/*
 * Copyright (c) 2017, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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
 * questions.
 */
package jdk.incubator.vector;

import jdk.internal.vm.annotation.ForceInline;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Objects;
import java.util.concurrent.ThreadLocalRandom;


/**
 * A specialized {@link Vector} representing an ordered immutable sequence of
 * {@code byte} values.
 *
 * @param <S> the type of shape of this vector
 */
@SuppressWarnings("cast")
public abstract class ByteVector<S extends Vector.Shape> extends Vector<Byte,S> {

    ByteVector() {}

    // Unary operator

    interface FUnOp {
        byte apply(int i, byte a);
    }

    abstract ByteVector<S> uOp(FUnOp f);

    abstract ByteVector<S> uOp(Mask<Byte, S> m, FUnOp f);

    // Binary operator

    interface FBinOp {
        byte apply(int i, byte a, byte b);
    }

    abstract ByteVector<S> bOp(Vector<Byte,S> v, FBinOp f);

    abstract ByteVector<S> bOp(Vector<Byte,S> v, Mask<Byte, S> m, FBinOp f);

    // Trinary operator

    interface FTriOp {
        byte apply(int i, byte a, byte b, byte c);
    }

    abstract ByteVector<S> tOp(Vector<Byte,S> v1, Vector<Byte,S> v2, FTriOp f);

    abstract ByteVector<S> tOp(Vector<Byte,S> v1, Vector<Byte,S> v2, Mask<Byte, S> m, FTriOp f);

    // Reduction operator

    abstract byte rOp(byte v, FBinOp f);

    // Binary test

    interface FBinTest {
        boolean apply(int i, byte a, byte b);
    }

    abstract Mask<Byte, S> bTest(Vector<Byte,S> v, FBinTest f);

    // Foreach

    interface FUnCon {
        void apply(int i, byte a);
    }

    abstract void forEach(FUnCon f);

    abstract void forEach(Mask<Byte, S> m, FUnCon f);

    //

    @Override
    public abstract ByteVector<S> add(Vector<Byte,S> v);

    /**
     * Adds this vector to the broadcast of an input scalar.
     * <p>
     * This is a vector binary operation where the primitive addition operation
     * ({@code +}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the result of adding this vector to the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> add(byte s);

    @Override
    public abstract ByteVector<S> add(Vector<Byte,S> v, Mask<Byte, S> m);

    /**
     * Adds this vector to broadcast of an input scalar,
     * selecting lane elements controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive addition operation
     * ({@code +}) is applied to lane elements.
     *
     * @param s the input scalar
     * @param m the mask controlling lane selection
     * @return the result of adding this vector to the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> add(byte s, Mask<Byte, S> m);

    @Override
    public abstract ByteVector<S> sub(Vector<Byte,S> v);

    /**
     * Subtracts the broadcast of an input scalar from this vector.
     * <p>
     * This is a vector binary operation where the primitive subtraction
     * operation ({@code -}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the result of subtracting the broadcast of an input
     * scalar from this vector
     */
    public abstract ByteVector<S> sub(byte s);

    @Override
    public abstract ByteVector<S> sub(Vector<Byte,S> v, Mask<Byte, S> m);

    /**
     * Subtracts the broadcast of an input scalar from this vector, selecting
     * lane elements controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive subtraction
     * operation ({@code -}) is applied to lane elements.
     *
     * @param s the input scalar
     * @param m the mask controlling lane selection
     * @return the result of subtracting the broadcast of an input
     * scalar from this vector
     */
    public abstract ByteVector<S> sub(byte s, Mask<Byte, S> m);

    @Override
    public abstract ByteVector<S> mul(Vector<Byte,S> v);

    /**
     * Multiplies this vector with the broadcast of an input scalar.
     * <p>
     * This is a vector binary operation where the primitive multiplication
     * operation ({@code *}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the result of multiplying this vector with the broadcast of an
     * input scalar
     */
    public abstract ByteVector<S> mul(byte s);

    @Override
    public abstract ByteVector<S> mul(Vector<Byte,S> v, Mask<Byte, S> m);

