/*

 * 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 static jdk.nashorn.internal.codegen.CompilerConstants.specialCall;

import static jdk.nashorn.internal.codegen.CompilerConstants.staticCall;

import static jdk.nashorn.internal.lookup.Lookup.MH;

import java.lang.invoke.MethodHandle;

import java.lang.invoke.MethodHandles;

import java.nio.ByteBuffer;

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.Property;

import jdk.nashorn.internal.objects.annotations.ScriptClass;

import jdk.nashorn.internal.objects.annotations.Where;

import jdk.nashorn.internal.runtime.JSType;

import jdk.nashorn.internal.runtime.PropertyMap;

import jdk.nashorn.internal.runtime.ScriptObject;

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

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

/**

 * Uint8 clamped array for TypedArray extension

 */

@ScriptClass("Uint8ClampedArray")

public final class NativeUint8ClampedArray extends ArrayBufferView {

    /**

     * The size in bytes of each element in the array.

     */

    @Property(attributes = Attribute.NOT_ENUMERABLE | Attribute.NOT_WRITABLE | Attribute.NOT_CONFIGURABLE, where = Where.CONSTRUCTOR)

    public static final int BYTES_PER_ELEMENT = 1;

    // initialized by nasgen

    @SuppressWarnings("unused")

    private static PropertyMap $nasgenmap$;

    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 NativeUint8ClampedArray(buffer, byteOffset, length);

        }

        @Override

        public Uint8ClampedArrayData createArrayData(final ByteBuffer nb, final int start, final int end) {

            return new Uint8ClampedArrayData(nb, start, end);

        }

        @Override

        public String getClassName() {

            return "Uint8ClampedArray";

        }

    };

    private static final class Uint8ClampedArrayData extends TypedArrayData<ByteBuffer> {

        private static final MethodHandle GET_ELEM = specialCall(MethodHandles.lookup(), Uint8ClampedArrayData.class, "getElem", int.class, int.class).methodHandle();

        private static final MethodHandle SET_ELEM = specialCall(MethodHandles.lookup(), Uint8ClampedArrayData.class, "setElem", void.class, int.class, int.class).methodHandle();

        private static final MethodHandle RINT_D   = staticCall(MethodHandles.lookup(), Uint8ClampedArrayData.class, "rint", double.class, double.class).methodHandle();

        private static final MethodHandle RINT_O   = staticCall(MethodHandles.lookup(), Uint8ClampedArrayData.class, "rint", Object.class, Object.class).methodHandle();

        private static final MethodHandle CLAMP_LONG = staticCall(MethodHandles.lookup(), Uint8ClampedArrayData.class, "clampLong", long.class, long.class).methodHandle();

        private Uint8ClampedArrayData(final ByteBuffer nb, final int start, final int end) {

            super(((ByteBuffer)nb.position(start).limit(end)).slice(), end - start);

        }

        @Override

        protected MethodHandle getGetElem() {

            return GET_ELEM;

        }

        @Override

        protected MethodHandle getSetElem() {

            return SET_ELEM;

        }

        @Override

        public Class<?> getElementType() {

            return int.class;

        }

        private int getElem(final int index) {

            try {

                return nb.get(index) & 0xff;

            } catch (final IndexOutOfBoundsException e) {

                throw new ClassCastException(); //force relink - this works for unoptimistic too

            }

        }

        @Override

        public MethodHandle getElementSetter(final Class<?> elementType) {

            final MethodHandle setter = super.getElementSetter(elementType); //getContinuousElementSetter(getClass(), setElem(), elementType);

            if (setter != null) {

                if (elementType == Object.class) {

                    return MH.filterArguments(setter, 2, RINT_O);

                } else if (elementType == double.class) {

                    return MH.filterArguments(setter, 2, RINT_D);

                } else if (elementType == long.class) {

                    return MH.filterArguments(setter, 2, CLAMP_LONG);

                }

            }

            return setter;

        }

        private void setElem(final int index, final int elem) {

            try {

                final byte clamped;

                if ((elem & 0xffff_ff00) == 0) {

                    clamped = (byte)elem;

                } else {

                    clamped = elem < 0 ? 0 : (byte)0xff;

                }

                nb.put(index, clamped);

            } catch (final IndexOutOfBoundsException e) {

                //swallow valid array indexes. it's ok.

                if (index < 0) {

                    throw new ClassCastException();

                }

            }

        }

        @Override

        public boolean isClamped() {

            return true;

        }

        @Override

        public boolean isUnsigned() {

            return true;

        }

        @Override

        public int getInt(final int index) {

            return getElem(index);

        }

        @Override

        public long getLong(final int index) {

            return getInt(index);

        }

        @Override

        public double getDouble(final int index) {

            return getInt(index);

        }

        @Override

        public Object getObject(final int index) {

            return getInt(index);

        }

        @Override

        public ArrayData set(final int index, final Object value, final boolean strict) {

            return set(index, JSType.toNumber(value), strict);

        }

        @Override

        public ArrayData set(final int index, final int value, final boolean strict) {

            setElem(index, value);

            return this;

        }

        @Override

        public ArrayData set(final int index, final long value, final boolean strict) {

            return set(index, (int)value, strict);

        }

        @Override

        public ArrayData set(final int index, final double value, final boolean strict) {

            return set(index, rint(value), strict);

        }

        private static double rint(final double rint) {

            return (int)Math.rint(rint);

        }

        @SuppressWarnings("unused")

        private static Object rint(final Object rint) {

            return rint(JSType.toNumber(rint));

        }

        @SuppressWarnings("unused")

        private static long clampLong(final long l) {

            if(l < 0L) {

                return 0L;

            } else if(l > 0xffL) {

                return 0xffL;

            }

            return l;

        }

    }

    /**

     * 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 NativeUint8ClampedArray constructor(final boolean newObj, final Object self, final Object... args) {

        return (NativeUint8ClampedArray)constructorImpl(newObj, args, FACTORY);

    }

    NativeUint8ClampedArray(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 NativeUint8ClampedArray subarray(final Object self, final Object begin, final Object end) {

        return (NativeUint8ClampedArray)ArrayBufferView.subarrayImpl(self, begin, end);

    }

    @Override

    protected ScriptObject getPrototype(final Global global) {

        return global.getUint8ClampedArrayPrototype();

    }

}