/*

 * Copyright (c) 2012, 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 Ensure that Murmur3 hash performs according to specification.

 * @compile -XDignore.symbol.file Hashing.java

 */

public class Hashing {

    static final byte ONE_BYTE[] = {

        (byte) 0x80};

    static final byte TWO_BYTE[] = {

        (byte) 0x80, (byte) 0x81};

    static final char ONE_CHAR[] = {

        (char) 0x8180};

    static final byte THREE_BYTE[] = {

        (byte) 0x80, (byte) 0x81, (byte) 0x82};

    static final byte FOUR_BYTE[] = {

        (byte) 0x80, (byte) 0x81, (byte) 0x82, (byte) 0x83};

    static final char TWO_CHAR[] = {

        (char) 0x8180, (char) 0x8382};

    static final int ONE_INT[] = {

        0x83828180};

    static final byte SIX_BYTE[] = {

        (byte) 0x80, (byte) 0x81, (byte) 0x82,

        (byte) 0x83, (byte) 0x84, (byte) 0x85};

    static final char THREE_CHAR[] = {

        (char) 0x8180, (char) 0x8382, (char) 0x8584};

    static final byte EIGHT_BYTE[] = {

        (byte) 0x80, (byte) 0x81, (byte) 0x82,

        (byte) 0x83, (byte) 0x84, (byte) 0x85,

        (byte) 0x86, (byte) 0x87};

    static final char FOUR_CHAR[] = {

        (char) 0x8180, (char) 0x8382,

        (char) 0x8584, (char) 0x8786};

    static final int TWO_INT[] = {

        0x83828180, 0x87868584};

    // per  http://code.google.com/p/smhasher/source/browse/trunk/main.cpp, line:72

    static final int MURMUR3_32_X86_CHECK_VALUE = 0xB0F57EE3;

    public static void testMurmur3_32_ByteArray() {

        System.out.println("testMurmur3_32_ByteArray");

        byte[] vector = new byte[256];

        byte[] hashes = new byte[4 * 256];

        for (int i = 0; i < 256; i++) {

            vector[i] = (byte) i;

        }

        // Hash subranges {}, {0}, {0,1}, {0,1,2}, ..., {0,...,255}

        for (int i = 0; i < 256; i++) {

            int hash = sun.misc.Hashing.murmur3_32(256 - i, vector, 0, i);

            hashes[i * 4] = (byte) hash;

            hashes[i * 4 + 1] = (byte) (hash >>> 8);

            hashes[i * 4 + 2] = (byte) (hash >>> 16);

            hashes[i * 4 + 3] = (byte) (hash >>> 24);

        }

        // hash to get final result.

        int final_hash = sun.misc.Hashing.murmur3_32(0, hashes);

        if (MURMUR3_32_X86_CHECK_VALUE != final_hash) {

            throw new RuntimeException(

                    String.format("Calculated hash result not as expected. Expected %08X got %08X",

                    MURMUR3_32_X86_CHECK_VALUE,

                    final_hash));

        }

    }

    public static void testEquivalentHashes() {

        int bytes, chars, ints;

        System.out.println("testEquivalentHashes");

        bytes = sun.misc.Hashing.murmur3_32(TWO_BYTE);

        chars = sun.misc.Hashing.murmur3_32(ONE_CHAR);

        if (bytes != chars) {

            throw new RuntimeException(String.format("Hashes did not match. b:%08x != c:%08x", bytes, chars));

        }

        bytes = sun.misc.Hashing.murmur3_32(FOUR_BYTE);

        chars = sun.misc.Hashing.murmur3_32(TWO_CHAR);

        ints = sun.misc.Hashing.murmur3_32(ONE_INT);

        if ((bytes != chars) || (bytes != ints)) {

            throw new RuntimeException(String.format("Hashes did not match. b:%08x != c:%08x != i:%08x", bytes, chars, ints));

        }

        bytes = sun.misc.Hashing.murmur3_32(SIX_BYTE);

        chars = sun.misc.Hashing.murmur3_32(THREE_CHAR);

        if (bytes != chars) {

            throw new RuntimeException(String.format("Hashes did not match. b:%08x != c:%08x", bytes, chars));

        }

        bytes = sun.misc.Hashing.murmur3_32(EIGHT_BYTE);

        chars = sun.misc.Hashing.murmur3_32(FOUR_CHAR);

        ints = sun.misc.Hashing.murmur3_32(TWO_INT);

        if ((bytes != chars) || (bytes != ints)) {

            throw new RuntimeException(String.format("Hashes did not match. b:%08x != c:%08x != i:%08x", bytes, chars, ints));

        }

    }

    public static void main(String[] args) {

        testMurmur3_32_ByteArray();

        testEquivalentHashes();

    }

}