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/*
* Copyright (C) 2002-2022 Sebastiano Vigna
*
* 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 it.unimi.dsi.fastutil.longs;
import static it.unimi.dsi.fastutil.BigArrays.copy;
import static it.unimi.dsi.fastutil.BigArrays.fill;
import static it.unimi.dsi.fastutil.BigArrays.set;
import it.unimi.dsi.fastutil.BigArrays;
import it.unimi.dsi.fastutil.Hash;
import it.unimi.dsi.fastutil.Size64;
import it.unimi.dsi.fastutil.HashCommon;
import static it.unimi.dsi.fastutil.HashCommon.bigArraySize;
import static it.unimi.dsi.fastutil.HashCommon.maxFill;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* A type-specific hash big set with with a fast, small-footprint implementation.
*
*
* Instances of this class use a hash table to represent a big set: the number of elements in the
* set is limited only by the amount of core memory. The table (backed by a
* {@linkplain it.unimi.dsi.fastutil.BigArrays big array}) is filled up to a specified load
* factor, and then doubled in size to accommodate new entries. If the table is emptied below
* one fourth of the load factor, it is halved in size; however, the table is never reduced
* to a size smaller than that at creation time: this approach makes it possible to create sets with
* a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover,
* halving is not performed when deleting entries from an iterator, as it would interfere with the
* iteration process.
*
*
* Note that {@link #clear()} does not modify the hash table size. Rather, a family of
* {@linkplain #trim() trimming methods} lets you control the size of the table; this is
* particularly useful if you reuse instances of this class.
*
*
* The methods of this class are about 30% slower than those of the corresponding non-big set.
*
* @see Hash
* @see HashCommon
*/
public class LongOpenHashBigSet extends AbstractLongSet implements java.io.Serializable, Cloneable, Hash, Size64 {
private static final long serialVersionUID = 0L;
private static final boolean ASSERTS = false;
/** The big array of keys. */
protected transient long[][] key;
/** The mask for wrapping a position counter. */
protected transient long mask;
/** The mask for wrapping a segment counter. */
protected transient int segmentMask;
/** The mask for wrapping a base counter. */
protected transient int baseMask;
/** Whether this set contains the null key. */
protected transient boolean containsNull;
/** The current table size (always a power of 2). */
protected transient long n;
/** Threshold after which we rehash. It must be the table size times {@link #f}. */
protected transient long maxFill;
/** We never resize below this threshold, which is the construction-time {#n}. */
protected final transient long minN;
/** The acceptable load factor. */
protected final float f;
/** Number of entries in the set. */
protected long size;
/** Initialises the mask values. */
private void initMasks() {
mask = n - 1;
/* Note that either we have more than one segment, and in this case all segments
* are BigArrays.SEGMENT_SIZE long, or we have exactly one segment whose length
* is a power of two. */
segmentMask = key[0].length - 1;
baseMask = key.length - 1;
}
/**
* Creates a new hash big set.
*
*
* The actual table size will be the least power of two greater than {@code expected}/{@code f}.
*
* @param expected the expected number of elements in the set.
* @param f the load factor.
*/
public LongOpenHashBigSet(final long expected, final float f) {
if (f <= 0 || f > 1) throw new IllegalArgumentException("Load factor must be greater than 0 and smaller than or equal to 1");
if (n < 0) throw new IllegalArgumentException("The expected number of elements must be nonnegative");
this.f = f;
minN = n = bigArraySize(expected, f);
maxFill = maxFill(n, f);
key = LongBigArrays.newBigArray(n);
initMasks();
}
/**
* Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
*
* @param expected the expected number of elements in the hash big set.
*/
public LongOpenHashBigSet(final long expected) {
this(expected, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash big set with initial expected {@link Hash#DEFAULT_INITIAL_SIZE} elements and
* {@link Hash#DEFAULT_LOAD_FACTOR} as load factor.
*/
public LongOpenHashBigSet() {
this(DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash big set copying a given collection.
*
* @param c a {@link Collection} to be copied into the new hash big set.
* @param f the load factor.
