/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* 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 org.robovm.objc;
import java.util.Iterator;
import java.util.NoSuchElementException;
/*
* RoboVM note: The LongMap and RandomXS128 classes in this file have been copied
* from the libGDX project and modified slightly (removed a few things we don't
* need).
*/
/** An unordered map that uses long keys. This implementation is a cuckoo hash map using 3 hashes, random walking, and a small
* stash for problematic keys. Null values are allowed. No allocation is done except when growing the table size. <br>
* <br>
* This map performs very fast get, containsKey, and remove (typically O(1), worst case O(log(n))). Put may be a bit slower,
* depending on hash collisions. Load factors greater than 0.91 greatly increase the chances the map will have to rehash to the
* next higher POT size.
* @author Nathan Sweet */
public class LongMap<V> implements Iterable<LongMap.Entry<V>> {
@SuppressWarnings("unused")
private static final int PRIME1 = 0xbe1f14b1;
private static final int PRIME2 = 0xb4b82e39;
private static final int PRIME3 = 0xced1c241;
private static final int EMPTY = 0;
public int size;
long[] keyTable;
V[] valueTable;
int capacity, stashSize;
V zeroValue;
boolean hasZeroValue;
private float loadFactor;
private int hashShift, mask, threshold;
private int stashCapacity;
private int pushIterations;
private Entries<V> entries1, entries2;
//private Values values1, values2;
//private Keys keys1, keys2;
/** Returns the next power of two. Returns the specified value if the value is already a power of two. */
// RoboVM note: Inlined from com.badlogic.gdx.math.MathUtils
static public int nextPowerOfTwo (int value) {
if (value == 0) return 1;
value--;
value |= value >> 1;
value |= value >> 2;
value |= value >> 4;
value |= value >> 8;
value |= value >> 16;
return value + 1;
}
/** Creates a new map with an initial capacity of 32 and a load factor of 0.8. This map will hold 25 items before growing the
* backing table. */
public LongMap () {
this(32, 0.8f);
}
/** Creates a new map with a load factor of 0.8. This map will hold initialCapacity * 0.8 items before growing the backing
* table. */
public LongMap (int initialCapacity) {
this(initialCapacity, 0.8f);
}
/** Creates a new map with the specified initial capacity and load factor. This map will hold initialCapacity * loadFactor items
* before growing the backing table. */
@SuppressWarnings("unchecked")
public LongMap (int initialCapacity, float loadFactor) {
if (initialCapacity < 0) throw new IllegalArgumentException("initialCapacity must be >= 0: " + initialCapacity);
if (initialCapacity > 1 << 30) throw new IllegalArgumentException("initialCapacity is too large: " + initialCapacity);
capacity = /*MathUtils.*/nextPowerOfTwo(initialCapacity);
if (loadFactor <= 0) throw new IllegalArgumentException("loadFactor must be > 0: " + loadFactor);
this.loadFactor = loadFactor;
threshold = (int)(capacity * loadFactor);
mask = capacity - 1;
hashShift = 63 - Long.numberOfTrailingZeros(capacity);
stashCapacity = Math.max(3, (int)Math.ceil(Math.log(capacity)) * 2);
pushIterations = Math.max(Math.min(capacity, 8), (int)Math.sqrt(capacity) / 8);
keyTable = new long[capacity + stashCapacity];
valueTable = (V[])new Object[keyTable.length];
}
/** Creates a new map identical to the specified map. */
public LongMap (LongMap<? extends V> map) {
this(map.capacity, map.loadFactor);
stashSize = map.stashSize;
System.arraycopy(map.keyTable, 0, keyTable, 0, map.keyTable.length);
System.arraycopy(map.valueTable, 0, valueTable, 0, map.valueTable.length);
size = map.size;
zeroValue = map.zeroValue;
hasZeroValue = map.hasZeroValue;
}
public V put (long key, V value) {
if (key == 0) {
V oldValue = zeroValue;
zeroValue = value;
if (!hasZeroValue) {
hasZeroValue = true;
size++;
}
return oldValue;
}
long[] keyTable = this.keyTable;
// Check for existing keys.
