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+/* concurrentset.vala
+ *
+ * Copyright (C) 2012 Maciej Piechotka
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Author:
+ * Maciej Piechotka <uzytkownik2@gmail.com>
+ */
+
+/**
+ * A skip-linked list. This implementation is based on
+ * [[http://www.cse.yorku.ca/~ruppert/Mikhail.pdf|Mikhail Fomitchev Master Thesis]].
+ *
+ * Many threads are allowed to operate on the same structure as well as modification
+ * of structure during iteration is allowed. However the change may not be immidiatly
+ * visible to other threads.
+ */
+public class Gee.ConcurrentSet<G> : AbstractSortedSet<G> {
+ public ConcurrentSet (owned CompareDataFunc<G>? compare_func = null) {
+ if (compare_func == null) {
+ compare_func = Functions.get_compare_func_for (typeof (G));
+ }
+ _cmp = compare_func;
+ }
+
+ ~ConcurrentSet () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ _head = null;
+ }
+
+ public override int size { get { return GLib.AtomicInt.get (ref _size); } }
+
+ public override bool read_only { get { return false; } }
+
+ public override Gee.Iterator<G> iterator () {
+ return new Iterator<G> (this, _head);
+ }
+
+ public override bool contains (G key) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G> prev = _head;
+ return Tower.search<G> (_cmp, key, ref prev, null);
+ }
+
+ public override bool add (G key) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Rand *rnd = rand.get ();
+ if (rnd == null) {
+ rand.set (rnd = new Rand ());
+ }
+ uint32 rand_int = rnd->int_range (0, int32.MAX);
+ uint8 height = 1 + (uint8)GLib.Bit.nth_lsf (~rand_int, -1);
+ TowerIter<G> prev = TowerIter<G>();
+ prev._iter[height - 1] = _head;
+ if (Tower.search<G> (_cmp, key, ref prev._iter[height - 1], null, height - 1)) {
+ return false;
+ }
+ for (int i = height - 2; i >= 0; i--) {
+ prev._iter[i] = prev._iter[height - 1];
+ }
+ Tower<G>? result = Tower.insert<G> (_cmp, ref prev, key, height - 1);
+ if (result != null) {
+ GLib.AtomicInt.inc (ref _size);
+ }
+ return result != null;
+ }
+
+ public override bool remove (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ TowerIter<G> prev = TowerIter<G>();
+ for (int i = 0; i < _MAX_HEIGHT; i++) {
+ prev._iter[i] = _head;
+ }
+ bool result = Tower.remove_key<G> (_cmp, ref prev, item);
+ if (result) {
+ GLib.AtomicInt.dec_and_test (ref _size);
+ }
+ return result;
+ }
+
+ public override void clear () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G>? first;
+ while ((first = _head.get_next (0)) != null) {
+ remove (first._data);
+ }
+ }
+
+ public override G first () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G>? prev = null;
+ Tower<G> curr = _head;
+ if (Tower.proceed<G> (_cmp, ref prev, ref curr, 0)) {
+ return curr._data;
+ } else {
+ return null;
+ }
+ }
+
+ public override G last () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G>? prev = null;
+ Tower<G> curr = _head;
+ bool found = false;
+ for (int i = _MAX_HEIGHT; i >= 0; i--) {
+ while (Tower.proceed<G> (_cmp, ref prev, ref curr, 0)) {
+ found = true;
+ }
+ }
+ if (!found) {
+ return null;
+ }
+ return curr._data;
+ }
+
+ public override Gee.Iterator<G>? iterator_at (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ TowerIter<G> prev = TowerIter<G> ();
+ TowerIter<G> curr;
+ for (int i = 0; i < _MAX_HEIGHT; i++) {
+ prev._iter[i] = _head;
+ }
+ if (!Tower.search_from_bookmark<G> (_cmp, element, ref prev, out curr)) {
+ return null;
+ }
+ return new Iterator<G>.point_at (this, ref prev, curr._iter[0]);
+ }
+
+ public override G? lower (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G> prev = _head;
+ Tower.search<G> (_cmp, element, ref prev);
+ if (prev == _head) {
+ return null;
+ }
+ return prev._data;
+ }
+
+ public override G? higher (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G> prev = _head;
+ Tower<G>? next;
+ if (Tower.search<G> (_cmp, element, ref prev, out next)) {
+ if (!Tower.proceed<G> (_cmp, ref prev, ref next, 0)) {
+ return null;
+ }
+ }
+ if (next == null) {
+ return null;
+ }
+ return next._data;
+ }
+
+ public override G? floor (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G> prev = _head;
+ Tower<G>? next;
+ if (Tower.search<G> (_cmp, element, ref prev, out next)) {
+ return next._data;
+ } else if (prev != _head) {
+ return prev._data;
+ } else {
+ return null;
+ }
+ }
+
+ public override G? ceil (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G> prev = _head;
+ Tower<G>? next;
+ Tower.search<G> (_cmp, element, ref prev, out next);
+ if (next == null) {
+ return null;
+ }
+ return next._data;
+ }
+
+ public override SortedSet<G> head_set (G before) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ return new SubSet<G> (new Range<G>.head (this, before));
