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/*
* Copyright (C) 2021 Thomas Wolf <thomas.wolf@paranor.ch> and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.util.io;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.util.zip.InflaterInputStream;
import org.junit.Test;
/**
* Crude tests for the {@link BinaryDeltaInputStream} using delta diffs
* generated by C git.
*/
public class BinaryDeltaInputStreamTest {
private InputStream getBinaryHunk(String name) {
return this.getClass().getResourceAsStream(name);
}
@Test
public void testBinaryDelta() throws Exception {
// Prepare our test data
byte[] data = new byte[8192];
for (int i = 0; i < data.length; i++) {
data[i] = (byte) (255 - (i % 256));
}
// Same, but with five 'x' inserted in the middle.
int middle = data.length / 2;
byte[] newData = new byte[data.length + 5];
System.arraycopy(data, 0, newData, 0, middle);
for (int i = 0; i < 5; i++) {
newData[middle + i] = 'x';
}
System.arraycopy(data, middle, newData, middle + 5, middle);
// delta1.forward has the instructions
// @formatter:off
// COPY 0 4096
// INSERT 5 xxxxx
// COPY 0 4096
// @formatter:on
// Note that the way we built newData could be expressed as
// @formatter:off
// COPY 0 4096
// INSERT 5 xxxxx
// COPY 4096 4096
// @formatter:on
try (ByteArrayOutputStream out = new ByteArrayOutputStream();
BinaryDeltaInputStream input = new BinaryDeltaInputStream(data,
new InflaterInputStream(new BinaryHunkInputStream(
getBinaryHunk("delta1.forward"))))) {
byte[] buf = new byte[1024];
int n;
while ((n = input.read(buf)) >= 0) {
out.write(buf, 0, n);
}
assertArrayEquals(newData, out.toByteArray());
assertTrue(input.isFullyConsumed());
}
// delta1.reverse has the instructions
// @formatter:off
// COPY 0 4096
// COPY 256 3840
// COPY 256 256
// @formatter:on
// Note that there are alternatives, for instance
// @formatter:off
// COPY 0 4096
// COPY 4101 4096
// @formatter:on
// or
// @formatter:off
// COPY 0 4096
// COPY 0 4096
// @formatter:on
try (ByteArrayOutputStream out = new ByteArrayOutputStream();
BinaryDeltaInputStream input = new BinaryDeltaInputStream(
newData,
new InflaterInputStream(new BinaryHunkInputStream(
getBinaryHunk("delta1.reverse"))))) {
long expectedSize = input.getExpectedResultSize();
assertEquals(data.length, expectedSize);
byte[] buf = new byte[1024];
int n;
while ((n = input.read(buf)) >= 0) {
out.write(buf, 0, n);
}
assertArrayEquals(data, out.toByteArray());
assertTrue(input.isFullyConsumed());
}
}
}
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