org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/IntSet.java

/*
 * Copyright (C) 2011, Google Inc.
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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package org.eclipse.jgit.internal.storage.pack;

class IntSet {
	private int[] set;

	private int cnt;

	IntSet() {
		set = new int[64];
	}

	boolean add(int key) {
		int high = cnt;
		int low = 0;

		if (high == 0) {
			set[0] = key;
			cnt = 1;
			return true;
		}

		do {
			int p = (low + high) >>> 1;
			if (key < set[p])
				high = p;
			else if (key == set[p])
				return false;
			else
				low = p + 1;
		} while (low < high);

		if (cnt == set.length) {
			int[] n = new int[set.length * 2];
			System.arraycopy(set, 0, n, 0, cnt);
			set = n;
		}

		if (low < cnt)
			System.arraycopy(set, low, set, low + 1, cnt - low);
		set[low] = key;
		cnt++;
		return true;
	}
}