/*
 * 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.
 */
/**
 * @test @summary Check that CRC-32C returns the expected CRC value for the
 * string 123456789
 * http://reveng.sourceforge.net/crc-catalogue/all.htm#crc.cat.crc-32c
 */
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.StandardCharsets;
import java.util.zip.CRC32C;

public class CheckCRC32C {

    private final static byte[] BYTES_123456789 = "123456789".getBytes(StandardCharsets.US_ASCII);
    private final static long EXPECTED_CRC = 0xE3069283L;

    public static void main(String[] args) {
        testBytes();
        testByteArray();
        testByteBuffer();
        testDirectByteBuffer();
        testByteArrayOffset();
        testDirectByteBufferOffset();
        testLittleEndianDirectByteBufferOffset();
        testWrappedByteBufferOffset();
        testLittleEndianWrappedByteBufferOffset();
    }

    private static void testBytes() {
        CRC32C crc32c = new CRC32C();
        for (byte bits : BYTES_123456789) {
            crc32c.update(bits);
        }
        checkChecksum(crc32c);
    }

    private static void testByteArray() {
        CRC32C crc32c = new CRC32C();
        crc32c.update(BYTES_123456789);
        checkChecksum(crc32c);
    }

    private static void testByteBuffer() {
        CRC32C crc32c = new CRC32C();
        ByteBuffer bb = ByteBuffer.wrap(BYTES_123456789);
        crc32c.update(bb);
        checkChecksum(crc32c);
    }

    private static void testDirectByteBuffer() {
        CRC32C crc32c = new CRC32C();
        ByteBuffer bb = ByteBuffer.allocateDirect(BYTES_123456789.length);
        bb.put(BYTES_123456789);
        bb.rewind();
        crc32c.update(bb);
        checkChecksum(crc32c);
    }

    private static void checkChecksum(CRC32C crc) {
        if (crc.getValue() != EXPECTED_CRC) {
            throw new RuntimeException("Calculated CRC32C result was invalid."
                    + " Expected " + Long.toHexString(EXPECTED_CRC)
                    + ", but got " + Long.toHexString(crc.getValue()) + ".");
        }
    }

    private static void testByteArrayOffset() {
        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];
        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {
            CRC32C crc = new CRC32C();
            System.arraycopy(BYTES_123456789, 0, unaligned_bytes_123456789, i, BYTES_123456789.length);
            crc.update(unaligned_bytes_123456789, i, BYTES_123456789.length);
            if (crc.getValue() != EXPECTED_CRC) {
                throw new RuntimeException("Calculated CRC32C result was invalid. Array offset "
                        + i + ". Expected: " + Long.toHexString(EXPECTED_CRC) + ", Got: "
                        + Long.toHexString(crc.getValue()));
            }
        }
    }

    private static void testDirectByteBufferOffset() {
        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];
        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {
            CRC32C crc = new CRC32C();
            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);
            crc.update(bb);
            if (crc.getValue() != EXPECTED_CRC) {
                throw new RuntimeException("Calculated CRC32C result was invalid. Array offset "
                        + i + ". Expected: " + Long.toHexString(EXPECTED_CRC) + ", Got: "
                        + Long.toHexString(crc.getValue()));
            }
        }
    }

    private static void testLittleEndianDirectByteBufferOffset() {
        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];
        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {
            CRC32C crc = new CRC32C();
            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);
            crc.update(bb);
            if (crc.getValue() != EXPECTED_CRC) {
                throw new RuntimeException("Calculated CRC32C result was invalid. Array offset "
                        + i + ". Expected: " + Long.toHexString(EXPECTED_CRC) + ", Got: "
                        + Long.toHexString(crc.getValue()));
            }
        }
    }

    private static void testWrappedByteBufferOffset() {
        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];
        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {
            CRC32C crc = new CRC32C();
            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);
            crc.update(bb);
            if (crc.getValue() != EXPECTED_CRC) {
                throw new RuntimeException("Calculated CRC32C result was invalid. Array offset "
                        + i + ". Expected: " + Long.toHexString(EXPECTED_CRC) + ", Got: "
                        + Long.toHexString(crc.getValue()));
            }
        }
    }

    private static void testLittleEndianWrappedByteBufferOffset() {
        byte[] unaligned_bytes_123456789 = new byte[BYTES_123456789.length + 64];
        for (int i = 0; i < unaligned_bytes_123456789.length - BYTES_123456789.length; i++) {
            CRC32C crc = new CRC32C();
            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);
            crc.update(bb);
            if (crc.getValue() != EXPECTED_CRC) {
                throw new RuntimeException("Calculated CRC32C result was invalid. Array offset "
                        + i + ". Expected: " + Long.toHexString(EXPECTED_CRC) + ", Got: "
                        + Long.toHexString(crc.getValue()));
            }
        }
    }
}