int index1 = (int)(key & mask);
long key1 = keyTable[index1];
if (key1 == key) {
V oldValue = valueTable[index1];
valueTable[index1] = value;
return oldValue;
}
int index2 = hash2(key);
long key2 = keyTable[index2];
if (key2 == key) {
V oldValue = valueTable[index2];
valueTable[index2] = value;
return oldValue;
}
int index3 = hash3(key);
long key3 = keyTable[index3];
if (key3 == key) {
V oldValue = valueTable[index3];
valueTable[index3] = value;
return oldValue;
}
// Update key in the stash.
for (int i = capacity, n = i + stashSize; i < n; i++) {
if (keyTable[i] == key) {
V oldValue = valueTable[i];
valueTable[i] = value;
return oldValue;
}
}
// Check for empty buckets.
if (key1 == EMPTY) {
keyTable[index1] = key;
valueTable[index1] = value;
if (size++ >= threshold) resize(capacity << 1);
return null;
}
if (key2 == EMPTY) {
keyTable[index2] = key;
valueTable[index2] = value;
if (size++ >= threshold) resize(capacity << 1);
return null;
}
if (key3 == EMPTY) {
keyTable[index3] = key;
valueTable[index3] = value;
if (size++ >= threshold) resize(capacity << 1);
return null;
}
push(key, value, index1, key1, index2, key2, index3, key3);
return null;
}
public void putAll (LongMap<V> map) {
for (Entry<V> entry : map.entries())
put(entry.key, entry.value);
}
/** Skips checks for existing keys. */
private void putResize (long key, V value) {
if (key == 0) {
zeroValue = value;
hasZeroValue = true;
return;
}
// Check for empty buckets.
int index1 = (int)(key & mask);
long key1 = keyTable[index1];
if (key1 == EMPTY) {
keyTable[index1] = key;
valueTable[index1] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
int index2 = hash2(key);
long key2 = keyTable[index2];
if (key2 == EMPTY) {
keyTable[index2] = key;
valueTable[index2] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
int index3 = hash3(key);
long key3 = keyTable[index3];
if (key3 == EMPTY) {
keyTable[index3] = key;
valueTable[index3] = value;
if (size++ >= threshold) resize(capacity << 1);
return;
}
push(key, value, index1, key1, index2, key2, index3, key3);
}
static public RandomXS128 random = new RandomXS128();
private void push (long insertKey, V insertValue, int index1, long key1, int index2, long key2, int index3, long key3) {
long[] keyTable = this.keyTable;
V[] valueTable = this.valueTable;
int mask = this.mask;
// Push keys until an empty bucket is found.
long evictedKey;
V evictedValue;
int i = 0, pushIterations = this.pushIterations;
do {
// Replace the key and value for one of the hashes.
switch (/*MathUtils.random(2)*/random.nextInt(3)) {
case 0:
evictedKey = key1;
evictedValue = valueTable[index1];
keyTable[index1] = insertKey;
valueTable[index1] = insertValue;
break;
case 1:
evictedKey = key2;
evictedValue = valueTable[index2];
keyTable[index2] = insertKey;
valueTable[index2] = insertValue;
break;
default:
evictedKey = key3;
evictedValue = valueTable[index3];
keyTable[index3] = insertKey;
valueTable[index3] = insertValue;
break;
}
// If the evicted key hashes to an empty bucket, put it there and stop.
index1 = (int)(evictedKey & mask);
key1 = keyTable[index1];
if (key1 == EMPTY) {
keyTable[index1] = evictedKey;
valueTable[index1] = evictedValue;
if (size++ >= threshold) resize(capacity << 1);
return;
}
index2 = hash2(evictedKey);
key2 = keyTable[index2];
if (key2 == EMPTY) {
keyTable[index2] = evictedKey;
valueTable[index2] = evictedValue;
if (size++ >= threshold) resize(capacity << 1);
return;
}
index3 = hash3(evictedKey);
key3 = keyTable[index3];
if (key3 == EMPTY) {
keyTable[index3] = evictedKey;
valueTable[index3] = evictedValue;
if (size++ >= threshold) resize(capacity << 1);
return;
}
if (++i == pushIterations) break;
insertKey = evictedKey;
insertValue = evictedValue;
} while (true);
putStash(evictedKey, evictedValue);
}
private void putStash (long key, V value) {
if (stashSize == stashCapacity) {
// Too many pushes occurred and the stash is full, increase the table size.
