/*
* Copyright (C) 2011 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.hash;
import static com.google.common.base.Charsets.UTF_16LE;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.hash.AbstractStreamingHashFunction.AbstractStreamingHasher;
import com.google.common.hash.HashTestUtils.RandomHasherAction;
import com.google.common.jdk5backport.Arrays;
import junit.framework.TestCase;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.Collections;
import java.util.List;
import java.util.Random;
/**
* Tests for AbstractStreamingHasher.
*
* @author Dimitris Andreou
*/
public class AbstractStreamingHasherTest extends TestCase {
public void testBytes() {
Sink sink = new Sink(4); // byte order insignificant here
byte[] expected = { 1, 2, 3, 4, 5, 6, 7, 8 };
sink.putByte((byte) 1);
sink.putBytes(new byte[] { 2, 3, 4, 5, 6 });
sink.putByte((byte) 7);
sink.putBytes(new byte[] {});
sink.putBytes(new byte[] { 8 });
sink.hash();
sink.assertInvariants(8);
sink.assertBytes(expected);
}
public void testShort() {
Sink sink = new Sink(4);
sink.putShort((short) 0x0201);
sink.hash();
sink.assertInvariants(2);
sink.assertBytes(new byte[] { 1, 2, 0, 0 }); // padded with zeros
}
public void testInt() {
Sink sink = new Sink(4);
sink.putInt(0x04030201);
sink.hash();
sink.assertInvariants(4);
sink.assertBytes(new byte[] { 1, 2, 3, 4 });
}
public void testLong() {
Sink sink = new Sink(8);
sink.putLong(0x0807060504030201L);
sink.hash();
sink.assertInvariants(8);
sink.assertBytes(new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 });
}
public void testChar() {
Sink sink = new Sink(4);
sink.putChar((char) 0x0201);
sink.hash();
sink.assertInvariants(2);
sink.assertBytes(new byte[] { 1, 2, 0, 0 }); // padded with zeros
}
public void testString() throws UnsupportedEncodingException {
Random random = new Random();
for (int i = 0; i < 100; i++) {
byte[] bytes = new byte[64];
random.nextBytes(bytes);
String s = new String(bytes, UTF_16LE.name()); // so all random strings are valid
assertEquals(
new Sink(4).putString(s).hash(),
new Sink(4).putBytes(s.getBytes(UTF_16LE.name())).hash());
assertEquals(
new Sink(4).putString(s).hash(),
new Sink(4).putString(s, UTF_16LE).hash());
}
}
public void testFloat() {
Sink sink = new Sink(4);
sink.putFloat(Float.intBitsToFloat(0x04030201));
sink.hash();
sink.assertInvariants(4);
sink.assertBytes(new byte[] { 1, 2, 3, 4 });
}
public void testDouble() {
Sink sink = new Sink(8);
sink.putDouble(Double.longBitsToDouble(0x0807060504030201L));
sink.hash();
sink.assertInvariants(8);
sink.assertBytes(new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 });
}
public void testCorrectExceptions() {
Sink sink = new Sink(4);
try {
sink.putBytes(new byte[8], -1, 4);
fail();
} catch (IndexOutOfBoundsException ok) {}
try {
sink.putBytes(new byte[8], 0, 16);
fail();
} catch (IndexOutOfBoundsException ok) {}
try {
sink.putBytes(new byte[8], 0, -1);
fail();
} catch (IndexOutOfBoundsException ok) {}
}
/**
* This test creates a long random sequence of inputs, then a lot of differently configured
* sinks process it; all should produce the same answer, the only difference should be the
* number of process()/processRemaining() invocations, due to alignment.
*/
public void testExhaustive() throws Exception {
Random random = new Random(0); // will iteratively make more debuggable, each time it breaks
for (int totalInsertions = 0; totalInsertions < 200; totalInsertions++) {
List<Sink> sinks = Lists.newArrayList();
for (int chunkSize = 4; chunkSize <= 32; chunkSize++) {
for (int bufferSize = chunkSize; bufferSize <= chunkSize * 4; bufferSize += chunkSize) {
// yes, that's a lot of sinks!
sinks.add(new Sink(chunkSize, bufferSize));
// For convenience, testing only with big endianness, to match DataOutputStream.
