2 * Copyright (c) 2021 PANTHEON.tech, s.r.o. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.controller.cluster.datastore.utils;
10 import static java.util.Objects.requireNonNull;
12 import com.google.common.annotations.Beta;
13 import com.google.common.annotations.VisibleForTesting;
14 import com.google.common.base.MoreObjects;
15 import com.google.common.collect.Collections2;
16 import com.google.common.collect.Range;
17 import com.google.common.collect.RangeSet;
18 import com.google.common.primitives.UnsignedLong;
19 import java.io.DataInput;
20 import java.io.DataOutput;
21 import java.io.IOException;
22 import java.util.Collections;
23 import java.util.NavigableSet;
24 import java.util.TreeSet;
25 import org.eclipse.jdt.annotation.NonNull;
26 import org.opendaylight.yangtools.concepts.Mutable;
27 import org.opendaylight.yangtools.concepts.WritableObjects;
30 * A class holding an equivalent of {@code Set<UnsignedLong>}. It is geared towards efficiently tracking ranges of
31 * objects, similar to what a {@link RangeSet} would do.
34 * Unlike a {@code RangeSet}, though, this class takes advantage of knowing that an unsigned long is a discrete unit
35 * and can be stored in a simple {@code long}.
37 * @author Robert Varga
39 abstract class UnsignedLongSet {
42 public static final class Entry implements Comparable<Entry>, Mutable {
43 // Note: mutable to allow efficient merges.
47 private Entry(final long lowerBits, final long upperBits) {
48 this.lowerBits = lowerBits;
49 this.upperBits = upperBits;
52 static Entry of(final long longBits) {
53 return of(longBits, longBits);
56 static Entry of(final long lowerBits, final long upperBits) {
57 return new Entry(lowerBits, upperBits);
61 public UnsignedLong lower() {
62 return UnsignedLong.fromLongBits(lowerBits);
66 public UnsignedLong upper() {
67 return UnsignedLong.fromLongBits(upperBits);
70 boolean contains(final long longBits) {
71 return Long.compareUnsigned(lowerBits, longBits) <= 0 && Long.compareUnsigned(upperBits, longBits) >= 0;
75 return new Entry(lowerBits, upperBits);
78 // Provides compatibility with RangeSet<UnsignedLong> using [lower, upper + 1)
79 Range<UnsignedLong> toUnsigned() {
80 return Range.closedOpen(UnsignedLong.fromLongBits(lowerBits), UnsignedLong.fromLongBits(upperBits + 1));
83 // These two methods provide the same serialization format as the one we've used to serialize
84 // Range<UnsignedLong>
85 static @NonNull Entry readUnsigned(final DataInput in) throws IOException {
86 final byte hdr = WritableObjects.readLongHeader(in);
87 final long first = WritableObjects.readFirstLong(in, hdr);
88 final long second = WritableObjects.readSecondLong(in, hdr) - 1;
89 if (Long.compareUnsigned(first, second) > 0) {
90 throw new IOException("Lower endpoint " + Long.toUnsignedString(first) + " is greater than upper "
91 + "endpoint " + Long.toUnsignedString(second));
94 return new Entry(first, second);
97 void writeUnsigned(final @NonNull DataOutput out) throws IOException {
98 WritableObjects.writeLongs(out, lowerBits, upperBits + 1);
102 @SuppressWarnings("checkstyle:parameterName")
103 public int compareTo(final Entry o) {
104 return Long.compareUnsigned(lowerBits, o.lowerBits);
108 public int hashCode() {
109 return Long.hashCode(lowerBits) * 31 + Long.hashCode(upperBits);
113 public boolean equals(final Object obj) {
117 if (!(obj instanceof Entry)) {
120 final var other = (Entry) obj;
121 return lowerBits == other.lowerBits && upperBits == other.upperBits;
125 public String toString() {
126 return "[" + Long.toUnsignedString(lowerBits) + ".." + Long.toUnsignedString(upperBits) + "]";
130 // The idea is rather simple, we track a NavigableSet of range entries, ordered by their lower bound. This means
131 // that for a contains() operation we just need the first headSet() entry. For insert operations we just update
132 // either the lower bound or the upper bound of an existing entry. When we do, we also look at prev/next entry and
133 // if they are contiguous with the updated entry, we adjust the entry once more and remove the prev/next entry.
134 private final @NonNull NavigableSet<Entry> ranges;
136 UnsignedLongSet(final NavigableSet<Entry> ranges) {
137 this.ranges = requireNonNull(ranges);
140 final void addImpl(final long longBits) {
141 final var range = Entry.of(longBits);
143 final var headIt = ranges.headSet(range, true).descendingIterator();
144 if (headIt.hasNext()) {
145 final var head = headIt.next();
146 if (head.contains(longBits)) {
149 if (head.upperBits + 1 == longBits) {
150 head.upperBits = longBits;
151 final var tail = ranges.higher(range);
153 if (tail.lowerBits - 1 == longBits) {
154 tail.lowerBits = head.lowerBits;
162 final var tail = ranges.higher(range);
164 if (tail.lowerBits - 1 == longBits) {
165 tail.lowerBits = longBits;
173 public final boolean contains(final long longBits) {
174 final var head = ranges.floor(Entry.of(longBits));
175 return head != null && head.contains(longBits);
178 public final boolean isEmpty() {
179 return ranges.isEmpty();
182 public final int size() {
183 return ranges.size();
186 public abstract @NonNull ImmutableUnsignedLongSet immutableCopy();
188 public final @NonNull MutableUnsignedLongSet mutableCopy() {
189 return new MutableUnsignedLongSet(new TreeSet<>(Collections2.transform(ranges, Entry::copy)));
192 public final @NonNull NavigableSet<Entry> ranges() {
193 return Collections.unmodifiableNavigableSet(ranges);
196 final @NonNull NavigableSet<Entry> trustedRanges() {
201 public final int hashCode() {
202 return ranges.hashCode();
206 public final boolean equals(final Object obj) {
207 return obj == this || obj instanceof UnsignedLongSet && ranges.equals(((UnsignedLongSet) obj).ranges);
211 public final String toString() {
212 final var helper = MoreObjects.toStringHelper(this);
214 final int size = ranges.size();
219 helper.add("span", ranges.first());
222 helper.add("span", Entry.of(ranges.first().lowerBits, ranges.last().upperBits));
225 return helper.add("size", size).toString();