+ }
+
+ public override SortedSet<G> tail_set (G after) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ return new SubSet<G> (new Range<G>.tail (this, after));
+ }
+ public override SortedSet<G> sub_set (G from, G to) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ return new SubSet<G> (new Range<G> (this, from, to));
+ }
+
+ private unowned G max (G a, G b, out bool changed = null) {
+ changed = _cmp (a, b) < 0;
+ return changed ? b : a;
+ }
+
+ private unowned G min (G a, G b, out bool changed = null) {
+ changed = _cmp (a, b) > 0;
+ return changed ? b : a;
+ }
+
+#if DEBUG
+ public void dump () {
+ for (int i = _MAX_HEIGHT - 1; i >= 0; i--) {
+ bool printed = false;
+ Tower<G>? curr = _head;
+ State state;
+ while ((curr = curr.get_succ (out state, (uint8)i)) != null) {
+ if (!printed) {
+ stderr.printf("Level %d\n", i);
+ printed = true;
+ }
+ stderr.printf(" Node %p%s - %s\n", curr, state == State.NONE ? "" : state == State.MARKED ? " (MARKED)" : " (FLAGGED)", (string)curr._data);
+ assert (curr._height > i);
+ }
+ }
+ }
+#endif
+
+ private int _size = 0;
+ private Tower<G> _head = new Tower<G>.head ();
+ private CompareDataFunc<G>? _cmp;
+ private static const int _MAX_HEIGHT = 31;
+ private static Private rand = new Private((ptr) => {
+ Rand *rnd = (Rand *)ptr;
+ delete rnd;
+ });
+
+ private class Iterator<G> : Object, Traversable<G>, Gee.Iterator<G> {
+ public Iterator (ConcurrentSet cset, Tower<G> head) {
+ _curr = head;
+ _set = cset;
+ assert (_curr != null);
+ }
+
+ public Iterator.point_at (ConcurrentSet cset, ref TowerIter<G> prev, Tower<G> curr) {
+ _curr = curr;
+ _set = cset;
+ _prev = prev;
+ assert (_curr != null);
+ }
+
+ public new bool foreach (ForallFunc<G> f) {
+ assert (_curr != null);
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (_prev._iter[0] != null && !_removed) {
+ if (!f (_curr._data)) {
+ assert (_curr != null);
+ return false;
+ }
+ }
+ Tower<G> new_prev = _prev._iter[0];
+ Tower<G>? new_curr = _curr;
+ while (Tower.proceed<G> (_set._cmp, ref new_prev, ref new_curr, 0)) {
+ assert (_curr != null);
+ if (!_removed) {
+ //FIXME: Help mark/delete on the way
+ _prev._iter[0] = new_prev;
+ int prev_height = _prev._iter[0].get_height();
+ for (int i = 1; i < prev_height; i++) {
+ _prev._iter[i] = _prev._iter[0];
+ }
+ }
+ _curr = new_curr;
+ _removed = false;
+ if (!f (_curr._data)) {
+ assert (_curr != null);
+ return false;
+ }
+ }
+ assert (_curr != null);
+ return true;
+ }
+
+ public bool next () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G>? new_prev = _prev._iter[0];
+ Tower<G>? new_curr = _curr;
+ bool success = Tower.proceed<G> (_set._cmp, ref new_prev, ref new_curr, 0);
+ if (success) {
+ if (!_removed) {
+ //FIXME: Help mark/delete on the way
+ _prev._iter[0] = (owned)new_prev;
+ int prev_height = _prev._iter[0].get_height();
+ for (int i = 1; i < prev_height; i++) {
+ _prev._iter[i] = _prev._iter[0];
+ }
+ }
+ _curr = (owned)new_curr;
+ _removed = false;
+ }
+ assert (_curr != null);
+ return success;
+ }
+
+ public bool has_next () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G> prev = _prev._iter[0];
+ Tower<G>? curr = _curr;
+ return Tower.proceed<G> (_set._cmp, ref prev, ref curr, 0);
+ }
+
+ public new G get () {
+ assert (valid);
+ return _curr._data;
+ }
+
+ public void remove () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (valid);
+ if (Tower.remove<G> (_set._cmp, ref _prev, _curr)) {
+ AtomicInt.dec_and_test (ref _set._size);
+ }
+ _removed = true;
+ }
+
+ public bool valid { get { return _prev._iter[0] != null && !_removed; } }
+
+ public bool read_only { get { return true; } }
+
+ private bool _removed = false;
+ private ConcurrentSet<G> _set;
+ private TowerIter<G> _prev;
+ private Tower<G> _curr;
+ }
+
+ private class SubSet<G> : AbstractSortedSet<G> {
+ public override int size {
+ get {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G>? curr;
+ Range.improve_bookmark<G> (_range, out curr);
+ if (curr != null) {
+ int acc = 1;
+ Tower<G>? prev = HazardPointer.get_pointer<Tower<G>> (&_range._bookmark._iter[0]);
+ while (Range.proceed<G> (_range, ref prev, ref curr, 0)) {
+ acc++;
+ }
+ return acc;
+ } else {
+ return 0;
+ }
+ }
+ }
+
+ public bool is_empty {
+ get {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G>? curr;
+ Range.improve_bookmark<G> (_range, out curr);
+ return curr != null;
+ }
+ }
+
+ public override bool read_only { get { return false; } }
+
+ public SubSet (Range<G> range) {
+ _range = range;
+ }
+
+ public override Gee.Iterator<G> iterator () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ return new SubIterator<G> (_range);
