/* * ProGuard -- shrinking, optimization, obfuscation, and preverification * of Java bytecode. * * Copyright (c) 2002-2007 Eric Lafortune (eric@graphics.cornell.edu) * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 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, write to the Free Software Foundation, * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package proguard.classfile.attribute.preverification; import proguard.classfile.*; import proguard.classfile.attribute.CodeAttribute; import proguard.classfile.attribute.preverification.visitor.StackMapFrameVisitor; /** * This abstract class represents a stack map frame. Specific types * of entries are subclassed from it. * * @author Eric Lafortune */ public abstract class StackMapFrame implements VisitorAccepter { public static final int SAME_ZERO_FRAME = 0; public static final int SAME_ONE_FRAME = 64; public static final int SAME_ONE_FRAME_EXTENDED = 247; public static final int LESS_ZERO_FRAME = 248; public static final int SAME_ZERO_FRAME_EXTENDED = 251; public static final int MORE_ZERO_FRAME = 252; public static final int FULL_FRAME = 255; public int u2offsetDelta; /** * An extra field in which visitors can store information. */ public Object visitorInfo; /** * Returns the bytecode offset delta relative to the previous stack map * frame. */ public int getOffsetDelta() { return u2offsetDelta; } // Abstract methods to be implemented by extensions. /** * Returns the stack map frame tag that specifies the entry type. */ public abstract int getTag(); /** * Accepts the given visitor. */ public abstract void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrameVisitor stackMapFrameVisitor); // Implementations for VisitorAccepter. public Object getVisitorInfo() { return visitorInfo; } public void setVisitorInfo(Object visitorInfo) { this.visitorInfo = visitorInfo; } // Implementations for Object. public boolean equals(Object object) { if (object == null || this.getClass() != object.getClass()) { return false; } StackMapFrame other = (StackMapFrame)object; return this.u2offsetDelta == other.u2offsetDelta; } public int hashCode() { return getClass().hashCode() ^ u2offsetDelta; } public String toString() { return "[" + u2offsetDelta + "] "; } }
