nashorn/src/jdk/nashorn/internal/objects/NativeInt8Array.java

/*
 * Copyright (c) 2010, 2013, 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 any
 * questions.
 */

package jdk.nashorn.internal.objects;

import jdk.nashorn.internal.objects.annotations.Attribute;
import jdk.nashorn.internal.objects.annotations.Constructor;
import jdk.nashorn.internal.objects.annotations.Function;
import jdk.nashorn.internal.objects.annotations.ScriptClass;
import jdk.nashorn.internal.runtime.ScriptObject;
import jdk.nashorn.internal.runtime.arrays.ArrayData;

/**
 * Int8Array for the TypedArray extension
 */
@ScriptClass("Int8Array")
public final class NativeInt8Array extends ArrayBufferView {
    private static final int BYTES_PER_ELEMENT = 1;
    private static final Factory FACTORY = new Factory(BYTES_PER_ELEMENT) {
        @Override
        public ArrayBufferView construct(final NativeArrayBuffer buffer, final int byteOffset, final int length) {
            return new NativeInt8Array(buffer, byteOffset, length);
        }

        @Override
        public ArrayData createArrayData(final NativeArrayBuffer buffer, final int byteOffset, final int length) {
            return new Int8ArrayData(buffer, byteOffset, length);
        }
    };

    private static final class Int8ArrayData extends ArrayDataImpl {
        private Int8ArrayData(final NativeArrayBuffer buffer, final int byteOffset, final int elementLength) {
            super(buffer, byteOffset, elementLength);
        }

        @Override
        protected int byteIndex(final int index) {
            return index * BYTES_PER_ELEMENT + byteOffset;
        }

        @Override
        protected int getIntImpl(final int index) {
            return buffer.getByteArray()[byteIndex(index)];
        }

        @Override
        protected void setImpl(final int index, final int value) {
            buffer.getByteArray()[byteIndex(index)] = (byte)value;
        }
    }

    /**
     * Constructor
     *
     * @param newObj is this typed array instantiated with the new operator
     * @param self   self reference
     * @param args   args
     *
     * @return new typed array
     */
    @Constructor(arity = 1)
    public static Object constructor(final boolean newObj, final Object self, final Object... args) {
        return constructorImpl(args, FACTORY);
    }

    NativeInt8Array(final NativeArrayBuffer buffer, final int byteOffset, final int length) {
        super(buffer, byteOffset, length);
    }

    @Override
    protected Factory factory() {
        return FACTORY;
    }

    /**
     * Set values
     * @param self   self reference
     * @param array  multiple values of array's type to set
     * @param offset optional start index, interpreted  0 if undefined
     * @return undefined
     */
    @Function(attributes = Attribute.NOT_ENUMERABLE)
    protected static Object set(final Object self, final Object array, final Object offset) {
        return ArrayBufferView.setImpl(self, array, offset);
    }

    /**
     * Returns a new TypedArray view of the ArrayBuffer store for this TypedArray,
     * referencing the elements at begin, inclusive, up to end, exclusive. If either
     * begin or end is negative, it refers to an index from the end of the array,
     * as opposed to from the beginning.
     * <p>
     * If end is unspecified, the subarray contains all elements from begin to the end
     * of the TypedArray. The range specified by the begin and end values is clamped to
     * the valid index range for the current array. If the computed length of the new
     * TypedArray would be negative, it is clamped to zero.
     * <p>
     * The returned TypedArray will be of the same type as the array on which this
     * method is invoked.
     *
     * @param self self reference
     * @param begin begin position
     * @param end end position
     *
     * @return sub array
     */
    @Function(attributes = Attribute.NOT_ENUMERABLE)
    protected static Object subarray(final Object self, final Object begin, final Object end) {
        return ArrayBufferView.subarrayImpl(self, begin, end);
    }

    @Override
    protected ScriptObject getPrototype() {
        return Global.instance().getInt8ArrayPrototype();
    }
}