+ }
+
+ public override bool contains (G item) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (!Range.inside<G> (_range, item)) {
+ return false;
+ }
+ TowerIter<G> prev;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ return Tower.search_from_bookmark<G> (_range._set._cmp, item, ref prev);
+ }
+
+ public override bool add (G key) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (!Range.inside<G> (_range, key)) {
+ return false;
+ }
+ TowerIter<G> prev;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ Rand *rnd = ConcurrentSet.rand.get ();
+ if (rnd == null) {
+ rand.set (rnd = new Rand ());
+ }
+ uint32 rand_int = rnd->int_range (0, int32.MAX);
+ uint8 height = 1 + (uint8)GLib.Bit.nth_lsf (~rand_int, -1);
+ if (Tower.search_from_bookmark<G> (_range._set._cmp, key, ref prev, null, height - 1)) {
+ return false;
+ }
+ for (int i = height - 2; i >= 0; i--) {
+ prev._iter[i] = prev._iter[height - 1];
+ }
+ Tower<G>? result = Tower.insert<G> (_range._set._cmp, ref prev, key, height - 1);
+ if (result != null) {
+ GLib.AtomicInt.inc (ref _range._set._size);
+ }
+ return result != null;
+ }
+
+ public override bool remove (G key) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (!Range.inside<G> (_range, key)) {
+ return false;
+ }
+ TowerIter<G> prev;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ // FIXME: Use full bookmark
+ bool result = Tower.remove_key<G> (_range._set._cmp, ref prev, key);
+ if (result) {
+ GLib.AtomicInt.dec_and_test (ref _range._set._size);
+ }
+ return result;
+ }
+
+ public override void clear () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ TowerIter<G> prev;
+ Tower<G>? first;
+ Range.improve_bookmark<G> (_range, out first, out prev);
+ while (first != null) {
+ Tower.remove<G> (_range._set._cmp, ref prev, first);
+ Range.improve_bookmark<G> (_range, out first, out prev);
+ }
+ }
+
+ public override G? first () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ Tower<G>? first;
+ Range.improve_bookmark<G> (_range, out first);
+ if (first == null) {
+ return null;
+ }
+ return first._data;
+ }
+
+ public override G? last () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ TowerIter<G> prev;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ Tower<G>? curr = null;
+ for (int i = _MAX_HEIGHT - 1; i >= 0; i--) {
+ if (curr == null) {
+ curr = prev._iter[i].get_next ((uint8)i);
+ if (curr == null || !Range.inside<G> (_range, curr._data)) {
+ curr = null;
+ continue;
+ }
+ }
+ bool improved = false;
+ while (Range.proceed<G> (_range, ref prev._iter[i], ref curr, (uint8)i)) {
+ improved = true;
+ }
+ if (improved && i > 0) {
+ prev._iter[i - 1] = prev._iter[i];
+ }
+ }
+ if (curr == null) {
+ return null;
+ }
+ return curr._data;
+ }
+
+ public override Gee.Iterator<G>? iterator_at (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (!Range.inside<G> (_range, element)) {
+ return null;
+ }
+ TowerIter<G> prev;
+ TowerIter<G> next;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ if (!Tower.search_from_bookmark<G> (_range._set._cmp, element, ref prev, out next)) {
+ return null;
+ }
+ return new SubIterator<G>.point_at (_range, ref prev, next._iter[0]);
+ }
+
+ public override G? lower (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ switch (Range.cmp<G> (_range, element)) {
+ case Range.Position.BEFORE:
+ case Range.Position.EMPTY:
+ return null;
+ case Range.Position.INSIDE:
+ TowerIter<G> prev;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ Tower.search_from_bookmark<G> (_range._set._cmp, element, ref prev);
+ if (prev._iter[0] == _range._set._head || !Range.inside (_range, prev._iter[0]._data)) {
+ return null;
+ }
+ return prev._iter[0]._data;
+ case Range.Position.AFTER:
+ return last ();
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ public override G? higher (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ switch (Range.cmp<G> (_range, element)) {
+ case Range.Position.BEFORE:
+ return first ();
+ case Range.Position.INSIDE:
+ TowerIter<G> prev;
+ TowerIter<G> curr;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ if (Tower.search_from_bookmark<G> (_range._set._cmp, element, ref prev, out curr)) {
+ if (!Tower.proceed<G> (_range._set._cmp, ref prev._iter[0], ref curr._iter[0], 0)) {
+ return null;
+ }
+ }
+ if (curr._iter[0] == null || !Range.inside(_range, curr._iter[0]._data)) {
+ return null;
+ }
+ return curr._iter[0]._data;
+ case Range.Position.AFTER:
+ case Range.Position.EMPTY:
+ return null;
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ public override G? floor (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ switch (Range.cmp<G> (_range, element)) {