    /**
     * Multiplies this vector with the broadcast of an input scalar, selecting
     * lane elements controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive multiplication
     * operation ({@code *}) is applied to lane elements.
     *
     * @param s the input scalar
     * @param m the mask controlling lane selection
     * @return the result of multiplying this vector with the broadcast of an
     * input scalar
     */
    public abstract ByteVector<S> mul(byte s, Mask<Byte, S> m);

    @Override
    public abstract ByteVector<S> neg();

    @Override
    public abstract ByteVector<S> neg(Mask<Byte, S> m);

    @Override
    public abstract ByteVector<S> abs();

    @Override
    public abstract ByteVector<S> abs(Mask<Byte, S> m);

    @Override
    public abstract ByteVector<S> min(Vector<Byte,S> v);

    /**
     * Returns the minimum of this vector and the broadcast of an input scalar.
     * <p>
     * This is a vector binary operation where the operation
     * {@code (a, b) -> a < b ? a : b}  is applied to lane elements.
     *
     * @param s the input scalar
     * @return the minimum of this vector and the broadcast of an input scalar
     */
    public abstract ByteVector<S> min(byte s);

    @Override
    public abstract ByteVector<S> max(Vector<Byte,S> v);

    /**
     * Returns the maximum of this vector and the broadcast of an input scalar.
     * <p>
     * This is a vector binary operation where the operation
     * {@code (a, b) -> a > b ? a : b}  is applied to lane elements.
     *
     * @param s the input scalar
     * @return the maximum of this vector and the broadcast of an input scalar
     */
    public abstract ByteVector<S> max(byte s);

    @Override
    public abstract Mask<Byte, S> equal(Vector<Byte,S> v);

    /**
     * Tests if this vector is equal to the broadcast of an input scalar.
     * <p>
     * This is a vector binary test operation where the primitive equals
     * operation ({@code ==}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the result mask of testing if this vector is equal to the
     * broadcast of an input scalar
     */
    public abstract Mask<Byte, S> equal(byte s);

    @Override
    public abstract Mask<Byte, S> notEqual(Vector<Byte,S> v);

    /**
     * Tests if this vector is not equal to the broadcast of an input scalar.
     * <p>
     * This is a vector binary test operation where the primitive not equals
     * operation ({@code !=}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the result mask of testing if this vector is not equal to the
     * broadcast of an input scalar
     */
    public abstract Mask<Byte, S> notEqual(byte s);

    @Override
    public abstract Mask<Byte, S> lessThan(Vector<Byte,S> v);

    /**
     * Tests if this vector is less than the broadcast of an input scalar.
     * <p>
     * This is a vector binary test operation where the primitive less than
     * operation ({@code <}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the mask result of testing if this vector is less than the
     * broadcast of an input scalar
     */
    public abstract Mask<Byte, S> lessThan(byte s);

    @Override
    public abstract Mask<Byte, S> lessThanEq(Vector<Byte,S> v);

    /**
     * Tests if this vector is less or equal to the broadcast of an input scalar.
     * <p>
     * This is a vector binary test operation where the primitive less than
     * or equal to operation ({@code <=}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the mask result of testing if this vector is less than or equal
     * to the broadcast of an input scalar
     */
    public abstract Mask<Byte, S> lessThanEq(byte s);

    @Override
    public abstract Mask<Byte, S> greaterThan(Vector<Byte,S> v);

    /**
     * Tests if this vector is greater than the broadcast of an input scalar.
     * <p>
     * This is a vector binary test operation where the primitive greater than
     * operation ({@code >}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the mask result of testing if this vector is greater than the
     * broadcast of an input scalar
     */
    public abstract Mask<Byte, S> greaterThan(byte s);

    @Override
    public abstract Mask<Byte, S> greaterThanEq(Vector<Byte,S> v);

    /**
     * Tests if this vector is greater than or equal to the broadcast of an
     * input scalar.
     * <p>
     * This is a vector binary test operation where the primitive greater than
     * or equal to operation ({@code >=}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the mask result of testing if this vector is greater than or
     * equal to the broadcast of an input scalar
     */
    public abstract Mask<Byte, S> greaterThanEq(byte s);

    @Override
    public abstract ByteVector<S> blend(Vector<Byte,S> v, Mask<Byte, S> m);