resize(capacity << 1);
put(key, value);
return;
}
// Store key in the stash.
int index = capacity + stashSize;
keyTable[index] = key;
valueTable[index] = value;
stashSize++;
size++;
}
public V get (long key) {
if (key == 0) {
if (!hasZeroValue) return null;
return zeroValue;
}
int index = (int)(key & mask);
if (keyTable[index] != key) {
index = hash2(key);
if (keyTable[index] != key) {
index = hash3(key);
if (keyTable[index] != key) return getStash(key, null);
}
}
return valueTable[index];
}
public V get (long key, V defaultValue) {
if (key == 0) {
if (!hasZeroValue) return defaultValue;
return zeroValue;
}
int index = (int)(key & mask);
if (keyTable[index] != key) {
index = hash2(key);
if (keyTable[index] != key) {
index = hash3(key);
if (keyTable[index] != key) return getStash(key, defaultValue);
}
}
return valueTable[index];
}
private V getStash (long key, V defaultValue) {
long[] keyTable = this.keyTable;
for (int i = capacity, n = i + stashSize; i < n; i++)
if (keyTable[i] == key) return valueTable[i];
return defaultValue;
}
public V remove (long key) {
if (key == 0) {
if (!hasZeroValue) return null;
V oldValue = zeroValue;
zeroValue = null;
hasZeroValue = false;
size--;
return oldValue;
}
int index = (int)(key & mask);
if (keyTable[index] == key) {
keyTable[index] = EMPTY;
V oldValue = valueTable[index];
valueTable[index] = null;
size--;
return oldValue;
}
index = hash2(key);
if (keyTable[index] == key) {
keyTable[index] = EMPTY;
V oldValue = valueTable[index];
valueTable[index] = null;
size--;
return oldValue;
}
index = hash3(key);
if (keyTable[index] == key) {
keyTable[index] = EMPTY;
V oldValue = valueTable[index];
valueTable[index] = null;
size--;
return oldValue;
}
return removeStash(key);
}
V removeStash (long key) {
long[] keyTable = this.keyTable;
for (int i = capacity, n = i + stashSize; i < n; i++) {
if (keyTable[i] == key) {
V oldValue = valueTable[i];
removeStashIndex(i);
size--;
return oldValue;
}
}
return null;
}
void removeStashIndex (int index) {
// If the removed location was not last, move the last tuple to the removed location.
stashSize--;
int lastIndex = capacity + stashSize;
if (index < lastIndex) {
keyTable[index] = keyTable[lastIndex];
valueTable[index] = valueTable[lastIndex];
valueTable[lastIndex] = null;
} else
valueTable[index] = null;
}
/** Reduces the size of the backing arrays to be the specified capacity or less. If the capacity is already less, nothing is
* done. If the map contains more items than the specified capacity, the next highest power of two capacity is used instead. */
public void shrink (int maximumCapacity) {
if (maximumCapacity < 0) throw new IllegalArgumentException("maximumCapacity must be >= 0: " + maximumCapacity);
if (size > maximumCapacity) maximumCapacity = size;
if (capacity <= maximumCapacity) return;
maximumCapacity = /*MathUtils.*/nextPowerOfTwo(maximumCapacity);
resize(maximumCapacity);
}
/** Clears the map and reduces the size of the backing arrays to be the specified capacity if they are larger. */
public void clear (int maximumCapacity) {
if (capacity <= maximumCapacity) {
clear();
return;
}
zeroValue = null;
hasZeroValue = false;
size = 0;
resize(maximumCapacity);
}
public void clear () {
if (size == 0) return;
long[] keyTable = this.keyTable;
V[] valueTable = this.valueTable;
for (int i = capacity + stashSize; i-- > 0;) {
keyTable[i] = EMPTY;
valueTable[i] = null;
}
size = 0;
stashSize = 0;
zeroValue = null;
hasZeroValue = false;
}
/** Returns true if the specified value is in the map. Note this traverses the entire map and compares every value, which may be
* an expensive operation. */
public boolean containsValue (Object value, boolean identity) {
V[] valueTable = this.valueTable;
if (value == null) {