+ case Range.Position.BEFORE:
+ case Range.Position.EMPTY:
+ return null;
+ case Range.Position.INSIDE:
+ TowerIter<G> curr;
+ TowerIter<G> prev;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ if (!Tower.search_from_bookmark<G> (_range._set._cmp, element, ref prev, out curr)) {
+ curr._iter[0] = (owned)prev._iter[0];
+ }
+ if (curr._iter[0] == null || curr._iter[0].is_head () || !Range.inside(_range, curr._iter[0]._data)) {
+ return null;
+ }
+ return curr._iter[0]._data;
+ case Range.Position.AFTER:
+ return last ();
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ public override G? ceil (G element) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ switch (Range.cmp<G> (_range, element)) {
+ case Range.Position.BEFORE:
+ return first ();
+ case Range.Position.INSIDE:
+ TowerIter<G> curr;
+ TowerIter<G> prev;
+ Range.improve_bookmark<G> (_range, null, out prev);
+ Tower.search_from_bookmark<G> (_range._set._cmp, element, ref prev, out curr);
+ if (curr._iter[0] == null || !Range.inside(_range, curr._iter[0]._data)) {
+ return null;
+ }
+ return curr._iter[0]._data;
+ case Range.Position.AFTER:
+ case Range.Position.EMPTY:
+ return null;
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ public override SortedSet<G> head_set (G before) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ return new SubSet<G> (Range.cut_tail (_range, before));
+ }
+
+ public override SortedSet<G> tail_set (G after) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ return new SubSet<G> (Range.cut_head (_range, after));
+ }
+
+ public override SortedSet<G> sub_set (G from, G to) {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ return new SubSet<G> (Range.cut (_range, from, to));
+ }
+
+ private Range<G> _range;
+ }
+
+ private class SubIterator<G> : Object, Traversable<G>, Gee.Iterator<G> {
+ public SubIterator (Range<G> range) {
+ Range.improve_bookmark<G> (range);
+ _range = range;
+ }
+
+ public SubIterator.point_at (Range<G> range, ref TowerIter<G> prev, owned Tower<G> curr) {
+ Range.improve_bookmark<G> (range);
+ _range = range;
+ _prev = prev;
+ _curr = curr;
+ }
+
+ public new bool foreach (ForallFunc<G> f) {
+ assert (_curr != null);
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (!begin ()) {
+ return true;
+ }
+ if (_prev._iter[0] != null && !_removed) {
+ if (!f (_curr._data)) {
+ assert (_curr != null);
+ return false;
+ }
+ }
+ Tower<G> new_prev = _prev._iter[0];
+ Tower<G>? new_curr = _curr;
+ while (Range.proceed<G> (_range, ref new_prev, ref new_curr, 0)) {
+ assert (_curr != null);
+ if (!f (_curr._data)) {
+ assert (_curr != null);
+ return false;
+ }
+ if (!_removed) {
+ //FIXME: Help mark/delete on the way
+ _prev._iter[0] = (owned)new_prev;
+ int prev_height = _prev._iter[0].get_height();
+ for (int i = 1; i < prev_height; i++) {
+ _prev._iter[i] = _prev._iter[0];
+ }
+ }
+ _curr = (owned)new_curr;
+ _removed = false;
+ }
+ assert (_curr != null);
+ return true;
+ }
+
+ public bool next () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (_prev._iter[0] == null) {
+ return begin ();
+ } else {
+ Tower<G> new_prev = _prev._iter[0];
+ Tower<G> new_curr = _curr;
+ if (Range.proceed<G> (_range, ref new_prev, ref new_curr, 0)) {
+ if (!_removed) {
+ //FIXME: Help mark/delete on the way
+ _prev._iter[0] = (owned)new_prev;
+ int prev_height = _prev._iter[0].get_height();
+ for (int i = 1; i < prev_height; i++) {
+ _prev._iter[i] = _prev._iter[0];
+ }
+ }
+ _curr = (owned)new_curr;
+ _removed = false;
+ return true;
+ } else {
+ return false;
+ }
+ }
+ }
+
+ public bool has_next () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ if (_prev._iter[0] == null) {
+ Tower<G> next;
+ Range.improve_bookmark<G> (_range, out next);
+ if (next != null && Range.beyond<G> (_range, next)) {
+ next = null;
+ }
+ return next != null;
+ } else {
+ Tower<G> new_prev = _prev._iter[0];
+ Tower<G> new_curr = _curr;
+ return Range.proceed<G> (_range, ref new_prev, ref new_curr, 0);
+ }
+ }
+
+ public new G get () {
+ assert (valid);
+ return _curr._data;
+ }
+
+ public void remove () {
+ HazardPointer.Context ctx = new HazardPointer.Context ();
+ assert (valid);
+ if (Tower.remove<G> (_range._set._cmp, ref _prev, _curr)) {
+ AtomicInt.dec_and_test (ref _range._set._size);
+ }
+ _removed = true;
+ }
+
+ public bool valid {
+ get {
+ bool is_valid = _prev._iter[0] != null && !_removed;
+ assert (!is_valid || _curr != null);
+ return is_valid;
+ }
+ }
+
+ public bool read_only { get { return false; } }
+
+ private bool begin () {
+ if (_prev._iter[0] != null) {
+ return true;
+ }
+ Range.improve_bookmark<G> (_range, out _curr, out _prev);
+ if (_curr == null) {
+ for (int i = 0; i < _MAX_HEIGHT; i++) {