    /**
     * Blends the lane elements of this vector with those of the broadcast of an
     * input scalar, selecting lanes controlled by a mask.
     * <p>
     * For each lane of the mask, at lane index {@code N}, if the mask lane
     * is set then the lane element at {@code N} from the input vector is
     * selected and placed into the resulting vector at {@code N},
     * otherwise the the lane element at {@code N} from this input vector is
     * selected and placed into the resulting vector at {@code N}.
     *
     * @param s the input scalar
     * @param m the mask controlling lane selection
     * @return the result of blending the lane elements of this vector with
     * those of the broadcast of an input scalar
     */
    public abstract ByteVector<S> blend(byte s, Mask<Byte, S> m);

    @Override
    public abstract ByteVector<S> rearrange(Vector<Byte, S> v,
                                                      Shuffle<Byte, S> s, Mask<Byte, S> m);

    @Override
    public abstract ByteVector<S> rearrange(Shuffle<Byte, S> m);

    @Override
    @ForceInline
    public <T extends Shape> ByteVector<T> resize(Species<Byte, T> species) {
        return (ByteVector<T>) species.resize(this);
    }

    @Override
    public abstract ByteVector<S> rotateEL(int i);

    @Override
    public abstract ByteVector<S> rotateER(int i);

    @Override
    public abstract ByteVector<S> shiftEL(int i);

    @Override
    public abstract ByteVector<S> shiftER(int i);



    /**
     * Bitwise ANDs this vector with an input vector.
     * <p>
     * This is a vector binary operation where the primitive bitwise AND
     * operation ({@code &}) is applied to lane elements.
     *
     * @param v the input vector
     * @return the bitwise AND of this vector with the input vector
     */
    public abstract ByteVector<S> and(Vector<Byte,S> v);

    /**
     * Bitwise ANDs this vector with the broadcast of an input scalar.
     * <p>
     * This is a vector binary operation where the primitive bitwise AND
     * operation ({@code &}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the bitwise AND of this vector with the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> and(byte s);

    /**
     * Bitwise ANDs this vector with an input vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive bitwise AND
     * operation ({@code &}) is applied to lane elements.
     *
     * @param v the input vector
     * @param m the mask controlling lane selection
     * @return the bitwise AND of this vector with the input vector
     */
    public abstract ByteVector<S> and(Vector<Byte,S> v, Mask<Byte, S> m);

    /**
     * Bitwise ANDs this vector with the broadcast of an input scalar, selecting
     * lane elements controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive bitwise AND
     * operation ({@code &}) is applied to lane elements.
     *
     * @param s the input scalar
     * @param m the mask controlling lane selection
     * @return the bitwise AND of this vector with the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> and(byte s, Mask<Byte, S> m);

    /**
     * Bitwise ORs this vector with an input vector.
     * <p>
     * This is a vector binary operation where the primitive bitwise OR
     * operation ({@code |}) is applied to lane elements.
     *
     * @param v the input vector
     * @return the bitwise OR of this vector with the input vector
     */
    public abstract ByteVector<S> or(Vector<Byte,S> v);

    /**
     * Bitwise ORs this vector with the broadcast of an input scalar.
     * <p>
     * This is a vector binary operation where the primitive bitwise OR
     * operation ({@code |}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the bitwise OR of this vector with the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> or(byte s);

    /**
     * Bitwise ORs this vector with an input vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive bitwise OR
     * operation ({@code |}) is applied to lane elements.
     *
     * @param v the input vector
     * @param m the mask controlling lane selection
     * @return the bitwise OR of this vector with the input vector
     */
    public abstract ByteVector<S> or(Vector<Byte,S> v, Mask<Byte, S> m);

    /**
     * Bitwise ORs this vector with the broadcast of an input scalar, selecting
     * lane elements controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive bitwise OR
     * operation ({@code |}) is applied to lane elements.
     *
     * @param s the input scalar
     * @param m the mask controlling lane selection
     * @return the bitwise OR of this vector with the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> or(byte s, Mask<Byte, S> m);

