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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you 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.apache.calcite.util;
import org.apache.calcite.linq4j.Linq4j;
import org.apache.calcite.runtime.Utilities;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Ordering;
import java.io.Serializable;
import java.nio.LongBuffer;
import java.util.AbstractList;
import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import javax.annotation.Nonnull;
/**
* An immutable list of bits.
*/
public class ImmutableBitSet
implements Iterable, Serializable, Comparable {
/** Compares bit sets topologically, so that enclosing bit sets come first,
* using natural ordering to break ties. */
public static final Comparator COMPARATOR = (o1, o2) -> {
if (o1.equals(o2)) {
return 0;
}
if (o1.contains(o2)) {
return -1;
}
if (o2.contains(o1)) {
return 1;
}
return o1.compareTo(o2);
};
public static final Ordering ORDERING =
Ordering.from(COMPARATOR);
// BitSets are packed into arrays of "words." Currently a word is
// a long, which consists of 64 bits, requiring 6 address bits.
// The choice of word size is determined purely by performance concerns.
private static final int ADDRESS_BITS_PER_WORD = 6;
private static final int BITS_PER_WORD = 1 << ADDRESS_BITS_PER_WORD;
/* Used to shift left or right for a partial word mask */
private static final long WORD_MASK = 0xffffffffffffffffL;
private static final long[] EMPTY_LONGS = new long[0];
private static final ImmutableBitSet EMPTY =
new ImmutableBitSet(EMPTY_LONGS);
@SuppressWarnings("Guava")
@Deprecated // to be removed before 2.0
public static final
com.google.common.base.Function
FROM_BIT_SET = ImmutableBitSet::fromBitSet;
private final long[] words;
/** Private constructor. Does not copy the array. */
private ImmutableBitSet(long[] words) {
this.words = words;
assert words.length == 0
? words == EMPTY_LONGS
: words[words.length - 1] != 0L;
}
/** Creates an ImmutableBitSet with no bits. */
public static ImmutableBitSet of() {
return EMPTY;
}
public static ImmutableBitSet of(int... bits) {
int max = -1;
for (int bit : bits) {
max = Math.max(bit, max);
}
if (max == -1) {
return EMPTY;
}
long[] words = new long[wordIndex(max) + 1];
for (int bit : bits) {
int wordIndex = wordIndex(bit);
words[wordIndex] |= 1L << bit;
}
return new ImmutableBitSet(words);
}
public static ImmutableBitSet of(Iterable bits) {
if (bits instanceof ImmutableBitSet) {
return (ImmutableBitSet) bits;
}
int max = -1;
for (int bit : bits) {
max = Math.max(bit, max);
}
if (max == -1) {
return EMPTY;
}
long[] words = new long[wordIndex(max) + 1];
for (int bit : bits) {
int wordIndex = wordIndex(bit);
words[wordIndex] |= 1L << bit;
}
return new ImmutableBitSet(words);
}
/**
* Creates an ImmutableBitSet with given bits set.
*
* For example, of(ImmutableIntList.of(0, 3)) returns a bit
* set with bits {0, 3} set.
*
* @param bits Collection of bits to set
* @return Bit set
*/
public static ImmutableBitSet of(ImmutableIntList bits) {
return builder().addAll(bits).build();
}
/**
* Returns a new immutable bit set containing all the bits in the given long
* array.
*
*
More precisely,
*
*
{@code ImmutableBitSet.valueOf(longs).get(n)
* == ((longs[n/64] & (1L<<(n%64))) != 0)}
*
* for all {@code n < 64 * longs.length}.
*
*
This method is equivalent to
* {@code ImmutableBitSet.valueOf(LongBuffer.wrap(longs))}.
*
* @param longs a long array containing a little-endian representation
* of a sequence of bits to be used as the initial bits of the
* new bit set
* @return a {@code ImmutableBitSet} containing all the bits in the long
* array
*/
public static ImmutableBitSet valueOf(long... longs) {
int n = longs.length;
while (n > 0 && longs[n - 1] == 0) {
--n;
}
if (n == 0) {
return EMPTY;
}
return new ImmutableBitSet(Arrays.copyOf(longs, n));
}
/**
* Returns a new immutable bit set containing all the bits in the given long
* buffer.
