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 * Institute of Molecular Cell Biology and Genetics, University of
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package org.scijava.io.handle;

import static org.junit.Assert.assertEquals;

import java.io.IOException;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.scijava.Context;
import org.scijava.event.EventService;
import org.scijava.io.location.BytesLocation;
import org.scijava.io.location.Location;
import org.scijava.task.DefaultTask;
import org.scijava.task.Task;
import org.scijava.thread.ThreadService;
import org.scijava.util.MersenneTwisterFast;

/**
 * Tests for utility methods in the {@link DataHandles} class.
 *
 * @author Gabriel Einsdorf
 */
public class DataHandlesTest {

	private static final int TEST_SIZE = 2_938_740;
	private DataHandleService handles;
	private Location inFile;
	private BytesLocation outFile;
	private byte[] data;
	private ThreadService threadService;
	private EventService eventService;

	@Before
	public void classSetup() {
		final Context ctx = new Context(DataHandleService.class,
			ThreadService.class, EventService.class);
		handles = ctx.service(DataHandleService.class);
		threadService = ctx.service(ThreadService.class);
		eventService = ctx.service(EventService.class);

		data = randomBytes(0xbabebabe);
		inFile = new BytesLocation(data);
		outFile = new BytesLocation(TEST_SIZE);
	}

	@After
	public void cleanup() {
		handles.context().dispose();
	}

	@Test
	public void testDefaultCopy() throws IOException {
		try (DataHandle<Location> src = handles.create(inFile);
				final DataHandle<Location> dest = handles.create(outFile))
		{
			DataHandles.copy(src, dest);
			assertHandleEquals(data, dest);
		}
	}

	@Test
	public void testCopyTask() throws IOException {
		try (DataHandle<Location> src = handles.create(inFile);
				final DataHandle<Location> dest = handles.create(outFile))
		{
			final Task t = new DefaultTask(threadService, eventService);
			DataHandles.copy(src, dest, t);
			assertEquals(t.getProgressValue(), src.length());
			assertHandleEquals(data, dest);
		}
	}

	@Test
	public void testCopyLength() throws IOException {
		final int sliceSize = 50_000;
		try (DataHandle<Location> src = handles.create(inFile);
				final DataHandle<Location> dest = handles.create(outFile))
		{
			DataHandles.copy(src, dest, sliceSize);
			final byte[] expected = new byte[sliceSize];
			System.arraycopy(data, 0, expected, 0, sliceSize);
			assertHandleEquals(expected, dest);
		}
	}

	@Test
	public void testCopyLengthTask() throws IOException {
		final int sliceSize = 50_000;
		try (DataHandle<Location> src = handles.create(inFile);
				final DataHandle<Location> dest = handles.create(outFile))
		{
			final Task t = new DefaultTask(threadService, eventService);
			DataHandles.copy(src, dest, sliceSize, t);
			assertEquals(t.getProgressValue(), sliceSize);

			final byte[] expected = new byte[sliceSize];
			System.arraycopy(data, 0, expected, 0, sliceSize);
			assertHandleEquals(expected, dest);
		}
	}

	private void assertHandleEquals(final byte[] expected,
		final DataHandle<Location> handle) throws IOException
	{
		handle.seek(0);
		for (int i = 0; i < expected.length; i++) {
			assertEquals(expected[i], handle.readByte());
		}
	}

	private byte[] randomBytes(final long seed) {
		final MersenneTwisterFast r = new MersenneTwisterFast(seed);
		final byte[] ldata = new byte[TEST_SIZE];
		for (int i = 0; i < ldata.length; i++) {
			ldata[i] = r.nextByte();
		}
		return ldata;
	}
}