*/
public LongOpenHashBigSet(final Collection c, final float f) {
this(Size64.sizeOf(c), f);
addAll(c);
}
/**
* Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor copying a given
* collection.
*
* @param c a {@link Collection} to be copied into the new hash big set.
*/
public LongOpenHashBigSet(final Collection c) {
this(c, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash big set copying a given type-specific collection.
*
* @param c a type-specific collection to be copied into the new hash big set.
* @param f the load factor.
*/
public LongOpenHashBigSet(final LongCollection c, final float f) {
this(Size64.sizeOf(c), f);
addAll(c);
}
/**
* Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor copying a given
* type-specific collection.
*
* @param c a type-specific collection to be copied into the new hash big set.
*/
public LongOpenHashBigSet(final LongCollection c) {
this(c, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash big set using elements provided by a type-specific iterator.
*
* @param i a type-specific iterator whose elements will fill the new hash big set.
* @param f the load factor.
*/
public LongOpenHashBigSet(final LongIterator i, final float f) {
this(DEFAULT_INITIAL_SIZE, f);
while (i.hasNext()) add(i.nextLong());
}
/**
* Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor using elements
* provided by a type-specific iterator.
*
* @param i a type-specific iterator whose elements will fill the new hash big set.
*/
public LongOpenHashBigSet(final LongIterator i) {
this(i, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash big set using elements provided by an iterator.
*
* @param i an iterator whose elements will fill the new hash big set.
* @param f the load factor.
*/
public LongOpenHashBigSet(final Iterator i, final float f) {
this(LongIterators.asLongIterator(i), f);
}
/**
* Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor using elements
* provided by an iterator.
*
* @param i an iterator whose elements will fill the new hash big set.
*/
public LongOpenHashBigSet(final Iterator i) {
this(LongIterators.asLongIterator(i));
}
/**
* Creates a new hash big set and fills it with the elements of a given array.
*
* @param a an array whose elements will be used to fill the new hash big set.
* @param offset the first element to use.
* @param length the number of elements to use.
* @param f the load factor.
*/
public LongOpenHashBigSet(final long[] a, final int offset, final int length, final float f) {
this(length < 0 ? 0 : length, f);
LongArrays.ensureOffsetLength(a, offset, length);
for (int i = 0; i < length; i++) add(a[offset + i]);
}
/**
* Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor and fills it with
* the elements of a given array.
*
* @param a an array whose elements will be used to fill the new hash big set.
* @param offset the first element to use.
* @param length the number of elements to use.
*/
public LongOpenHashBigSet(final long[] a, final int offset, final int length) {
this(a, offset, length, DEFAULT_LOAD_FACTOR);
}
/**
* Creates a new hash big set copying the elements of an array.
*
* @param a an array to be copied into the new hash big set.
* @param f the load factor.
*/
public LongOpenHashBigSet(final long[] a, final float f) {
this(a, 0, a.length, f);
}
/**
* Creates a new hash big set with {@link Hash#DEFAULT_LOAD_FACTOR} as load factor copying the
* elements of an array.
*
* @param a an array to be copied into the new hash big set.
*/
public LongOpenHashBigSet(final long[] a) {
this(a, DEFAULT_LOAD_FACTOR);
}
/**
* Collects the result of a primitive {@code Stream} into a new big hash set.
*
*
* This method performs a terminal operation on the given {@code Stream}
*
* @apiNote Taking a primitive stream instead of returning something like a
* {@link java.util.stream.Collector Collector} is necessary because there is no primitive
* {@code Collector} equivalent in the Java API.
*/
public static LongOpenHashBigSet toBigSet(java.util.stream.LongStream stream) {
return stream.collect(LongOpenHashBigSet::new, LongOpenHashBigSet::add, LongOpenHashBigSet::addAll);
}
/**
* Collects the result of a primitive {@code Stream} into a new big hash set.
*
*
* This method performs a terminal operation on the given {@code Stream}
*
* @apiNote Taking a primitive stream instead returning something like a
* {@link java.util.stream.Collector Collector} is necessary because there is no primitive
* {@code Collector} equivalent in the Java API.
