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import static java.lang.Math.abs;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import static java.nio.ByteOrder.BIG_ENDIAN;
import static java.nio.ByteOrder.LITTLE_ENDIAN;
import java.util.SplittableRandom;
import java.util.Arrays;

/**
 * @test
 * @bug 8026049
 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:-UseUnalignedAccesses HeapByteBufferTest
 * @run main/othervm HeapByteBufferTest
 * @summary Verify that byte buffers are correctly accessed.
 */

// A wrapper for a ByteBuffer which maintains a backing array and a
// position.  Whenever this wrapper is written the backing array and
// the wrapped byte buffer are updated together, and whenever it is
// read we check that the ByteBuffer and the backing array are identical.

class MyByteBuffer {
    final ByteBuffer buf;
    final byte[] bytes;
    int pos;
    ByteOrder byteOrder = BIG_ENDIAN;

    MyByteBuffer(ByteBuffer buf, byte[] bytes) {
        this.buf = buf;
        this.bytes = Arrays.copyOf(bytes, bytes.length);
        pos = 0;
    }

    public final MyByteBuffer order(ByteOrder bo) {
        byteOrder = bo;
        buf.order(bo);
        return this;
    }

    static MyByteBuffer wrap(byte[] bytes) {
        return new MyByteBuffer(ByteBuffer.wrap(bytes), bytes);
    }

    int capacity() { return bytes.length; }
    int position() {
        if (buf.position() != pos)
            throw new RuntimeException();
        return buf.position();
    }

    byte[] array() { return buf.array(); }
    byte[] backingArray() { return bytes; }

    private static byte long7(long x) { return (byte)(x >> 56); }
    private static byte long6(long x) { return (byte)(x >> 48); }
    private static byte long5(long x) { return (byte)(x >> 40); }
    private static byte long4(long x) { return (byte)(x >> 32); }
    private static byte long3(long x) { return (byte)(x >> 24); }
    private static byte long2(long x) { return (byte)(x >> 16); }
    private static byte long1(long x) { return (byte)(x >>  8); }
    private static byte long0(long x) { return (byte)(x      ); }

    private static byte int3(int x) { return (byte)(x >> 24); }
    private static byte int2(int x) { return (byte)(x >> 16); }
    private static byte int1(int x) { return (byte)(x >>  8); }
    private static byte int0(int x) { return (byte)(x      ); }

    private static byte short1(short x) { return (byte)(x >> 8); }
    private static byte short0(short x) { return (byte)(x     ); }

    byte _get(long i) { return bytes[(int)i]; }
    void _put(long i, byte x) { bytes[(int)i] = x; }

    private void putLongX(long a, long x) {
        if (byteOrder == BIG_ENDIAN) {
            x = Long.reverseBytes(x);
        }
        _put(a + 7, long7(x));
        _put(a + 6, long6(x));
        _put(a + 5, long5(x));
        _put(a + 4, long4(x));
        _put(a + 3, long3(x));
        _put(a + 2, long2(x));
        _put(a + 1, long1(x));
        _put(a    , long0(x));
    }

    private void putIntX(long a, int x) {
        if (byteOrder == BIG_ENDIAN) {
            x = Integer.reverseBytes(x);
        }
        _put(a + 3, int3(x));
        _put(a + 2, int2(x));
        _put(a + 1, int1(x));
        _put(a    , int0(x));
    }

    private void putShortX(int bi, short x) {
        if (byteOrder == BIG_ENDIAN) {
            x = Short.reverseBytes(x);
        }
        _put(bi    , short0(x));
        _put(bi + 1, short1(x));
    }

    static private int makeInt(byte b3, byte b2, byte b1, byte b0) {
        return (((b3       ) << 24) |
                ((b2 & 0xff) << 16) |
                ((b1 & 0xff) <<  8) |
                ((b0 & 0xff)      ));
    }
    int getIntX(long a) {
        int x = makeInt(_get(a + 3),
                _get(a + 2),
                _get(a + 1),
                _get(a));
        if (byteOrder == BIG_ENDIAN) {
            x = Integer.reverseBytes(x);
        }
        return x;
    }

    static private long makeLong(byte b7, byte b6, byte b5, byte b4,
                                 byte b3, byte b2, byte b1, byte b0)
    {
        return ((((long)b7       ) << 56) |
                (((long)b6 & 0xff) << 48) |
                (((long)b5 & 0xff) << 40) |
                (((long)b4 & 0xff) << 32) |
                (((long)b3 & 0xff) << 24) |
                (((long)b2 & 0xff) << 16) |
                (((long)b1 & 0xff) <<  8) |
                (((long)b0 & 0xff)      ));
    }

