lucee.transformer.bytecode.visitor.ForIntVisitor.java Source code

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Here is the source code for lucee.transformer.bytecode.visitor.ForIntVisitor.java

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/**
 *
 * Copyright (c) 2014, the Railo Company Ltd. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either 
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public 
 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 * 
 **/
package lucee.transformer.bytecode.visitor;

import lucee.transformer.bytecode.BytecodeContext;
import lucee.transformer.bytecode.Position;
import lucee.transformer.bytecode.util.ExpressionUtil;
import lucee.transformer.bytecode.util.Types;

import org.objectweb.asm.Label;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.commons.GeneratorAdapter;

public final class ForIntVisitor implements Opcodes, LoopVisitor {

    private Label beforeInit = new Label();
    private Label beforeExpr = new Label(), afterExpr = new Label();
    private Label beforeBody = new Label(), afterBody = new Label();
    private Label beforeUpdate = new Label(), afterUpdate = new Label();
    private int i;

    public int visitBeforeExpression(GeneratorAdapter adapter, int start, int step, boolean isLocal) {
        // init
        adapter.visitLabel(beforeInit);
        forInit(adapter, start, isLocal);
        adapter.goTo(beforeExpr);

        // update
        adapter.visitLabel(beforeUpdate);
        forUpdate(adapter, step, isLocal);

        // expression
        adapter.visitLabel(beforeExpr);
        return i;
    }

    public void visitAfterExpressionBeginBody(GeneratorAdapter adapter) {
        adapter.ifZCmp(Opcodes.IFEQ, afterBody);
    }

    public void visitEndBody(BytecodeContext bc, Position line) {
        bc.getAdapter().goTo(beforeUpdate);
        ExpressionUtil.visitLine(bc, line);
        bc.getAdapter().visitLabel(afterBody);
        //adapter.visitLocalVariable("i", "I", null, beforeInit, afterBody, i);
    }

    private void forInit(GeneratorAdapter adapter, int start, boolean isLocal) {
        i = adapter.newLocal(Types.INT_VALUE);
        if (isLocal)
            adapter.loadLocal(start, Types.INT_VALUE);
        else
            adapter.push(start);
        adapter.visitVarInsn(ISTORE, i);
    }

    private void forUpdate(GeneratorAdapter adapter, int step, boolean isLocal) {
        if (isLocal) {
            adapter.visitVarInsn(ILOAD, i);
            adapter.loadLocal(step);
            adapter.visitInsn(IADD);
            adapter.visitVarInsn(ISTORE, i);
        } else
            adapter.visitIincInsn(i, step);
    }

    /**
     *
     * @see lucee.transformer.bytecode.visitor.LoopVisitor#visitContinue(org.objectweb.asm.commons.GeneratorAdapter)
     */
    public void visitContinue(BytecodeContext bc) {
        bc.getAdapter().visitJumpInsn(Opcodes.GOTO, beforeUpdate);
    }

    /**
     *
     * @see lucee.transformer.bytecode.visitor.LoopVisitor#visitBreak(org.objectweb.asm.commons.GeneratorAdapter)
     */
    public void visitBreak(BytecodeContext bc) {
        bc.getAdapter().visitJumpInsn(Opcodes.GOTO, afterBody);
    }

    /**
     *
     * @see lucee.transformer.bytecode.visitor.LoopVisitor#getContinueLabel()
     */
    public Label getContinueLabel() {
        return beforeUpdate;
    }

    /**
     *
     * @see lucee.transformer.bytecode.visitor.LoopVisitor#getBreakLabel()
     */
    public Label getBreakLabel() {
        return afterBody;
    }

}