    /**
     * Bitwise XORs this vector with an input vector.
     * <p>
     * This is a vector binary operation where the primitive bitwise XOR
     * operation ({@code ^}) is applied to lane elements.
     *
     * @param v the input vector
     * @return the bitwise XOR of this vector with the input vector
     */
    public abstract ByteVector<S> xor(Vector<Byte,S> v);

    /**
     * Bitwise XORs this vector with the broadcast of an input scalar.
     * <p>
     * This is a vector binary operation where the primitive bitwise XOR
     * operation ({@code ^}) is applied to lane elements.
     *
     * @param s the input scalar
     * @return the bitwise XOR of this vector with the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> xor(byte s);

    /**
     * Bitwise XORs this vector with an input vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive bitwise XOR
     * operation ({@code ^}) is applied to lane elements.
     *
     * @param v the input vector
     * @param m the mask controlling lane selection
     * @return the bitwise XOR of this vector with the input vector
     */
    public abstract ByteVector<S> xor(Vector<Byte,S> v, Mask<Byte, S> m);

    /**
     * Bitwise XORs this vector with the broadcast of an input scalar, selecting
     * lane elements controlled by a mask.
     * <p>
     * This is a vector binary operation where the primitive bitwise XOR
     * operation ({@code ^}) is applied to lane elements.
     *
     * @param s the input scalar
     * @param m the mask controlling lane selection
     * @return the bitwise XOR of this vector with the broadcast of an input
     * scalar
     */
    public abstract ByteVector<S> xor(byte s, Mask<Byte, S> m);

    /**
     * Bitwise NOTs this vector.
     * <p>
     * This is a vector unary operation where the primitive bitwise NOT
     * operation ({@code ~}) is applied to lane elements.
     *
     * @return the bitwise NOT of this vector
     */
    public abstract ByteVector<S> not();

    /**
     * Bitwise NOTs this vector, selecting lane elements controlled by a mask.
     * <p>
     * This is a vector unary operation where the primitive bitwise NOT
     * operation ({@code ~}) is applied to lane elements.
     *
     * @param m the mask controlling lane selection
     * @return the bitwise NOT of this vector
     */
    public abstract ByteVector<S> not(Mask<Byte, S> m);

/*
@@@ Check the shift operations against the JLS definition and vector
    instructions.

    For int values the low 5 bits of s are used.
    For long values the low 6 bits of s are used.
 */


    @Override
    public abstract void intoByteArray(byte[] a, int ix);

    @Override
    public abstract void intoByteArray(byte[] a, int ix, Mask<Byte, S> m);

    @Override
    public abstract void intoByteBuffer(ByteBuffer bb, int ix);

    @Override
    public abstract void intoByteBuffer(ByteBuffer bb, int ix, Mask<Byte, S> m);


    // Type specific horizontal reductions

// @@@ For floating point vectors order matters for reproducibility
//     with equivalent sequential reduction. Some order needs to be specified
//     by default. If that default is sequential encounter order then there
//     could be a "go faster" option that is unspecified, essentially giving
//     implementation flexibility at the expense of reproducibility and/or
//     accuracy.
// @@@ Mask versions?

    /**
     * Adds all lane elements of this vector.
     * <p>
     * This is an associative vector reduction operation where the addition
     * operation ({@code +}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @return the addition of all the lane elements of this vector
     */
    public abstract byte addAll();

    /**
     * Adds all lane elements of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the addition
     * operation ({@code +}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @param m the mask controlling lane selection
     * @return the addition of all the lane elements of this vector
     */
    public abstract byte addAll(Mask<Byte, S> m);

    /**
     * Subtracts all lane elements of this vector.
     * <p>
     * This is an associative vector reduction operation where the subtraction
     * operation ({@code -}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @return the subtraction of all the lane elements of this vector
     */
    public abstract byte subAll();

    /**
     * Subtracts all lane elements of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the subtraction
     * operation ({@code -}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @param m the mask controlling lane selection
     * @return the subtraction of all the lane elements of this vector
     */
    public abstract byte subAll(Mask<Byte, S> m);

    /**
     * Multiplies all lane elements of this vector.
     * <p>
     * This is an associative vector reduction operation where the
     * multiplication operation ({@code *}) is applied to lane elements,
     * and the identity value is {@code 1}.
     *
     * @return the multiplication of all the lane elements of this vector
     */
    public abstract byte mulAll();