if (hasZeroValue && zeroValue == null) return true;
long[] keyTable = this.keyTable;
for (int i = capacity + stashSize; i-- > 0;)
if (keyTable[i] != EMPTY && valueTable[i] == null) return true;
} else if (identity) {
if (value == zeroValue) return true;
for (int i = capacity + stashSize; i-- > 0;)
if (valueTable[i] == value) return true;
} else {
if (hasZeroValue && value.equals(zeroValue)) return true;
for (int i = capacity + stashSize; i-- > 0;)
if (value.equals(valueTable[i])) return true;
}
return false;
}
public boolean containsKey (long key) {
if (key == 0) return hasZeroValue;
int index = (int)(key & mask);
if (keyTable[index] != key) {
index = hash2(key);
if (keyTable[index] != key) {
index = hash3(key);
if (keyTable[index] != key) return containsKeyStash(key);
}
}
return true;
}
private boolean containsKeyStash (long key) {
long[] keyTable = this.keyTable;
for (int i = capacity, n = i + stashSize; i < n; i++)
if (keyTable[i] == key) return true;
return false;
}
/** Returns the key for the specified value, or <tt>notFound</tt> if it is not in the map. Note this traverses the entire map
* and compares every value, which may be an expensive operation.
* @param identity If true, uses == to compare the specified value with values in the map. If false, uses
* {@link #equals(Object)}. */
public long findKey (Object value, boolean identity, long notFound) {
V[] valueTable = this.valueTable;
if (value == null) {
if (hasZeroValue && zeroValue == null) return 0;
long[] keyTable = this.keyTable;
for (int i = capacity + stashSize; i-- > 0;)
if (keyTable[i] != EMPTY && valueTable[i] == null) return keyTable[i];
} else if (identity) {
if (value == zeroValue) return 0;
for (int i = capacity + stashSize; i-- > 0;)
if (valueTable[i] == value) return keyTable[i];
} else {
if (hasZeroValue && value.equals(zeroValue)) return 0;
for (int i = capacity + stashSize; i-- > 0;)
if (value.equals(valueTable[i])) return keyTable[i];
}
return notFound;
}
/** Increases the size of the backing array to accommodate the specified number of additional items. Useful before adding many
* items to avoid multiple backing array resizes. */
public void ensureCapacity (int additionalCapacity) {
int sizeNeeded = size + additionalCapacity;
if (sizeNeeded >= threshold) resize(/*MathUtils.*/nextPowerOfTwo((int)(sizeNeeded / loadFactor)));
}
@SuppressWarnings("unchecked")
private void resize (int newSize) {
int oldEndIndex = capacity + stashSize;
capacity = newSize;
threshold = (int)(newSize * loadFactor);
mask = newSize - 1;
hashShift = 63 - Long.numberOfTrailingZeros(newSize);
stashCapacity = Math.max(3, (int)Math.ceil(Math.log(newSize)) * 2);
pushIterations = Math.max(Math.min(newSize, 8), (int)Math.sqrt(newSize) / 8);
long[] oldKeyTable = keyTable;
V[] oldValueTable = valueTable;
keyTable = new long[newSize + stashCapacity];
valueTable = (V[])new Object[newSize + stashCapacity];
int oldSize = size;
size = hasZeroValue ? 1 : 0;
stashSize = 0;
if (oldSize > 0) {
for (int i = 0; i < oldEndIndex; i++) {
long key = oldKeyTable[i];
if (key != EMPTY) putResize(key, oldValueTable[i]);
}
}
}
private int hash2 (long h) {
h *= PRIME2;
return (int)((h ^ h >>> hashShift) & mask);
}
private int hash3 (long h) {
h *= PRIME3;
return (int)((h ^ h >>> hashShift) & mask);
}
public String toString () {
if (size == 0) return "[]";
StringBuilder buffer = new StringBuilder(32);
buffer.append('[');
long[] keyTable = this.keyTable;
V[] valueTable = this.valueTable;
int i = keyTable.length;
while (i-- > 0) {
long key = keyTable[i];
if (key == EMPTY) continue;
buffer.append(key);
buffer.append('=');
buffer.append(valueTable[i]);
break;
}
while (i-- > 0) {
long key = keyTable[i];
if (key == EMPTY) continue;
buffer.append(", ");
buffer.append(key);
