Add hash map for long to long mappings.

This commit is contained in:
2019-09-07 14:36:51 +02:00
parent 097b7ab110
commit 86f12e0af6
6 changed files with 634 additions and 0 deletions

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package org.lucares.collections;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import java.util.stream.LongStream;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;
@State(Scope.Benchmark)
@BenchmarkMode(Mode.Throughput)
@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(1)
public class BenchmarkLongLongMapForEach {
@Param({ "1000", "10000", "50000" })
private int values;
private LongLongHashMap unsortedMap = new LongLongHashMap();
private LongLongHashMap unsortedMapLowValues = new LongLongHashMap();
private org.eclipse.collections.impl.map.mutable.primitive.LongLongHashMap eclipseUnsortedMap = new org.eclipse.collections.impl.map.mutable.primitive.LongLongHashMap();
@Setup
public void setup() throws Exception {
final int seed = 6789;
final Random rand = new Random(seed);
LongStream.generate(rand::nextLong).limit(values).forEach(l -> unsortedMap.put(l, 2 * l));
rand.setSeed(seed);
final LongList lowValues = LongList.range(0, values);
lowValues.shuffle(rand);
lowValues.stream().forEach(l -> unsortedMapLowValues.put(l, 2 * l));
rand.setSeed(seed);
LongStream.generate(rand::nextLong).limit(values).forEach(l -> eclipseUnsortedMap.put(l, 2 * l));
}
@TearDown
public void tearDown() {
unsortedMap = null;
unsortedMapLowValues = null;
eclipseUnsortedMap = null;
}
@Benchmark
public void testLongLongMapForEach(final Blackhole blackhole) throws Exception {
final long[] tmp = new long[] { 0 };
unsortedMap.forEach((k, v) -> tmp[0] += k);
blackhole.consume(tmp[0]);
}
@Benchmark
public void testLongLongMapForEachLowValues(final Blackhole blackhole) throws Exception {
final long[] tmp = new long[] { 0 };
unsortedMapLowValues.forEach((k, v) -> tmp[0] += k);
blackhole.consume(tmp[0]);
}
@Benchmark
public void testLongLongMapForEachOrdered(final Blackhole blackhole) throws Exception {
final long[] tmp = new long[] { 0 };
unsortedMap.forEachOrdered((k, v) -> tmp[0] += k);
blackhole.consume(tmp[0]);
}
@Benchmark
public void testLongLongMapForEachOrderedLowValues(final Blackhole blackhole) throws Exception {
final long[] tmp = new long[] { 0 };
unsortedMapLowValues.forEachOrdered((k, v) -> tmp[0] += k);
blackhole.consume(tmp[0]);
}
@Benchmark
public void testEclipseLongLongMapForEach(final Blackhole blackhole) throws Exception {
final long[] tmp = new long[] { 0 };
eclipseUnsortedMap.forEachKeyValue((k, v) -> tmp[0] += k);
blackhole.consume(tmp[0]);
}
}

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package org.lucares.collections;
@FunctionalInterface
public interface LongFunction {
long apply(long value);
}

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package org.lucares.collections;
public interface LongLongConsumer {
public void accept(long key, long value);
}

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package org.lucares.collections;
import java.util.Arrays;
import java.util.NoSuchElementException;
/**
* A hash map where key and value are primitive longs.
*/
public class LongLongHashMap {
// There is no equivalent to null for primitive values. Therefore we have to add
// special handling for one long value. Otherwise we couldn't tell if a key is
// in the map or not. We chose 0L, because LongList is initially all 0L.
private static final long NULL_KEY = 0L;
private static final long EMPTY_SLOT = 0L;
/**
* The maximum size of an array.
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
private final double fillFactor;
private long[] keys;
private long[] values;
private int size = 0;
private Long zeroValue = null;
/**
* Create a new {@link LongLongHashMap} with the given initial capacity and load
* factor.
*
* @param initialCapacity the initial capacity
* @param loadFactor the load factor
*/
public LongLongHashMap(final int initialCapacity, final double loadFactor) {
if (initialCapacity < 0) {
throw new IllegalArgumentException("initial capacity must be non-negative");
}
if (initialCapacity > MAX_ARRAY_SIZE) {
throw new IllegalArgumentException("initial capacity must be smaller or equal to " + MAX_ARRAY_SIZE);
}
if (loadFactor <= 0 || Double.isNaN(loadFactor))
throw new IllegalArgumentException("Illegal load factor: " + loadFactor);
this.fillFactor = loadFactor;
keys = new long[initialCapacity];
values = new long[initialCapacity];
}
/**
* Create a new {@link LongLongHashMap} with initial capacity 8 and load factor
* 0.75.