*/
public static ImmutableBitSet valueOf(LongBuffer longs) {
longs = longs.slice();
int n = longs.remaining();
while (n > 0 && longs.get(n - 1) == 0) {
--n;
}
if (n == 0) {
return EMPTY;
}
long[] words = new long[n];
longs.get(words);
return new ImmutableBitSet(words);
}
/**
* Returns a new immutable bit set containing all the bits in the given
* {@link BitSet}.
*/
public static ImmutableBitSet fromBitSet(BitSet input) {
return ImmutableBitSet.of(BitSets.toIter(input));
}
/**
* Creates an ImmutableBitSet with bits from {@code fromIndex} (inclusive) to
* specified {@code toIndex} (exclusive) set to {@code true}.
*
*
For example, {@code range(0, 3)} returns a bit set with bits
* {0, 1, 2} set.
*
* @param fromIndex Index of the first bit to be set.
* @param toIndex Index after the last bit to be set.
* @return Bit set
*/
public static ImmutableBitSet range(int fromIndex, int toIndex) {
if (fromIndex > toIndex) {
throw new IllegalArgumentException();
}
if (toIndex < 0) {
throw new IllegalArgumentException();
}
if (fromIndex == toIndex) {
return EMPTY;
}
int startWordIndex = wordIndex(fromIndex);
int endWordIndex = wordIndex(toIndex - 1);
long[] words = new long[endWordIndex + 1];
long firstWordMask = WORD_MASK << fromIndex;
long lastWordMask = WORD_MASK >>> -toIndex;
if (startWordIndex == endWordIndex) {
// One word
words[startWordIndex] |= firstWordMask & lastWordMask;
} else {
// First word, middle words, last word
words[startWordIndex] |= firstWordMask;
for (int i = startWordIndex + 1; i < endWordIndex; i++) {
words[i] = WORD_MASK;
}
words[endWordIndex] |= lastWordMask;
}
return new ImmutableBitSet(words);
}
/** Creates an ImmutableBitSet with bits between 0 and {@code toIndex} set. */
public static ImmutableBitSet range(int toIndex) {
return range(0, toIndex);
}
/**
* Given a bit index, return word index containing it.
*/
private static int wordIndex(int bitIndex) {
return bitIndex >> ADDRESS_BITS_PER_WORD;
}
/** Computes the power set (set of all sets) of this bit set. */
public Iterable powerSet() {
List> singletons = new ArrayList<>();
for (int bit : this) {
singletons.add(
ImmutableList.of(ImmutableBitSet.of(), ImmutableBitSet.of(bit)));
}
return Iterables.transform(Linq4j.product(singletons),
ImmutableBitSet::union);
}
/**
* Returns the value of the bit with the specified index. The value
* is {@code true} if the bit with the index {@code bitIndex}
* is currently set in this {@code ImmutableBitSet}; otherwise, the result
* is {@code false}.
*
* @param bitIndex the bit index
* @return the value of the bit with the specified index
* @throws IndexOutOfBoundsException if the specified index is negative
*/
public boolean get(int bitIndex) {
if (bitIndex < 0) {
throw new IndexOutOfBoundsException("bitIndex < 0: " + bitIndex);
}
int wordIndex = wordIndex(bitIndex);
return (wordIndex < words.length)
&& ((words[wordIndex] & (1L << bitIndex)) != 0);
}
/**
* Returns a new {@code ImmutableBitSet}
* composed of bits from this {@code ImmutableBitSet}
* from {@code fromIndex} (inclusive) to {@code toIndex} (exclusive).
*
* @param fromIndex index of the first bit to include
* @param toIndex index after the last bit to include
* @return a new {@code ImmutableBitSet} from a range of
* this {@code ImmutableBitSet}
* @throws IndexOutOfBoundsException if {@code fromIndex} is negative,
* or {@code toIndex} is negative, or {@code fromIndex} is
* larger than {@code toIndex}
*/
public ImmutableBitSet get(int fromIndex, int toIndex) {
checkRange(fromIndex, toIndex);
final Builder builder = builder();
for (int i = nextSetBit(fromIndex); i >= 0 && i < toIndex;
i = nextSetBit(i + 1)) {
builder.set(i);
}
return builder.build();
}
/**
* Checks that fromIndex ... toIndex is a valid range of bit indices.
