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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.io;

/*
 * DSI utilities
 *
 * Copyright (C) 2010-2019 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.io.FastByteArrayOutputStream;
import it.unimi.dsi.fastutil.longs.LongArrayList;
import it.unimi.dsi.util.XoRoShiRo128PlusRandom;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Arrays;
import java.util.Random;

import org.junit.Test;

@SuppressWarnings("resource")
public class InputBitStreamTest {

	@Test
	public void testReadAligned() throws IOException {
		byte[] a = { 1 }, A = new byte[1];
		new InputBitStream(a).read(A, 8);
		assertTrue(Arrays.toString(a) + " != " + Arrays.toString(A), Arrays.equals(a, A));
		byte[] b = { 1, 2 }, B = new byte[2];
		new InputBitStream(b).read(B, 16);
		assertTrue(Arrays.toString(b) + " != " + Arrays.toString(B), Arrays.equals(b, B));
		byte[] c = { 1, 2, 3 }, C = new byte[3];
		new InputBitStream(c).read(C, 24);
		assertTrue(Arrays.toString(c) + " != " + Arrays.toString(C), Arrays.equals(c, C));
	}

	@Test
	public void testOverflow() throws IOException {
		InputBitStream ibs = new InputBitStream(new byte[0]);
		ibs.readInt(0);
	}

	@Test
	public void testPosition() throws IOException {
		InputBitStream ibs = new InputBitStream(new byte[100]);
		for(int i = 0; i < 800; i++) {
			ibs.position(i);
			assertEquals(i, ibs.position());
		}
		for(int i = 800; i-- != 0;) {
			ibs.position(i);
			assertEquals(i, ibs.position());
		}
	}

	@Test
	public void readWriteLongs() throws IOException, NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
		Random random = new Random(0);
		File tempFile = File.createTempFile("readWriteLongs", "os");
		tempFile.deleteOnExit();

		String[] oneArgs = { "LongGamma", "LongShiftedGamma", "LongDelta", "LongNibble" };
		String[] twoArgsLong = { "LongGolomb", "LongSkewedGolomb" };

		LongArrayList longs = new LongArrayList();
		for (int i = 0; i < 10; i++) longs.add(5000000000L + random.nextInt());
		//for (int i = 24; i < 60; i++) longs.add(1L << i);
		LongArrayList extraArgLong = new LongArrayList();
		for (int i = 0; i < 5; i++) extraArgLong.add(100000 + random.nextInt(1000000));

		// Write
		OutputBitStream obs = new OutputBitStream(tempFile);

		for (String methSuffix: oneArgs) {
			for (long longValue: longs)
				OutputBitStream.class.getMethod("write" + methSuffix, long.class).invoke(obs, Long.valueOf(longValue));
		}
		for (String methSuffix: twoArgsLong) {
			for (long longValue: longs)
				for (long longXValue: extraArgLong)
				OutputBitStream.class.getMethod("write" + methSuffix, long.class, long.class).invoke(obs, Long.valueOf(longValue), Long.valueOf(longXValue));
		}
		// Special methods
		for (long longValue: longs) {
			obs.writeLong(longValue, Long.SIZE);
			obs.writeLongMinimalBinary(longValue, longValue + 5);
			for (int i = 3; i < 10; i++) obs.writeLongZeta(longValue, i);
		}
		obs.writeLongUnary(15 + 1L << 20);

		obs.close();

		// Read
		InputBitStream ibs = new InputBitStream(tempFile);

		for (String methSuffix: oneArgs) {
			for (long longValue: longs)
				assertEquals(Long.valueOf(longValue), InputBitStream.class.getMethod("read" + methSuffix).invoke(ibs));
		}
		for (String methSuffix: twoArgsLong) {
			for (long longValue: longs)
				for (long longXValue: extraArgLong)
					assertEquals(Long.valueOf(longValue), InputBitStream.class.getMethod("read" + methSuffix, long.class).invoke(ibs, Long.valueOf(longXValue)));
		}
		for (long longValue: longs) {
			assertEquals(longValue, ibs.readLong(Long.SIZE));
			assertEquals(longValue, ibs.readLongMinimalBinary(longValue + 5));
			for (int i = 3; i < 10; i++) assertEquals(longValue, ibs.readLongZeta(i));
		}
		assertEquals(15 + 1L << 20, ibs.readLongUnary());

		ibs.close();

	}

	@Test
	public void testUnary() throws IOException {
		final XoRoShiRo128PlusRandom random = new XoRoShiRo128PlusRandom(0);
		final FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
		final OutputBitStream obs = new OutputBitStream(fbaos);
		for(int i = 0; i < 100000000; i++) obs.writeUnary(Long.numberOfTrailingZeros(random.nextLong()));
		obs.flush();
		final InputBitStream ibs = new InputBitStream(fbaos.array);
		random.setSeed(0);
		long start = - System.nanoTime();
		for(int i = 0; i < 100000000; i++) assertEquals(Long.numberOfTrailingZeros(random.nextLong()), ibs.readUnary());
		System.err.println((start + System.nanoTime()) / 1E9);
	}

	@Test
	public void testLongUnary() throws IOException {
		final XoRoShiRo128PlusRandom random = new XoRoShiRo128PlusRandom(0);
		final FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
		final OutputBitStream obs = new OutputBitStream(fbaos);
		for(int i = 0; i < 100000000; i++) obs.writeLongUnary(Long.numberOfTrailingZeros(random.nextLong()));
		obs.flush();
		final InputBitStream ibs = new InputBitStream(fbaos.array);
		random.setSeed(0);
		long start = - System.nanoTime();
		for(int i = 0; i < 100000000; i++) assertEquals(Long.numberOfTrailingZeros(random.nextLong()), ibs.readLongUnary());
		System.err.println((start + System.nanoTime()) / 1E9);
	}

	public static void main(String arg[]) throws IOException {
		final XoRoShiRo128PlusRandom random = new XoRoShiRo128PlusRandom(0);
		final FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
		final OutputBitStream obs = new OutputBitStream(fbaos);
		for(int i = 0; i < 100000000; i++) obs.writeUnary(Long.numberOfTrailingZeros(random.nextLong()));
		obs.flush();
		final InputBitStream ibs = new InputBitStream(fbaos.array);
		long start = - System.nanoTime();
		for(int i = 0; i < 100000000; i++) ibs.readUnary();
		System.err.println((start + System.nanoTime()) / 1E9);

		ibs.position(0);
		start = - System.nanoTime();
		for(int i = 0; i < 100000000; i++) ibs.readUnary();
		System.err.println((start + System.nanoTime()) / 1E9);

		ibs.position(0);
		start = - System.nanoTime();
		for(int i = 0; i < 100000000; i++) ibs.readUnary();
		System.err.println((start + System.nanoTime()) / 1E9);
	}
}