/*
    * 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
    *
   *   https://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.commons.compress.harmony.unpack200.bytecode;
  
  import java.io.DataOutputStream;
  import java.io.IOException;
  import java.util.Objects;
  
  import org.apache.commons.compress.harmony.unpack200.SegmentUtils;
  
  /**
   * Name and Type pair constant pool entry.
   */
  public class CPNameAndType extends ConstantPoolEntry {
  
      CPUTF8 descriptor;
  
      transient int descriptorIndex;
  
      CPUTF8 name;
  
      transient int nameIndex;
  
      private boolean hashCodeComputed;
  
      private int cachedHashCode;
  
      /**
       * Constructs a new CPNameAndType.
       *
       * @param name        TODO
       * @param descriptor  TODO
       * @param globalIndex index in CpBands
       * @throws NullPointerException if name or descriptor is null
       */
      public CPNameAndType(final CPUTF8 name, final CPUTF8 descriptor, final int globalIndex) {
          super(CP_NameAndType, globalIndex);
          this.name = Objects.requireNonNull(name, "name");
          this.descriptor = Objects.requireNonNull(descriptor, "descriptor");
      }
  
      /*
       * field_info { u2 access_flags; u2 name_index; u2 descriptor_index; u2 attributes_count; attribute_info attributes[attributes_count]; }
       */
  
      @Override
      public boolean equals(final Object obj) {
          if (this == obj) {
              return true;
          }
          if (obj == null || getClass() != obj.getClass()) {
              return false;
          }
          final CPNameAndType other = (CPNameAndType) obj;
          return Objects.equals(descriptor, other.descriptor)
                  && Objects.equals(name, other.name);
      }
  
      private void generateHashCode() {
          hashCodeComputed = true;
          final int PRIME = 31;
          int result = 1;
          result = PRIME * result + descriptor.hashCode();
          result = PRIME * result + name.hashCode();
          cachedHashCode = result;
      }
  
      @Override
      protected ClassFileEntry[] getNestedClassFileEntries() {
          return new ClassFileEntry[] { name, descriptor };
      }
  
      @Override
      public int hashCode() {
          if (!hashCodeComputed) {
              generateHashCode();
          }
          return cachedHashCode;
      }
  
      /**
       * Answers the invokeinterface count argument when the receiver is treated as an invokeinterface target. This value is not meaningful if the receiver is not
       * an invokeinterface target.
      *
      * @return count
      */
     public int invokeInterfaceCount() {
         return 1 + SegmentUtils.countInvokeInterfaceArgs(descriptor.underlyingString());
     }
 
     @Override
     protected void resolve(final ClassConstantPool pool) {
         super.resolve(pool);
         descriptorIndex = pool.indexOf(descriptor);
         nameIndex = pool.indexOf(name);
     }
 
     @Override
     public String toString() {
         return "NameAndType: " + name + "(" + descriptor + ")";
     }
 
     @Override
     protected void writeBody(final DataOutputStream dos) throws IOException {
         dos.writeShort(nameIndex);
         dos.writeShort(descriptorIndex);
     }
 }