// I regard highly unlikely that both the little endianness tests above and this one
// passes, and there is still a little endianness bug lurking around.
}
}
Control control = new Control();
Hasher controlSink = control.newHasher(1024);
Iterable<Hasher> sinksAndControl =
Iterables.concat(sinks, Collections.singleton(controlSink));
for (int insertion = 0; insertion < totalInsertions; insertion++) {
RandomHasherAction.pickAtRandom(random).performAction(random, sinksAndControl);
}
// We need to ensure that at least 4 bytes have been put into the hasher or else
// Hasher#hash will throw an ISE.
int intToPut = random.nextInt();
for (Hasher hasher : sinksAndControl) {
hasher.putInt(intToPut);
}
for (Sink sink : sinks) {
sink.hash();
}
byte[] expected = controlSink.hash().asBytes();
for (Sink sink : sinks) {
sink.assertInvariants(expected.length);
sink.assertBytes(expected);
}
}
}
private static class Sink extends AbstractStreamingHasher {
final int chunkSize;
final int bufferSize;
final ByteArrayOutputStream out = new ByteArrayOutputStream();
int processCalled = 0;
boolean remainingCalled = false;
Sink(int chunkSize, int bufferSize) {
super(chunkSize, bufferSize);
this.chunkSize = chunkSize;
this.bufferSize = bufferSize;
}
Sink(int chunkSize) {
super(chunkSize);
this.chunkSize = chunkSize;
this.bufferSize = chunkSize;
}
@Override HashCode makeHash() {
return HashCode.fromBytes(out.toByteArray());
}
@Override protected void process(ByteBuffer bb) {
processCalled++;
assertEquals(ByteOrder.LITTLE_ENDIAN, bb.order());
assertTrue(bb.remaining() >= chunkSize);
for (int i = 0; i < chunkSize; i++) {
out.write(bb.get());
}
}
@Override protected void processRemaining(ByteBuffer bb) {
assertFalse(remainingCalled);
remainingCalled = true;
assertEquals(ByteOrder.LITTLE_ENDIAN, bb.order());
assertTrue(bb.remaining() > 0);
assertTrue(bb.remaining() < bufferSize);
int before = processCalled;
super.processRemaining(bb);
int after = processCalled;
assertEquals(before + 1, after); // default implementation pads and calls process()
processCalled--; // don't count the tail invocation (makes tests a bit more understandable)
}
// ensures that the number of invocations looks sane
void assertInvariants(int expectedBytes) {
// we should have seen as many bytes as the next multiple of chunk after expectedBytes - 1
assertEquals(out.toByteArray().length, ceilToMultiple(expectedBytes, chunkSize));
assertEquals(expectedBytes / chunkSize, processCalled);
assertEquals(expectedBytes % chunkSize != 0, remainingCalled);
}
// returns the minimum x such as x >= a && (x % b) == 0
private static int ceilToMultiple(int a, int b) {
int remainder = a % b;
return remainder == 0 ? a : a + b - remainder;
}
void assertBytes(byte[] expected) {
byte[] got = out.toByteArray();
for (int i = 0; i < expected.length; i++) {
assertEquals(expected[i], got[i]);
}
}
}
// Assumes that AbstractNonStreamingHashFunction works properly (must be tested elsewhere!)
private static class Control extends AbstractNonStreamingHashFunction {
@Override
public HashCode hashBytes(byte[] input) {
return HashCode.fromBytes(input);
}
@Override
public HashCode hashBytes(byte[] input, int off, int len) {
return hashBytes(Arrays.copyOfRange(input, off, off + len));
}
@Override
public int bits() {
throw new UnsupportedOperationException();
}
@Override
public HashCode hashString(CharSequence input) {
throw new UnsupportedOperationException();
}
@Override
public HashCode hashString(CharSequence input, Charset charset) {
throw new UnsupportedOperationException();
}
@Override
public HashCode hashLong(long input) {
throw new UnsupportedOperationException();
}
@Override
public HashCode hashInt(int input) {
throw new UnsupportedOperationException();
}
}
}