    /**
     * Multiplies all lane elements of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the
     * multiplication operation ({@code *}) is applied to lane elements,
     * and the identity value is {@code 1}.
     *
     * @param m the mask controlling lane selection
     * @return the multiplication of all the lane elements of this vector
     */
    public abstract byte mulAll(Mask<Byte, S> m);

    /**
     * Returns the minimum lane element of this vector.
     * <p>
     * This is an associative vector reduction operation where the operation
     * {@code (a, b) -> a > b ? b : a} is applied to lane elements,
     * and the identity value is {@link Byte.MAX_VALUE}.
     *
     * @return the minimum lane element of this vector
     */
    public abstract byte minAll();

    /**
     * Returns the minimum lane element of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the operation
     * {@code (a, b) -> a > b ? b : a} is applied to lane elements,
     * and the identity value is {@link Byte.MAX_VALUE}.
     *
     * @param m the mask controlling lane selection
     * @return the minimum lane element of this vector
     */
    public abstract byte minAll(Mask<Byte, S> m);

    /**
     * Returns the maximum lane element of this vector.
     * <p>
     * This is an associative vector reduction operation where the operation
     * {@code (a, b) -> a < b ? b : a} is applied to lane elements,
     * and the identity value is {@link Byte.MIN_VALUE}.
     *
     * @return the maximum lane element of this vector
     */
    public abstract byte maxAll();

    /**
     * Returns the maximum lane element of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the operation
     * {@code (a, b) -> a < b ? b : a} is applied to lane elements,
     * and the identity value is {@link Byte.MIN_VALUE}.
     *
     * @param m the mask controlling lane selection
     * @return the maximum lane element of this vector
     */
    public abstract byte maxAll(Mask<Byte, S> m);

    /**
     * Logically ORs all lane elements of this vector.
     * <p>
     * This is an associative vector reduction operation where the logical OR
     * operation ({@code |}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @return the logical OR all the lane elements of this vector
     */
    public abstract byte orAll();

    /**
     * Logically ORs all lane elements of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the logical OR
     * operation ({@code |}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @param m the mask controlling lane selection
     * @return the logical OR all the lane elements of this vector
     */
    public abstract byte orAll(Mask<Byte, S> m);

    /**
     * Logically ANDs all lane elements of this vector.
     * <p>
     * This is an associative vector reduction operation where the logical AND
     * operation ({@code |}) is applied to lane elements,
     * and the identity value is {@code -1}.
     *
     * @return the logical AND all the lane elements of this vector
     */
    public abstract byte andAll();

    /**
     * Logically ANDs all lane elements of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the logical AND
     * operation ({@code |}) is applied to lane elements,
     * and the identity value is {@code -1}.
     *
     * @param m the mask controlling lane selection
     * @return the logical AND all the lane elements of this vector
     */
    public abstract byte andAll(Mask<Byte, S> m);

    /**
     * Logically XORs all lane elements of this vector.
     * <p>
     * This is an associative vector reduction operation where the logical XOR
     * operation ({@code ^}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @return the logical XOR all the lane elements of this vector
     */
    public abstract byte xorAll();

    /**
     * Logically XORs all lane elements of this vector, selecting lane elements
     * controlled by a mask.
     * <p>
     * This is an associative vector reduction operation where the logical XOR
     * operation ({@code ^}) is applied to lane elements,
     * and the identity value is {@code 0}.
     *
     * @param m the mask controlling lane selection
     * @return the logical XOR all the lane elements of this vector
     */
    public abstract byte xorAll(Mask<Byte, S> m);

    // Type specific accessors

    /**
     * Gets the lane element at lane index {@code i}
     *
     * @param i the lane index
     * @return the lane element at lane index {@code i}
     * @throws IllegalArgumentException if the index is is out of range
     * ({@code < 0 || >= length()})
     */
    public abstract byte get(int i);

