/*

 * 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.JSType;

import jdk.nashorn.internal.runtime.ScriptObject;

import jdk.nashorn.internal.runtime.arrays.ArrayData;

/**

 * Float32 array for the TypedArray extension

 */

@ScriptClass("Float32Array")

    private static final int BYTES_PER_ELEMENT = 4;

    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 NativeFloat32Array(buffer, byteOffset, length);

        }

        @Override

        public ArrayData createArrayData(final NativeArrayBuffer buffer, final int byteOffset, final int length) {

            return new Float32ArrayData(buffer, byteOffset, length);

        }

    };

    private static final class Float32ArrayData extends ArrayDataImpl {

        private Float32ArrayData(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 double getDoubleImpl(final int index) {

            final int byteIndex = byteIndex(index);

            final byte[] byteArray = buffer.getByteArray();

            final int bits = byteArray[byteIndex  ]       & 0x0000_00ff |

                             byteArray[byteIndex+1] <<  8 & 0x0000_ff00 |

                             byteArray[byteIndex+2] << 16 & 0x00ff_0000 |

                             byteArray[byteIndex+3] << 24 & 0xff00_0000 ;

            return Float.intBitsToFloat(bits);

        }

        @Override

        protected int getIntImpl(final int index) {

            return (int)getDoubleImpl(index);

        }

        @Override

        protected long getLongImpl(final int key) {

            return (long)getDoubleImpl(key);

        }

        @Override

        protected Object getObjectImpl(final int key) {

            return getDoubleImpl(key);

        }

        @Override

        protected void setImpl(final int index, final double value) {

            final int bits = Float.floatToRawIntBits((float)value);

            final int byteIndex = byteIndex(index);

            @SuppressWarnings("MismatchedReadAndWriteOfArray")

            final byte[] byteArray = buffer.getByteArray();

            byteArray[byteIndex  ] = (byte)(bits        & 0xff);

            byteArray[byteIndex+1] = (byte)(bits >>>  8 & 0xff);

            byteArray[byteIndex+2] = (byte)(bits >>> 16 & 0xff);

            byteArray[byteIndex+3] = (byte)(bits >>> 24 & 0xff);

        }

        @Override

        protected void setImpl(final int key, final int value) {

            setImpl(key, (double)value);

        }

        @Override

        protected void setImpl(final int key, final long value) {

            setImpl(key, (double)value);

        }

        @Override

        protected void setImpl(final int key, final Object value) {

            setImpl(key, JSType.toNumber(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);

    }

    NativeFloat32Array(final NativeArrayBuffer buffer, final int byteOffset, final int length) {

        super(buffer, byteOffset, length);

    }

    @Override

    protected Factory factory() {

        return FACTORY;

    }

    @Override

    protected boolean isFloatArray() {

        return true;

    }

    /**

     * 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().getFloat32ArrayPrototype();

    }

}