+ _prev._iter[i] = null;
+ }
+ }
+ return _curr != null;
+ }
+
+ private Range<G> _range;
+ private TowerIter<G> _prev;
+ private Tower<G>? _curr = null;
+ private bool _removed = false;
+ }
+
+ private class Range<G> {
+ public G? _start;
+ public G? _end;
+ public RangeType _type;
+ public TowerIter<G> _bookmark;
+ public ConcurrentSet<G> _set;
+
+ public Range (ConcurrentSet<G> cset, G start, G end) {
+ _start = start;
+ _end = end;
+ if (cset._cmp(start, end) < 0) {
+ _type = RangeType.BOUNDED;
+ for (int i = 0; i < _MAX_HEIGHT; i++) {
+ _bookmark._iter[i] = cset._head;
+ }
+ } else {
+ _type = RangeType.EMPTY;
+ }
+ _set = cset;
+ }
+
+ public Range.head (ConcurrentSet<G> cset, G end) {
+ _end = end;
+ _type = RangeType.HEAD;
+ for (int i = 0; i < _MAX_HEIGHT; i++) {
+ _bookmark._iter[i] = cset._head;
+ }
+ _set = cset;
+ }
+
+ public Range.tail (ConcurrentSet<G> cset, G start) {
+ _start = start;
+ _type = RangeType.TAIL;
+ for (int i = 0; i < _MAX_HEIGHT; i++) {
+ _bookmark._iter[i] = cset._head;
+ }
+ _set = cset;
+ }
+
+ public Range.empty (ConcurrentSet<G> cset) {
+ _type = RangeType.EMPTY;
+ _set = cset;
+ }
+
+ private void copy_bookmark (Range<G> range) {
+ for (int i = 0; i < _MAX_HEIGHT; i++) {
+ _bookmark._iter[i] = HazardPointer.get_pointer<Tower<G>> (&range._bookmark._iter[i]);
+ }
+ }
+
+ public static Range<G> cut_head<G> (Range<G> from, G start) {
+ Range<G> result = new Range<G>.empty (from._set);
+ switch (from._type) {
+ case RangeType.HEAD:
+ if (from._set._cmp (start, from._end) < 0) {
+ result._start = start;
+ result._end = from._end;
+ result._type = RangeType.BOUNDED;
+ } else {
+ result._type = RangeType.EMPTY;
+ }
+ break;
+ case RangeType.TAIL:
+ result._start = from._set.max (from._start, start);
+ result._type = RangeType.TAIL;
+ break;
+ case RangeType.BOUNDED:
+ if (from._set._cmp (from._start, start) < 0) {
+ result._start = from._set.max (from._start, start);
+ result._end = from._end;
+ result._type = RangeType.BOUNDED;
+ } else {
+ result._type = RangeType.EMPTY;
+ }
+ break;
+ case RangeType.EMPTY:
+ result._type = RangeType.EMPTY;
+ break;
+ default:
+ assert_not_reached ();
+ }
+ if (result._type != RangeType.EMPTY) {
+ improve_bookmark<G> (from);
+ result.copy_bookmark (from);
+ improve_bookmark<G> (result);
+ }
+ return result;
+ }
+
+ public static Range<G> cut_tail<G> (Range<G> from, G end) {
+ Range<G> result = new Range<G>.empty (from._set);
+ switch (from._type) {
+ case RangeType.HEAD:
+ result._end = from._set.min (from._end, end);
+ result._type = RangeType.HEAD;
+ break;
+ case RangeType.TAIL:
+ if (from._set._cmp (from._start, end) < 0) {
+ result._start = from._start;
+ result._end = end;
+ result._type = RangeType.BOUNDED;
+ } else {
+ result._type = RangeType.EMPTY;
+ }
+ break;
+ case RangeType.BOUNDED:
+ if (from._set._cmp (from._start, end) < 0) {
+ result._start = from._start;
+ result._end = from._set.min (from._end, end);
+ result._type = RangeType.BOUNDED;
+ } else {
+ result._type = RangeType.EMPTY;
+ }
+ break;
+ case RangeType.EMPTY:
+ result._type = RangeType.EMPTY;
+ break;
+ default:
+ assert_not_reached ();
+ }
+ if (result._type != RangeType.EMPTY) {
+ improve_bookmark<G> (from);
+ result.copy_bookmark (from);
+ improve_bookmark<G> (result);
+ }
+ return result;
+ }
+
+ public static Range<G> cut<G> (Range<G> from, G start, G end) {
+ Range<G> result = new Range<G>.empty (from._set);
+ result._type = RangeType.BOUNDED;
+ switch (from._type) {
+ case RangeType.HEAD:
+ end = from._set.min (from._end, end);
+ break;
+ case RangeType.TAIL:
+ start = from._set.max (from._start, start);
+ break;
+ case RangeType.BOUNDED:
+ start = from._set.max (from._start, start);
+ end = from._set.min (from._end, end);
+ break;
+ case RangeType.EMPTY:
+ result._type = RangeType.EMPTY;
+ break;
+ default:
+ assert_not_reached ();
+ }
+ if (result._type != RangeType.EMPTY && from._set._cmp (start, end) < 0) {
+ result._start = start;
+ result._end = end;
+ result._type = RangeType.BOUNDED;
+ } else {
+ result._type = RangeType.EMPTY;
+ }
+ if (result._type != RangeType.EMPTY) {
+ improve_bookmark<G> (from);
+ result.copy_bookmark (from);
+ improve_bookmark<G> (result);
+ }
+ return result;
+ }
+
+ public static void improve_bookmark<G> (Range<G> range, out Tower<G>? out_curr = null, out TowerIter<G> prev = null) {
+ prev = TowerIter<G>();
+ switch (range._type) {
+ case RangeType.HEAD:
+ if (&out_curr != null) {
+ out_curr = HazardPointer.get_pointer<Tower<G>> (&range._bookmark._iter[0]);
+ if (&prev != null) {
+ prev._iter[0] = (owned)out_curr;
+ out_curr = prev._iter[0].get_next (0);
+ } else {
+ out_curr = out_curr.get_next (0);
+ }
+ }
+ if (&prev != null) {
