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.Iterator;
24 import java.util.NavigableSet;
25 import java.util.TreeSet;
26 import org.eclipse.jdt.annotation.NonNull;
27 import org.opendaylight.yangtools.concepts.Mutable;
28 import org.opendaylight.yangtools.concepts.WritableObjects;
31 * A class holding an equivalent of {@code Set<UnsignedLong>}. It is geared towards efficiently tracking ranges of
32 * objects, similar to what a {@link RangeSet} would do.
35 * Unlike a {@code RangeSet}, though, this class takes advantage of knowing that an unsigned long is a discrete unit
36 * and can be stored in a simple {@code long}.
38 * @author Robert Varga
40 abstract class UnsignedLongSet {
43 public static final class Entry implements Comparable<Entry>, Mutable {
44 // Note: mutable to allow efficient merges.
48 private Entry(final long lowerBits, final long upperBits) {
49 this.lowerBits = lowerBits;
50 this.upperBits = upperBits;
53 static Entry of(final long longBits) {
54 return of(longBits, longBits);
57 static Entry of(final long lowerBits, final long upperBits) {
58 return new Entry(lowerBits, upperBits);
62 public UnsignedLong lower() {
63 return UnsignedLong.fromLongBits(lowerBits);
67 public UnsignedLong upper() {
68 return UnsignedLong.fromLongBits(upperBits);
71 boolean contains(final long longBits) {
72 return Long.compareUnsigned(lowerBits, longBits) <= 0 && Long.compareUnsigned(upperBits, longBits) >= 0;
76 return new Entry(lowerBits, upperBits);
79 // Provides compatibility with RangeSet<UnsignedLong> using [lower, upper + 1)
80 Range<UnsignedLong> toUnsigned() {
81 return Range.closedOpen(UnsignedLong.fromLongBits(lowerBits), UnsignedLong.fromLongBits(upperBits + 1));
84 // These two methods provide the same serialization format as the one we've used to serialize
85 // Range<UnsignedLong>
86 static @NonNull Entry readUnsigned(final DataInput in) throws IOException {
87 final byte hdr = WritableObjects.readLongHeader(in);
88 final long first = WritableObjects.readFirstLong(in, hdr);
89 final long second = WritableObjects.readSecondLong(in, hdr) - 1;
90 if (Long.compareUnsigned(first, second) > 0) {
91 throw new IOException("Lower endpoint " + Long.toUnsignedString(first) + " is greater than upper "
92 + "endpoint " + Long.toUnsignedString(second));
95 return new Entry(first, second);
98 void writeUnsigned(final @NonNull DataOutput out) throws IOException {
99 WritableObjects.writeLongs(out, lowerBits, upperBits + 1);
103 @SuppressWarnings("checkstyle:parameterName")
104 public int compareTo(final Entry o) {
105 return Long.compareUnsigned(lowerBits, o.lowerBits);
109 public int hashCode() {
110 return Long.hashCode(lowerBits) * 31 + Long.hashCode(upperBits);
114 public boolean equals(final Object obj) {
118 if (!(obj instanceof Entry)) {
121 final var other = (Entry) obj;
122 return lowerBits == other.lowerBits && upperBits == other.upperBits;
126 public String toString() {
127 return "[" + Long.toUnsignedString(lowerBits) + ".." + Long.toUnsignedString(upperBits) + "]";
131 // The idea is rather simple, we track a NavigableSet of range entries, ordered by their lower bound. This means
132 // that for a contains() operation we just need the first headSet() entry. For insert operations we just update
133 // either the lower bound or the upper bound of an existing entry. When we do, we also look at prev/next entry and
134 // if they are contiguous with the updated entry, we adjust the entry once more and remove the prev/next entry.
135 private final @NonNull NavigableSet<Entry> ranges;
137 UnsignedLongSet(final NavigableSet<Entry> ranges) {
138 this.ranges = requireNonNull(ranges);
141 final void addImpl(final long longBits) {
142 final var range = Entry.of(longBits);
144 final var headIt = headIter(range);
145 if (headIt.hasNext()) {
146 final var head = headIt.next();
147 if (head.contains(longBits)) {
150 if (head.upperBits + 1 == longBits) {
151 head.upperBits = longBits;
152 final var tailSet = ranges.tailSet(range);
153 if (!tailSet.isEmpty()) {
154 final var tail = tailSet.first();
155 if (tail.lowerBits - 1 == longBits) {
156 tail.lowerBits = head.lowerBits;
164 final var tailSet = ranges.tailSet(range);
165 if (!tailSet.isEmpty()) {
166 final var tail = tailSet.first();
167 if (tail.lowerBits - 1 == longBits) {
168 tail.lowerBits = longBits;
176 public final boolean contains(final long longBits) {
177 final var headIt = headIter(Entry.of(longBits));
178 return headIt.hasNext() && headIt.next().contains(longBits);
181 public final boolean isEmpty() {
182 return ranges.isEmpty();
185 public final int size() {
186 return ranges.size();
189 public abstract @NonNull ImmutableUnsignedLongSet immutableCopy();
191 public final @NonNull MutableUnsignedLongSet mutableCopy() {
192 return new MutableUnsignedLongSet(new TreeSet<>(Collections2.transform(ranges, Entry::copy)));
195 public final @NonNull NavigableSet<Entry> ranges() {
196 return Collections.unmodifiableNavigableSet(ranges);
199 final @NonNull NavigableSet<Entry> trustedRanges() {
204 public final int hashCode() {
205 return ranges.hashCode();
209 public final boolean equals(final Object obj) {
210 return obj == this || obj instanceof UnsignedLongSet && ranges.equals(((UnsignedLongSet) obj).ranges);
214 public final String toString() {
215 final var helper = MoreObjects.toStringHelper(this);
217 final int size = ranges.size();
222 helper.add("span", ranges.first());
225 helper.add("span", Entry.of(ranges.first().lowerBits, ranges.last().upperBits));
228 return helper.add("size", size).toString();
231 private Iterator<Entry> headIter(final Entry range) {
232 return ranges.headSet(range, true).descendingIterator();