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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.*;
     26 
     27 /**
     28  * This StackMapFrame represents an "append frame".
     29  *
     30  * @author Eric Lafortune
     31  */
     32 public class MoreZeroFrame extends StackMapFrame
     33 {
     34     public int                additionalVariablesCount;
     35     public VerificationType[] additionalVariables;
     36 
     37 
     38     /**
     39      * Creates an uninitialized MoreZeroFrame.
     40      */
     41     public MoreZeroFrame()
     42     {
     43     }
     44 
     45 
     46     /**
     47      * Creates a MoreZeroFrame with the given tag.
     48      */
     49     public MoreZeroFrame(int tag)
     50     {
     51         additionalVariablesCount = tag + 1 - MORE_ZERO_FRAME;
     52     }
     53 
     54 
     55     /**
     56      * Creates a MoreZeroFrame with the given additional variables.
     57      */
     58     public MoreZeroFrame(VerificationType[] additionalVariables)
     59     {
     60         this(additionalVariables.length, additionalVariables);
     61     }
     62 
     63 
     64     /**
     65      * Creates a MoreZeroFrame with the given additional variables.
     66      */
     67     public MoreZeroFrame(int                additionalVariablesCount,
     68                          VerificationType[] additionalVariables)
     69     {
     70         this.additionalVariablesCount = additionalVariablesCount;
     71         this.additionalVariables      = additionalVariables;
     72     }
     73 
     74 
     75     /**
     76      * Applies the given verification type visitor to all variables.
     77      */
     78     public void additionalVariablesAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, VerificationTypeVisitor verificationTypeVisitor)
     79     {
     80         for (int index = 0; index < additionalVariablesCount; index++)
     81         {
     82             additionalVariables[index].accept(clazz, method, codeAttribute, offset, verificationTypeVisitor);
     83         }
     84     }
     85 
     86 
     87     // Implementations for StackMapFrame.
     88 
     89     public int getTag()
     90     {
     91         return MORE_ZERO_FRAME + additionalVariablesCount - 1;
     92     }
     93 
     94 
     95     public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrameVisitor stackMapFrameVisitor)
     96     {
     97         stackMapFrameVisitor.visitMoreZeroFrame(clazz, method, codeAttribute, offset, this);
     98     }
     99 
    100 
    101     // Implementations for Object.
    102 
    103     public boolean equals(Object object)
    104     {
    105         if (!super.equals(object))
    106         {
    107             return false;
    108         }
    109 
    110         MoreZeroFrame other = (MoreZeroFrame)object;
    111 
    112         if (this.u2offsetDelta            != other.u2offsetDelta ||
    113             this.additionalVariablesCount != other.additionalVariablesCount)
    114         {
    115             return false;
    116         }
    117 
    118         for (int index = 0; index < additionalVariablesCount; index++)
    119         {
    120             VerificationType thisType  = this.additionalVariables[index];
    121             VerificationType otherType = other.additionalVariables[index];
    122 
    123             if (!thisType.equals(otherType))
    124             {
    125                 return false;
    126             }
    127         }
    128 
    129         return true;
    130     }
    131 
    132 
    133     public int hashCode()
    134     {
    135         int hashCode = super.hashCode();
    136 
    137         for (int index = 0; index < additionalVariablesCount; index++)
    138         {
    139             hashCode ^= additionalVariables[index].hashCode();
    140         }
    141 
    142         return hashCode;
    143     }
    144 
    145 
    146     public String toString()
    147     {
    148         StringBuffer buffer = new StringBuffer(super.toString()).append("Var: ...");
    149 
    150         for (int index = 0; index < additionalVariablesCount; index++)
    151         {
    152             buffer = buffer.append('[')
    153                            .append(additionalVariables[index].toString())
    154                            .append(']');
    155         }
    156 
    157         buffer.append(", Stack: (empty)");
    158 
    159         return buffer.toString();
    160     }
    161 }
    162