497 строки
13 KiB
C#
497 строки
13 KiB
C#
// SplitOrderedList.cs
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//
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// Copyright (c) 2010 Jérémie "Garuma" Laval
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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//
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using System;
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using System.Collections.Generic;
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using System.Threading;
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namespace Xamarin.Forms
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{
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internal class SplitOrderedList<TKey, T>
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{
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const int MaxLoad = 5;
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const uint BucketSize = 512;
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static readonly byte[] ReverseTable =
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{
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0, 128, 64, 192, 32, 160, 96, 224, 16, 144, 80, 208, 48, 176, 112, 240, 8, 136, 72, 200, 40, 168, 104, 232, 24, 152, 88, 216, 56, 184, 120, 248, 4,
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132, 68, 196, 36, 164, 100, 228, 20, 148, 84, 212, 52, 180, 116, 244, 12, 140, 76, 204, 44, 172, 108, 236, 28, 156, 92, 220, 60, 188, 124, 252, 2, 130, 66, 194, 34, 162, 98, 226, 18, 146, 82, 210,
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50, 178, 114, 242, 10, 138, 74, 202, 42, 170, 106, 234, 26, 154, 90, 218, 58, 186, 122, 250, 6, 134, 70, 198, 38, 166, 102, 230, 22, 150, 86, 214, 54, 182, 118, 246, 14, 142, 78, 206, 46, 174, 110,
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238, 30, 158, 94, 222, 62, 190, 126, 254, 1, 129, 65, 193, 33, 161, 97, 225, 17, 145, 81, 209, 49, 177, 113, 241, 9, 137, 73, 201, 41, 169, 105, 233, 25, 153, 89, 217, 57, 185, 121, 249, 5, 133, 69,
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197, 37, 165, 101, 229, 21, 149, 85, 213, 53, 181, 117, 245, 13, 141, 77, 205, 45, 173, 109, 237, 29, 157, 93, 221, 61, 189, 125, 253, 3, 131, 67, 195, 35, 163, 99, 227, 19, 147, 83, 211, 51, 179,
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115, 243, 11, 139, 75, 203, 43, 171, 107, 235, 27, 155, 91, 219, 59, 187, 123, 251, 7, 135, 71, 199, 39, 167, 103, 231, 23, 151, 87, 215, 55, 183, 119, 247, 15, 143, 79, 207, 47, 175, 111, 239, 31,
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159, 95, 223, 63, 191, 127, 255
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};
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static readonly byte[] LogTable =
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{
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0xFF, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
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5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7
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};
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readonly IEqualityComparer<TKey> _comparer;
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readonly Node _head;
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readonly Node _tail;
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Node[] _buckets = new Node[BucketSize];
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int _count;
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int _size = 2;
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SimpleRwLock _slim = new SimpleRwLock();
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public SplitOrderedList(IEqualityComparer<TKey> comparer)
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{
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_comparer = comparer;
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_head = new Node().Init(0);
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_tail = new Node().Init(ulong.MaxValue);
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_head.Next = _tail;
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SetBucket(0, _head);
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}
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public int Count
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{
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get { return _count; }
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}
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public bool CompareExchange(uint key, TKey subKey, T data, Func<T, bool> check)
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{
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Node node;
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uint b = key % (uint)_size;
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Node bucket;
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if ((bucket = GetBucket(b)) == null)
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bucket = InitializeBucket(b);
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if (!ListFind(ComputeRegularKey(key), subKey, bucket, out node))
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return false;
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if (!check(node.Data))
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return false;
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node.Data = data;
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return true;
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}
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public bool Delete(uint key, TKey subKey, out T data)
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{
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uint b = key % (uint)_size;
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Node bucket;
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if ((bucket = GetBucket(b)) == null)
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bucket = InitializeBucket(b);
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if (!ListDelete(bucket, ComputeRegularKey(key), subKey, out data))
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return false;
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Interlocked.Decrement(ref _count);
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return true;
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}
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public bool Find(uint key, TKey subKey, out T data)
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{
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Node node;
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uint b = key % (uint)_size;
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data = default(T);
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Node bucket;
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if ((bucket = GetBucket(b)) == null)
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bucket = InitializeBucket(b);
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if (!ListFind(ComputeRegularKey(key), subKey, bucket, out node))
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return false;
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data = node.Data;
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return !node.Marked;
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}
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public IEnumerator<T> GetEnumerator()
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{
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Node node = _head.Next;
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while (node != _tail)
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{
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while (node.Marked || (node.Key & 1) == 0)
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{
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node = node.Next;
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if (node == _tail)
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yield break;
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}
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yield return node.Data;
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node = node.Next;
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}
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}
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public bool Insert(uint key, TKey subKey, T data)
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{
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Node current;
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return InsertInternal(key, subKey, data, null, out current);
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}
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public T InsertOrGet(uint key, TKey subKey, T data, Func<T> dataCreator)
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{
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Node current;
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InsertInternal(key, subKey, data, dataCreator, out current);
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return current.Data;
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}
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public T InsertOrUpdate(uint key, TKey subKey, Func<T> addGetter, Func<T, T> updateGetter)
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{
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Node current;
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bool result = InsertInternal(key, subKey, default(T), addGetter, out current);
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if (result)
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return current.Data;
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// FIXME: this should have a CAS-like behavior
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return current.Data = updateGetter(current.Data);
