/*
* Copyright (C) 2012 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.common.collect;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkElementIndex;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.SortedLists.KeyAbsentBehavior.NEXT_LOWER;
import static com.google.common.collect.SortedLists.KeyPresentBehavior.ANY_PRESENT;
import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.SortedLists.KeyAbsentBehavior;
import com.google.common.collect.SortedLists.KeyPresentBehavior;
import com.google.common.primitives.Ints;
import java.io.Serializable;
import java.util.Collections;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Set;
import javax.annotation.Nullable;
/**
* An efficient immutable implementation of a {@link RangeSet}.
*
* @author Louis Wasserman
* @since 14.0
*/
@Beta
public final class ImmutableRangeSet<C extends Comparable> extends AbstractRangeSet<C>
implements Serializable {
private static final ImmutableRangeSet<Comparable<?>> EMPTY =
new ImmutableRangeSet<Comparable<?>>(ImmutableList.<Range<Comparable<?>>>of());
private static final ImmutableRangeSet<Comparable<?>> ALL =
new ImmutableRangeSet<Comparable<?>>(ImmutableList.of(Range.<Comparable<?>>all()));
/**
* Returns an empty immutable range set.
*/
@SuppressWarnings("unchecked")
public static <C extends Comparable> ImmutableRangeSet<C> of() {
return (ImmutableRangeSet<C>) EMPTY;
}
/**
* Returns an immutable range set containing the single range {@link Range#all()}.
*/
@SuppressWarnings("unchecked")
static <C extends Comparable> ImmutableRangeSet<C> all() {
return (ImmutableRangeSet<C>) ALL;
}
/**
* Returns an immutable range set containing the specified single range. If {@link Range#isEmpty()
* range.isEmpty()}, this is equivalent to {@link ImmutableRangeSet#of()}.
*/
public static <C extends Comparable> ImmutableRangeSet<C> of(Range<C> range) {
checkNotNull(range);
if (range.isEmpty()) {
return of();
} else if (range.equals(Range.all())) {
return all();
} else {
return new ImmutableRangeSet<C>(ImmutableList.of(range));
}
}
/**
* Returns an immutable copy of the specified {@code RangeSet}.
*/
public static <C extends Comparable> ImmutableRangeSet<C> copyOf(RangeSet<C> rangeSet) {
checkNotNull(rangeSet);
if (rangeSet.isEmpty()) {
return of();
} else if (rangeSet.encloses(Range.<C>all())) {
return all();
}
if (rangeSet instanceof ImmutableRangeSet) {
ImmutableRangeSet<C> immutableRangeSet = (ImmutableRangeSet<C>) rangeSet;
if (!immutableRangeSet.isPartialView()) {
return immutableRangeSet;
}
}
return new ImmutableRangeSet<C>(ImmutableList.copyOf(rangeSet.asRanges()));
}
ImmutableRangeSet(ImmutableList<Range<C>> ranges) {
this.ranges = ranges;
}
private ImmutableRangeSet(ImmutableList<Range<C>> ranges, ImmutableRangeSet<C> complement) {
this.ranges = ranges;
this.complement = complement;
}
private transient final ImmutableList<Range<C>> ranges;
@Override
public boolean encloses(Range<C> otherRange) {
int index = SortedLists.binarySearch(ranges,
Range.<C>lowerBoundFn(),
otherRange.lowerBound,
Ordering.natural(),
ANY_PRESENT,
NEXT_LOWER);
return index != -1 && ranges.get(index).encloses(otherRange);
}
@Override
public Range<C> rangeContaining(C value) {
int index = SortedLists.binarySearch(ranges,
Range.<C>lowerBoundFn(),
Cut.belowValue(value),
Ordering.natural(),
ANY_PRESENT,
NEXT_LOWER);
if (index != -1) {
Range<C> range = ranges.get(index);
return range.contains(value) ? range : null;
}
return null;
}
@Override
public Range<C> span() {
if (ranges.isEmpty()) {
throw new NoSuchElementException();
}
return Range.create(
ranges.get(0).lowerBound,
ranges.get(ranges.size() - 1).upperBound);
}
@Override
public boolean isEmpty() {
return ranges.isEmpty();
}
@Override
public void add(Range<C> range) {
throw new UnsupportedOperationException();
}
@Override
public void addAll(RangeSet<C> other) {
throw new UnsupportedOperationException();
}
@Override
public void remove(Range<C> range) {
throw new UnsupportedOperationException();
}
@Override
public void removeAll(RangeSet<C> other) {
throw new UnsupportedOperationException();
}
@Override
public ImmutableSet<Range<C>> asRanges() {
if (ranges.isEmpty()) {
return ImmutableSet.of();
}
return new RegularImmutableSortedSet<Range<C>>(ranges, Range.RANGE_LEX_ORDERING);
}
private transient ImmutableRangeSet<C> complement;
private final class ComplementRanges extends ImmutableList<Range<C>> {
// True if the "positive" range set is empty or bounded below.