*/
public static LongOpenHashBigSet toBigSetWithExpectedSize(java.util.stream.LongStream stream, long expectedSize) {
return stream.collect(() -> new LongOpenHashBigSet(expectedSize), LongOpenHashBigSet::add, LongOpenHashBigSet::addAll);
}
private long realSize() {
return containsNull ? size - 1 : size;
}
private void ensureCapacity(final long capacity) {
final long needed = bigArraySize(capacity, f);
if (needed > n) rehash(needed);
}
@Override
public boolean addAll(Collection c) {
final long size = Size64.sizeOf(c);
// The resulting collection will be at least c.size() big
if (f <= .5) ensureCapacity(size); // The resulting collection will be sized for c.size() elements
else ensureCapacity(size64() + size); // The resulting collection will be sized for size() + c.size() elements
return super.addAll(c);
}
@Override
public boolean addAll(LongCollection c) {
final long size = Size64.sizeOf(c);
if (f <= .5) ensureCapacity(size); // The resulting collection will be size for c.size() elements
else ensureCapacity(size64() + size); // The resulting collection will be sized for size() + c.size() elements
return super.addAll(c);
}
@Override
public boolean add(final long k) {
int displ, base;
if (((k) == (0))) {
if (containsNull) return false;
containsNull = true;
} else {
long curr;
final long[][] key = this.key;
final long h = it.unimi.dsi.fastutil.HashCommon.mix((k));
// The starting point.
if (!((curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)]) == (0))) {
if (((curr) == (k))) return false;
while (!((curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ]) == (0))) if (((curr) == (k))) return false;
}
key[base][displ] = k;
}
if (size++ >= maxFill) rehash(2 * n);
if (ASSERTS) checkTable();
return true;
}
/**
* Shifts left entries with the specified hash code, starting at the specified position, and empties
* the resulting free entry.
*
* @param pos a starting position.
*/
protected final void shiftKeys(long pos) {
// Shift entries with the same hash.
long last, slot;
final long[][] key = this.key;
for (;;) {
pos = ((last = pos) + 1) & mask;
for (;;) {
if (((BigArrays.get(key, pos)) == (0))) {
set(key, last, (0));
return;
}
slot = it.unimi.dsi.fastutil.HashCommon.mix((BigArrays.get(key, pos))) & mask;
if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos) break;
pos = (pos + 1) & mask;
}
set(key, last, BigArrays.get(key, pos));
}
}
private boolean removeEntry(final int base, final int displ) {
size--;
shiftKeys(base * (long)BigArrays.SEGMENT_SIZE + displ);
if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE) rehash(n / 2);
return true;
}
private boolean removeNullEntry() {
containsNull = false;
size--;
if (n > minN && size < maxFill / 4 && n > DEFAULT_INITIAL_SIZE) rehash(n / 2);
return true;
}
@Override
public boolean remove(final long k) {
if (((k) == (0))) {
if (containsNull) return removeNullEntry();
return false;
}
long curr;
final long[][] key = this.key;
final long h = it.unimi.dsi.fastutil.HashCommon.mix((k));
int displ, base;
// The starting point.
if (((curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)]) == (0))) return false;
if (((curr) == (k))) return removeEntry(base, displ);
while (true) {
if (((curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ]) == (0))) return false;
if (((curr) == (k))) return removeEntry(base, displ);
}
}
@Override
public boolean contains(final long k) {
if (((k) == (0))) return containsNull;
long curr;
final long[][] key = this.key;
final long h = it.unimi.dsi.fastutil.HashCommon.mix((k));
int displ, base;
// The starting point.
if (((curr = key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)]) == (0))) return false;
if (((curr) == (k))) return true;
while (true) {
if (((curr = key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ]) == (0))) return false;
if (((curr) == (k))) return true;
}
}
/* Removes all elements from this set.
*
*/
/**
* {@inheritDoc}
*
*
* To increase object reuse, this method does not change the table size. If you want to reduce the
* table size, you must use {@link #trim(long)}.