*/
private static void checkRange(int fromIndex, int toIndex) {
if (fromIndex < 0) {
throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex);
}
if (toIndex < 0) {
throw new IndexOutOfBoundsException("toIndex < 0: " + toIndex);
}
if (fromIndex > toIndex) {
throw new IndexOutOfBoundsException("fromIndex: " + fromIndex
+ " > toIndex: " + toIndex);
}
}
/**
* Returns a string representation of this bit set. For every index
* for which this {@code BitSet} contains a bit in the set
* state, the decimal representation of that index is included in
* the result. Such indices are listed in order from lowest to
* highest, separated by ", " (a comma and a space) and
* surrounded by braces, resulting in the usual mathematical
* notation for a set of integers.
*
* Example:
*
* BitSet drPepper = new BitSet();
* Now {@code drPepper.toString()} returns "{@code {}}".
*
* drPepper.set(2);
* Now {@code drPepper.toString()} returns "{@code {2}}".
*
* drPepper.set(4);
* drPepper.set(10);
* Now {@code drPepper.toString()} returns "{@code {2, 4, 10}}".
*
* @return a string representation of this bit set
*/
public String toString() {
int numBits = words.length * BITS_PER_WORD;
StringBuilder b = new StringBuilder(6 * numBits + 2);
b.append('{');
int i = nextSetBit(0);
if (i != -1) {
b.append(i);
for (i = nextSetBit(i + 1); i >= 0; i = nextSetBit(i + 1)) {
int endOfRun = nextClearBit(i);
do {
b.append(", ").append(i);
}
while (++i < endOfRun);
}
}
b.append('}');
return b.toString();
}
/**
* Returns true if the specified {@code ImmutableBitSet} has any bits set to
* {@code true} that are also set to {@code true} in this
* {@code ImmutableBitSet}.
*
* @param set {@code ImmutableBitSet} to intersect with
* @return boolean indicating whether this {@code ImmutableBitSet} intersects
* the specified {@code ImmutableBitSet}
*/
public boolean intersects(ImmutableBitSet set) {
for (int i = Math.min(words.length, set.words.length) - 1; i >= 0; i--) {
if ((words[i] & set.words[i]) != 0) {
return true;
}
}
return false;
}
/** Returns the number of bits set to {@code true} in this
* {@code ImmutableBitSet}.
*
* @see #size() */
public int cardinality() {
return countBits(words);
}
private static int countBits(long[] words) {
int sum = 0;
for (long word : words) {
sum += Long.bitCount(word);
}
return sum;
}
/**
* Returns the hash code value for this bit set. The hash code
* depends only on which bits are set within this {@code ImmutableBitSet}.
*
* The hash code is defined using the same calculation as
* {@link java.util.BitSet#hashCode()}.
*
* @return the hash code value for this bit set
*/
public int hashCode() {
long h = 1234;
for (int i = words.length; --i >= 0;) {
h ^= words[i] * (i + 1);
}
return (int) ((h >> 32) ^ h);
}
/**
* Returns the number of bits of space actually in use by this
* {@code ImmutableBitSet} to represent bit values.
* The maximum element in the set is the size - 1st element.
*
* @return the number of bits currently in this bit set
*
* @see #cardinality()
*/
public int size() {
return words.length * BITS_PER_WORD;
}
/**
* Compares this object against the specified object.
* The result is {@code true} if and only if the argument is
* not {@code null} and is a {@code ImmutableBitSet} object that has
* exactly the same set of bits set to {@code true} as this bit
* set.
*
* @param obj the object to compare with
* @return {@code true} if the objects are the same;
* {@code false} otherwise
* @see #size()
*/
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof ImmutableBitSet)) {
return false;
}
ImmutableBitSet set = (ImmutableBitSet) obj;
return Arrays.equals(words, set.words);
}
/** Compares this ImmutableBitSet with another, using a lexicographic
* ordering.
*
*
Bit sets {@code (), (0), (0, 1), (0, 1, 3), (1), (2, 3)} are in sorted
* order.
*/
public int compareTo(@Nonnull ImmutableBitSet o) {
int i = 0;
for (;;) {
int n0 = nextSetBit(i);
int n1 = o.nextSetBit(i);
int c = Utilities.compare(n0, n1);
if (c != 0 || n0 < 0) {
return c;
}
i = n0 + 1;
}
}
/**
* Returns the index of the first bit that is set to {@code true}
* that occurs on or after the specified starting index. If no such
* bit exists then {@code -1} is returned.
*
* Based upon {@link BitSet#nextSetBit}.
