/*

 * 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

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 */

package jdk.nashorn.internal.runtime.arrays;

import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

import java.lang.reflect.Array;

import jdk.nashorn.internal.runtime.BitVector;

/**

 * This filter handles the deletion of array elements.

 */

final class DeletedArrayFilter extends ArrayFilter {

    /** Bit vector tracking deletions. */

    private final BitVector deleted;

    DeletedArrayFilter(final ArrayData underlying) {

        super(underlying);

        this.deleted = new BitVector(underlying.length());

    }

    @Override

    public ArrayData copy() {

        final DeletedArrayFilter copy = new DeletedArrayFilter(underlying.copy());

        copy.getDeleted().copy(deleted);

        return copy;

    }

    @Override

    public Object[] asObjectArray() {

        final Object[] value = super.asObjectArray();

        for (int i = 0; i < value.length; i++) {

            if (deleted.isSet(i)) {

                value[i] = UNDEFINED;

            }

        }

        return value;

    }

    @Override

    public Object asArrayOfType(final Class<?> componentType) {

        final Object value = super.asArrayOfType(componentType);

        final Object undefValue = convertUndefinedValue(componentType);

        final int l = Array.getLength(value);

        for (int i = 0; i < l; i++) {

            if (deleted.isSet(i)) {

                Array.set(value, i, undefValue);

            }

        }

        return value;

    }

    @Override

    public ArrayData shiftLeft(final int by) {

        super.shiftLeft(by);

        deleted.shiftLeft(by, length());

        return this;

    }

    @Override

    public ArrayData shiftRight(final int by) {

        super.shiftRight(by);

        deleted.shiftRight(by, length());

        return this;

    }

    @Override

    public ArrayData ensure(final long safeIndex) {

        if (safeIndex >= SparseArrayData.MAX_DENSE_LENGTH && safeIndex >= length()) {

            return new SparseArrayData(this, safeIndex + 1);

        }

        super.ensure(safeIndex);

        deleted.resize(length());

        return this;

    }

    @Override

    public ArrayData shrink(final long newLength) {

        super.shrink(newLength);

        deleted.resize(length());

        return this;

    }

    @Override

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

        deleted.clear(ArrayIndex.toLongIndex(index));

        return super.set(index, value, strict);

    }

    @Override

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

        deleted.clear(ArrayIndex.toLongIndex(index));

        return super.set(index, value, strict);

    }

    @Override

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

        deleted.clear(ArrayIndex.toLongIndex(index));

        return super.set(index, value, strict);

    }

    @Override

    public boolean has(final int index) {

        return super.has(index) && deleted.isClear(ArrayIndex.toLongIndex(index));

    }

    @Override

    public ArrayData delete(final int index) {

        final long longIndex = ArrayIndex.toLongIndex(index);

        assert longIndex >= 0 && longIndex < length();

        deleted.set(longIndex);

        underlying.setEmpty(index);

        return this;

    }

    @Override

    public ArrayData delete(final long fromIndex, final long toIndex) {

        assert fromIndex >= 0 && fromIndex <= toIndex && toIndex < length();

        deleted.setRange(fromIndex, toIndex + 1);

        underlying.setEmpty(fromIndex, toIndex);

        return this;

    }

    @Override

    public Object pop() {

        final long index = length() - 1;

        if (super.has((int)index)) {

            final boolean isDeleted = deleted.isSet(index);

            final Object value = super.pop();

            return isDeleted ? UNDEFINED : value;

        }

        return super.pop();

    }

    @Override

    public ArrayData slice(final long from, final long to) {

        final ArrayData newArray = underlying.slice(from, to);

        final DeletedArrayFilter newFilter = new DeletedArrayFilter(newArray);

        newFilter.getDeleted().copy(deleted);

        newFilter.getDeleted().shiftLeft(from, newFilter.length());

        return newFilter;

    }

    private BitVector getDeleted() {

        return deleted;

    }

}