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}
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public T InsertOrUpdate(uint key, TKey subKey, T addValue, T updateValue)
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{
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Node current;
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if (InsertInternal(key, subKey, addValue, null, out current))
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return current.Data;
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// FIXME: this should have a CAS-like behavior
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return current.Data = updateValue;
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}
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// When we run out of space for bucket storage, we use a lock-based array resize
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void CheckSegment(uint segment, bool readLockTaken)
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{
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if (segment < _buckets.Length)
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return;
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if (readLockTaken)
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_slim.ExitReadLock();
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try
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{
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_slim.EnterWriteLock();
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while (segment >= _buckets.Length)
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Array.Resize(ref _buckets, _buckets.Length * 2);
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}
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finally
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{
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_slim.ExitWriteLock();
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}
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if (readLockTaken)
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_slim.EnterReadLock();
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}
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// Reverse integer bits
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static ulong ComputeDummyKey(uint key)
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{
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return (ulong)(((uint)ReverseTable[key & 0xff] << 24) | ((uint)ReverseTable[(key >> 8) & 0xff] << 16) | ((uint)ReverseTable[(key >> 16) & 0xff] << 8) | ReverseTable[(key >> 24) & 0xff]) << 1;
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}
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// Reverse integer bits and make sure LSB is set
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static ulong ComputeRegularKey(uint key)
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{
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return ComputeDummyKey(key) | 1;
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}
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// Bucket storage is abstracted in a simple two-layer tree to avoid too much memory resize
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Node GetBucket(uint index)
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{
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if (index >= _buckets.Length)
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return null;
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return _buckets[index];
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}
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// Turn v's MSB off
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static uint GetParent(uint v)
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{
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uint t, tt;
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// Find MSB position in v
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int pos = (tt = v >> 16) > 0 ? (t = tt >> 8) > 0 ? 24 + LogTable[t] : 16 + LogTable[tt] : (t = v >> 8) > 0 ? 8 + LogTable[t] : LogTable[v];
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return (uint)(v & ~(1 << pos));
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}
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Node InitializeBucket(uint b)
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{
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Node current;
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uint parent = GetParent(b);
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Node bucket;
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if ((bucket = GetBucket(parent)) == null)
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bucket = InitializeBucket(parent);
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Node dummy = new Node().Init(ComputeDummyKey(b));
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if (!ListInsert(dummy, bucket, out current, null))
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return current;
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return SetBucket(b, dummy);
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}
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bool InsertInternal(uint key, TKey subKey, T data, Func<T> dataCreator, out Node current)
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{
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Node node = new Node().Init(ComputeRegularKey(key), subKey, data);
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uint b = key % (uint)_size;
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Node bucket;
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if ((bucket = GetBucket(b)) == null)
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bucket = InitializeBucket(b);
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if (!ListInsert(node, bucket, out current, dataCreator))
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return false;
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int csize = _size;
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if (Interlocked.Increment(ref _count) / csize > MaxLoad && (csize & 0x40000000) == 0)
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Interlocked.CompareExchange(ref _size, 2 * csize, csize);
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current = node;
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return true;
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}
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bool ListDelete(Node startPoint, ulong key, TKey subKey, out T data)
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{
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Node rightNode = null, rightNodeNext = null, leftNode = null;
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data = default(T);
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Node markedNode = null;
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do
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{
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rightNode = ListSearch(key, subKey, ref leftNode, startPoint);
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if (rightNode == _tail || rightNode.Key != key || !_comparer.Equals(subKey, rightNode.SubKey))
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return false;
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data = rightNode.Data;
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rightNodeNext = rightNode.Next;
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if (!rightNodeNext.Marked)
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{
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if (markedNode == null)
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markedNode = new Node();
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markedNode.Init(rightNodeNext);
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if (Interlocked.CompareExchange(ref rightNode.Next, markedNode, rightNodeNext) == rightNodeNext)
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break;
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}
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} while (true);
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if (Interlocked.CompareExchange(ref leftNode.Next, rightNodeNext, rightNode) != rightNode)
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ListSearch(rightNode.Key, subKey, ref leftNode, startPoint);
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return true;
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}
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bool ListFind(ulong key, TKey subKey, Node startPoint, out Node data)
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{
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Node rightNode = null, leftNode = null;
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data = null;
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rightNode = ListSearch(key, subKey, ref leftNode, startPoint);
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data = rightNode;
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return rightNode != _tail && rightNode.Key == key && _comparer.Equals(subKey, rightNode.SubKey);
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}
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bool ListInsert(Node newNode, Node startPoint, out Node current, Func<T> dataCreator)
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{
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ulong key = newNode.Key;
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Node rightNode = null, leftNode = null;
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do
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{
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rightNode = current = ListSearch(key, newNode.SubKey, ref leftNode, startPoint);
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if (rightNode != _tail && rightNode.Key == key && _comparer.Equals(newNode.SubKey, rightNode.SubKey))