private final boolean positiveBoundedBelow;
// True if the "positive" range set is empty or bounded above.
private final boolean positiveBoundedAbove;
private final int size;
ComplementRanges() {
this.positiveBoundedBelow = ranges.get(0).hasLowerBound();
this.positiveBoundedAbove = Iterables.getLast(ranges).hasUpperBound();
int size = ranges.size() - 1;
if (positiveBoundedBelow) {
size++;
}
if (positiveBoundedAbove) {
size++;
}
this.size = size;
}
@Override
public int size() {
return size;
}
@Override
public Range<C> get(int index) {
checkElementIndex(index, size);
Cut<C> lowerBound;
if (positiveBoundedBelow) {
lowerBound = (index == 0) ? Cut.<C>belowAll() : ranges.get(index - 1).upperBound;
} else {
lowerBound = ranges.get(index).upperBound;
}
Cut<C> upperBound;
if (positiveBoundedAbove && index == size - 1) {
upperBound = Cut.<C>aboveAll();
} else {
upperBound = ranges.get(index + (positiveBoundedBelow ? 0 : 1)).lowerBound;
}
return Range.create(lowerBound, upperBound);
}
@Override
boolean isPartialView() {
return true;
}
}
@Override
public ImmutableRangeSet<C> complement() {
ImmutableRangeSet<C> result = complement;
if (result != null) {
return result;
} else if (ranges.isEmpty()) {
return complement = all();
} else if (ranges.size() == 1 && ranges.get(0).equals(Range.all())) {
return complement = of();
} else {
ImmutableList<Range<C>> complementRanges = new ComplementRanges();
result = complement = new ImmutableRangeSet<C>(complementRanges, this);
}
return result;
}
/**
* Returns a list containing the nonempty intersections of {@code range}
* with the ranges in this range set.
*/
private ImmutableList<Range<C>> intersectRanges(final Range<C> range) {
if (ranges.isEmpty() || range.isEmpty()) {
return ImmutableList.of();
} else if (range.encloses(span())) {
return ranges;
}
final int fromIndex;
if (range.hasLowerBound()) {
fromIndex = SortedLists.binarySearch(
ranges, Range.<C>upperBoundFn(), range.lowerBound, KeyPresentBehavior.FIRST_AFTER,
KeyAbsentBehavior.NEXT_HIGHER);
} else {
fromIndex = 0;
}
int toIndex;
if (range.hasUpperBound()) {
toIndex = SortedLists.binarySearch(
ranges, Range.<C>lowerBoundFn(), range.upperBound, KeyPresentBehavior.FIRST_PRESENT,
KeyAbsentBehavior.NEXT_HIGHER);
} else {
toIndex = ranges.size();
}
final int length = toIndex - fromIndex;
if (length == 0) {
return ImmutableList.of();
} else {
return new ImmutableList<Range<C>>() {
@Override
public int size() {
return length;
}
@Override
public Range<C> get(int index) {
checkElementIndex(index, length);
if (index == 0 || index == length - 1) {
return ranges.get(index + fromIndex).intersection(range);
} else {
return ranges.get(index + fromIndex);
}
}
@Override
boolean isPartialView() {
return true;
}
};
}
}
/**
* Returns a view of the intersection of this range set with the given range.