*
* @param fromIndex the index to start checking from (inclusive)
* @return the index of the next set bit, or {@code -1} if there
* is no such bit
* @throws IndexOutOfBoundsException if the specified index is negative
*/
public int nextSetBit(int fromIndex) {
if (fromIndex < 0) {
throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex);
}
int u = wordIndex(fromIndex);
if (u >= words.length) {
return -1;
}
long word = words[u] & (WORD_MASK << fromIndex);
while (true) {
if (word != 0) {
return (u * BITS_PER_WORD) + Long.numberOfTrailingZeros(word);
}
if (++u == words.length) {
return -1;
}
word = words[u];
}
}
/**
* Returns the index of the first bit that is set to {@code false}
* that occurs on or after the specified starting index.
*
* @param fromIndex the index to start checking from (inclusive)
* @return the index of the next clear bit
* @throws IndexOutOfBoundsException if the specified index is negative
*/
public int nextClearBit(int fromIndex) {
if (fromIndex < 0) {
throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex);
}
int u = wordIndex(fromIndex);
if (u >= words.length) {
return fromIndex;
}
long word = ~words[u] & (WORD_MASK << fromIndex);
while (true) {
if (word != 0) {
return (u * BITS_PER_WORD) + Long.numberOfTrailingZeros(word);
}
if (++u == words.length) {
return words.length * BITS_PER_WORD;
}
word = ~words[u];
}
}
/**
* Returns the index of the nearest bit that is set to {@code false}
* that occurs on or before the specified starting index.
* If no such bit exists, or if {@code -1} is given as the
* starting index, then {@code -1} is returned.
*
* @param fromIndex the index to start checking from (inclusive)
* @return the index of the previous clear bit, or {@code -1} if there
* is no such bit
* @throws IndexOutOfBoundsException if the specified index is less
* than {@code -1}
*/
public int previousClearBit(int fromIndex) {
if (fromIndex < 0) {
if (fromIndex == -1) {
return -1;
}
throw new IndexOutOfBoundsException("fromIndex < -1: " + fromIndex);
}
int u = wordIndex(fromIndex);
if (u >= words.length) {
return fromIndex;
}
long word = ~words[u] & (WORD_MASK >>> -(fromIndex + 1));
while (true) {
if (word != 0) {
return (u + 1) * BITS_PER_WORD - 1 - Long.numberOfLeadingZeros(word);
}
if (u-- == 0) {
return -1;
}
word = ~words[u];
}
}
public Iterator iterator() {
return new Iterator() {
int i = nextSetBit(0);
public boolean hasNext() {
return i >= 0;
}
public Integer next() {
int prev = i;
i = nextSetBit(i + 1);
return prev;
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
/** Converts this bit set to a list. */
public List toList() {
final List list = new ArrayList<>();
for (int i = nextSetBit(0); i >= 0; i = nextSetBit(i + 1)) {
list.add(i);
}
return list;
}
/** Creates a view onto this bit set as a list of integers.
*
* The {@code cardinality} and {@code get} methods are both O(n), but
* the iterator is efficient. The list is memory efficient, and the CPU cost
* breaks even (versus {@link #toList}) if you intend to scan it only once. */
public List asList() {
return new AbstractList() {
@Override public Integer get(int index) {
return nth(index);
}
@Override public int size() {
return cardinality();
}
@Nonnull @Override public Iterator iterator() {
return ImmutableBitSet.this.iterator();
}
};
}
/** Creates a view onto this bit set as a set of integers.
*
* The {@code size} and {@code contains} methods are both O(n), but the
* iterator is efficient. */
public Set asSet() {
return new AbstractSet() {
@Nonnull public Iterator iterator() {
return ImmutableBitSet.this.iterator();
}
public int size() {
return cardinality();
}
@Override public boolean contains(Object o) {
return ImmutableBitSet.this.get((Integer) o);
}
};
}
/**
* Converts this bit set to an array.
*
* Each entry of the array is the ordinal of a set bit. The array is
* sorted.
*
* @return Array of set bits
*/
public int[] toArray() {
final int[] integers = new int[cardinality()];
int j = 0;
for (int i = nextSetBit(0); i >= 0; i = nextSetBit(i + 1)) {
integers[j++] = i;
}
return integers;
}
/**
* Converts this bit set to an array of little-endian words.