*/
public LongLongHashMap() {
this(8, 0.75);
}
/**
* The number of entries in this map.
*
* @return the size
*/
public int size() {
return size;
}
/**
* The capacity of this map.
*
* @return the capacity
*/
int getCapacity() {
return keys.length;
}
/**
* Add the given key and value to the map.
*
* @param key the key
* @param value the value
*/
public void put(final long key, final long value) {
if (key == NULL_KEY) {
size += zeroValue == null ? 1 : 0;
zeroValue = value;
return;
}
if ((keys.length * fillFactor) < size) {
growAndRehash();
}
final boolean added = putInternal(key, value);
if (added) {
size++;
}
}
private boolean putInternal(final long key, final long value) {
final int searchStart = spread(key);
int currentPosition = searchStart;
do {
// found a free place, insert the value
if (keys[currentPosition] == EMPTY_SLOT) {
keys[currentPosition] = key;
values[currentPosition] = value;
return true;
}
// value exists, update it
if (keys[currentPosition] == key) {
keys[currentPosition] = key;
values[currentPosition] = value;
return false;
}
currentPosition = (currentPosition + 1) % keys.length;
} while (currentPosition != searchStart);
throw new IllegalStateException("map is full");
}
/**
* Returns the value for the given key if it exists. This method throws a
* {@link NoSuchElementException} if the key does not exist. Use
* {@link #containsKey(long)} to check before calling {@link #get(long)}.
*
* @param key the key
* @return the value if it exists
* @throws NoSuchElementException if the value does not exist
*/
public long get(final long key) {
if (key == NULL_KEY) {
if (zeroValue != null) {
return zeroValue;
}
throw new NoSuchElementException();
}
final int searchStart = spread(key);
int currentPosition = searchStart;
do {
if (keys[currentPosition] == key) {
return values[currentPosition];
}
currentPosition = (currentPosition + 1) % keys.length;
} while (currentPosition != searchStart);
throw new NoSuchElementException();
}
/**
* Check if the map contains the given key.
*
* @param key the key
* @return true iff the map contains the key
*/
public boolean containsKey(final long key) {
if (key == NULL_KEY) {
return zeroValue != null;
}
final int searchStart = spread(key);
int currentPosition = searchStart;
do {
if (keys[currentPosition] == key) {
return true;
}
currentPosition = (currentPosition + 1) % keys.length;
} while (currentPosition != searchStart);
return false;
}
/**
* Remove the given key and its value from the map.
*
* @param key the key
*/
public void remove(final long key) {
if (key == NULL_KEY) {
size -= zeroValue != null ? 1 : 0;
zeroValue = null;
return;
}
final int searchStart = spread(key);
int currentPosition = searchStart;
do {
if (keys[currentPosition] == key) {
keys[currentPosition] = EMPTY_SLOT;
size--;
return;
}
currentPosition = (currentPosition + 1) % keys.length;
} while (currentPosition != searchStart);
}
/**
* Computes a mapping for the given key and its current value.
* <p>
* The mapping for given key is updated by calling {@code function} with the old
* value. The return value will be set as new value. If the map does not contain
* a mapping for the key, then {@code function} is with
* {@code initialValueIfAbsent}.
*
* @param key the key
* @param initialValueIfAbsent value used if there is no current mapping for the
* key
* @param function called to update an existing value
*/
public void compute(final long key, final long initialValueIfAbsent, final LongFunction function) {
if (key == NULL_KEY) {
if (zeroValue != null) {
zeroValue = function.apply(zeroValue);
return;
}
zeroValue = function.apply(initialValueIfAbsent);
return;
}
final int searchStart = spread(key);
int currentPosition = searchStart;
do {
if (keys[currentPosition] == key) {
final long updatedValue = function.apply(values[currentPosition]);
values[currentPosition] = updatedValue;
return;
}
currentPosition = (currentPosition + 1) % keys.length;
} while (currentPosition != searchStart);
// key not found -> add it
final long newZeroValue = function.apply(initialValueIfAbsent);
put(key, newZeroValue);
}
/**
* Calls the {@link LongLongConsumer#accept(long, long)} method for all entries
* in this map. The order is based on the hash value and is therefore not
* deterministic. Don't rely on the order!