*/
@Override
public ImmutableRangeSet<C> subRangeSet(Range<C> range) {
if (!isEmpty()) {
Range<C> span = span();
if (range.encloses(span)) {
return this;
} else if (range.isConnected(span)) {
return new ImmutableRangeSet<C>(intersectRanges(range));
}
}
return of();
}
/**
* Returns an {@link ImmutableSortedSet} containing the same values in the given domain
* {@linkplain RangeSet#contains contained} by this range set.
*
* <p><b>Note:</b> {@code a.asSet(d).equals(b.asSet(d))} does not imply {@code a.equals(b)}! For
* example, {@code a} and {@code b} could be {@code [2..4]} and {@code (1..5)}, or the empty
* ranges {@code [3..3)} and {@code [4..4)}.
*
* <p><b>Warning:</b> Be extremely careful what you do with the {@code asSet} view of a large
* range set (such as {@code ImmutableRangeSet.of(Range.greaterThan(0))}). Certain operations on
* such a set can be performed efficiently, but others (such as {@link Set#hashCode} or
* {@link Collections#frequency}) can cause major performance problems.
*
* <p>The returned set's {@link Object#toString} method returns a short-hand form of the set's
* contents, such as {@code "[1..100]}"}.
*
* @throws IllegalArgumentException if neither this range nor the domain has a lower bound, or if
* neither has an upper bound
*/
public ImmutableSortedSet<C> asSet(DiscreteDomain<C> domain) {
checkNotNull(domain);
if (isEmpty()) {
return ImmutableSortedSet.of();
}
Range<C> span = span().canonical(domain);
if (!span.hasLowerBound()) {
// according to the spec of canonical, neither this ImmutableRangeSet nor
// the range have a lower bound
throw new IllegalArgumentException(
"Neither the DiscreteDomain nor this range set are bounded below");
} else if (!span.hasUpperBound()) {
try {
domain.maxValue();
} catch (NoSuchElementException e) {
throw new IllegalArgumentException(
"Neither the DiscreteDomain nor this range set are bounded above");
}
}
return new AsSet(domain);
}
private final class AsSet extends ImmutableSortedSet<C> {
private final DiscreteDomain<C> domain;
AsSet(DiscreteDomain<C> domain) {
super(Ordering.natural());
this.domain = domain;
}
private transient Integer size;
@Override
public int size() {
// racy single-check idiom
Integer result = size;
if (result == null) {
long total = 0;
for (Range<C> range : ranges) {
total += ContiguousSet.create(range, domain).size();
if (total >= Integer.MAX_VALUE) {
break;
}
}
result = size = Ints.saturatedCast(total);
}
return result.intValue();
}
@Override
public UnmodifiableIterator<C> iterator() {
return new AbstractIterator<C>() {
final Iterator<Range<C>> rangeItr = ranges.iterator();
Iterator<C> elemItr = Iterators.emptyIterator();
@Override
protected C computeNext() {
while (!elemItr.hasNext()) {
if (rangeItr.hasNext()) {
elemItr = ContiguousSet.create(rangeItr.next(), domain).iterator();
} else {
return endOfData();
}
}
return elemItr.next();
}
};
}
@Override
@GwtIncompatible("NavigableSet")
public UnmodifiableIterator<C> descendingIterator() {
return new AbstractIterator<C>() {
final Iterator<Range<C>> rangeItr = ranges.reverse().iterator();
Iterator<C> elemItr = Iterators.emptyIterator();
@Override
protected C computeNext() {
while (!elemItr.hasNext()) {
if (rangeItr.hasNext()) {
elemItr = ContiguousSet.create(rangeItr.next(), domain).descendingIterator();
} else {
return endOfData();
}
}
return elemItr.next();
}
};
}
ImmutableSortedSet<C> subSet(Range<C> range) {
return subRangeSet(range).asSet(domain);
}
@Override
ImmutableSortedSet<C> headSetImpl(C toElement, boolean inclusive) {
return subSet(Range.upTo(toElement, BoundType.forBoolean(inclusive)));
}
@Override
ImmutableSortedSet<C> subSetImpl(
C fromElement, boolean fromInclusive, C toElement, boolean toInclusive) {
if (!fromInclusive && !toInclusive && Range.compareOrThrow(fromElement, toElement) == 0) {
return ImmutableSortedSet.of();
}
return subSet(Range.range(
fromElement, BoundType.forBoolean(fromInclusive),