+ for (int i = &out_curr != null ? 1 : 0; i < _MAX_HEIGHT; i++) {
+ prev._iter[i] = HazardPointer.get_pointer<Tower<G>> (&range._bookmark._iter[i]);
+ }
+ }
+ break;
+ case RangeType.EMPTY:
+ out_curr = null;
+ break;
+ case RangeType.TAIL:
+ case RangeType.BOUNDED:
+ Tower<G>? last_best = null;
+ for (int i = _MAX_HEIGHT - 1; i >= 0; i--) {
+ Tower<G> curr = HazardPointer.get_pointer<Tower<G>> (&range._bookmark._iter[i]);
+ Tower<G> curr_old = curr;
+ assert (curr != null);
+ Tower.backtrace<G> (ref curr, (uint8)i);
+ if (last_best != null && last_best != curr && Tower.compare<G> (range._set._cmp, curr, last_best) < 0) {
+ curr = last_best;
+ }
+ if (curr != curr_old) {
+ if (!HazardPointer.compare_and_exchange_pointer<Tower<G>> (&range._bookmark._iter[i], curr_old, curr)) {
+ curr = HazardPointer.get_pointer<Tower<G>> (&range._bookmark._iter[i]);
+ }
+ }
+ Tower<G> next = curr.get_next ((uint8)i);
+ if (&out_curr != null && i == 0) {
+ out_curr = next;
+ }
+ while (next != null && Tower.compare_data<G> (range._set._cmp, next, range._start) < 0) {
+ Tower.proceed<G> (range._set._cmp, ref curr, ref next, (uint8)i, true);
+ if (&curr != null && i == 0 && next != null) {
+ out_curr = next;
+ }
+ if (Tower.compare_data<G> (range._set._cmp, curr, range._start) < 0) {
+ if (!HazardPointer.compare_and_exchange_pointer<Tower<G>> (&range._bookmark._iter[i], curr_old, curr)) {
+ curr = HazardPointer.get_pointer<Tower<G>> (&range._bookmark._iter[i]);
+ }
+ curr_old = curr;
+ } else {
+ break;
+ }
+ }
+ if (&prev != null) {
+ prev._iter[i] = curr;
+ }
+ last_best = (owned)curr;
+ }
+ break;
+ default:
+ assert_not_reached ();
+ }
+ if (&out_curr != null && out_curr != null && Range.beyond<G> (range, out_curr)) {
+ out_curr = null;
+ }
+#if DEBUG
+ stderr.printf("Bookmark after:\n");
+ for (int i = _MAX_HEIGHT - 1; i >= 0; i--) {
+ stderr.printf(" Level %d:\n", i);
+ Tower<string>? t = HazardPointer.get_pointer<Tower<string>> (&range._bookmark._iter[i]);
+ assert (t == null || t.get_height () > i);
+ while (t != null) {
+ stderr.printf(" %s\n", t.is_head () ? "<<head>>" : t._data);
+ t = t.get_next ((uint8)i);
+ assert (t == null || t.get_height () > i);
+ }
+ }
+#endif
+ }
+
+ public static bool proceed<G> (Range<G> range, ref Tower<G>? prev, ref Tower<G> curr, uint8 level) {
+ switch (range._type) {
+ case RangeType.EMPTY:
+ return false;
+ case RangeType.TAIL:
+ return Tower.proceed<G> (range._set._cmp, ref prev, ref curr, level);
+ case RangeType.HEAD:
+ case RangeType.BOUNDED:
+ Tower<G>? tmp_prev = prev;
+ Tower<G>? tmp_curr = curr;
+ if (!Tower.proceed<G> (range._set._cmp, ref tmp_prev, ref tmp_curr, level)) {
+ return false;
+ } else if (Tower.compare_data<G> (range._set._cmp, tmp_curr, range._end) >= 0) {
+ return false;
+ } else {
+ prev = (owned)tmp_prev;
+ curr = (owned)tmp_curr;
+ return true;
+ }
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ public static bool inside<G> (Range<G> range, G val) {
+ switch (range._type) {
+ case RangeType.HEAD:
+ return range._set._cmp (val, range._end) < 0;
+ case RangeType.TAIL:
+ return range._set._cmp (val, range._start) >= 0;
+ case RangeType.BOUNDED:
+ return range._set._cmp (val, range._start) >= 0 && range._set._cmp (val, range._end) < 0;
+ case RangeType.EMPTY:
+ return false;
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ public static bool beyond<G> (Range<G> range, Tower<G> tw) {
+ switch (range._type) {
+ case RangeType.EMPTY:
+ return true;
+ case RangeType.TAIL:
+ return false;
+ case RangeType.HEAD:
+ case RangeType.BOUNDED:
+ return Tower.compare_data<G> (range._set._cmp, tw, range._end) >= 0;
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ public static int cmp<G> (Range<G> range, G val) {
+ switch (range._type) {
+ case RangeType.HEAD:
+ return range._set._cmp (val, range._end) < 0 ? Position.INSIDE : Position.AFTER;
+ case RangeType.TAIL:
+ return range._set._cmp (val, range._start) >= 0 ? Position.INSIDE : Position.BEFORE;
+ case RangeType.BOUNDED:
+ return range._set._cmp (val, range._start) >= 0 ? (range._set._cmp (val, range._end) < 0 ? Position.INSIDE : Position.AFTER) : Position.BEFORE;
+ case RangeType.EMPTY:
+ return Position.EMPTY;
+ default:
+ assert_not_reached ();
+ }
+ }
+
+ enum Position {
+ BEFORE = -1,
+ INSIDE = 0,
+ AFTER = 1,
+ EMPTY
+ }
+ }
+
+ public enum RangeType {
+ HEAD,
+ TAIL,
+ BOUNDED,
+ EMPTY
+ }
+
+ private class Tower<G> {
+ public inline Tower (G data, uint8 height) {
+ _nodes = new TowerNode<G>[height];
+ _data = data;
+ _height = 0;
+ AtomicPointer.set (&_nodes[0]._backlink, null); // FIXME: This should be memory barrier
+ }
+
+ public inline Tower.head () {
+ _nodes = new TowerNode<G>[_MAX_HEIGHT];