*
* @param consumer the consumer
*/
public void forEach(final LongLongConsumer consumer) {
if (zeroValue != null) {
consumer.accept(0, zeroValue);
}
for (int i = 0; i < keys.length; i++) {
if (keys[i] != EMPTY_SLOT) {
consumer.accept(keys[i], values[i]);
}
}
}
/**
* Calls the {@link LongLongConsumer#accept(long, long)} method for all entries
* in this map. This method iterates over the keys in ascending order.
* <p>
* Note: this method is slower than {@link #forEach(LongLongConsumer)}.
*
* @param consumer the consumer
*/
public void forEachOrdered(final LongLongConsumer consumer) {
if (zeroValue != null) {
consumer.accept(0, zeroValue);
}
final long[] sortedKeys = Arrays.copyOf(keys, keys.length);
Arrays.parallelSort(sortedKeys);
for (int i = 0; i < sortedKeys.length; i++) {
final long key = sortedKeys[i];
if (key != EMPTY_SLOT) {
consumer.accept(key, get(key));
} else if (key == EMPTY_SLOT) {
final int posFirstKey = findPosOfFirstPositiveKey(sortedKeys);
i = posFirstKey - 1;
}
}
}
static int findPosOfFirstPositiveKey(final long[] sortedKeys) {
if (sortedKeys.length == 0) {
return -1;
}
if (sortedKeys.length == 1) {
return sortedKeys[0] > EMPTY_SLOT ? 0 : -1;
}
int low = 0;
int high = sortedKeys.length - 1;
int pos = -1;
while (low <= high) {
pos = (low + high) / 2;
if (sortedKeys[pos] <= EMPTY_SLOT) {
low = pos + 1;
} else {
high = pos - 1;
}
}
if (low < sortedKeys.length && sortedKeys[low] <= EMPTY_SLOT) {
low++;
}
return low < sortedKeys.length && sortedKeys[low] > EMPTY_SLOT ? low : -1;
}
private void growAndRehash() {
final long[] oldKeys = keys;
final long[] oldValues = values;
final int newSize = Math.min(keys.length * 2, MAX_ARRAY_SIZE);
keys = new long[newSize];
values = new long[newSize];
for (int i = 0; i < oldKeys.length; i++) {
final long key = oldKeys[i];
if (key != EMPTY_SLOT) {
final long value = oldValues[i];
putInternal(key, value);
}
}
}
// visible for test
int spread(final long key) {
return hash(key) % keys.length;
}
private int hash(final long l) {
return Math.abs(Long.hashCode(l));
}
}

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package org.lucares.collections;
import java.util.Random;
import java.util.stream.LongStream;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
public class LongLongHashMapTest {
@Test
public void testPutRemove() {
putGetRemove(1);
}
@Test
public void testNullValue() {
putGetRemove(0);
}
private void putGetRemove(final long key) {
final LongLongHashMap map = new LongLongHashMap();
final long valueA = 2L;
final long valueB = 3L;
// value does not exist
Assertions.assertFalse(map.containsKey(key));
Assertions.assertEquals(0, map.size());
// add value and check it is in the map
map.put(key, valueA);
Assertions.assertTrue(map.containsKey(key));
Assertions.assertEquals(valueA, map.get(key));
Assertions.assertEquals(1, map.size());
// overwrite value
map.put(key, valueB);
Assertions.assertEquals(valueB, map.get(key));
Assertions.assertEquals(1, map.size());
// remove value and check it is gone
map.remove(key);
Assertions.assertFalse(map.containsKey(key));
Assertions.assertEquals(0, map.size());
}
@Test
public void testComputeZeroKey() {
final LongLongHashMap map = new LongLongHashMap();
final long key = 1;
map.compute(key, 6, l -> l + 1);
Assertions.assertEquals(7, map.get(key), "initialValueIfAbsent is used when there is no mapping for the key");
map.compute(key, 6, l -> l + 1);
Assertions.assertEquals(8, map.get(key), "update function is called when 'zeroKey' is set");
}
@Test
public void testCompute() {
final LongLongHashMap map = new LongLongHashMap();
final long key = 1;
map.compute(key, 6, l -> l + 1);
Assertions.assertEquals(7, map.get(key), "initialValueIfAbsent is used when there is no mapping for the key");
map.compute(key, 6, l -> l + 1);
Assertions.assertEquals(8, map.get(key), "update function is called when key is set");
}
@Test
public void testGrowMap() {
final LongLongHashMap map = new LongLongHashMap(4, 0.75);
final int numEntries = 12;
final Random rand = new Random(12345);
final LongList entries = LongList.of(LongStream.generate(rand::nextLong).limit(numEntries).toArray());
entries.stream().forEachOrdered(l -> {
map.put(l, l);
});
entries.stream().forEachOrdered(l -> {
Assertions.assertEquals(l, map.get(l));
