/*
* Copyright 2000-2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.bcel5_2_0.generic;
/**
* Equality of instructions isn't clearly to be defined. You might
* wish, for example, to compare whether instructions have the same
* meaning. E.g., whether two INVOKEVIRTUALs describe the same
* call.<br>The DEFAULT comparator however, considers two instructions
* to be equal if they have same opcode and point to the same indexes
* (if any) in the constant pool or the same local variable index. Branch
* instructions must have the same target.
*
* @see Instruction
* @version $Id: InstructionComparator.java 386056 2006-03-15 11:31:56Z tcurdt $
* @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
*/
public interface InstructionComparator {
public static final InstructionComparator DEFAULT = new InstructionComparator() {
public boolean equals( Instruction i1, Instruction i2 ) {
if (i1.opcode == i2.opcode) {
if (i1 instanceof Select) {
InstructionHandle[] t1 = ((Select) i1).getTargets();
InstructionHandle[] t2 = ((Select) i2).getTargets();
if (t1.length == t2.length) {
for (int i = 0; i < t1.length; i++) {
if (t1[i] != t2[i]) {
return false;
}
}
return true;
}
} else if (i1 instanceof BranchInstruction) {
return ((BranchInstruction) i1).target == ((BranchInstruction) i2).target;
} else if (i1 instanceof ConstantPushInstruction) {
return ((ConstantPushInstruction) i1).getValue().equals(
((ConstantPushInstruction) i2).getValue());
} else if (i1 instanceof IndexedInstruction) {
return ((IndexedInstruction) i1).getIndex() == ((IndexedInstruction) i2)
.getIndex();
} else if (i1 instanceof NEWARRAY) {
return ((NEWARRAY) i1).getTypecode() == ((NEWARRAY) i2).getTypecode();
} else {
return true;
}
}
return false;
}
};
public boolean equals( Instruction i1, Instruction i2 );
}