*/
@Override
public void clear() {
if (size == 0) return;
size = 0;
containsNull = false;
fill(key, (0));
}
/** An iterator over a hash big set. */
private class SetIterator implements LongIterator {
/**
* The base of the last entry returned, if positive or zero; initially, the number of components of
* the key array. If negative, the last element returned was that of index {@code - base - 1} from
* the {@link #wrapped} list.
*/
int base = key.length;
/** The displacement of the last entry returned; initially, zero. */
int displ;
/**
* The index of the last entry that has been returned (or {@link Long#MIN_VALUE} if {@link #base} is
* negative). It is -1 if either we did not return an entry yet, or the last returned entry has been
* removed.
*/
long last = -1;
/** A downward counter measuring how many entries must still be returned. */
long c = size;
/** A boolean telling us whether we should return the null key. */
boolean mustReturnNull = LongOpenHashBigSet.this.containsNull;
/**
* A lazily allocated list containing elements that have wrapped around the table because of
* removals.
*/
LongArrayList wrapped;
@Override
public boolean hasNext() {
return c != 0;
}
@Override
public long nextLong() {
if (!hasNext()) throw new NoSuchElementException();
c--;
if (mustReturnNull) {
mustReturnNull = false;
last = n;
return (0);
}
final long[][] key = LongOpenHashBigSet.this.key;
for (;;) {
if (displ == 0 && base <= 0) {
// We are just enumerating elements from the wrapped list.
last = Long.MIN_VALUE;
return wrapped.getLong(-(--base) - 1);
}
if (displ-- == 0) displ = key[--base].length - 1;
final long k = key[base][displ];
if (!((k) == (0))) {
last = base * (long)BigArrays.SEGMENT_SIZE + displ;
return k;
}
}
}
/**
* Shifts left entries with the specified hash code, starting at the specified position, and empties
* the resulting free entry.
*
* @param pos a starting position.
*/
private final void shiftKeys(long pos) {
// Shift entries with the same hash.
long last, slot;
long curr;
final long[][] key = LongOpenHashBigSet.this.key;
for (;;) {
pos = ((last = pos) + 1) & mask;
for (;;) {
if (((curr = BigArrays.get(key, pos)) == (0))) {
set(key, last, (0));
return;
}
slot = it.unimi.dsi.fastutil.HashCommon.mix((curr)) & mask;
if (last <= pos ? last >= slot || slot > pos : last >= slot && slot > pos) break;
pos = (pos + 1) & mask;
}
if (pos < last) { // Wrapped entry.
if (wrapped == null) wrapped = new LongArrayList();
wrapped.add(BigArrays.get(key, pos));
}
set(key, last, curr);
}
}
@Override
public void remove() {
if (last == -1) throw new IllegalStateException();
if (last == n) LongOpenHashBigSet.this.containsNull = false;
else if (base >= 0) shiftKeys(last);
else {
// We're removing wrapped entries.
LongOpenHashBigSet.this.remove(wrapped.getLong(-base - 1));
last = -1; // Note that we must not decrement size
return;
}
size--;
last = -1; // You can no longer remove this entry.
if (ASSERTS) checkTable();
}
}
@Override
public LongIterator iterator() {
return new SetIterator();
}
private class SetSpliterator implements LongSpliterator {
/* For the sake of keeping things at least somewhat simple
* (aka. my sanity), the spliterator will NOT handle the indexing
* of the subarrays directly, like iterator does. Instead, it will
* delegate to BigArrays and have only a single, unified index it
* will fence on. This is probably less effecient, but it avoids having
* to track what it means to split on two sets of indexes.
* This may change in the future if the performance hit high.