});
Assertions.assertEquals(16, map.getCapacity(), "capacity after adding 12 entries must be a the smallest number "
+ "that satisfies initialCapacity * 2^n >= entries/fillFactor");
}
@Test
public void testMultipleValuesOnSamePosition() {
final int initialCapacity = 20;
final LongLongHashMap map = new LongLongHashMap(initialCapacity, 0.75);
// find to values that yield the same 'spread' (position in the table)
final LongList keysWithSameSpread = findKeysWithSameSpread(map);
Assertions.assertTrue(keysWithSameSpread.size() > 5);
keysWithSameSpread.stream().forEach(l -> map.put(l, l));
Assertions.assertEquals(keysWithSameSpread.size(), map.size());
keysWithSameSpread.stream().forEach(l -> Assertions.assertEquals(l, map.get(l)));
}
@Test
public void testForEach() {
final LongLongHashMap map = new LongLongHashMap();
final Random rand = new Random(6789);
final LongList entries = LongList.of(LongStream.generate(rand::nextLong).limit(15).toArray());
entries.stream().forEachOrdered(l -> {
map.put(l, 2 * l);
});
map.forEach((k, v) -> {
Assertions.assertEquals(k * 2, v, "value is key*2");
Assertions.assertTrue(entries.indexOf(k) >= 0, "value " + k + " in entries: " + entries);
});
}
@Test
public void testForEachOrdered() {
final LongLongHashMap map = new LongLongHashMap();
final Random rand = new Random(6789);
final LongList entries = LongList.of(LongStream.generate(rand::nextLong).limit(15).toArray());
entries.stream().forEachOrdered(l -> {
map.put(l, 2 * l);
});
final LongList actualOrderOfKeys = new LongList();
map.forEachOrdered((k, v) -> {
Assertions.assertEquals(k * 2, v, "value is key*2");
Assertions.assertTrue(entries.indexOf(k) >= 0, "value " + k + " in entries: " + entries);
actualOrderOfKeys.add(k);
});
Assertions.assertTrue(actualOrderOfKeys.isSorted(), "keys are sorted");
}
@Test
public void testFindPositionOfFirstPositiveKey() {
Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] {}));
Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0 }));
Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1 }));
Assertions.assertEquals(1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 1 }));
Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1, 1 }));
Assertions.assertEquals(2, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 1 }));
Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1, 1, 1, 1, 1, 1, 1, 1, 1 }));
Assertions.assertEquals(0, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 1, 1, 1, 1, 1, 1, 1, 1 }));
Assertions.assertEquals(4,
LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, -1, 1, 1, 1, 1, 1 }));
Assertions.assertEquals(4,
LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, -1, 1, 1, 1, 1 }));
Assertions.assertEquals(3,
LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, 1, 1, 1, 1, 1, 1 }));
Assertions.assertEquals(3, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, -1, -1, 1, 1, 1, 1, 1 }));
Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0 }));
Assertions.assertEquals(-1, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 0 }));
Assertions.assertEquals(4, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 1, 1, 1, 1 }));
Assertions.assertEquals(5, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 1, 1, 1 }));
Assertions.assertEquals(6, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 0, 1, 1 }));
Assertions.assertEquals(4, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 1, 1, 1 }));
Assertions.assertEquals(5, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 1, 1 }));
Assertions.assertEquals(6, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { 0, 0, 0, 0, 0, 0, 1 }));
Assertions.assertEquals(4, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 0, 0, 1, 1, 1 }));
Assertions.assertEquals(5, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 0, 0, 0, 1, 1 }));
Assertions.assertEquals(6, LongLongHashMap.findPosOfFirstPositiveKey(new long[] { -1, 0, 0, 0, 0, 0, 1 }));
}
private LongList findKeysWithSameSpread(final LongLongHashMap map) {
final LongList result = new LongList();
final int spread = map.spread(1);
result.add(1);
for (long l = 2; l < 10000; l++) {
final int s = map.spread(l);
if (s == spread) {
result.add(l);
if (result.size() > 10) {
break;
}
}
}
return result;
}
}