buffer.append('=');
buffer.append(valueTable[i]);
}
buffer.append(']');
return buffer.toString();
}
public Iterator<Entry<V>> iterator () {
return entries();
}
/** Returns an iterator for the entries in the map. Remove is supported. Note that the same iterator instance is returned each
* time this method is called. Use the {@link Entries} constructor for nested or multithreaded iteration. */
public Entries<V> entries () {
if (entries1 == null) {
entries1 = new Entries<V>(this);
entries2 = new Entries<V>(this);
}
if (!entries1.valid) {
entries1.reset();
entries1.valid = true;
entries2.valid = false;
return entries1;
}
entries2.reset();
entries2.valid = true;
entries1.valid = false;
return entries2;
}
// RoboVM note: Not needed
/** Returns an iterator for the values in the map. Remove is supported. Note that the same iterator instance is returned each
* time this method is called. Use the {@link Entries} constructor for nested or multithreaded iteration. */
/* public Values<V> values () {
if (values1 == null) {
values1 = new Values(this);
values2 = new Values(this);
}
if (!values1.valid) {
values1.reset();
values1.valid = true;
values2.valid = false;
return values1;
}
values2.reset();
values2.valid = true;
values1.valid = false;
return values2;
}*/
/** Returns an iterator for the keys in the map. Remove is supported. Note that the same iterator instance is returned each time
* this method is called. Use the {@link Entries} constructor for nested or multithreaded iteration. */
/* public Keys keys () {
if (keys1 == null) {
keys1 = new Keys(this);
keys2 = new Keys(this);
}
if (!keys1.valid) {
keys1.reset();
keys1.valid = true;
keys2.valid = false;
return keys1;
}
keys2.reset();
keys2.valid = true;
keys1.valid = false;
return keys2;
}*/
static public class Entry<V> {
public long key;
public V value;
public String toString () {
return key + "=" + value;
}
}
static private class MapIterator<V> {
static final int INDEX_ILLEGAL = -2;
static final int INDEX_ZERO = -1;
public boolean hasNext;
final LongMap<V> map;
int nextIndex, currentIndex;
boolean valid = true;
public MapIterator (LongMap<V> map) {
this.map = map;
reset();
}
public void reset () {
currentIndex = INDEX_ILLEGAL;
nextIndex = INDEX_ZERO;
if (map.hasZeroValue)
hasNext = true;
else
findNextIndex();
}
void findNextIndex () {
hasNext = false;
long[] keyTable = map.keyTable;
for (int n = map.capacity + map.stashSize; ++nextIndex < n;) {
if (keyTable[nextIndex] != EMPTY) {
hasNext = true;
break;
}
}
}
public void remove () {
if (currentIndex == INDEX_ZERO && map.hasZeroValue) {
map.zeroValue = null;
map.hasZeroValue = false;
} else if (currentIndex < 0) {
throw new IllegalStateException("next must be called before remove.");
} else if (currentIndex >= map.capacity) {
map.removeStashIndex(currentIndex);
nextIndex = currentIndex - 1;
findNextIndex();
} else {
map.keyTable[currentIndex] = EMPTY;
map.valueTable[currentIndex] = null;
}
currentIndex = INDEX_ILLEGAL;
map.size--;
}
}
static public class Entries<V> extends MapIterator<V> implements Iterable<Entry<V>>, Iterator<Entry<V>> {
private Entry<V> entry = new Entry<V>();
public Entries (LongMap<V> map) {
super(map);
}
/** Note the same entry instance is returned each time this method is called. */
public Entry<V> next () {
if (!hasNext) throw new NoSuchElementException();
if (!valid) throw new IllegalStateException("#iterator() cannot be used nested.");
long[] keyTable = map.keyTable;
if (nextIndex == INDEX_ZERO) {
entry.key = 0;
entry.value = map.zeroValue;
} else {
entry.key = keyTable[nextIndex];
entry.value = map.valueTable[nextIndex];
}
currentIndex = nextIndex;
findNextIndex();
return entry;
}
public boolean hasNext () {
if (!valid) throw new IllegalStateException("#iterator() cannot be used nested.");
