/*

 * Copyright (c) 1994, 2003, 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 sun.tools.tree;

import sun.tools.java.*;

import sun.tools.asm.Assembler;

import sun.tools.asm.Label;

import java.util.Hashtable;

/**

 * WARNING: The contents of this source file are not part of any

 * supported API.  Code that depends on them does so at its own risk:

 * they are subject to change or removal without notice.

 */

public

class OrExpression extends BinaryLogicalExpression {

    /**

     * constructor

     */

    public OrExpression(long where, Expression left, Expression right) {

        super(OR, where, left, right);

    }

    /*

     * Check an "or" expression.

     *

     * cvars is modified so that

     *    cvar.vsTrue indicates variables with a known value if

     *        either the left and right hand side isn true

     *    cvars.vsFalse indicates variables with a known value if

     *        both the left or right hand side are false

     */

    public void checkCondition(Environment env, Context ctx, Vset vset,

                               Hashtable exp, ConditionVars cvars) {

        // Find out when the left side is true/false

        left.checkCondition(env, ctx, vset, exp, cvars);

        left = convert(env, ctx, Type.tBoolean, left);

        Vset vsTrue = cvars.vsTrue.copy();

        Vset vsFalse = cvars.vsFalse.copy();

        // Only look at the right side if the left side is false

        right.checkCondition(env, ctx, vsFalse, exp, cvars);

        right = convert(env, ctx, Type.tBoolean, right);

        // cvars.vsFalse actually reports that both returned false

        // cvars.vsTrue must be set back to either left side or the right

        //     side returning false;

        cvars.vsTrue = cvars.vsTrue.join(vsTrue);

    }

    /**

     * Evaluate

     */

    Expression eval(boolean a, boolean b) {

        return new BooleanExpression(where, a || b);

    }

    /**

     * Simplify

     */

    Expression simplify() {

        if (right.equals(false)) {

            return left;

        }

        if (left.equals(true)) {

            return left;

        }

        if (left.equals(false)) {

            return right;

        }

        if (right.equals(true)) {

            // Preserve effects of left argument.

            return new CommaExpression(where, left, right).simplify();

        }

        return this;

    }

    /**

     * Code

     */

    void codeBranch(Environment env, Context ctx, Assembler asm, Label lbl, boolean whenTrue) {

        if (whenTrue) {

            left.codeBranch(env, ctx, asm, lbl, true);

            right.codeBranch(env, ctx, asm, lbl, true);

        } else {

            Label lbl2 = new Label();

            left.codeBranch(env, ctx, asm, lbl2, true);

            right.codeBranch(env, ctx, asm, lbl, false);

            asm.add(lbl2);

        }

    }

}