+ _height = -1;
+#if DEBUG
+ _data = (G)"<<head>>";
+#endif
+ }
+
+ inline ~Tower () {
+ int height = get_height();
+ for (uint8 i = 0; i < height; i++) {
+ set_succ (null, State.NONE, i);
+ set_backlink (null, i);
+ }
+ _nodes = null;
+ }
+
+ public static inline bool search<G> (CompareDataFunc<G>? cmp, G key, ref Tower<G> prev, out Tower<G>? next = null, uint8 to_level = 0, uint8 from_level = (uint8)_MAX_HEIGHT - 1) {
+ assert (from_level >= to_level);
+ bool res = false;
+ next = null;
+ for (int i = from_level; i >= to_level; i--) {
+ res = search_helper<G> (cmp, key, ref prev, out next, (uint8)i);
+ }
+ return res;
+ }
+
+ public static inline bool search_from_bookmark<G> (CompareDataFunc<G>? cmp, G key, ref TowerIter<G> prev, out TowerIter<G> next = null, uint8 to_level = 0, uint8 from_level = (uint8)_MAX_HEIGHT - 1) {
+ assert (from_level >= to_level);
+ bool res = false;
+ for (int i = from_level; i >= to_level; i--) {
+ unowned Tower<G> tmp_prev = prev._iter[i]; // Should be treated as NULL-like value
+ Tower<G> tmp_next;
+ res = search_helper<G> (cmp, key, ref prev._iter[i], out tmp_next, (uint8)i);
+ if (&next != null) {
+ next._iter[i] = (owned)tmp_next;
+ }
+ if (prev._iter[i] != tmp_prev) {
+ prev._iter[i] = prev._iter[i];
+ if (i > to_level && compare<G> (cmp, prev._iter[i - 1], prev._iter[i]) <= 0) {
+ prev._iter[i - 1] = prev._iter[i];
+ }
+ }
+ }
+ return res;
+ }
+
+ private static inline bool search_helper<G> (CompareDataFunc<G>? cmp, G key, ref Tower<G>? prev, out Tower<G>? next, uint8 level) {
+ next = prev.get_next (level);
+ while (next != null && compare_data<G> (cmp, next, key) < 0 && proceed<G> (cmp, ref prev, ref next, level, true));
+ return next != null && cmp(key, next._data) == 0;
+ }
+
+ public static inline Tower<G>? insert<G> (CompareDataFunc<G>? cmp, ref TowerIter<G> prev, G key, uint8 chosen_level) {
+ return insert_helper<G> (cmp, ref prev, key, chosen_level, chosen_level);
+ }
+
+ private static inline Tower<G>? insert_helper<G> (CompareDataFunc<G>? cmp, ref TowerIter<G> prev, G key, uint8 chosen_level, uint8 level) {
+ Tower<G>? new_tower;
+ Tower<G>? next;
+ if (search_helper (cmp, key, ref prev._iter[level], out next, level)) {
+ return null;
+ }
+ if (level > 0) {
+ if (compare<G> (cmp, prev._iter[level], prev._iter[level - 1]) >= 0) {
+ prev._iter[level - 1] = prev._iter[level];
+ }
+ new_tower = insert_helper<G> (cmp, ref prev, key, chosen_level, level - 1);
+ } else {
+ new_tower = new Tower<G> (key, chosen_level + 1);
+ }
+ if (new_tower == null) {
+ return null;
+ }
+ while (true) {
+ State prev_state;
+ Tower<G>? prev_next = prev._iter[level].get_succ (out prev_state, level);
+ if (prev_state == State.FLAGGED) {
+ prev_next.help_flagged (prev._iter[level], level);
+ } else {
+ new_tower.set_succ (next, State.NONE, level);
+ bool result = prev._iter[level].compare_and_exchange (next, State.NONE, new_tower, State.NONE, level);
+ if (result)
+ break;
+ prev_next = prev._iter[level].get_succ (out prev_state, level);
+ if (prev_state == State.FLAGGED) {
+ prev_next.help_flagged (prev._iter[level], level);
+ }
+ backtrace<G> (ref prev._iter[level], level);
+ }
+ if (search_helper (cmp, key, ref prev._iter[level], null, level)) {
+ return null;
+ }
+ }
+ GLib.AtomicInt.inc (ref new_tower._height);
+ if (new_tower.get_state (0) == State.MARKED) {
+ remove_level (cmp, ref prev._iter[level], new_tower, level);
+ return null;
+ }
+ return new_tower;
+ }
+
+ public static inline bool remove_key<G> (CompareDataFunc<G>? cmp, ref TowerIter<G> prev, G key, uint8 from_level = (uint8)_MAX_HEIGHT - 1) {
+ for (int i = from_level; i >= 1; i--) {
+ Tower<G> next;
+ search_helper<G> (cmp, key, ref prev._iter[i], out next, (uint8)i);
+ if (compare<G> (cmp, prev._iter[i - 1], prev._iter[i]) < 0) {
+ prev._iter[i - 1] = prev._iter[i];
+ }
+ }
+ Tower<G>? curr;
+ if (search_helper<G> (cmp, key, ref prev._iter[0], out curr, 0)) {
+ return remove<G> (cmp, ref prev, curr);
+ } else {
+ return false;
+ }
+ }
+
+ public static inline bool remove<G> (CompareDataFunc<G>? cmp, ref TowerIter<G> prev, Tower<G> curr) {
+ bool removed = remove_level (cmp, ref prev._iter[0], curr, 0);
+ for (int i = 1; i < _MAX_HEIGHT; i++) {
+ remove_level (cmp, ref prev._iter[i], curr, (uint8)i);
+ }
+ return removed;
+ }
+
+ private static inline bool remove_level (CompareDataFunc<G>? cmp, ref Tower<G> prev, Tower<G> curr, uint8 level) {
+ bool status;
+ bool flagged = curr.try_flag (cmp, ref prev, out status, level);
+ if (status) {
+ curr.help_flagged (prev, level);
+ }
+ return flagged;
+ }
+
+ public static inline bool proceed<G> (CompareDataFunc<G>? cmp, ref Tower<G>? arg_prev, ref Tower<G> arg_curr, uint8 level, bool force = false) {
