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The software distributed by the Laboratory for Web Algorithmics (LAW).
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package it.unimi.dsi.law.util;

/*
 * Copyright (C) 2004-2020 Paolo Boldi, Massimo Santini and Sebastiano Vigna
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by the Free
 *  Software Foundation; either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 *  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see .
 *
 */

import java.util.NoSuchElementException;

import it.unimi.dsi.fastutil.ints.IntIterator;

/** TODO: doesnt' work
 * An {@link it.unimi.dsi.fastutil.ints.IntIterator} that starts at a given offset,
 * can be incremented optionally at most a given number of times and every time is increased
 * by a given step.
 */
public class OffsetStepLimitIntIterator implements IntIterator {

	private int step, limit, curr, calls;

	/**
	 * Creates a new {@link OffsetStepLimitIntIterator}.
	 *
	 * @param offset the starting value of the iterator.
	 * @param step the step of the iterator.
	 * @param limit the maximum number of allowed increments for the iterator (infinite if -1).
	 */
	public OffsetStepLimitIntIterator(final int offset, final int step, final int limit) {
		this.step = step;
		this.limit = limit;
		curr = offset;
		calls = 0;
	}

	/**
	 * Creates a new {@link OffsetStepLimitIntIterator} from a string.
	 * The accepted syntax is [offset[:[step][:limit]]], offset is assumed to be 0 if absent,
	 * step is assumed to be 1 if absent, limit is assumedd to be -1 if absent.
	 *
	 * @param str the string to parse to obtain the iterator.
	 */
	public OffsetStepLimitIntIterator(String str) {

		curr = 0;
		step = 1;
		limit = -1;
		calls = 0;

		if (str.length() == 0) return;
		int sc = str.indexOf(':');
		if (sc < 0) sc = str.length();
		if (sc > 0) curr = Integer.parseInt(str.substring(0, sc));

		str = str.substring(sc + 1);
		if (str.length() == 0) return;
		sc = str.indexOf(':');
		if (sc < 0) sc = str.length();
		if (sc > 0) step = Integer.parseInt(str.substring(0, sc));

		str = str.substring(sc + 1);
		if (str.length() == 0) return;
		sc = str.indexOf(':');
		if (sc < 0) sc = str.length();
		if (sc > 0) limit = Integer.parseInt(str.substring(0, sc));

	}

	@Override
	public boolean hasNext() {
		return (limit < 0) || (calls < limit);
	}

	@Override
	public int nextInt() {
		if (!hasNext()) throw new NoSuchElementException();
		calls++;
		curr = curr + step;
		return curr - step;
	}
}