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return false;
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newNode.Next = rightNode;
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if (dataCreator != null)
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newNode.Data = dataCreator();
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if (Interlocked.CompareExchange(ref leftNode.Next, newNode, rightNode) == rightNode)
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return true;
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} while (true);
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}
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Node ListSearch(ulong key, TKey subKey, ref Node left, Node h)
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{
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Node leftNodeNext = null, rightNode = null;
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do
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{
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Node t = h;
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Node tNext = t.Next;
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do
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{
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if (!tNext.Marked)
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{
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left = t;
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leftNodeNext = tNext;
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}
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t = tNext.Marked ? tNext.Next : tNext;
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if (t == _tail)
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break;
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tNext = t.Next;
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} while (tNext.Marked || t.Key < key || (tNext.Key == key && !_comparer.Equals(subKey, t.SubKey)));
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rightNode = t;
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if (leftNodeNext == rightNode)
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{
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if (rightNode != _tail && rightNode.Next.Marked)
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continue;
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return rightNode;
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}
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if (Interlocked.CompareExchange(ref left.Next, rightNode, leftNodeNext) == leftNodeNext)
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{
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if (rightNode != _tail && rightNode.Next.Marked)
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continue;
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return rightNode;
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}
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} while (true);
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}
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Node SetBucket(uint index, Node node)
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{
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try
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{
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_slim.EnterReadLock();
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CheckSegment(index, true);
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Interlocked.CompareExchange(ref _buckets[index], node, null);
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return _buckets[index];
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}
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finally
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{
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_slim.ExitReadLock();
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}
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}
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class Node
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{
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public T Data;
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public ulong Key;
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public bool Marked;
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public Node Next;
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public TKey SubKey;
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public Node Init(ulong key, TKey subKey, T data)
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{
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Key = key;
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SubKey = subKey;
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Data = data;
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Marked = false;
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Next = null;
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return this;
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}
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// Used to create dummy node
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public Node Init(ulong key)
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{
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Key = key;
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Data = default(T);
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Next = null;
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Marked = false;
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SubKey = default(TKey);
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return this;
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}
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// Used to create marked node
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public Node Init(Node wrapped)
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{
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Marked = true;
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Next = wrapped;
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Key = 0;
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Data = default(T);
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SubKey = default(TKey);
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return this;
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}
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}
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struct SimpleRwLock
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{
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const int RwWait = 1;
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const int RwWrite = 2;
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const int RwRead = 4;
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int _rwlock;
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public void EnterReadLock()
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{
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var sw = new SpinWait();
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do
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{
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while ((_rwlock & (RwWrite | RwWait)) > 0)
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sw.SpinOnce();
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if ((Interlocked.Add(ref _rwlock, RwRead) & (RwWait | RwWait)) == 0)
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return;
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Interlocked.Add(ref _rwlock, -RwRead);
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} while (true);
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}
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public void ExitReadLock()
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{
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Interlocked.Add(ref _rwlock, -RwRead);
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}
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public void EnterWriteLock()
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{
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var sw = new SpinWait();
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do
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{
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int state = _rwlock;
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if (state < RwWrite)
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{
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if (Interlocked.CompareExchange(ref _rwlock, RwWrite, state) == state)
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return;
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state = _rwlock;
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}
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// We register our interest in taking the Write lock (if upgradeable it's already done)
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while ((state & RwWait) == 0 && Interlocked.CompareExchange(ref _rwlock, state | RwWait, state) != state)
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state = _rwlock;
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// Before falling to sleep
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while (_rwlock > RwWait)
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sw.SpinOnce();
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} while (true);
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}
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public void ExitWriteLock()
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{
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Interlocked.Add(ref _rwlock, -RwWrite);
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}
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}
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}
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} |