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The DSI utilities are a mishmash of classes accumulated during the last twenty years in projects developed at the DSI (Dipartimento di Scienze dell'Informazione, i.e., Information Sciences Department), now DI (Dipartimento di Informatica, i.e., Informatics Department), of the Universita` degli Studi di Milano.

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package it.unimi.dsi.big.util;

/*		 
 * DSI utilities
 *
 * Copyright (C) 2002-2019 Sebastiano Vigna 
 *
 *  This library is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This library 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 Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, see .
 *
 */


import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import it.unimi.dsi.fastutil.longs.LongArrayList;
import it.unimi.dsi.fastutil.longs.LongList;
import it.unimi.dsi.io.InputBitStream;
import it.unimi.dsi.io.OutputBitStream;

import java.io.IOException;

import org.junit.Test;

/**
 * @author Fabien Campagne
 * @author Sebastiano Vigna
 */
public class SemiExternalGammaBigListTest {

	private static InputBitStream buildInputStream(LongList longs) throws IOException {
		byte[] array = new byte[longs.size() * 4];
		@SuppressWarnings("resource")
		OutputBitStream streamer = new OutputBitStream(array);
		for (int i = 0; i < longs.size(); i++) streamer.writeLongGamma(longs.getLong(i));
		int size = (int)(streamer.writtenBits() / 8) + ((streamer.writtenBits() % 8) == 0 ? 0 : 1);
		byte[] smaller = new byte[size];
		System.arraycopy(array, 0, smaller, 0, size);

		return new InputBitStream(smaller);

	}

	@Test
    public void testSemiExternalGammaBigListGammaCoding() throws IOException {

		long[] longs = { 10, 300, 450, 650, 1000, 1290, 1699 };
		LongList listLongs = new LongArrayList(longs);

		SemiExternalGammaBigList list = new SemiExternalGammaBigList(buildInputStream(listLongs), 1, listLongs.size());
		for (long i = 0; i < longs.length; ++i) {
			assertEquals(("test failed for index: " + i), longs[(int) i], list.getLong(i));
		}

		list = new SemiExternalGammaBigList(buildInputStream(listLongs), 2, listLongs.size());
		for (long i = 0; i < longs.length; ++i) {
			assertEquals(("test failed for index: " + i), longs[(int) i], list.getLong(i));
		}

		list = new SemiExternalGammaBigList(buildInputStream(listLongs), 4, listLongs.size());
		for (long i = 0; i < longs.length; ++i) {
			assertEquals(("test failed for index: " + i), longs[(int) i], list.getLong(i));
		}

		list = new SemiExternalGammaBigList(buildInputStream(listLongs), 7, listLongs.size());
		for (long i = 0; i < longs.length; ++i) {
			assertEquals(("test failed for index: " + i), longs[(int) i], list.getLong(i));
		}
		
		list = new SemiExternalGammaBigList(buildInputStream(listLongs), 8, listLongs.size());
		for (long i = 0; i < longs.length; ++i) {
			assertEquals(("test failed for index: " + i), longs[(int) i], list.getLong(i));
		}
    }

	@Test
    public void testEmptySemiExternalGammaBigListGammaCoding() throws IOException {

		long[] longs = {  };
		LongList listOffsets = new LongArrayList(longs);

		new SemiExternalGammaBigList(buildInputStream(listOffsets), 1, listOffsets.size());
		assertTrue(true);
    }

}