1 /* 2 * ProGuard -- shrinking, optimization, obfuscation, and preverification 3 * of Java bytecode. 4 * 5 * Copyright (c) 2002-2009 Eric Lafortune (eric@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 abstract class represents a stack map frame. Specific types 29 * of entries are subclassed from it. 30 * 31 * @author Eric Lafortune 32 */ 33 public abstract class StackMapFrame implements VisitorAccepter 34 { 35 public static final int SAME_ZERO_FRAME = 0; 36 public static final int SAME_ONE_FRAME = 64; 37 public static final int SAME_ONE_FRAME_EXTENDED = 247; 38 public static final int LESS_ZERO_FRAME = 248; 39 public static final int SAME_ZERO_FRAME_EXTENDED = 251; 40 public static final int MORE_ZERO_FRAME = 252; 41 public static final int FULL_FRAME = 255; 42 43 44 public int u2offsetDelta; 45 46 /** 47 * An extra field in which visitors can store information. 48 */ 49 public Object visitorInfo; 50 51 52 53 /** 54 * Returns the bytecode offset delta relative to the previous stack map 55 * frame. 56 */ getOffsetDelta()57 public int getOffsetDelta() 58 { 59 return u2offsetDelta; 60 } 61 62 63 // Abstract methods to be implemented by extensions. 64 65 /** 66 * Returns the stack map frame tag that specifies the entry type. 67 */ getTag()68 public abstract int getTag(); 69 70 71 /** 72 * Accepts the given visitor. 73 */ accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrameVisitor stackMapFrameVisitor)74 public abstract void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrameVisitor stackMapFrameVisitor); 75 76 77 // Implementations for VisitorAccepter. 78 getVisitorInfo()79 public Object getVisitorInfo() 80 { 81 return visitorInfo; 82 } 83 setVisitorInfo(Object visitorInfo)84 public void setVisitorInfo(Object visitorInfo) 85 { 86 this.visitorInfo = visitorInfo; 87 } 88 89 90 // Implementations for Object. 91 equals(Object object)92 public boolean equals(Object object) 93 { 94 if (object == null || 95 this.getClass() != object.getClass()) 96 { 97 return false; 98 } 99 100 StackMapFrame other = (StackMapFrame)object; 101 102 return this.u2offsetDelta == other.u2offsetDelta; 103 } 104 105 hashCode()106 public int hashCode() 107 { 108 return getClass().hashCode() ^ 109 u2offsetDelta; 110 } 111 112 toString()113 public String toString() 114 { 115 return "[" + u2offsetDelta + "] "; 116 } 117 } 118