return hasNext;
}
public Iterator<Entry<V>> iterator () {
return this;
}
public void remove () {
super.remove();
}
}
// RoboVM note: Not needed
/* static public class Values<V> extends MapIterator<V> implements Iterable<V>, Iterator<V> {
public Values (LongMap<V> map) {
super(map);
}
public boolean hasNext () {
if (!valid) throw new GdxRuntimeExceptionIllegalStateException("#iterator() cannot be used nested.");
return hasNext;
}
public V next () {
if (!hasNext) throw new NoSuchElementException();
if (!valid) throw new GdxRuntimeExceptionIllegalStateException("#iterator() cannot be used nested.");
V value;
if (nextIndex == INDEX_ZERO)
value = map.zeroValue;
else
value = map.valueTable[nextIndex];
currentIndex = nextIndex;
findNextIndex();
return value;
}
public Iterator<V> iterator () {
return this;
}
*//** Returns a new array containing the remaining values. *//*
public Array<V> toArray () {
Array array = new Array(true, map.size);
while (hasNext)
array.add(next());
return array;
}
public void remove () {
super.remove();
}
}*/
/* static public class Keys extends MapIterator {
public Keys (LongMap map) {
super(map);
}
public long next () {
if (!hasNext) throw new NoSuchElementException();
if (!valid) throw new GdxRuntimeExceptionIllegalStateException("#iterator() cannot be used nested.");
long key = nextIndex == INDEX_ZERO ? 0 : map.keyTable[nextIndex];
currentIndex = nextIndex;
findNextIndex();
return key;
}
*//** Returns a new array containing the remaining values. *//*
public LongArray toArray () {
LongArray array = new LongArray(true, map.size);
while (hasNext)
array.add(next());
return array;
}
}*/
}
/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* 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.
******************************************************************************/
//import java.util.Random;
/** This class implements the xorshift128+ algorithm that is a very fast, top-quality 64-bit pseudo-random number generator. The
* quality of this PRNG is much higher than {@link Random}'s, and its cycle length is 2<sup>128</sup> − 1, which
* is more than enough for any single-thread application. More details and algorithms can be found <a
* href="http://xorshift.di.unimi.it/">here</a>.
* <p>
* Instances of RandomXS128 are not thread-safe.
*
* @author Inferno
* @author davebaol */
@SuppressWarnings("serial")
class RandomXS128 extends java.util.Random {
/** Normalization constant for double. */
private static final double NORM_DOUBLE = 1.0 / (1L << 53);
/** Normalization constant for float. */
private static final double NORM_FLOAT = 1.0 / (1L << 24);
/** The first half of the internal state of this pseudo-random number generator. */
private long seed0;
/** The second half of the internal state of this pseudo-random number generator. */
private long seed1;
/** Creates a new random number generator. This constructor sets the seed of the random number generator to a value very likely
* to be distinct from any other invocation of this constructor.
* <p>
* This implementation creates a {@link Random} instance to generate the initial seed. */
public RandomXS128 () {
setSeed(new java.util.Random().nextLong());
}
/** Creates a new random number generator using a single {@code long} seed.
* @param seed the initial seed */
public RandomXS128 (long seed) {
setSeed(seed);
}
/** Creates a new random number generator using two {@code long} seeds.
* @param seed0 the first part of the initial seed
* @param seed1 the second part of the initial seed */
public RandomXS128 (long seed0, long seed1) {
setState(seed0, seed1);
}
/** Returns the next pseudo-random, uniformly distributed {@code long} value from this random number generator's sequence.