    long getLongX(long a) {
        long x = makeLong(_get(a + 7),
                _get(a + 6),
                _get(a + 5),
                _get(a + 4),
                _get(a + 3),
                _get(a + 2),
                _get(a + 1),
                _get(a));
        if (byteOrder == BIG_ENDIAN) {
            x = Long.reverseBytes(x);
        }
        return x;
    }

    static private short makeShort(byte b1, byte b0) {
        return (short)((b1 << 8) | (b0 & 0xff));
    }

    short getShortX(long a) {
        short x = makeShort(_get(a + 1),
                            _get(a    ));
        if (byteOrder == BIG_ENDIAN) {
            x = Short.reverseBytes(x);
        }
        return x;
    }

    double getDoubleX(long a) {
        long x = getLongX(a);
        return Double.longBitsToDouble(x);
    }

    double getFloatX(long a) {
        int x = getIntX(a);
        return Float.intBitsToFloat(x);
    }

    void ck(long x, long y) {
        if (x != y) {
            throw new RuntimeException(" x = " + Long.toHexString(x) + ", y = " + Long.toHexString(y));
        }
    }

    void ck(double x, double y) {
        if (x == x && y == y && x != y) {
            ck(x, y);
        }
    }

    long getLong(int i) { ck(buf.getLong(i), getLongX(i)); return buf.getLong(i); }
    int getInt(int i) { ck(buf.getInt(i), getIntX(i)); return buf.getInt(i); }
    short getShort(int i) { ck(buf.getShort(i), getShortX(i)); return buf.getShort(i); }
    char getChar(int i) { ck(buf.getChar(i), (char)getShortX(i)); return buf.getChar(i); }
    double getDouble(int i) { ck(buf.getDouble(i), getDoubleX(i)); return buf.getDouble(i); }
    float getFloat(int i) { ck(buf.getFloat(i), getFloatX(i)); return buf.getFloat(i); }

    void putLong(int i, long x) { buf.putLong(i, x); putLongX(i, x); }
    void putInt(int i, int x) { buf.putInt(i, x); putIntX(i, x); }
    void putShort(int i, short x) { buf.putShort(i, x); putShortX(i, x); }
    void putChar(int i, char x) { buf.putChar(i, x); putShortX(i, (short)x); }
    void putDouble(int i, double x) { buf.putDouble(i, x); putLongX(i, Double.doubleToRawLongBits(x)); }
    void putFloat(int i, float x) { buf.putFloat(i, x); putIntX(i, Float.floatToRawIntBits(x)); }

    long getLong() { ck(buf.getLong(buf.position()), getLongX(pos)); long x = buf.getLong(); pos += 8; return x; }
    int getInt() { ck(buf.getInt(buf.position()), getIntX(pos)); int x = buf.getInt(); pos += 4; return x; }
    short getShort() { ck(buf.getShort(buf.position()), getShortX(pos)); short x = buf.getShort(); pos += 2; return x; }
    char getChar() {  ck(buf.getChar(buf.position()), (char)getShortX(pos)); char x = buf.getChar(); pos += 2; return x; }
    double getDouble() { ck(buf.getDouble(buf.position()), getDoubleX(pos)); double x = buf.getDouble(); pos += 8; return x; }
    float getFloat() { ck(buf.getFloat(buf.position()), getFloatX(pos)); float x = buf.getFloat(); pos += 4; return x; }

    void putLong(long x) { putLongX(pos, x); pos += 8; buf.putLong(x); }
    void putInt(int x) { putIntX(pos, x); pos += 4; buf.putInt(x); }
    void putShort(short x) { putShortX(pos, x); pos += 2; buf.putShort(x); }
    void putChar(char x) { putShortX(pos, (short)x); pos += 2; buf.putChar(x); }
    void putDouble(double x) { putLongX(pos, Double.doubleToRawLongBits(x)); pos += 8; buf.putDouble(x); }
    void putFloat(float x) { putIntX(pos, Float.floatToRawIntBits(x)); pos += 4; buf.putFloat(x); }

    void rewind() { pos = 0; buf.rewind(); }
}

public class HeapByteBufferTest implements Runnable {

    SplittableRandom random = new SplittableRandom();
    MyByteBuffer data = MyByteBuffer.wrap(new byte[1024]);

    int randomOffset(SplittableRandom r, MyByteBuffer buf, int size) {
        return abs(r.nextInt()) % (buf.capacity() - size);
    }

    long iterations;

