/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.bcel.classfile;
  
  import java.io.DataInput;
  import java.io.DataOutputStream;
  import java.io.IOException;
  
  import org.apache.bcel.Const;
  import org.apache.bcel.Constants;
  import org.apache.bcel.util.Args;
  
  /**
   * This class represents an entry in the exception table of the <em>Code</em> attribute and is used only there. It
   * contains a range in which a particular exception handler is active.
   *
   * <pre>
   * Code_attribute {
   *   u2 attribute_name_index;
   *   u4 attribute_length;
   *   u2 max_stack;
   *   u2 max_locals;
   *   u4 code_length;
   *   u1 code[code_length];
   *   u2 exception_table_length;
   *   {
   *     u2 start_pc;
   *     u2 end_pc;
   *     u2 handler_pc;
   *     u2 catch_type;
   *   } exception_table[exception_table_length];
   *   u2 attributes_count;
   *   attribute_info attributes[attributes_count];
   * }
   * </pre>
   *
   * @see Code
   */
  public final class CodeException implements Cloneable, Node, Constants {
  
      /**
       * Empty array.
       */
      static final CodeException[] EMPTY_ARRAY = {};
  
      /** Range in the code the exception handler. */
      private int startPc;
  
      /** Active. startPc is inclusive, endPc exclusive. */
      private int endPc;
  
      /**
       * Starting address of exception handler, i.e., an offset from start of code.
       */
      private int handlerPc;
  
      /*
       * If this is zero the handler catches any exception, otherwise it points to the exception class which is to be caught.
       */
      private int catchType;
  
      /**
       * Constructs a new instance from another instance.
       *
       * @param c Source for copying.
       */
      public CodeException(final CodeException c) {
          this(c.getStartPC(), c.getEndPC(), c.getHandlerPC(), c.getCatchType());
      }
  
      /**
       * Constructs a new instance from a DataInput.
       *
       * @param file Input stream
       * @throws IOException if an I/O error occurs.
       */
      CodeException(final DataInput file) throws IOException {
          this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort());
      }
  
      /**
       * Constructs a new instance.
       *
       * @param startPc Range in the code the exception handler is active, startPc is inclusive while
       * @param endPc is exclusive
      * @param handlerPc Starting address of exception handler, i.e., an offset from start of code.
      * @param catchType If zero the handler catches any exception, otherwise it points to the exception class which is to be
      *        caught.
      */
     public CodeException(final int startPc, final int endPc, final int handlerPc, final int catchType) {
         this.startPc = Args.requireU2(startPc, "startPc");
         this.endPc = Args.requireU2(endPc, "endPc");
         this.handlerPc = Args.requireU2(handlerPc, "handlerPc");
         this.catchType = Args.requireU2(catchType, "catchType");
     }
 
     /**
      * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
      * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
      *
      * @param v Visitor object
      */
     @Override
     public void accept(final Visitor v) {
         v.visitCodeException(this);
     }
 
     /**
      * @return deep copy of this object
      */
     public CodeException copy() {
         try {
             return (CodeException) clone();
         } catch (final CloneNotSupportedException e) {
             // TODO should this throw?
         }
         return null;
     }
 
     /**
      * Dumps code exception to file stream in binary format.
      *
      * @param file Output file stream
      * @throws IOException if an I/O error occurs.
      */
     public void dump(final DataOutputStream file) throws IOException {
         file.writeShort(startPc);
         file.writeShort(endPc);
         file.writeShort(handlerPc);
         file.writeShort(catchType);
     }
 
     /**
      * @return 0, if the handler catches any exception, otherwise it points to the exception class which is to be caught.
      */
     public int getCatchType() {
         return catchType;
     }
 
     /**
      * @return Exclusive end index of the region where the handler is active.
      */
     public int getEndPC() {
         return endPc;
     }
 
     /**
      * @return Starting address of exception handler, relative to the code.
      */
     public int getHandlerPC() {
         return handlerPc;
     }
 
     /**
      * @return Inclusive start index of the region where the handler is active.
      */
     public int getStartPC() {
         return startPc;
     }
 
     /**
      * @param catchType the type of exception that is caught
      */
     public void setCatchType(final int catchType) {
         this.catchType = catchType;
     }
 
     /**
      * @param endPc end of handled block
      */
     public void setEndPC(final int endPc) {
         this.endPc = endPc;
     }
 
     /**
      * @param handlerPc where the actual code is
      */
     public void setHandlerPC(final int handlerPc) { // TODO unused
         this.handlerPc = handlerPc;
     }
 
     /**
      * @param startPc start of handled block
      */
     public void setStartPC(final int startPc) { // TODO unused
         this.startPc = startPc;
     }
 
     /**
      * @return String representation.
      */
     @Override
     public String toString() {
         return "CodeException(startPc = " + startPc + ", endPc = " + endPc + ", handlerPc = " + handlerPc + ", catchType = " + catchType + ")";
     }
 
     public String toString(final ConstantPool cp) {
         return toString(cp, true);
     }
 
     /**
      * @param cp constant pool source.
      * @param verbose Output more if true.
      * @return String representation.
      */
     public String toString(final ConstantPool cp, final boolean verbose) {
         String str;
         if (catchType == 0) {
             str = "<Any exception>(0)";
         } else {
             str = Utility.compactClassName(cp.getConstantString(catchType, Const.CONSTANT_Class), false) + (verbose ? "(" + catchType + ")" : "");
         }
         return startPc + "\t" + endPc + "\t" + handlerPc + "\t" + str;
     }
 }