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121 lines
3.9 KiB
121 lines
3.9 KiB
/* ReferenceType Copyright (C) 1999 Jochen Hoenicke.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id$
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*/
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package jode.type;
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import jode.GlobalOptions;
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import jode.bytecode.ClassInfo;
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import java.util.Vector;
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import java.util.Stack;
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/**
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* This is an abstrace super class of all reference types. Reference
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* types are ClassInterfacesType, ArrayType and NullType. <p>
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*
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* @author Jochen Hoenicke
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*/
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public abstract class ReferenceType extends Type {
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public ReferenceType(int typecode) {
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super(typecode);
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}
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/**
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* Returns the specialized type of this and type.
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* The result should be the Type that extends both Types
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* (this and type). This correspondents to the common bottom Type
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* in a range type.
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* @param type the other type.
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* @return the specialized type.
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*/
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public abstract Type getSpecializedType(Type typ);
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/**
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* Returns the generalized type of this and type. The result
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* should be the types that both types extends or implements. This
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* correspondents to the common top Type in a range type.
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* @param type the other type.
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* @return the generalized type
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*/
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public abstract Type getGeneralizedType(Type typ);
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public abstract Type createRangeType(ReferenceType bottom);
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/**
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* Tells if all otherIfaces, are implemented by at least one
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* ifaces or by clazz.
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*
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* This is a useful function for generalizing/specializing interface
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* types or arrays.
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* @param clazz The clazz, can be null.
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* @param ifaces The ifaces.
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* @param otherifaces The other ifaces, that must be implemented.
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* @return true, if all otherIfaces are implemented.
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*/
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protected static boolean implementsAllIfaces(ClassInfo clazz,
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ClassInfo[] ifaces,
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ClassInfo[] otherIfaces) {
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big:
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for (int i=0; i < otherIfaces.length; i++) {
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ClassInfo iface = otherIfaces[i];
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if (clazz != null && iface.implementedBy(clazz))
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continue big;
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for (int j=0; j < ifaces.length; j++) {
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if (iface.implementedBy(ifaces[j]))
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continue big;
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}
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return false;
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}
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return true;
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}
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public Type getSuperType() {
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return (this == tObject) ? tObject : tRange(tObject, this);
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}
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public Type getSubType() {
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return tRange(this, tNull);
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}
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/**
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* Intersect this type with another type and return the new type.
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* @param type the other type.
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* @return the intersection, or tError, if a type conflict happens.
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*/
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public Type intersection(Type type) {
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if (type == tError)
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return type;
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if (type == Type.tUnknown)
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return this;
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Type newBottom = getSpecializedType(type);
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Type newTop = getGeneralizedType(type);
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Type result;
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if (newTop.equals(newBottom))
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result = newTop;
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else if (newTop instanceof ReferenceType
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&& newBottom instanceof ReferenceType)
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result = ((ReferenceType) newTop)
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.createRangeType((ReferenceType) newBottom);
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else
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result = tError;
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if ((GlobalOptions.debuggingFlags & GlobalOptions.DEBUG_TYPES) != 0) {
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GlobalOptions.err.println("intersecting "+ this +" and "+ type +
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" to " + result);
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}
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return result;
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}
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}
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