2 * (C) Copyright 2016 Pantheon Technologies, s.r.o. and others.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package org.opendaylight.yangtools.triemap;
18 final class CNode<K, V> extends CNodeBase<K, V> {
19 private static final BasicNode[] EMPTY_ARRAY = new BasicNode[0];
22 final BasicNode[] array;
25 CNode(final Gen gen) {
26 this(gen, 0, EMPTY_ARRAY);
29 private CNode(final Gen gen, final int bitmap, final BasicNode... array) {
35 // this should only be called from within read-only snapshots
37 int cachedSize(final TrieMap<K, V> ct) {
38 final int currsz = READ_SIZE();
43 final int sz = computeSize(ct);
44 while (READ_SIZE () == -1) {
50 // lends itself towards being parallelizable by choosing
51 // a random starting offset in the array
52 // => if there are concurrent size computations, they start
53 // at different positions, so they are more likely to
55 private int computeSize(final TrieMap<K, V> ct) {
58 // final int offset = (array.length > 0) ?
59 // // util.Random.nextInt(array.length) /* <-- benchmarks show that
60 // // this causes observable contention */
61 // scala.concurrent.forkjoin.ThreadLocalRandom.current.nextInt (0,
66 while (i < array.length) {
67 int pos = (i + offset) % array.length;
68 BasicNode elem = array [pos];
69 if (elem instanceof SNode) {
71 } else if (elem instanceof INode) {
72 sz += ((INode<K, V>) elem).cachedSize (ct);
79 CNode<K, V> updatedAt(final int pos, final BasicNode nn, final Gen gen) {
80 int len = array.length;
81 BasicNode[] narr = new BasicNode[len];
82 System.arraycopy(array, 0, narr, 0, len);
84 return new CNode<>(gen, bitmap, narr);
87 CNode<K, V> removedAt(final int pos, final int flag, final Gen gen) {
88 BasicNode[] arr = array;
90 BasicNode[] narr = new BasicNode[len - 1];
91 System.arraycopy(arr, 0, narr, 0, pos);
92 System.arraycopy(arr, pos + 1, narr, pos, len - pos - 1);
93 return new CNode<>(gen, bitmap ^ flag, narr);
96 CNode<K, V> insertedAt(final int pos, final int flag, final BasicNode nn, final Gen gen) {
97 int len = array.length;
99 BasicNode[] narr = new BasicNode[len + 1];
100 System.arraycopy(array, 0, narr, 0, pos);
102 System.arraycopy(array, pos, narr, pos + 1, len - pos);
103 return new CNode<>(gen, bmp | flag, narr);
107 * Returns a copy of this cnode such that all the i-nodes below it are
108 * copied to the specified generation `ngen`.
110 CNode<K, V> renewed(final Gen ngen, final TrieMap<K, V> ct) {
112 BasicNode[] arr = array;
113 int len = arr.length;
114 BasicNode[] narr = new BasicNode[len];
116 BasicNode elem = arr[i];
117 if (elem instanceof INode) {
118 INode<K, V> in = (INode<K, V>) elem;
119 narr [i] = in.copyToGen(ngen, ct);
120 } else if (elem != null) {
125 return new CNode<>(ngen, bitmap, narr);
128 private BasicNode resurrect(final INode<K, V> inode, final Object inodemain) {
129 if (inodemain instanceof TNode) {
130 TNode<K, V> tn = (TNode<K, V>) inodemain;
131 return tn.copyUntombed();
137 MainNode<K, V> toContracted(final int lev) {
138 if (array.length == 1 && lev > 0) {
139 if (array [0] instanceof SNode) {
140 SNode<K, V> sn = (SNode<K, V>) array[0];
141 return sn.copyTombed();
150 // - if the branching factor is 1 for this CNode, and the child
151 // is a tombed SNode, returns its tombed version
152 // - otherwise, if there is at least one non-null node below,
153 // returns the version of this node with at least some null-inodes
154 // removed (those existing when the op began)
155 // - if there are only null-i-nodes below, returns null
156 MainNode<K, V> toCompressed(final TrieMap<K, V> ct, final int lev, final Gen gen) {
159 BasicNode[] arr = array;
160 BasicNode[] tmparray = new BasicNode[arr.length];
161 while (i < arr.length) { // construct new bitmap
162 BasicNode sub = arr[i];
163 if (sub instanceof INode) {
164 INode<K, V> in = (INode<K, V>) sub;
165 MainNode<K, V> inodemain = in.gcasRead (ct);
166 assert (inodemain != null);
167 tmparray [i] = resurrect (in, inodemain);
168 } else if (sub instanceof SNode) {
174 return new CNode<K, V>(gen, bmp, tmparray).toContracted(lev);
178 String string(final int lev) {
179 // "CNode %x\n%s".format(bitmap, array.map(_.string(lev +
180 // 1)).mkString("\n"));
185 * quiescently consistent - don't call concurrently to anything
188 // protected Seq<K,V> collectElems() {
190 // case sn: SNode[K, V] => Some(sn.kvPair)
191 // case in: INode[K, V] => in.mainnode match {
192 // case tn: TNode[K, V] => Some(tn.kvPair)
193 // case ln: LNode[K, V] => ln.listmap.toList
194 // case cn: CNode[K, V] => cn.collectElems
199 // protected Seq<String> collectLocalElems() {
200 // // array flatMap {
201 // // case sn: SNode[K, V] => Some(sn.kvPair._2.toString)
202 // // case in: INode[K, V] => Some(in.toString.drop(14) + "(" + in.gen +
209 public String toString () {
210 // val elems = collectLocalElems
211 // "CNode(sz: %d; %s)".format(elems.size,
212 // elems.sorted.mkString(", "))
216 static <K, V> MainNode<K,V> dual(final SNode<K, V> x, final int xhc, final SNode<K, V> y, final int yhc,
217 final int lev, final Gen gen) {
219 int xidx = (xhc >>> lev) & 0x1f;
220 int yidx = (yhc >>> lev) & 0x1f;
221 int bmp = (1 << xidx) | (1 << yidx);
224 INode<K, V> subinode = new INode<>(gen, dual(x, xhc, y, yhc, lev + 5, gen));
225 return new CNode<>(gen, bmp, subinode);
228 return new CNode<>(gen, bmp, x, y);
230 return new CNode<>(gen, bmp, y, x);
234 return new LNode<>(x.k, x.v, y.k, y.v);