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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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/*
 * DSI utilities
 *
 * Copyright (C) 2011-2020 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 .
 *
 */

package it.unimi.dsi.io;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;

import java.io.IOException;

import org.junit.Test;

import it.unimi.dsi.fastutil.io.FastByteArrayOutputStream;
import it.unimi.dsi.util.SplitMix64Random;

@SuppressWarnings("resource")
public class OutputBitStreamTest {

	@Test
	public void testPositionWrapped() throws IOException {
		final byte[] a = new byte[2];
		final OutputBitStream obs = new OutputBitStream(a);
		obs.position(8);
		obs.writeInt(1, 8);
		assertArrayEquals(new byte[] { 0, 1 }, a);
		obs.position(0);
		obs.writeInt(1, 1);
		obs.flush();
		assertArrayEquals(new byte[] { -128, 1 }, a);
	}

	@Test(expected=IllegalArgumentException.class)
	public void testPositionUnaligned() throws IOException {
		final byte[] a = new byte[2];
		final OutputBitStream obs = new OutputBitStream(a);
		obs.position(1);
	}

	@Test
	public void testWriteGammas() throws IOException {
		final FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
		final OutputBitStream obs = new OutputBitStream(fbaos);
		SplitMix64Random random = new SplitMix64Random(0);
		for(int i = 0; i < 100; i++) {
			final int l = random.nextInt(20);
			final int[] a = new int[l + 5];
			for(int p = 0; p < l; p++) a[p] = random.nextInt(10000);
			final long writtenBits = obs.writtenBits();
			final long length = obs.writeGammas(a, l);
			assertEquals(obs.writtenBits() - writtenBits, length);
		}

		obs.flush();
		final InputBitStream ibs = new InputBitStream(fbaos.array);
		random = new SplitMix64Random(0);
		for(int i = 0; i < 100; i++) {
			final int l = random.nextInt(20);
			final int[] a = new int[l];
			ibs.readGammas(a, l);
			for(int p = 0; p < l; p++) assertEquals(random.nextInt(10000), a[p]);
		}
	}

	@Test
	public void testWriteShiftedGammas() throws IOException {
		final FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
		final OutputBitStream obs = new OutputBitStream(fbaos);
		SplitMix64Random random = new SplitMix64Random(0);
		for(int i = 0; i < 100; i++) {
			final int l = random.nextInt(20);
			final int[] a = new int[l + 5];
			for(int p = 0; p < l; p++) a[p] = random.nextInt(10000);
			final long writtenBits = obs.writtenBits();
			final long length = obs.writeShiftedGammas(a, l);
			assertEquals(obs.writtenBits() - writtenBits, length);
		}

		obs.flush();
		final InputBitStream ibs = new InputBitStream(fbaos.array);
		random = new SplitMix64Random(0);
		for(int i = 0; i < 100; i++) {
			final int l = random.nextInt(20);
			final int[] a = new int[l];
			ibs.readShiftedGammas(a, l);
			for(int p = 0; p < l; p++) assertEquals(random.nextInt(10000), a[p]);
		}
	}

	@Test
	public void testWriteDeltas() throws IOException {
		final FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
		final OutputBitStream obs = new OutputBitStream(fbaos);
		SplitMix64Random random = new SplitMix64Random(0);
		for(int i = 0; i < 100; i++) {
			final int l = random.nextInt(20);
			final int[] a = new int[l + 5];
			for(int p = 0; p < l; p++) a[p] = random.nextInt(10000);
			final long writtenBits = obs.writtenBits();
			final long length = obs.writeDeltas(a, l);
			assertEquals(obs.writtenBits() - writtenBits, length);
		}

		obs.flush();
		final InputBitStream ibs = new InputBitStream(fbaos.array);
		random = new SplitMix64Random(0);
		for(int i = 0; i < 100; i++) {
			final int l = random.nextInt(20);
			final int[] a = new int[l];
			ibs.readDeltas(a, l);
			for(int p = 0; p < l; p++) assertEquals(random.nextInt(10000), a[p]);
		}
	}
}