/*
 * Copyright (C) 2010-2022 Sebastiano Vigna
 *
 * 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 PACKAGE;

import it.unimi.dsi.fastutil.BigListIterator;
import it.unimi.dsi.fastutil.SafeMath;

/** A type-specific {@link BigListIterator}.
 *
 * @see BigListIterator
 */

public interface KEY_BIG_LIST_ITERATOR KEY_GENERIC extends KEY_BIDI_ITERATOR KEY_GENERIC, BigListIterator<KEY_GENERIC_CLASS> {

	/**
	 * Replaces the last element returned by {@link BigListIterator#next() next()} or
	 * {@link BigListIterator#previous() previous()} with the specified element (optional operation).
	 * @see java.util.ListIterator#set(Object)
	 */

#if KEYS_REFERENCE
	@Override
#endif
	default void set(@SuppressWarnings("unused") final KEY_GENERIC_TYPE k) { throw new UnsupportedOperationException(); }

	/**
	 * Inserts the specified element into the list (optional operation).
	 * @see java.util.ListIterator#add(Object)
	 */

#if KEYS_REFERENCE
	@Override
#endif
	default void add(@SuppressWarnings("unused") final KEY_GENERIC_TYPE k)  { throw new UnsupportedOperationException(); }

#if KEYS_PRIMITIVE

	/** Replaces the last element returned by {@link #next()} or {@link #previous()} with the specified element (optional operation).
	 * @deprecated Please use the corresponding type-specific method instead. */
	@Deprecated
	@Override
	default void set(final KEY_GENERIC_CLASS k) { set(k.KEY_VALUE()); }

	/** Inserts the specified element into the list (optional operation).
	 * @deprecated Please use the corresponding type-specific method instead. */
	@Deprecated
	@Override
	default void add(final KEY_GENERIC_CLASS k) { add(k.KEY_VALUE()); }

#endif


	/** Skips the given number of elements.
	 *
	 * <p>The effect of this call is exactly the same as that of
	 * calling {@link BigListIterator#next() next()} for {@code n} times (possibly stopping
	 * if {@link #hasNext()} becomes false).
	 *
	 * @param n the number of elements to skip.
	 * @return the number of elements actually skipped.
	 * @see BigListIterator#next()
	 */
	default long skip(final long n) {
		long i = n;
		while(i-- != 0 && hasNext()) NEXT_KEY();
		return n - i - 1;
	}

	/** Moves back for the given number of elements.
	 *
	 * <p>The effect of this call is exactly the same as that of
	 * calling {@link BigListIterator#previous() previous()} for {@code n} times (possibly stopping
	 * if {@link #hasPrevious()} becomes false).
	 *
	 * @param n the number of elements to skip back.
	 * @return the number of elements actually skipped.
	 * @see BigListIterator#previous()
	 */
	default long back(final long n) {
		long i = n;
		while(i-- != 0 && hasPrevious()) PREV_KEY();
		return n - i - 1;
	}

	/** {@inheritDoc}
	 */
	@Override
	default int skip(int n) {
		return SafeMath.safeLongToInt(skip((long) n));
	}
}