1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 /*
   6  * Licensed to the Apache Software Foundation (ASF) under one or more
   7  * contributor license agreements.  See the NOTICE file distributed with
   8  * this work for additional information regarding copyright ownership.
   9  * The ASF licenses this file to You under the Apache License, Version 2.0
  10  * (the "License"); you may not use this file except in compliance with
  11  * the License.  You may obtain a copy of the License at
  12  *
  13  *      http://www.apache.org/licenses/LICENSE-2.0
  14  *
  15  * Unless required by applicable law or agreed to in writing, software
  16  * distributed under the License is distributed on an "AS IS" BASIS,
  17  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  18  * See the License for the specific language governing permissions and
  19  * limitations under the License.
  20  */
  21 
  22 
  23 package com.sun.org.apache.xalan.internal.xsltc.compiler.util;
  24 import java.io.DataOutputStream;
  25 import java.io.IOException;
  26 
  27 import com.sun.org.apache.bcel.internal.Constants;
  28 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
  29 import com.sun.org.apache.bcel.internal.generic.Instruction;
  30 import com.sun.org.apache.bcel.internal.generic.Visitor;
  31 
  32 /**
  33  * A special abstract dummy subclass of
  34  * {@link org.apache.bcel.generic.Instruction} used to mark locations of
  35  * interest in an {@link com.sun.org.apache.bcel.internal.generic.InstructionList}.  It and
  36  * its subclasses are only used as placeholders, and do not contribute to the
  37  * actual byte code instruction stream.
  38  */
  39 abstract class MarkerInstruction extends Instruction {
  40     /**
  41      * Zero-argument constructor.  Sets the opcode to an invalid value and
  42      * sets the length to zero, as it will not be written as part of the
  43      * generated byte code.
  44      */
  45     public MarkerInstruction() {
  46         super(Constants.UNDEFINED, (short) 0);
  47     }
  48 
  49     /**
  50      * {@link com.sun.org.apache.bcel.internal.generic.Visitor}s will know nothing about this
  51      * kind of {@link org.apche.bcel.generic.Instruction}, so this method does
  52      * nothing.
  53      */
  54     public void accept(Visitor v) {
  55     }
  56 
  57     /**
  58      * The number of JVM stack entries consumed by the instruction.
  59      * This instruction is just a place holder, so it does not consume any
  60      * stack entries.
  61      * @param cpg The {@link com.sun.org.apache.bcel.internal.generic.ConstantPoolGen} for the
  62      * current {@link com.sun.org.apache.bcel.internal.generic.ClassGen}
  63      * @return <code>0</code> always
  64      */
  65     final public int consumeStack(ConstantPoolGen cpg) {
  66         return 0;

   1 /*
   2  * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

   3  */
   4 /*
   5  * Licensed to the Apache Software Foundation (ASF) under one or more
   6  * contributor license agreements.  See the NOTICE file distributed with
   7  * this work for additional information regarding copyright ownership.
   8  * The ASF licenses this file to You under the Apache License, Version 2.0
   9  * (the "License"); you may not use this file except in compliance with
  10  * the License.  You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20 
  21 
  22 package com.sun.org.apache.xalan.internal.xsltc.compiler.util;
  23 import java.io.DataOutputStream;
  24 import java.io.IOException;
  25 
  26 import com.sun.org.apache.bcel.internal.Const;
  27 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
  28 import com.sun.org.apache.bcel.internal.generic.Instruction;
  29 import com.sun.org.apache.bcel.internal.generic.Visitor;
  30 
  31 /**
  32  * A special abstract dummy subclass of
  33  * {@link org.apache.bcel.generic.Instruction} used to mark locations of
  34  * interest in an {@link com.sun.org.apache.bcel.internal.generic.InstructionList}.  It and
  35  * its subclasses are only used as placeholders, and do not contribute to the
  36  * actual byte code instruction stream.
  37  */
  38 abstract class MarkerInstruction extends Instruction {
  39     /**
  40      * Zero-argument constructor.  Sets the opcode to an invalid value and
  41      * sets the length to zero, as it will not be written as part of the
  42      * generated byte code.
  43      */
  44     public MarkerInstruction() {
  45         super(Const.UNDEFINED, (short) 0);
  46     }
  47 
  48     /**
  49      * {@link com.sun.org.apache.bcel.internal.generic.Visitor}s will know nothing about this
  50      * kind of {@link org.apche.bcel.generic.Instruction}, so this method does
  51      * nothing.
  52      */
  53     public void accept(Visitor v) {
  54     }
  55 
  56     /**
  57      * The number of JVM stack entries consumed by the instruction.
  58      * This instruction is just a place holder, so it does not consume any
  59      * stack entries.
  60      * @param cpg The {@link com.sun.org.apache.bcel.internal.generic.ConstantPoolGen} for the
  61      * current {@link com.sun.org.apache.bcel.internal.generic.ClassGen}
  62      * @return <code>0</code> always
  63      */
  64     final public int consumeStack(ConstantPoolGen cpg) {
  65         return 0;