*/
private static final int POST_SPLIT_CHARACTERISTICS = LongSpliterators.SET_SPLITERATOR_CHARACTERISTICS & ~java.util.Spliterator.SIZED;
/** The index (which bucket) of the next item to give to the action. */
long pos = 0;
/** The maximum bucket (exclusive) to iterate to */
long max = n;
/** An upwards counter counting how many we have given */
long c = 0;
/** A boolean telling us whether we should return the null key. */
boolean mustReturnNull = LongOpenHashBigSet.this.containsNull;
boolean hasSplit = false;
SetSpliterator() {
}
SetSpliterator(long pos, long max, boolean mustReturnNull, boolean hasSplit) {
this.pos = pos;
this.max = max;
this.mustReturnNull = mustReturnNull;
this.hasSplit = hasSplit;
}
@Override
public boolean tryAdvance(final java.util.function.LongConsumer action) {
if (mustReturnNull) {
mustReturnNull = false;
++c;
action.accept((0));
return true;
}
final long key[][] = LongOpenHashBigSet.this.key;
while (pos < max) {
long gotten = BigArrays.get(key, pos);
if (!((gotten) == (0))) {
++c;
++pos;
action.accept(gotten);
return true;
} else {
++pos;
}
}
return false;
}
@Override
public void forEachRemaining(final java.util.function.LongConsumer action) {
if (mustReturnNull) {
mustReturnNull = false;
action.accept((0));
++c;
}
final long key[][] = LongOpenHashBigSet.this.key;
while (pos < max) {
long gotten = BigArrays.get(key, pos);
if (!((gotten) == (0))) {
action.accept(gotten);
++c;
}
++pos;
}
}
@Override
public int characteristics() {
return hasSplit ? POST_SPLIT_CHARACTERISTICS : LongSpliterators.SET_SPLITERATOR_CHARACTERISTICS;
}
@Override
public long estimateSize() {
if (!hasSplit) {
// Root spliterator; we know how many are remaining.
return size - c;
} else {
// After we split, we can no longer know exactly how many we have (or at least not efficiently).
// (size / n) * (max - pos) aka currentTableDensity * numberOfBucketsLeft seems like a good
// estimate.
return Math.min(size - c, (long)(((double)realSize() / n) * (max - pos)) + (mustReturnNull ? 1 : 0));
}
}
@Override
public SetSpliterator trySplit() {
if (pos >= max - 1) return null;
long retLen = (max - pos) >> 1;
if (retLen <= 1) return null;
long myNewPos = pos + retLen;
// Align to an outer array boundary if possible
// We add/subtract one to the bounds to ensure the new pos will always shrink the range
myNewPos = BigArrays.nearestSegmentStart(myNewPos, pos + 1, max - 1);
long retPos = pos;
long retMax = myNewPos;
// Since null is returned first, and the convention is that the returned split is the prefix of
// elements,
// the split will take care of returning null (if needed), and we won't return it anymore.
SetSpliterator split = new SetSpliterator(retPos, retMax, mustReturnNull, true);
this.pos = myNewPos;
this.mustReturnNull = false;
this.hasSplit = true;
return split;
}
@Override
public long skip(long n) {
if (n < 0) throw new IllegalArgumentException("Argument must be nonnegative: " + n);
if (n == 0) return 0;
long skipped = 0;
if (mustReturnNull) {
mustReturnNull = false;
++skipped;
--n;
}
final long key[][] = LongOpenHashBigSet.this.key;
while (pos < max && n > 0) {
if (!((BigArrays.get(key, pos++)) == (0))) {
++skipped;
--n;
}
}
return skipped;
}
}
@Override
public LongSpliterator spliterator() {
return new SetSpliterator();
}
@Override
public void forEach(final java.util.function.LongConsumer action) {
if (containsNull) {
action.accept((0));
}
long pos = 0;
final long max = n;
final long key[][] = this.key;
while (pos < max) {
long gotten = BigArrays.get(key, pos++);
if (!((gotten) == (0))) {
action.accept(gotten);
}
}
}
/**
* Rehashes this set, making the table as small as possible.
*
*
* This method rehashes the table to the smallest size satisfying the load factor. It can be used
* when the set will not be changed anymore, so to optimize access speed and size.
*
*
* If the table size is already the minimum possible, this method does nothing.
*
* @return true if there was enough memory to trim the set.
* @see #trim(long)
*/
public boolean trim() {
return trim(size);
}
/**
* Rehashes this set if the table is too large.
*
*
* Let N be the smallest table size that can hold max(n,{@link #size64()})
* entries, still satisfying the load factor. If the current table size is smaller than or equal to
* N, this method does nothing. Otherwise, it rehashes this set in a table of size
* N.
