/*

 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/**

 * Base class for Checksum tests

 */

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.nio.charset.StandardCharsets;

import java.util.zip.Checksum;

public class ChecksumBase {

    private final static byte[] BYTES_123456789 = "123456789".getBytes(StandardCharsets.US_ASCII);

    public static void testAll(Checksum checksum, long expected) {

        testBytes(checksum, expected);

        testByteArray(checksum, expected);

        testWrappedByteBuffer(checksum, expected);

        testReadonlyByteBuffer(checksum, expected);

        testDirectByteBuffer(checksum, expected);

        testByteArrayOffset(checksum, expected);

        testDirectByteBufferOffset(checksum, expected);

        testLittleEndianDirectByteBufferOffset(checksum, expected);

        testWrappedByteBufferOffset(checksum, expected);

        testLittleEndianWrappedByteBufferOffset(checksum, expected);

        testReadonlyByteBufferOffset(checksum, expected);

        testLittleEndianReadonlyByteBufferOffset(checksum, expected);

    }

    private static void testBytes(Checksum checksum, long expected) {

        checksum.reset();

        for (byte bits : BYTES_123456789) {

            checksum.update(bits);

        }

        checkChecksum(checksum, expected);

    }

    private static void testByteArray(Checksum checksum, long expected) {

        checksum.reset();

        checksum.update(BYTES_123456789);

        checkChecksum(checksum, expected);

    }

    private static void testWrappedByteBuffer(Checksum checksum, long expected) {

        checksum.reset();

        ByteBuffer bb = ByteBuffer.wrap(BYTES_123456789);

        checksum.update(bb);

        checkChecksum(checksum, expected);

    }

    private static void testReadonlyByteBuffer(Checksum checksum, long expected) {

        checksum.reset();

        ByteBuffer bb = ByteBuffer.wrap(BYTES_123456789).asReadOnlyBuffer();

        checksum.update(bb);

        checkChecksum(checksum, expected);

    }

    private static void testDirectByteBuffer(Checksum checksum, long expected) {

        checksum.reset();

        ByteBuffer bb = ByteBuffer.allocateDirect(BYTES_123456789.length);

        bb.put(BYTES_123456789);

        bb.rewind();

        checksum.update(bb);

        checkChecksum(checksum, expected);

    }

    private static void checkChecksum(Checksum checksum, long expected) {

        if (checksum.getValue() != expected) {

            throw new RuntimeException("Calculated checksum result was invalid."

                    + " Expected " + Long.toHexString(expected)

                    + ", but got " + Long.toHexString(checksum.getValue()) + ".");

        }

    }

    private static void testByteArrayOffset(Checksum checksum, long expected) {

        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];

        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {

            checksum.reset();

            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);

            checksum.update(unaligned_bytes_123456789, i, BYTES_123456789.length);

            checkChecksumOffset(checksum, expected, i);

        }

    }

    private static void testDirectByteBufferOffset(Checksum checksum, long expected) {

        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];

        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {

            checksum.reset();

            ByteBuffer bb = ByteBuffer.allocateDirect(unaligned_bytes_123456789.length);

            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);

            bb.put(unaligned_bytes_123456789);

            bb.position(i);

            bb.limit(i + BYTES_123456789.length);

            checksum.update(bb);

            checkChecksumOffset(checksum, expected, i);

        }

    }

    private static void testLittleEndianDirectByteBufferOffset(Checksum checksum, long expected) {

        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];

        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {

            checksum.reset();

            ByteBuffer bb = ByteBuffer.allocateDirect(unaligned_bytes_123456789.length);

            bb.order(ByteOrder.LITTLE_ENDIAN);

            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);

            bb.put(unaligned_bytes_123456789);

            bb.position(i);

            bb.limit(i + BYTES_123456789.length);

            checksum.update(bb);

            checkChecksumOffset(checksum, expected, i);

        }

    }

    private static void testWrappedByteBufferOffset(Checksum checksum, long expected) {

        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];

        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {

            checksum.reset();

            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);

            ByteBuffer bb = ByteBuffer.wrap(unaligned_bytes_123456789);

            bb.position(i);

            bb.limit(i + BYTES_123456789.length);

            checksum.update(bb);

            checkChecksumOffset(checksum, expected, i);

        }

    }

    private static void testLittleEndianWrappedByteBufferOffset(Checksum checksum, long expected) {

        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];

        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {

            checksum.reset();

            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);

            ByteBuffer bb = ByteBuffer.wrap(unaligned_bytes_123456789);

            bb.order(ByteOrder.LITTLE_ENDIAN);

            bb.position(i);

            bb.limit(i + BYTES_123456789.length);

            checksum.update(bb);

            checkChecksumOffset(checksum, expected, i);

        }

    }

    private static void testReadonlyByteBufferOffset(Checksum checksum, long expected) {

        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];

        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {

            checksum.reset();

            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);

            ByteBuffer bb = ByteBuffer.wrap(unaligned_bytes_123456789).asReadOnlyBuffer();

            bb.position(i);

            bb.limit(i + BYTES_123456789.length);

            checksum.update(bb);

            checkChecksumOffset(checksum, expected, i);

        }

    }

    private static void testLittleEndianReadonlyByteBufferOffset(Checksum checksum, long expected) {

        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];

        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {

            checksum.reset();

            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);

            ByteBuffer bb = ByteBuffer.wrap(unaligned_bytes_123456789).asReadOnlyBuffer();

            bb.order(ByteOrder.LITTLE_ENDIAN);

            bb.position(i);

            bb.limit(i + BYTES_123456789.length);

            checksum.update(bb);

            checkChecksumOffset(checksum, expected, i);

        }

    }

    private static void checkChecksumOffset(Checksum checksum, long expected, int offset) {

        if (checksum.getValue() != expected) {

            throw new RuntimeException("Calculated CRC32C result was invalid. Array offset "

                    + offset + ". Expected: " + Long.toHexString(expected) + ", Got: "

                    + Long.toHexString(checksum.getValue()));

        }

    }

}