted or decrypted, depending on how this cipher was initialized.
     * </p>
     *
     * <p>
     * All <code>input.remaining()</code> bytes starting at
     * <code>input.position()</code> are processed. The result is stored in the
     * output buffer.
     * </p>
     *
     * <p>
     * Upon return, the input buffer's position will be equal to its limit; its
     * limit will not have changed. The output buffer's position will have
     * advanced by n, when n is the value returned by this method; the output
     * buffer's limit will not have changed.
     * </p>
     *
     * If <code>output.remaining()</code> bytes are insufficient to hold the
     * result, a <code>ShortBufferException</code> is thrown.
     *
     * @param input the input ByteBuffer
     * @param output the output ByteBuffer
     * @return int number of bytes stored in <code>output</code>
     * @throws ShortBufferException if there is insufficient space in the output
     *         buffer
     */
    public int update(ByteBuffer input, ByteBuffer output)
            throws ShortBufferException {
        checkState();
        Utils.checkArgument(input.isDirect() && output.isDirect(),
                "Direct buffers are required.");
        int len = OpenSslNative.update(context, input, input.position(),
                input.remaining(), output, output.position(),
                output.remaining());
        input.position(input.limit());
        output.position(output.position() + len);
        return len;
    }

    
Continues a multiple-part encryption/decryption operation. The data is
encrypted or decrypted, depending on how this cipher was initialized.
Params:
input – the input byte array
inputOffset – the offset in input where the input starts
inputLen – the input length
output – the byte array for the result
outputOffset – the offset in output where the result is stored
Throws:
ShortBufferException – if there is insufficient space in the output
        byte array
Returns:
the number of bytes stored in output/**
     * Continues a multiple-part encryption/decryption operation. The data is
     * encrypted or decrypted, depending on how this cipher was initialized.
     *
     * @param input the input byte array
     * @param inputOffset the offset in input where the input starts
     * @param inputLen the input length
     * @param output the byte array for the result
     * @param outputOffset the offset in output where the result is stored
     * @return the number of bytes stored in output
     * @throws ShortBufferException if there is insufficient space in the output
     *         byte array
     */
    public int update(byte[] input, int inputOffset, int inputLen,
            byte[] output, int outputOffset) throws ShortBufferException {
        checkState();
        return OpenSslNative.updateByteArray(context, input, inputOffset,
                inputLen, output, outputOffset, output.length - outputOffset);
    }

    

Finishes a multiple-part operation. The data is encrypted or decrypted,
depending on how this cipher was initialized.


The result is stored in the output buffer. Upon return, the output
buffer's position will have advanced by n, where n is the value returned
by this method; the output buffer's limit will not have changed.


If output.remaining() bytes are insufficient to hold the
result, a ShortBufferException is thrown.


Upon finishing, this method resets this cipher object to the state it was
in when previously initialized. That is, the object is available to
encrypt or decrypt more data.

If any exception is thrown, this cipher object need to be reset before it
can be used again.
Params:
output – the output ByteBuffer
Throws:
ShortBufferException – if the given output byte array is too small
        to hold the result.
IllegalBlockSizeException – if this cipher is a block cipher, no
        padding has been requested (only in encryption mode), and the
        total input length of the data processed by this cipher is not a
        multiple of block size; or if this encryption algorithm is unable
        to process the input data provided.
BadPaddingException – if this cipher is in decryption mode, and
        (un)padding has been requested, but the decrypted data is not
        bounded by the appropriate padding bytes
Returns:
int number of bytes stored in output/**
     * <p>
     * Finishes a multiple-part operation. The data is encrypted or decrypted,
     * depending on how this cipher was initialized.
     * </p>
     *
     * <p>
     * The result is stored in the output buffer. Upon return, the output
     * buffer's position will have advanced by n, where n is the value returned
     * by this method; the output buffer's limit will not have changed.
     * </p>
     *
     * <p>
     * If <code>output.remaining()</code> bytes are insufficient to hold the
     * result, a <code>ShortBufferException</code> is thrown.
     * </p>
     *
     * <p>
     * Upon finishing, this method resets this cipher object to the state it was
     * in when previously initialized. That is, the object is available to
     * encrypt or decrypt more data.
     * </p>
     *
     * If any exception is thrown, this cipher object need to be reset before it
     * can be used again.
     *
     * @param output the output ByteBuffer
     * @return int number of bytes stored in <code>output</code>
     * @throws ShortBufferException if the given output byte array is too small
     *         to hold the result.
     * @throws IllegalBlockSizeException if this cipher is a block cipher, no
     *         padding has been requested (only in encryption mode), and the
     *         total input length of the data processed by this cipher is not a
     *         multiple of block size; or if this encryption algorithm is unable
     *         to process the input data provided.
     * @throws BadPaddingException if this cipher is in decryption mode, and
     *         (un)padding has been requested, but the decrypted data is not
     *         bounded by the appropriate padding bytes
     */
    public int doFinal(ByteBuffer output) throws ShortBufferException,
            IllegalBlockSizeException, BadPaddingException {
        checkState();
        Utils.checkArgument(output.isDirect(), "Direct buffer is required.");
        int len = OpenSslNative.doFinal(context, output, output.position(),
                output.remaining());
        output.position(output.position() + len);
        return len;
    }

    
Encrypts or decrypts data in a single-part operation, or finishes a
multiple-part operation.
Params:
output – the byte array for the result
outputOffset – the offset in output where the result is stored
Throws:
ShortBufferException – if the given output byte array is too small
        to hold the result
BadPaddingException – if this cipher is in decryption mode, and
        (un)padding has been requested, but the decrypted data is not
        bounded by the appropriate padding bytes
IllegalBlockSizeException – if this cipher is a block cipher, no
        padding has been requested (only in encryption mode), and the
        total input length of the data processed by this cipher is not a
        multiple of block size; or if this encryption algorithm is unable
        to process the input data provided.
Returns:
the number of bytes stored in output/**
     * Encrypts or decrypts data in a single-part operation, or finishes a
     * multiple-part operation.
     *
     * @param output the byte array for the result
     * @param outputOffset the offset in output where the result is stored
     * @return the number of bytes stored in output
     * @throws ShortBufferException if the given output byte array is too small
     *         to hold the result
     * @throws BadPaddingException if this cipher is in decryption mode, and
     *         (un)padding has been requested, but the decrypted data is not
     *         bounded by the appropriate padding bytes
     * @throws IllegalBlockSizeException if this cipher is a block cipher, no
     *         padding has been requested (only in encryption mode), and the
     *         total input length of the data processed by this cipher is not a
     *         multiple of block size; or if this encryption algorithm is unable
     *         to process the input data provided.
     */
    public int doFinal(byte[] output, int outputOffset)
            throws ShortBufferException, IllegalBlockSizeException,
            BadPaddingException {
        checkState();
        return OpenSslNative.doFinalByteArray(context, output, outputOffset,
                output.length - outputOffset);
    }

    
Forcibly clean the context. /** Forcibly clean the context. */
    public void clean() {
        if (context != 0) {
            OpenSslNative.clean(context);
            context = 0;
        }
    }

    
Checks whether context is initialized. /** Checks whether context is initialized. */
    private void checkState() {
        Utils.checkState(context != 0);
    }

    @Override
    protected void finalize() throws Throwable {
        clean();
    }

}