/*
 * 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;
	}
}
