1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * https://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 */ 19 package org.apache.bcel.generic; 20 21 /** 22 * Equality of instructions isn't clearly to be defined. You might wish, for example, to compare whether instructions 23 * have the same meaning. E.g., whether two INVOKEVIRTUALs describe the same call. 24 * <p> 25 * The DEFAULT comparator however, considers two instructions to be equal if they have same opcode and point to the same 26 * indexes (if any) in the constant pool or the same local variable index. Branch instructions must have the same 27 * target. 28 * </p> 29 * 30 * @see Instruction 31 */ 32 public interface InstructionComparator { 33 34 InstructionComparator DEFAULT = (i1, i2) -> { 35 if (i1.getOpcode() == i2.getOpcode()) { 36 if (i1 instanceof BranchInstruction) { 37 // BIs are never equal to make targeters work correctly (BCEL-195) 38 return false; 39 // } else if (i1 == i2) { TODO consider adding this shortcut 40 // return true; // this must be AFTER the BI test 41 } 42 if (i1 instanceof ConstantPushInstruction) { 43 return ((ConstantPushInstruction) i1).getValue().equals(((ConstantPushInstruction) i2).getValue()); 44 } 45 if (i1 instanceof IndexedInstruction) { 46 return ((IndexedInstruction) i1).getIndex() == ((IndexedInstruction) i2).getIndex(); 47 } 48 if (i1 instanceof NEWARRAY) { 49 return ((NEWARRAY) i1).getTypecode() == ((NEWARRAY) i2).getTypecode(); 50 } 51 return true; 52 } 53 return false; 54 }; 55 56 boolean equals(Instruction i1, Instruction i2); 57 }