+ Tower<G> curr = arg_curr;
+ Tower<G>? next = curr.get_next (level);
+ if (next != null) {
+ while (next != null && next.get_state (0) == State.MARKED) {
+ bool status;
+ next.try_flag (cmp, ref curr, out status, level);
+ if (status) {
+ next.help_flagged (curr, level);
+ }
+ next = curr.get_next (level);
+ }
+ }
+ bool success = next != null;
+ if (success || force) {
+ arg_prev = (owned)curr;
+ arg_curr = (owned)next;
+ }
+ return success;
+ }
+
+ public inline void help_marked (Tower<G> prev_tower, uint8 level) {
+ prev_tower.compare_and_exchange (this, State.FLAGGED, get_next (level), State.NONE, level);
+ }
+
+ public inline void help_flagged (Tower<G> prev, uint8 level) {
+ set_backlink (prev, level);
+ if (get_state (level) != State.MARKED)
+ try_mark (level);
+ help_marked (prev, level);
+ }
+
+ public inline void try_mark (uint8 level) {
+ do {
+ Tower<G>? next_tower = get_next (level);
+ bool result = compare_and_exchange (next_tower, State.NONE, next_tower, State.MARKED, level);
+ if (!result) {
+ State state;
+ next_tower = get_succ (out state, level);
+ if (state == State.FLAGGED)
+ help_flagged (next_tower, level);
+ }
+ } while (get_state (level) != State.MARKED);
+ }
+
+ public inline bool try_flag (CompareDataFunc<G>? cmp, ref Tower<G> prev_tower, out bool status, uint8 level) {
+ while (true) {
+ if (prev_tower.compare_succ (this, State.FLAGGED, level)) {
+ status = true;
+ return false;
+ }
+ bool result = prev_tower.compare_and_exchange (this, State.NONE, this, State.FLAGGED, level);
+ if (result) {
+ status = true;
+ return true;
+ }
+ State result_state;
+ Tower<G>? result_tower = prev_tower.get_succ (out result_state, level);
+ if (result_tower == this && result_state == State.FLAGGED) {
+ status = true;
+ return false;
+ }
+ backtrace<G> (ref prev_tower, level);
+ if (!search_helper (cmp, _data, ref prev_tower, null, level)) {
+ status = false;
+ return false;
+ }
+ }
+ }
+
+ public static inline void backtrace<G> (ref Tower<G>? curr, uint8 level) {
+ while (curr.get_state (level) == State.MARKED)
+ curr = curr.get_backlink (level);
+ }
+
+ public inline bool compare_and_exchange (Tower<G>? old_tower, State old_state, Tower<G>? new_tower, State new_state, uint8 level) {
+ return HazardPointer.compare_and_exchange_pointer<Tower<G>?> (&_nodes[level]._succ, old_tower, new_tower, 3, (size_t)old_state, (size_t)new_state);
+ }
+
+ public inline bool compare_succ (Tower<G>? next, State state, uint8 level) {
+ size_t cur = (size_t)AtomicPointer.get (&_nodes[level]._succ);
+ return cur == ((size_t)next | (size_t)state);
+ }
+
+ public inline Tower<G>? get_next (uint8 level) {
+ return get_succ (null, level);
+ }
+
+ public inline State get_state (uint8 level) {
+ return (State)((size_t)AtomicPointer.get (&_nodes[level]._succ) & 3);
+ }
+
+ public inline Tower<G>? get_succ (out State state, uint8 level) {
+ size_t rstate;
+ Tower<G>? succ = HazardPointer.get_pointer<Tower<G>> (&_nodes[level]._succ, 3, out rstate);
+ state = (State)rstate;
+ return (owned)succ;
+ }
+
+ public inline void set_succ (Tower<G>? next, State state, uint8 level) {
+ HazardPointer.set_pointer<Tower<G>> (&_nodes[level]._succ, next, 3, (size_t)state);
+ }
+
+ public inline Tower<G>? get_backlink (uint8 level) {
+ return HazardPointer.get_pointer<Tower<G>> (&_nodes[level]._backlink);
+ }
+
+ public inline void set_backlink (Tower<G>? backlink, uint8 level) {
+ HazardPointer.compare_and_exchange_pointer<Tower<G>?> (&_nodes[level]._backlink, null, backlink);
+ }
+
+ public inline int get_height () {
+ int height = GLib.AtomicInt.get (ref _height);
+ return height != -1 ? height : _MAX_HEIGHT;
+ }
+
+ public inline bool is_head () {
+ int height = GLib.AtomicInt.get (ref _height);
+ return height == -1;
+ }
+
+ public inline static int compare<G> (CompareDataFunc<G>? cmp, Tower<G> a, Tower<G> b) {
+ bool ah = GLib.AtomicInt.get (ref a._height) == -1;
+ bool bh = GLib.AtomicInt.get (ref b._height) == -1;
+ return ah ? (bh ? 0 : -1) : (bh ? 1 : cmp(a._data, b._data));
+ }
+
+ public inline static int compare_data<G> (CompareDataFunc<G>? cmp, Tower<G> a, G b) {
+ bool ah = GLib.AtomicInt.get (ref a._height) == -1;
+ return ah ? -1 : cmp(a._data, b);
+ }
+
+ [NoArrayLength]
+ public TowerNode<G>[] _nodes;
+ public G _data;
+ public int _height;
+ }
+
+ private struct TowerNode<G> {
+ public Tower<G> *_succ;
+ public Tower<G> *_backlink;
+ }
+
+ private struct TowerIter<G> {
+ [NoArrayLength]
+ public Tower<G>? _iter[31 /*_MAX_HEIGHT*/];
+ }
+
+
+ private enum State {
+ NONE = 0,
+ MARKED = 1,
+ FLAGGED = 2
+ }
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-13 07:03:56 +0000