/*

 * 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 org.graalvm.compiler.java;

public class JsrScope {

    public static final JsrScope EMPTY_SCOPE = new JsrScope();

    private final long scope;

    private JsrScope(long scope) {

        this.scope = scope;

    }

    public JsrScope() {

        this.scope = 0;

    }

    public int nextReturnAddress() {

        return (int) (scope & 0xffff);

    }

    public JsrScope push(int jsrReturnBci) {

        if ((scope & 0xffff000000000000L) != 0) {

            throw new JsrNotSupportedBailout("only four jsr nesting levels are supported");

        }

        return new JsrScope((scope << 16) | jsrReturnBci);

    }

    public boolean isEmpty() {

        return scope == 0;

    }

    public boolean isPrefixOf(JsrScope other) {

        return (scope & other.scope) == scope;

    }

    public JsrScope pop() {

        return new JsrScope(scope >>> 16);

    }

    @Override

    public int hashCode() {

        return (int) (scope ^ (scope >>> 32));

    }

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        return obj != null && getClass() == obj.getClass() && scope == ((JsrScope) obj).scope;

    }

    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder();

        long tmp = scope;

        sb.append(" [");

        while (tmp != 0) {

            sb.append(", ").append(tmp & 0xffff);

            tmp = tmp >>> 16;

        }

        sb.append(']');

        return sb.toString();

    }

}