* <p>
* Subclasses should override this, as this is used by all other methods. */
@Override
public long nextLong () {
long s1 = this.seed0;
final long s0 = this.seed1;
this.seed0 = s0;
s1 ^= s1 << 23;
return (this.seed1 = (s1 ^ s0 ^ (s1 >>> 17) ^ (s0 >>> 26))) + s0;
}
/** This protected method is final because, contrary to the superclass, it's not used anymore by the other methods. */
@Override
protected final int next (int bits) {
return (int)(nextLong() & ((1L << bits) - 1));
}
/** Returns the next pseudo-random, uniformly distributed {@code int} value from this random number generator's sequence.
* <p>
* This implementation uses {@link #nextLong()} internally. */
@Override
public int nextInt () {
return (int)nextLong();
}
/** Returns a pseudo-random, uniformly distributed {@code int} value between 0 (inclusive) and the specified value (exclusive),
* drawn from this random number generator's sequence.
* <p>
* This implementation uses {@link #nextLong()} internally.
* @param n the positive bound on the random number to be returned.
* @return the next pseudo-random {@code int} value between {@code 0} (inclusive) and {@code n} (exclusive). */
@Override
public int nextInt (final int n) {
return (int)nextLong(n);
}
/** Returns a pseudo-random, uniformly distributed {@code long} value between 0 (inclusive) and the specified value (exclusive),
* drawn from this random number generator's sequence. The algorithm used to generate the value guarantees that the result is
* uniform, provided that the sequence of 64-bit values produced by this generator is.
* <p>
* This implementation uses {@link #nextLong()} internally.
* @param n the positive bound on the random number to be returned.
* @return the next pseudo-random {@code long} value between {@code 0} (inclusive) and {@code n} (exclusive). */
public long nextLong (final long n) {
if (n <= 0) throw new IllegalArgumentException("n must be positive");
for (;;) {
final long bits = nextLong() >>> 1;
final long value = bits % n;
if (bits - value + (n - 1) >= 0) return value;
}
}
/** Returns a pseudo-random, uniformly distributed {@code double} value between 0.0 and 1.0from this random number generator's
* sequence.
* <p>
* This implementation uses {@link #nextLong()} internally. */
@Override
public double nextDouble () {
return (nextLong() >>> 11) * NORM_DOUBLE;
}
/** Returns a pseudo-random, uniformly distributed {@code float} value between 0.0 and 1.0 from this random number generator's
* sequence.
* <p>
* This implementation uses {@link #nextLong()} internally. */
@Override
public float nextFloat () {
return (float)((nextLong() >>> 40) * NORM_FLOAT);
}
/** Returns a pseudo-random, uniformly distributed {@code boolean } value from this random number generator's sequence.
* <p>
* This implementation uses {@link #nextLong()} internally. */
@Override
public boolean nextBoolean () {
return (nextLong() & 1) != 0;
}
/** Generates random bytes and places them into a user-supplied byte array. The number of random bytes produced is equal to the
* length of the byte array.
* <p>
* This implementation uses {@link #nextLong()} internally. */
@Override
public void nextBytes (final byte[] bytes) {
int n = 0;
int i = bytes.length;
while (i != 0) {
n = i < 8 ? i : 8; // min(i, 8);
for (long bits = nextLong(); n-- != 0; bits >>= 8)
bytes[--i] = (byte)bits;
}
}
/** Sets the internal seed of this generator based on the given {@code long} value.
* <p>
* The given seed is passed twice through an hash function. This way, if the user passes a small value we avoid the short
* irregular transient associated with states having a very small number of bits set.
* @param seed a nonzero seed for this generator (if zero, the generator will be seeded with {@link Long#MIN_VALUE}). */
@Override
public void setSeed (final long seed) {
long seed0 = murmurHash3(seed == 0 ? Long.MIN_VALUE : seed);
setState(seed0, murmurHash3(seed0));
}
/** Sets the internal state of this generator.
* @param seed0 the first part of the internal state
* @param seed1 the second part of the internal state */
public void setState (final long seed0, final long seed1) {
this.seed0 = seed0;
this.seed1 = seed1;
}
private final static long murmurHash3 (long x) {
x ^= x >>> 33;
x *= 0xff51afd7ed558ccdL;
x ^= x >>> 33;
x *= 0xc4ceb9fe1a85ec53L;
x ^= x >>> 33;
return x;
}
}