    HeapByteBufferTest(long iterations) {
        this.iterations = iterations;
    }

    // The core of the test.  Walk over the buffer reading and writing
    // random data, XORing it as we go.  We can detect writes in the
    // wrong place, writes which are too long or too short, and reads
    // or writes of the wrong data,
    void step(SplittableRandom r) {
        data.order((r.nextInt() & 1) != 0 ? BIG_ENDIAN : LITTLE_ENDIAN);

        data.rewind();
        while (data.position() < data.capacity())
            data.putLong(data.getLong() ^ random.nextLong());

        data.rewind();
        while (data.position() < data.capacity())
            data.putInt(data.getInt() ^ random.nextInt());

        data.rewind();
        while (data.position() < data.capacity())
            data.putShort((short)(data.getShort() ^ random.nextInt()));

        data.rewind();
        while (data.position() < data.capacity())
            data.putChar((char)(data.getChar() ^ random.nextInt()));

        data.rewind();
        while (data.position() < data.capacity()) {
            data.putDouble(combine(data.getDouble(), random.nextLong()));
        }

        data.rewind();
        while (data.position() < data.capacity())
            data.putFloat(combine(data.getFloat(), random.nextInt()));

        for (int i = 0; i < 100; i++) {
            int offset = randomOffset(r, data, 8);
            data.putLong(offset, data.getLong(offset) ^ random.nextLong());
        }
        for (int i = 0; i < 100; i++) {
            int offset = randomOffset(r, data, 4);
            data.putInt(offset, data.getInt(offset) ^ random.nextInt());
        }
        for (int i = 0; i < 100; i++) {
            int offset = randomOffset(r, data, 4);
            data.putShort(offset, (short)(data.getShort(offset) ^ random.nextInt()));
        }
        for (int i = 0; i < 100; i++) {
            int offset = randomOffset(r, data, 4);
            data.putChar(offset, (char)(data.getChar(offset) ^ random.nextInt()));
        }
        for (int i = 0; i < 100; i++) {
            int offset = randomOffset(r, data, 8);
            data.putDouble(offset, combine(data.getDouble(offset), random.nextLong()));
        }
        for (int i = 0; i < 100; i++) {
            int offset = randomOffset(r, data, 4);
            data.putFloat(offset, combine(data.getFloat(offset), random.nextInt()));
        }
    }

    // XOR the bit pattern of a double and a long, returning the
    // result as a double.
    //
    // We convert signalling NaNs to quiet NaNs.  We need to do this
    // because some platforms (in particular legacy 80x87) do not
    // provide transparent conversions between integer and
    // floating-point types even when using raw conversions but
    // quietly convert sNaN to qNaN.  This causes spurious test
    // failures when the template interpreter uses 80x87 and the JITs
    // use XMM registers.
    //
    public double combine(double prev, long bits) {
        bits ^= Double.doubleToRawLongBits(prev);
        double result = Double.longBitsToDouble(bits);
        if (Double.isNaN(result)) {
            result = Double.longBitsToDouble(bits | 0x8000000000000l);
        }
        return result;
    }

    // XOR the bit pattern of a float and an int, returning the result
    // as a float.  Convert sNaNs to qNaNs.
    public Float combine(float prev, int bits) {
        bits ^= Float.floatToRawIntBits(prev);
        Float result = Float.intBitsToFloat(bits);
        if (Float.isNaN(result)) {
            result = Float.intBitsToFloat(bits | 0x400000);
        }
        return result;
    }

    public void run() {
        SplittableRandom r = new SplittableRandom();

        for (int i = 0; i < data.capacity(); i += 8) {
            data.putLong(i, random.nextLong());
        }

        for (int i = 0; i < iterations; i++) {
            step(r);
        }

        if (!Arrays.equals(data.array(), data.backingArray())) {
            throw new RuntimeException();
        }
    }

    public static void main(String[] args) {
        // The number of iterations is high to ensure that tiered
        // compilation kicks in all the way up to C2.
        long iterations = 100000;
        if (args.length > 0)
            iterations = Long.parseLong(args[0]);

        new HeapByteBufferTest(iterations).run();
    }
}