*
*
* This method is useful when reusing sets. {@linkplain #clear() Clearing a set} leaves the table
* size untouched. If you are reusing a set many times, you can call this method with a typical size
* to avoid keeping around a very large table just because of a few large transient sets.
*
* @param n the threshold for the trimming.
* @return true if there was enough memory to trim the set.
* @see #trim()
*/
public boolean trim(final long n) {
final long l = bigArraySize(n, f);
if (l >= this.n || size > maxFill(l, f)) return true;
try {
rehash(l);
} catch (OutOfMemoryError cantDoIt) {
return false;
}
return true;
}
/**
* Resizes the set.
*
*
* This method implements the basic rehashing strategy, and may be overriden by subclasses
* implementing different rehashing strategies (e.g., disk-based rehashing). However, you should not
* override this method unless you understand the internal workings of this class.
*
* @param newN the new size
*/
protected void rehash(final long newN) {
final long key[][] = this.key;
final long newKey[][] = LongBigArrays.newBigArray(newN);
final long mask = newN - 1; // Note that this is used by the hashing macro
final int newSegmentMask = newKey[0].length - 1;
final int newBaseMask = newKey.length - 1;
int base = 0, displ = 0, b, d;
long h;
long k;
for (long i = realSize(); i-- != 0;) {
while (((key[base][displ]) == (0))) base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));
k = key[base][displ];
h = it.unimi.dsi.fastutil.HashCommon.mix((k));
// The starting point.
if (!((newKey[b = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][d = (int)(h & newSegmentMask)]) == (0))) while (!((newKey[b = (b + ((d = (d + 1) & newSegmentMask) == 0 ? 1 : 0)) & newBaseMask][d]) == (0)));
newKey[b][d] = k;
base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));
}
this.n = newN;
this.key = newKey;
initMasks();
maxFill = maxFill(n, f);
}
@Deprecated
@Override
public int size() {
return (int)Math.min(Integer.MAX_VALUE, size);
}
@Override
public long size64() {
return size;
}
@Override
public boolean isEmpty() {
return size == 0;
}
/**
* Returns a deep copy of this big set.
*
*
* This method performs a deep copy of this big hash set; the data stored in the set, however, is
* not cloned. Note that this makes a difference only for object keys.
*
* @return a deep copy of this big set.
*/
@Override
public LongOpenHashBigSet clone() {
LongOpenHashBigSet c;
try {
c = (LongOpenHashBigSet)super.clone();
} catch (CloneNotSupportedException cantHappen) {
throw new InternalError();
}
c.key = copy(key);
c.containsNull = containsNull;
return c;
}
/**
* Returns a hash code for this set.
*
* This method overrides the generic method provided by the superclass. Since {@code equals()} is
* not overriden, it is important that the value returned by this method is the same value as the
* one returned by the overriden method.
*
* @return a hash code for this set.
*/
@Override
public int hashCode() {
final long key[][] = this.key;
int h = 0, base = 0, displ = 0;
for (long j = realSize(); j-- != 0;) {
while (((key[base][displ]) == (0))) base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));
h += it.unimi.dsi.fastutil.HashCommon.long2int(key[base][displ]);
base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0));
}
return h;
}
private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
final LongIterator i = iterator();
s.defaultWriteObject();
for (long j = size; j-- != 0;) s.writeLong(i.nextLong());
}
private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
n = bigArraySize(size, f);
maxFill = maxFill(n, f);
final long[][] key = this.key = LongBigArrays.newBigArray(n);
initMasks();
long h;
long k;
int base, displ;
for (long i = size; i-- != 0;) {
k = s.readLong();
if (((k) == (0))) containsNull = true;
else {
h = it.unimi.dsi.fastutil.HashCommon.mix((k));
if (!((key[base = (int)((h & mask) >>> BigArrays.SEGMENT_SHIFT)][displ = (int)(h & segmentMask)]) == (0))) while (!((key[base = (base + ((displ = (displ + 1) & segmentMask) == 0 ? 1 : 0)) & baseMask][displ]) == (0)));
key[base][displ] = k;
}
}
if (ASSERTS) checkTable();
}
private void checkTable() {
}
}