    /**
     * Replaces the lane element of this vector at lane index {@code i} with
     * value {@code e}.
     * <p>
     * This is a cross-lane operation and behaves as if it returns the result
     * of blending this vector with an input vector that is the result of
     * broadcasting {@code e} and a mask that has only one lane set at lane
     * index {@code i}.
     *
     * @param i the lane index of the lane element to be replaced
     * @param e the value to be placed
     * @return the result of replacing the lane element of this vector at lane
     * index {@code i} with value {@code e}.
     * @throws IllegalArgumentException if the index is is out of range
     * ({@code < 0 || >= length()})
     */
    public abstract ByteVector<S> with(int i, byte e);

    // Type specific extractors

    /**
     * Returns an array containing the lane elements of this vector.
     * <p>
     * This method behaves as if it {@link #intoArray(byte[], int)} stores}
     * this vector into an allocated array and returns the array as follows:
     * <pre>{@code
     *   byte[] a = new byte[this.length()];
     *   this.intoArray(a, 0);
     *   return a;
     * }</pre>
     *
     * @return an array containing the the lane elements of this vector
     */
    @ForceInline
    public final byte[] toArray() {
        // @@@ could allocate without zeroing, see Unsafe.allocateUninitializedArray
        byte[] a = new byte[species().length()];
        intoArray(a, 0);
        return a;
    }

    /**
     * Stores this vector into an array starting at offset.
     * <p>
     * For each vector lane, where {@code N} is the vector lane index,
     * the lane element at index {@code N} is stored into the array at index
     * {@code i + N}.
     *
     * @param a the array
     * @param i the offset into the array
     * @throws IndexOutOfBoundsException if {@code i < 0}, or
     * {@code i > a.length - this.length()}
     */
    public abstract void intoArray(byte[] a, int i);

    /**
     * Stores this vector into an array starting at offset and using a mask.
     * <p>
     * For each vector lane, where {@code N} is the vector lane index,
     * if the mask lane at index {@code N} is set then the lane element at
     * index {@code N} is stored into the array index {@code i + N}.
     *
     * @param a the array
     * @param i the offset into the array
     * @param m the mask
     * @throws IndexOutOfBoundsException if {@code i < 0}, or
     * for any vector lane index {@code N} where the mask at lane {@code N}
     * is set {@code i >= a.length - N}
     */
    public abstract void intoArray(byte[] a, int i, Mask<Byte, S> m);

    /**
     * Stores this vector into an array using indexes obtained from an index
     * map.
     * <p>
     * For each vector lane, where {@code N} is the vector lane index, the
     * lane element at index {@code N} is stored into the array at index
     * {@code i + indexMap[j + N]}.
     *
     * @param a the array
     * @param i the offset into the array, may be negative if relative
     * indexes in the index map compensate to produce a value within the
     * array bounds
     * @param indexMap the index map
     * @param j the offset into the index map
     * @throws IndexOutOfBoundsException if {@code j < 0}, or
     * {@code j > indexMap.length - this.length()},
     * or for any vector lane index {@code N} the result of
     * {@code i + indexMap[j + N]} is {@code < 0} or {@code >= a.length}
     */
    public void intoArray(byte[] a, int i, int[] indexMap, int j) {
        forEach((n, e) -> a[i + indexMap[j + n]] = e);
    }

    /**
     * Stores this vector into an array using indexes obtained from an index
     * map and using a mask.
     * <p>
     * For each vector lane, where {@code N} is the vector lane index,
     * if the mask lane at index {@code N} is set then the lane element at
     * index {@code N} is stored into the array at index
     * {@code i + indexMap[j + N]}.
     *
     * @param a the array
     * @param i the offset into the array, may be negative if relative
     * indexes in the index map compensate to produce a value within the
     * array bounds
     * @param m the mask
     * @param indexMap the index map
     * @param j the offset into the index map
     * @throws IndexOutOfBoundsException if {@code j < 0}, or
     * {@code j > indexMap.length - this.length()},
     * or for any vector lane index {@code N} where the mask at lane
     * {@code N} is set the result of {@code i + indexMap[j + N]} is
     * {@code < 0} or {@code >= a.length}
     */
    public void intoArray(byte[] a, int i, Mask<Byte, S> m, int[] indexMap, int j) {
        forEach(m, (n, e) -> a[i + indexMap[j + n]] = e);
    }

    // Species

    @Override
    public abstract ByteSpecies<S> species();

