/*
    * Copyright (C) 2007 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.annotations.VisibleForTesting;
  
  /**
   * Implementation of {@link ImmutableSet} with two or more elements.
   *
   * @author Kevin Bourrillion
   */
  @GwtCompatible(serializable = true, emulated = true)
  @SuppressWarnings("serial") // uses writeReplace(), not default serialization
  final class RegularImmutableSet<E> extends ImmutableSet<E> {
    private final Object[] elements;
    // the same elements in hashed positions (plus nulls)
    @VisibleForTesting final transient Object[] table;
    // 'and' with an int to get a valid table index.
    private final transient int mask;
    private final transient int hashCode;
  
    RegularImmutableSet(
        Object[] elements, int hashCode, Object[] table, int mask) {
      this.elements = elements;
      this.table = table;
      this.mask = mask;
      this.hashCode = hashCode;
    }
  
    @Override public boolean contains(Object target) {
      if (target == null) {
        return false;
      }
      for (int i = Hashing.smear(target.hashCode()); true; i++) {
        Object candidate = table[i & mask];
        if (candidate == null) {
          return false;
        }
        if (candidate.equals(target)) {
          return true;
        }
      }
    }
  
    @Override
    public int size() {
      return elements.length;
    }
  
    @SuppressWarnings("unchecked") // all elements are E's
    @Override
    public UnmodifiableIterator<E> iterator() {
      return (UnmodifiableIterator<E>) Iterators.forArray(elements);
    }
  
    @Override
    int copyIntoArray(Object[] dst, int offset) {
      System.arraycopy(elements, 0, dst, offset, elements.length);
      return offset + elements.length;
    }
  
    @Override
    ImmutableList<E> createAsList() {
      return new RegularImmutableAsList<E>(this, elements);
    }
  
    @Override
    boolean isPartialView() {
      return false;
    }
  
    @Override public int hashCode() {
      return hashCode;
    }
  
    @Override boolean isHashCodeFast() {
      return true;
    }
  }