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      1 /*
      2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
      3  *             of Java bytecode.
      4  *
      5  * Copyright (c) 2002-2014 Eric Lafortune (eric (at) graphics.cornell.edu)
      6  *
      7  * This program is free software; you can redistribute it and/or modify it
      8  * under the terms of the GNU General Public License as published by the Free
      9  * Software Foundation; either version 2 of the License, or (at your option)
     10  * any later version.
     11  *
     12  * This program is distributed in the hope that it will be useful, but WITHOUT
     13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
     15  * more details.
     16  *
     17  * You should have received a copy of the GNU General Public License along
     18  * with this program; if not, write to the Free Software Foundation, Inc.,
     19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
     20  */
     21 package proguard.classfile.attribute.preverification;
     22 
     23 import proguard.classfile.*;
     24 import proguard.classfile.attribute.CodeAttribute;
     25 import proguard.classfile.attribute.preverification.visitor.StackMapFrameVisitor;
     26 
     27 /**
     28  * This StackMapFrame represents an "chop frame".
     29  *
     30  * @author Eric Lafortune
     31  */
     32 public class LessZeroFrame extends StackMapFrame
     33 {
     34     public int choppedVariablesCount;
     35 
     36 
     37     /**
     38      * Creates an uninitialized LessZeroFrame.
     39      */
     40     public LessZeroFrame()
     41     {
     42     }
     43 
     44 
     45     /**
     46      * Creates a LessZeroFrame with the given tag.
     47      */
     48     public LessZeroFrame(int tag)
     49     {
     50         choppedVariablesCount = LESS_ZERO_FRAME + 3 - tag;
     51     }
     52 
     53 
     54     /**
     55      * Creates a LessZeroFrame with the given number of chopped variables.
     56      */
     57     public LessZeroFrame(byte choppedVariablesCount)
     58     {
     59         this.choppedVariablesCount = (int)choppedVariablesCount;
     60     }
     61 
     62 
     63     // Implementations for StackMapFrame.
     64 
     65     public int getTag()
     66     {
     67         return LESS_ZERO_FRAME + 3 - choppedVariablesCount;
     68     }
     69 
     70 
     71     public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrameVisitor stackMapFrameVisitor)
     72     {
     73         stackMapFrameVisitor.visitLessZeroFrame(clazz, method, codeAttribute, offset, this);
     74     }
     75 
     76 
     77     // Implementations for Object.
     78 
     79     public boolean equals(Object object)
     80     {
     81         if (!super.equals(object))
     82         {
     83             return false;
     84         }
     85 
     86         LessZeroFrame other = (LessZeroFrame)object;
     87 
     88         return this.u2offsetDelta == other.u2offsetDelta &&
     89                this.choppedVariablesCount != other.choppedVariablesCount;
     90     }
     91 
     92 
     93     public int hashCode()
     94     {
     95         return super.hashCode() ^ choppedVariablesCount;
     96     }
     97 
     98 
     99     public String toString()
    100     {
    101         return super.toString()+"Var: (chopped "+choppedVariablesCount+"), Stack: (empty)";
    102     }
    103 }
    104