*/
public long[] toLongArray() {
return words.length == 0 ? words : words.clone();
}
/** Returns the union of this immutable bit set with a {@link BitSet}. */
public ImmutableBitSet union(BitSet other) {
return rebuild() // remember "this" and try to re-use later
.addAll(BitSets.toIter(other))
.build();
}
/** Returns the union of this bit set with another. */
public ImmutableBitSet union(ImmutableBitSet other) {
return rebuild() // remember "this" and try to re-use later
.addAll(other)
.build(other); // try to re-use "other"
}
/** Returns the union of a number of bit sets. */
public static ImmutableBitSet union(
Iterable sets) {
final Builder builder = builder();
for (ImmutableBitSet set : sets) {
builder.addAll(set);
}
return builder.build();
}
/** Returns a bit set with all the bits in this set that are not in
* another.
*
* @see BitSet#andNot(java.util.BitSet) */
public ImmutableBitSet except(ImmutableBitSet that) {
final Builder builder = rebuild();
builder.removeAll(that);
return builder.build();
}
/** Returns a bit set with all the bits set in both this set and in
* another.
*
* @see BitSet#and */
public ImmutableBitSet intersect(ImmutableBitSet that) {
final Builder builder = rebuild();
builder.intersect(that);
return builder.build();
}
/**
* Returns true if all bits set in the second parameter are also set in the
* first. In other words, whether x is a super-set of y.
*
* @param set1 Bitmap to be checked
*
* @return Whether all bits in set1 are set in set0
*/
public boolean contains(ImmutableBitSet set1) {
for (int i = set1.nextSetBit(0); i >= 0; i = set1.nextSetBit(i + 1)) {
if (!get(i)) {
return false;
}
}
return true;
}
/**
* The ordinal of a given bit, or -1 if it is not set.
*/
public int indexOf(int bit) {
for (int i = nextSetBit(0), k = 0;; i = nextSetBit(i + 1), ++k) {
if (i < 0) {
return -1;
}
if (i == bit) {
return k;
}
}
}
/** Computes the closure of a map from integers to bits.
*
*
The input must have an entry for each position.
*
*
Does not modify the input map or its bit sets. */
public static SortedMap closure(
SortedMap equivalence) {
if (equivalence.isEmpty()) {
return ImmutableSortedMap.of();
}
int length = equivalence.lastKey();
for (ImmutableBitSet bitSet : equivalence.values()) {
length = Math.max(length, bitSet.length());
}
if (equivalence.size() < length
|| equivalence.firstKey() != 0) {
SortedMap old = equivalence;
equivalence = new TreeMap<>();
for (int i = 0; i < length; i++) {
final ImmutableBitSet bitSet = old.get(i);
equivalence.put(i, bitSet == null ? ImmutableBitSet.of() : bitSet);
}
}
final Closure closure = new Closure(equivalence);
return closure.closure;
}
/**
* Returns the "logical size" of this {@code ImmutableBitSet}: the index of
* the highest set bit in the {@code ImmutableBitSet} plus one. Returns zero
* if the {@code ImmutableBitSet} contains no set bits.
*
* @return the logical size of this {@code ImmutableBitSet}
*/
public int length() {
if (words.length == 0) {
return 0;
}
return BITS_PER_WORD * (words.length - 1)
+ (BITS_PER_WORD - Long.numberOfLeadingZeros(words[words.length - 1]));
}
/**
* Returns true if this {@code ImmutableBitSet} contains no bits that are set
* to {@code true}.
*/
public boolean isEmpty() {
return words.length == 0;
}
/** Creates an empty Builder. */
public static Builder builder() {
return new Builder(EMPTY_LONGS);
}
@Deprecated // to be removed before 2.0
public static Builder builder(ImmutableBitSet bitSet) {
return bitSet.rebuild();
}
/** Creates a Builder whose initial contents are the same as this
* ImmutableBitSet. */
public Builder rebuild() {
return new Rebuilder(this);
}
/** Returns the {@code n}th set bit.