    /**
     * A specialized factory for creating {@link ByteVector} value of the same
     * shape, and a {@link Mask} and {@link Shuffle} values of the same shape
     * and {@code int} element type.
     *
     * @param <S> the type of shape of this species
     */
    public static abstract class ByteSpecies<S extends Vector.Shape> extends Vector.Species<Byte, S> {
        interface FOp {
            byte apply(int i);
        }

        abstract ByteVector<S> op(FOp f);

        abstract ByteVector<S> op(Mask<Byte, S> m, FOp f);

        // Factories

        @Override
        public abstract ByteVector<S> zero();

        /**
         * Returns a vector where all lane elements are set to the primitive
         * value {@code e}.
         *
         * @param e the value
         * @return a vector of vector where all lane elements are set to
         * the primitive value {@code e}
         */
        public abstract ByteVector<S> broadcast(byte e);

        /**
         * Returns a vector where the first lane element is set to the primtive
         * value {@code e}, all other lane elements are set to the default
         * value.
         *
         * @param e the value
         * @return a vector where the first lane element is set to the primitive
         * value {@code e}
         */
        @ForceInline
        public final ByteVector<S> single(byte e) {
            return zero().with(0, e);
        }

        /**
         * Returns a vector where each lane element is set to a randomly
         * generated primitive value.
         * @@@ what are the properties of the random number generator?
         *
         * @return a vector where each lane elements is set to a randomly
         * generated primitive value
         */
        public ByteVector<S> random() {
            ThreadLocalRandom r = ThreadLocalRandom.current();
            return op(i -> (byte) r.nextInt());
        }

        /**
         * Returns a vector where each lane element is set to a given
         * primitive value.
         * <p>
         * For each vector lane, where {@code N} is the vector lane index, the
         * the primitive value at index {@code N} is placed into the resulting
         * vector at lane index {@code N}.
         *
         * @@@ What should happen if es.length < this.length() ? use the default
         * value or throw IndexOutOfBoundsException
         *
         * @param es the given primitive values
         * @return a vector where each lane element is set to a given primitive
         * value
         */
        public abstract ByteVector<S> scalars(byte... es);

        /**
         * Loads a vector from an array starting at offset.
         * <p>
         * For each vector lane, where {@code N} is the vector lane index, the
         * array element at index {@code i + N} is placed into the
         * resulting vector at lane index {@code N}.
         *
         * @param a the array
         * @param i the offset into the array
         * @return the vector loaded from an array
         * @throws IndexOutOfBoundsException if {@code i < 0}, or
         * {@code i > a.length - this.length()}
         */
        public abstract ByteVector<S> fromArray(byte[] a, int i);

        /**
         * Loads a vector from an array starting at offset and using a mask.
         * <p>
         * For each vector lane, where {@code N} is the vector lane index,
         * if the mask lane at index {@code N} is set then the array element at
         * index {@code i + N} is placed into the resulting vector at lane index
         * {@code N}, otherwise the default element value is placed into the
         * resulting vector at lane index {@code N}.
         *
         * @param a the array
         * @param i the offset into the array
         * @param m the mask
         * @return the vector loaded from an array
         * @throws IndexOutOfBoundsException if {@code i < 0}, or
         * for any vector lane index {@code N} where the mask at lane {@code N}
         * is set {@code i > a.length - N}
         */
        public abstract ByteVector<S> fromArray(byte[] a, int i, Mask<Byte, S> m);

        /**
         * Loads a vector from an array using indexes obtained from an index
         * map.
         * <p>
         * For each vector lane, where {@code N} is the vector lane index, the
         * array element at index {@code i + indexMap[j + N]} is placed into the
         * resulting vector at lane index {@code N}.
         *
         * @param a the array
         * @param i the offset into the array, may be negative if relative
         * indexes in the index map compensate to produce a value within the
         * array bounds
         * @param indexMap the index map
         * @param j the offset into the index map
         * @return the vector loaded from an array
         * @throws IndexOutOfBoundsException if {@code j < 0}, or
         * {@code j > indexMap.length - this.length()},
         * or for any vector lane index {@code N} the result of
         * {@code i + indexMap[j + N]} is {@code < 0} or {@code >= a.length}
         */
        public ByteVector<S> fromArray(byte[] a, int i, int[] indexMap, int j) {
            return op(n -> a[i + indexMap[j + n]]);
        }

