001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.generic; 019 020/** 021 * Equality of instructions isn't clearly to be defined. You might 022 * wish, for example, to compare whether instructions have the same 023 * meaning. E.g., whether two INVOKEVIRTUALs describe the same 024 * call. 025 * <p> 026 * The DEFAULT comparator however, considers two instructions 027 * to be equal if they have same opcode and point to the same indexes 028 * (if any) in the constant pool or the same local variable index. Branch 029 * instructions must have the same target. 030 * </p> 031 * 032 * @see Instruction 033 */ 034public interface InstructionComparator { 035 036 InstructionComparator DEFAULT = (i1, i2) -> { 037 if (i1.getOpcode() == i2.getOpcode()) { 038 if (i1 instanceof BranchInstruction) { 039 // BIs are never equal to make targeters work correctly (BCEL-195) 040 return false; 041// } else if (i1 == i2) { TODO consider adding this shortcut 042// return true; // this must be AFTER the BI test 043 } else if (i1 instanceof ConstantPushInstruction) { 044 return ((ConstantPushInstruction) i1).getValue().equals( 045 ((ConstantPushInstruction) i2).getValue()); 046 } else if (i1 instanceof IndexedInstruction) { 047 return ((IndexedInstruction) i1).getIndex() == ((IndexedInstruction) i2) 048 .getIndex(); 049 } else if (i1 instanceof NEWARRAY) { 050 return ((NEWARRAY) i1).getTypecode() == ((NEWARRAY) i2).getTypecode(); 051 } else { 052 return true; 053 } 054 } 055 return false; 056 }; 057 058 059 boolean equals( Instruction i1, Instruction i2 ); 060}