/*
    * Copyright (C) 2009 The Guava Authors
    *
    * Licensed 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 com.google.common.collect;
  
  import com.google.common.annotations.GwtCompatible;
  import com.google.common.base.Preconditions;
  
  import javax.annotation.Nullable;
  
  /**
   * Implementation of {@link ImmutableList} with one or more elements.
   *
   * @author Kevin Bourrillion
   */
  @GwtCompatible(serializable = true, emulated = true)
  @SuppressWarnings("serial") // uses writeReplace(), not default serialization
  class RegularImmutableList<E> extends ImmutableList<E> {
    private final transient int offset;
    private final transient int size;
    private final transient Object[] array;
  
    RegularImmutableList(Object[] array, int offset, int size) {
      this.offset = offset;
      this.size = size;
      this.array = array;
    }
  
    RegularImmutableList(Object[] array) {
      this(array, 0, array.length);
    }
  
    @Override
    public int size() {
      return size;
    }
  
    @Override boolean isPartialView() {
      return size != array.length;
    }
  
    @Override
    int copyIntoArray(Object[] dst, int dstOff) {
      System.arraycopy(array, offset, dst, dstOff, size);
      return dstOff + size;
    }
  
    // The fake cast to E is safe because the creation methods only allow E's
    @Override
    @SuppressWarnings("unchecked")
    public E get(int index) {
      Preconditions.checkElementIndex(index, size);
      return (E) array[index + offset];
    }
  
    @Override
    public int indexOf(@Nullable Object object) {
      if (object == null) {
        return -1;
      }
      for (int i = 0; i < size; i++) {
        if (array[offset + i].equals(object)) {
          return i;
        }
      }
      return -1;
    }
  
    @Override
    public int lastIndexOf(@Nullable Object object) {
      if (object == null) {
        return -1;
      }
      for (int i = size - 1; i >= 0; i--) {
        if (array[offset + i].equals(object)) {
          return i;
        }
      }
      return -1;
    }
  
    @Override
    ImmutableList<E> subListUnchecked(int fromIndex, int toIndex) {
      return new RegularImmutableList<E>(
          array, offset + fromIndex, toIndex - fromIndex);
    }
 
   @SuppressWarnings("unchecked")
   @Override
   public UnmodifiableListIterator<E> listIterator(int index) {
     // for performance
     // The fake cast to E is safe because the creation methods only allow E's
     return (UnmodifiableListIterator<E>)
         Iterators.forArray(array, offset, size, index);
   }
 
   // TODO(user): benchmark optimizations for equals() and see if they're worthwhile
 }