*
* @throws java.lang.IndexOutOfBoundsException if n is less than 0 or greater
* than the number of bits set */
public int nth(int n) {
int start = 0;
for (long word : words) {
final int bitCount = Long.bitCount(word);
if (n < bitCount) {
while (word != 0) {
if ((word & 1) == 1) {
if (n == 0) {
return start;
}
--n;
}
word >>= 1;
++start;
}
}
start += 64;
n -= bitCount;
}
throw new IndexOutOfBoundsException("index out of range: " + n);
}
/** Returns a bit set the same as this but with a given bit set. */
public ImmutableBitSet set(int i) {
return union(ImmutableBitSet.of(i));
}
/** Returns a bit set the same as this but with a given bit set (if b is
* true) or unset (if b is false). */
public ImmutableBitSet set(int i, boolean b) {
if (get(i) == b) {
return this;
}
return b ? set(i) : clear(i);
}
/** Returns a bit set the same as this but with a given bit set if condition
* is true. */
public ImmutableBitSet setIf(int bit, boolean condition) {
return condition ? set(bit) : this;
}
/** Returns a bit set the same as this but with a given bit cleared. */
public ImmutableBitSet clear(int i) {
return except(ImmutableBitSet.of(i));
}
/** Returns a bit set the same as this but with a given bit cleared if
* condition is true. */
public ImmutableBitSet clearIf(int i, boolean condition) {
return condition ? except(ImmutableBitSet.of(i)) : this;
}
/** Returns a {@link BitSet} that has the same contents as this
* {@code ImmutableBitSet}. */
public BitSet toBitSet() {
return BitSets.of(this);
}
/** Permutes a bit set according to a given mapping. */
public ImmutableBitSet permute(Map map) {
final Builder builder = builder();
for (int i = nextSetBit(0); i >= 0; i = nextSetBit(i + 1)) {
builder.set(map.get(i));
}
return builder.build();
}
/** Permutes a collection of bit sets according to a given mapping. */
public static Iterable permute(
Iterable bitSets,
final Map map) {
return Iterables.transform(bitSets, bitSet -> bitSet.permute(map));
}
/** Returns a bit set with every bit moved up {@code offset} positions.
* Offset may be negative, but throws if any bit ends up negative. */
public ImmutableBitSet shift(int offset) {
if (offset == 0) {
return this;
}
final Builder builder = builder();
for (int i = nextSetBit(0); i >= 0; i = nextSetBit(i + 1)) {
builder.set(i + offset);
}
return builder.build();
}
/**
* Setup equivalence Sets for each position. If i and j are equivalent then
* they will have the same equivalence Set. The algorithm computes the
* closure relation at each position for the position wrt to positions
* greater than it. Once a closure is computed for a position, the closure
* Set is set on all its descendants. So the closure computation bubbles up
* from lower positions and the final equivalence Set is propagated down
* from the lowest element in the Set.
*/
private static class Closure {
private SortedMap equivalence;
private final SortedMap closure =
new TreeMap<>();
Closure(SortedMap equivalence) {
this.equivalence = equivalence;
final ImmutableIntList keys =
ImmutableIntList.copyOf(equivalence.keySet());
for (int pos : keys) {
computeClosure(pos);
}
}
private ImmutableBitSet computeClosure(int pos) {
ImmutableBitSet o = closure.get(pos);
if (o != null) {
return o;
}
final ImmutableBitSet b = equivalence.get(pos);
o = b;
int i = b.nextSetBit(pos + 1);
for (; i >= 0; i = b.nextSetBit(i + 1)) {
o = o.union(computeClosure(i));
}
closure.put(pos, o);
i = o.nextSetBit(pos + 1);
for (; i >= 0; i = b.nextSetBit(i + 1)) {
closure.put(i, o);
}
return o;
}
}
/** Builder. */
public static class Builder {
private long[] words;
private Builder(long[] words) {
this.words = words;
}
/** Builds an ImmutableBitSet from the contents of this Builder.
*
* After calling this method, the Builder cannot be used again. */
public ImmutableBitSet build() {
if (words.length == 0) {
return EMPTY;
}
long[] words = this.words;
this.words = null; // prevent re-use of builder
return new ImmutableBitSet(words);
}
/** Builds an ImmutableBitSet from the contents of this Builder, using
* an existing ImmutableBitSet if it happens to have the same contents.