toElement, BoundType.forBoolean(toInclusive)));
}
@Override
ImmutableSortedSet<C> tailSetImpl(C fromElement, boolean inclusive) {
return subSet(Range.downTo(fromElement, BoundType.forBoolean(inclusive)));
}
@Override
public boolean contains(@Nullable Object o) {
if (o == null) {
return false;
}
try {
@SuppressWarnings("unchecked") // we catch CCE's
C c = (C) o;
return ImmutableRangeSet.this.contains(c);
} catch (ClassCastException e) {
return false;
}
}
@Override
int indexOf(Object target) {
if (contains(target)) {
@SuppressWarnings("unchecked") // if it's contained, it's definitely a C
C c = (C) target;
long total = 0;
for (Range<C> range : ranges) {
if (range.contains(c)) {
return Ints.saturatedCast(total + ContiguousSet.create(range, domain).indexOf(c));
} else {
total += ContiguousSet.create(range, domain).size();
}
}
throw new AssertionError("impossible");
}
return -1;
}
@Override
boolean isPartialView() {
return ranges.isPartialView();
}
@Override
public String toString() {
return ranges.toString();
}
@Override
Object writeReplace() {
return new AsSetSerializedForm<C>(ranges, domain);
}
}
private static class AsSetSerializedForm<C extends Comparable> implements Serializable {
private final ImmutableList<Range<C>> ranges;
private final DiscreteDomain<C> domain;
AsSetSerializedForm(ImmutableList<Range<C>> ranges, DiscreteDomain<C> domain) {
this.ranges = ranges;
this.domain = domain;
}
Object readResolve() {
return new ImmutableRangeSet<C>(ranges).asSet(domain);
}
}
/**
* Returns {@code true} if this immutable range set's implementation contains references to
* user-created objects that aren't accessible via this range set's methods. This is generally
* used to determine whether {@code copyOf} implementations should make an explicit copy to avoid
* memory leaks.
*/
boolean isPartialView() {
return ranges.isPartialView();
}
/**
* Returns a new builder for an immutable range set.
*/
public static <C extends Comparable<?>> Builder<C> builder() {
return new Builder<C>();
}
/**
* A builder for immutable range sets.
*/
public static class Builder<C extends Comparable<?>> {
private final RangeSet<C> rangeSet;
public Builder() {
this.rangeSet = TreeRangeSet.create();
}
/**
* Add the specified range to this builder. Adjacent/abutting ranges are permitted, but
* empty ranges, or ranges with nonempty overlap, are forbidden.
*
* @throws IllegalArgumentException if {@code range} is empty or has nonempty intersection with
* any ranges already added to the builder
*/
public Builder<C> add(Range<C> range) {
if (range.isEmpty()) {
throw new IllegalArgumentException("range must not be empty, but was " + range);
} else if (!rangeSet.complement().encloses(range)) {
for (Range<C> currentRange : rangeSet.asRanges()) {
checkArgument(
!currentRange.isConnected(range) || currentRange.intersection(range).isEmpty(),
"Ranges may not overlap, but received %s and %s", currentRange, range);
}
throw new AssertionError("should have thrown an IAE above");
}
rangeSet.add(range);
return this;
}
/**
* Add all ranges from the specified range set to this builder. Duplicate or connected ranges
* are permitted, and will be merged in the resulting immutable range set.
*/
public Builder<C> addAll(RangeSet<C> ranges) {
for (Range<C> range : ranges.asRanges()) {
add(range);
}
return this;
}
/**
* Returns an {@code ImmutableRangeSet} containing the ranges added to this builder.
*/
public ImmutableRangeSet<C> build() {
return copyOf(rangeSet);
}
}
private static final class SerializedForm<C extends Comparable> implements Serializable {
private final ImmutableList<Range<C>> ranges;
SerializedForm(ImmutableList<Range<C>> ranges) {
this.ranges = ranges;
}
Object readResolve() {
if (ranges.isEmpty()) {
return of();
} else if (ranges.equals(ImmutableList.of(Range.all()))) {
return all();
} else {
return new ImmutableRangeSet<C>(ranges);
}
}
}
Object writeReplace() {
return new SerializedForm<C>(ranges);
}
}