/*

 * Copyright (c) 2011, 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.

 *

 * 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 org.graalvm.compiler.virtual.phases.ea;

import java.util.Iterator;

import java.util.Map;

public abstract class EffectsBlockState<T extends EffectsBlockState<T>> {

    /**

     * This flag specifies whether this block is unreachable, which can happen during analysis if

     * conditions turn constant or nodes canonicalize to cfg sinks.

     */

    private boolean dead;

    public EffectsBlockState() {

        // emtpy

    }

    public EffectsBlockState(EffectsBlockState<T> other) {

        this.dead = other.dead;

    }

    @Override

    public String toString() {

        return "";

    }

    protected abstract boolean equivalentTo(T other);

    public boolean isDead() {

        return dead;

    }

    public void markAsDead() {

        this.dead = true;

    }

    /**

     * Returns true if every value in subMap is also present in the superMap (according to "equals"

     * semantics).

     */

    protected static <K, V> boolean isSubMapOf(EconomicMap<K, V> superMap, EconomicMap<K, V> subMap) {

        if (superMap == subMap) {

            return true;

        }

        UnmodifiableMapCursor<K, V> cursor = subMap.getEntries();

        while (cursor.advance()) {

            K key = cursor.getKey();

            V value = cursor.getValue();

            assert value != null;

            V otherValue = superMap.get(key);

            if (otherValue != value && !value.equals(otherValue)) {

                return false;

            }

        }

        return true;

    }

    /**

     * Modifies target so that only entries that have corresponding entries in source remain.

     */

    protected static <U, V> void meetMaps(Map<U, V> target, Map<U, V> source) {

        Iterator<Map.Entry<U, V>> iter = target.entrySet().iterator();

        while (iter.hasNext()) {

            Map.Entry<U, V> entry = iter.next();

            if (source.containsKey(entry.getKey())) {

                assert source.get(entry.getKey()) == entry.getValue();

            } else {

                iter.remove();

            }

        }

    }

}