*
*
Supplying the existing bit set if useful for set operations,
* where there is a significant chance that the original bit set is
* unchanged. We save memory because we use the same copy. For example:
*
*
* ImmutableBitSet primeNumbers;
* ImmutableBitSet hundreds = ImmutableBitSet.of(100, 200, 300);
* return primeNumbers.except(hundreds);
*
* After calling this method, the Builder cannot be used again. */
public ImmutableBitSet build(ImmutableBitSet bitSet) {
if (wouldEqual(bitSet)) {
return bitSet;
}
return build();
}
public Builder set(int bit) {
if (words == null) {
throw new IllegalArgumentException("can only use builder once");
}
int wordIndex = wordIndex(bit);
if (wordIndex >= words.length) {
words = Arrays.copyOf(words, wordIndex + 1);
}
words[wordIndex] |= 1L << bit;
return this;
}
private void trim(int wordCount) {
while (wordCount > 0 && words[wordCount - 1] == 0L) {
--wordCount;
}
if (wordCount == words.length) {
return;
}
if (wordCount == 0) {
words = EMPTY_LONGS;
} else {
words = Arrays.copyOfRange(words, 0, wordCount);
}
}
public Builder clear(int bit) {
int wordIndex = wordIndex(bit);
if (wordIndex < words.length) {
words[wordIndex] &= ~(1L << bit);
trim(words.length);
}
return this;
}
/** Returns whether the bit set that would be created by this Builder would
* equal a given bit set. */
public boolean wouldEqual(ImmutableBitSet bitSet) {
if (words == null) {
throw new IllegalArgumentException("can only use builder once");
}
return Arrays.equals(words, bitSet.words);
}
/** Returns the number of set bits. */
public int cardinality() {
if (words == null) {
throw new IllegalArgumentException("can only use builder once");
}
return countBits(words);
}
/** Sets all bits in a given bit set. */
public Builder addAll(ImmutableBitSet bitSet) {
for (Integer bit : bitSet) {
set(bit);
}
return this;
}
/** Sets all bits in a given list of bits. */
public Builder addAll(Iterable integers) {
for (Integer integer : integers) {
set(integer);
}
return this;
}
/** Sets all bits in a given list of {@code int}s. */
public Builder addAll(ImmutableIntList integers) {
//noinspection ForLoopReplaceableByForEach
for (int i = 0; i < integers.size(); i++) {
set(integers.get(i));
}
return this;
}
/** Clears all bits in a given bit set. */
public Builder removeAll(ImmutableBitSet bitSet) {
for (Integer bit : bitSet) {
clear(bit);
}
return this;
}
/** Sets a range of bits, from {@code from} to {@code to} - 1. */
public Builder set(int fromIndex, int toIndex) {
if (fromIndex > toIndex) {
throw new IllegalArgumentException();
}
if (toIndex < 0) {
throw new IllegalArgumentException();
}
if (fromIndex < toIndex) {
// Increase capacity if necessary
int startWordIndex = wordIndex(fromIndex);
int endWordIndex = wordIndex(toIndex - 1);
if (endWordIndex >= words.length) {
words = Arrays.copyOf(words, endWordIndex + 1);
}
long firstWordMask = WORD_MASK << fromIndex;
long lastWordMask = WORD_MASK >>> -toIndex;
if (startWordIndex == endWordIndex) {
// One word
words[startWordIndex] |= firstWordMask & lastWordMask;
} else {
// First word, middle words, last word
words[startWordIndex] |= firstWordMask;
for (int i = startWordIndex + 1; i < endWordIndex; i++) {
words[i] = WORD_MASK;
}
words[endWordIndex] |= lastWordMask;
}
}
return this;
}
public boolean isEmpty() {
return words.length == 0;
}
public void intersect(ImmutableBitSet that) {
int x = Math.min(words.length, that.words.length);
for (int i = 0; i < x; i++) {
words[i] &= that.words[i];
}
trim(x);
}
}
/** Refinement of {@link Builder} that remembers its original
* {@link org.apache.calcite.util.ImmutableBitSet} and tries to use it
* when {@link #build} is called. */
private static class Rebuilder extends Builder {
private final ImmutableBitSet originalBitSet;
private Rebuilder(ImmutableBitSet originalBitSet) {
super(originalBitSet.words.clone());
this.originalBitSet = originalBitSet;
}
@Override public ImmutableBitSet build() {
if (wouldEqual(originalBitSet)) {
return originalBitSet;
}
return super.build();
}
@Override public ImmutableBitSet build(ImmutableBitSet bitSet) {
// We try to re-use both originalBitSet and bitSet.
if (wouldEqual(originalBitSet)) {
return originalBitSet;
}
return super.build(bitSet);
}
}
}
// End ImmutableBitSet.java