        /**
         * Loads a vector from an array using indexes obtained from an index
         * map and using a mask.
         * <p>
         * For each vector lane, where {@code N} is the vector lane index,
         * if the mask lane at index {@code N} is set then the array element at
         * index {@code i + indexMap[j + N]} is placed into the resulting vector
         * at lane index {@code N}.
         *
         * @param a the array
         * @param i the offset into the array, may be negative if relative
         * indexes in the index map compensate to produce a value within the
         * array bounds
         * @param indexMap the index map
         * @param j the offset into the index map
         * @return the vector loaded from an array
         * @throws IndexOutOfBoundsException if {@code j < 0}, or
         * {@code j > indexMap.length - this.length()},
         * or for any vector lane index {@code N} where the mask at lane
         * {@code N} is set the result of {@code i + indexMap[j + N]} is
         * {@code < 0} or {@code >= a.length}
         */
        public ByteVector<S> fromArray(byte[] a, int i, Mask<Byte, S> m, int[] indexMap, int j) {
            return op(m, n -> a[i + indexMap[j + n]]);
        }

        @Override
        public abstract ByteVector<S> fromByteArray(byte[] a, int ix);

        @Override
        public abstract ByteVector<S> fromByteArray(byte[] a, int ix, Mask<Byte, S> m);

        @Override
        public abstract ByteVector<S> fromByteBuffer(ByteBuffer bb, int ix);

        @Override
        public abstract ByteVector<S> fromByteBuffer(ByteBuffer bb, int ix, Mask<Byte, S> m);

        @Override
        public <F, T extends Shape> ByteVector<S> reshape(Vector<F, T> o) {
            int blen = Math.max(o.species().bitSize(), bitSize()) / Byte.SIZE;
            ByteBuffer bb = ByteBuffer.allocate(blen).order(ByteOrder.nativeOrder());
            o.intoByteBuffer(bb, 0);
            return fromByteBuffer(bb, 0);
        }

        @Override
        public abstract <F> ByteVector<S> rebracket(Vector<F, S> o);

        @Override
        public abstract <T extends Shape> ByteVector<S> resize(Vector<Byte, T> o);

        @Override
        public abstract <F, T extends Shape> ByteVector<S> cast(Vector<F, T> v);

    }

    /**
     * Finds the preferred species for an element type of {@code byte}.
     * <p>
     * A preferred species is a species chosen by the platform that has a
     * shape of maximal bit size.  A preferred species for different element
     * types will have the same shape, and therefore vectors, masks, and
     * shuffles created from such species will be shape compatible.
     *
     * @return the preferred species for an element type of {@code byte}
     */
    @SuppressWarnings("unchecked")
    public static ByteSpecies<?> preferredSpecies() {
        return (ByteSpecies<?>) Vector.preferredSpecies(byte.class);
    }

    /**
     * Finds a species for an element type of {@code byte} and shape.
     *
     * @param s the shape
     * @param <S> the type of shape
     * @return a species for an element type of {@code byte} and shape
     * @throws IllegalArgumentException if no such species exists for the shape
     */
    @SuppressWarnings("unchecked")
    public static <S extends Shape> ByteSpecies<S> species(S s) {
        Objects.requireNonNull(s);
        if (s == Shapes.S_64_BIT) {
            return (ByteSpecies<S>) Byte64Vector.SPECIES;
        } else if (s == Shapes.S_128_BIT) {
            return (ByteSpecies<S>) Byte128Vector.SPECIES;
        } else if (s == Shapes.S_256_BIT) {
            return (ByteSpecies<S>) Byte256Vector.SPECIES;
        } else if (s == Shapes.S_512_BIT) {
            return (ByteSpecies<S>) Byte512Vector.SPECIES;
        } else if (s == Shapes.S_Scalable_BIT) {
            return (ByteSpecies<S>) ByteScalableVector.SPECIES;
        } else {
            throw new IllegalArgumentException("Bad shape: " + s);
        }
    }
}