/*

 * Copyright (c) 2011, 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 jdk.vm.ci.meta;

import java.util.ArrayList;

import java.util.List;

/**

 * Describes the {@link Local}s for a Java method.

 *

 * @see "https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.13"

 */

public class LocalVariableTable {

    private final Local[] locals;

    /**

     * Creates an object describing the {@link Local}s for a Java method.

     *

     * @param locals array of objects describing local variables. This array is now owned by this

     *            object and must not be mutated by the caller.

     */

    @SuppressFBWarnings(value = "EI_EXPOSE_REP2", justification = "caller transfers ownership of `locals`")

    public LocalVariableTable(Local[] locals) {

        this.locals = locals;

    }

    /**

     * Gets a description of a local variable that occupies the bytecode frame slot indexed by

     * {@code slot} and is live at the bytecode index {@code bci}.

     *

     * @return a description of the requested local variable or null if no such variable matches

     *         {@code slot} and {@code bci}

     */

    public Local getLocal(int slot, int bci) {

        Local result = null;

        for (Local local : locals) {

            if (local.getSlot() == slot && local.getStartBCI() <= bci && local.getEndBCI() >= bci) {

                if (result == null) {

                    result = local;

                } else {

                    throw new IllegalStateException("Locals overlap!");

                }

            }

        }

        return result;

    }

    /**

     * Gets a copy of the array of {@link Local}s that was passed to this object's constructor.

     */

    public Local[] getLocals() {

        return locals.clone();

    }

    /**

     * Gets a description of all the local variables live at the bytecode index {@code bci}.

     */

    public Local[] getLocalsAt(int bci) {

        List<Local> result = new ArrayList<>();

        for (Local l : locals) {

            if (l.getStartBCI() <= bci && bci <= l.getEndBCI()) {

                result.add(l);

            }

        }

        return result.toArray(new Local[result.size()]);

    }

}