/*
    * 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.DataInputStream;
  import java.io.DataOutputStream;
  import java.io.IOException;
  import org.apache.bcel.Constants;
  
  /**
   * This class represents colection of local variables in a
   * method. This attribute is contained in the <em>Code</em> attribute.
   *
   * @version $Id: LocalVariableTable.java 1152306 2011-07-29 17:22:24Z sebb $
   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
   * @see     Code
   * @see LocalVariable
   */
  public class LocalVariableTable extends Attribute {
  
      private static final long serialVersionUID = 6780929007774637689L;
      private int local_variable_table_length; // Table of local
      private LocalVariable[] local_variable_table; // variables
  
  
      /**
       * Initialize from another object. Note that both objects use the same
       * references (shallow copy). Use copy() for a physical copy.
       */
      public LocalVariableTable(LocalVariableTable c) {
          this(c.getNameIndex(), c.getLength(), c.getLocalVariableTable(), c.getConstantPool());
      }
  
  
      /**
       * @param name_index Index in constant pool to `LocalVariableTable'
       * @param length Content length in bytes
       * @param local_variable_table Table of local variables
       * @param constant_pool Array of constants
       */
      public LocalVariableTable(int name_index, int length, LocalVariable[] local_variable_table,
              ConstantPool constant_pool) {
          super(Constants.ATTR_LOCAL_VARIABLE_TABLE, name_index, length, constant_pool);
          setLocalVariableTable(local_variable_table);
      }
  
  
      /**
       * Construct object from file stream.
       * @param name_index Index in constant pool
       * @param length Content length in bytes
       * @param file Input stream
       * @param constant_pool Array of constants
       * @throws IOException
       */
      LocalVariableTable(int name_index, int length, DataInputStream file, ConstantPool constant_pool)
              throws IOException {
          this(name_index, length, (LocalVariable[]) null, constant_pool);
          local_variable_table_length = (file.readUnsignedShort());
          local_variable_table = new LocalVariable[local_variable_table_length];
          for (int i = 0; i < local_variable_table_length; i++) {
              local_variable_table[i] = new LocalVariable(file, constant_pool);
          }
      }
  
  
      /**
       * Called by objects that are traversing the nodes of the tree implicitely
       * 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( Visitor v ) {
          v.visitLocalVariableTable(this);
      }
  
  
      /**
       * Dump local variable table attribute to file stream in binary format.
       *
       * @param file Output file stream
       * @throws IOException
      */
     @Override
     public final void dump( DataOutputStream file ) throws IOException {
         super.dump(file);
         file.writeShort(local_variable_table_length);
         for (int i = 0; i < local_variable_table_length; i++) {
             local_variable_table[i].dump(file);
         }
     }
 
 
     /**
      * @return Array of local variables of method.
      */
     public final LocalVariable[] getLocalVariableTable() {
         return local_variable_table;
     }
 
 
     /** 
      * 
      * @param index the variable slot
      * 
      * @return the first LocalVariable that matches the slot or null if not found
      * 
      * @deprecated since 5.2 because multiple variables can share the
      *             same slot, use getLocalVariable(int index, int pc) instead.
      */
     @java.lang.Deprecated
     public final LocalVariable getLocalVariable( int index ) {
         for (int i = 0; i < local_variable_table_length; i++) {
             if (local_variable_table[i].getIndex() == index) {
                 return local_variable_table[i];
             }
         }
         return null;
     }
 
 
     /** 
      * 
      * @param index the variable slot
      * @param pc the current pc that this variable is alive
      * 
      * @return the LocalVariable that matches or null if not found
      */
     public final LocalVariable getLocalVariable( int index, int pc ) {
         for (int i = 0; i < local_variable_table_length; i++) {
             if (local_variable_table[i].getIndex() == index) {
                 int start_pc = local_variable_table[i].getStartPC();
                 int end_pc = start_pc + local_variable_table[i].getLength();
                 if ((pc >= start_pc) && (pc <= end_pc)) {
                     return local_variable_table[i];
                 }
             }
         }
         return null;
     }
 
 
     public final void setLocalVariableTable( LocalVariable[] local_variable_table ) {
         this.local_variable_table = local_variable_table;
         local_variable_table_length = (local_variable_table == null)
                 ? 0
                 : local_variable_table.length;
     }
 
 
     /**
      * @return String representation.
      */
     @Override
     public final String toString() {
         StringBuilder buf = new StringBuilder();
         for (int i = 0; i < local_variable_table_length; i++) {
             buf.append(local_variable_table[i].toString());
             if (i < local_variable_table_length - 1) {
                 buf.append('\n');
             }
         }
         return buf.toString();
     }
 
 
     /**
      * @return deep copy of this attribute
      */
     @Override
     public Attribute copy( ConstantPool _constant_pool ) {
         LocalVariableTable c = (LocalVariableTable) clone();
         c.local_variable_table = new LocalVariable[local_variable_table_length];
         for (int i = 0; i < local_variable_table_length; i++) {
             c.local_variable_table[i] = local_variable_table[i].copy();
         }
         c.constant_pool = _constant_pool;
         return c;
     }
 
 
     public final int getTableLength() {
         return local_variable_table_length;
     }
 }