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maui-linux/Xamarin.Forms.Platform.WP8/SplitOrderedList.cs

497 строки
13 KiB
C#
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// SplitOrderedList.cs
//
// Copyright (c) 2010 Jérémie "Garuma" Laval
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
//
using System;
using System.Collections.Generic;
using System.Threading;
namespace Xamarin.Forms
{
internal class SplitOrderedList<TKey, T>
{
const int MaxLoad = 5;
const uint BucketSize = 512;
static readonly byte[] ReverseTable =
{
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,
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,
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,
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,
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,
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,
159, 95, 223, 63, 191, 127, 255
};
static readonly byte[] LogTable =
{
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,
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,
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,
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,
7, 7, 7, 7, 7, 7, 7
};
readonly IEqualityComparer<TKey> _comparer;
readonly Node _head;
readonly Node _tail;
Node[] _buckets = new Node[BucketSize];
int _count;
int _size = 2;
SimpleRwLock _slim = new SimpleRwLock();
public SplitOrderedList(IEqualityComparer<TKey> comparer)
{
_comparer = comparer;
_head = new Node().Init(0);
_tail = new Node().Init(ulong.MaxValue);
_head.Next = _tail;
SetBucket(0, _head);
}
public int Count
{
get { return _count; }
}
public bool CompareExchange(uint key, TKey subKey, T data, Func<T, bool> check)
{
Node node;
uint b = key % (uint)_size;
Node bucket;
if ((bucket = GetBucket(b)) == null)
bucket = InitializeBucket(b);
if (!ListFind(ComputeRegularKey(key), subKey, bucket, out node))
return false;
if (!check(node.Data))
return false;
node.Data = data;
return true;
}
public bool Delete(uint key, TKey subKey, out T data)
{
uint b = key % (uint)_size;
Node bucket;
if ((bucket = GetBucket(b)) == null)
bucket = InitializeBucket(b);
if (!ListDelete(bucket, ComputeRegularKey(key), subKey, out data))
return false;
Interlocked.Decrement(ref _count);
return true;
}
public bool Find(uint key, TKey subKey, out T data)
{
Node node;
uint b = key % (uint)_size;
data = default(T);
Node bucket;
if ((bucket = GetBucket(b)) == null)
bucket = InitializeBucket(b);
if (!ListFind(ComputeRegularKey(key), subKey, bucket, out node))
return false;
data = node.Data;
return !node.Marked;
}
public IEnumerator<T> GetEnumerator()
{
Node node = _head.Next;
while (node != _tail)
{
while (node.Marked || (node.Key & 1) == 0)
{
node = node.Next;
if (node == _tail)
yield break;
}
yield return node.Data;
node = node.Next;
}
}
public bool Insert(uint key, TKey subKey, T data)
{
Node current;
return InsertInternal(key, subKey, data, null, out current);
}
public T InsertOrGet(uint key, TKey subKey, T data, Func<T> dataCreator)
{
Node current;
InsertInternal(key, subKey, data, dataCreator, out current);
return current.Data;
}
public T InsertOrUpdate(uint key, TKey subKey, Func<T> addGetter, Func<T, T> updateGetter)
{
Node current;
bool result = InsertInternal(key, subKey, default(T), addGetter, out current);
if (result)
return current.Data;
// FIXME: this should have a CAS-like behavior
return current.Data = updateGetter(current.Data);
}
public T InsertOrUpdate(uint key, TKey subKey, T addValue, T updateValue)
{
Node current;
if (InsertInternal(key, subKey, addValue, null, out current))
return current.Data;
// FIXME: this should have a CAS-like behavior
return current.Data = updateValue;
}
// When we run out of space for bucket storage, we use a lock-based array resize
void CheckSegment(uint segment, bool readLockTaken)
{
if (segment < _buckets.Length)
return;
if (readLockTaken)
_slim.ExitReadLock();
try
{
_slim.EnterWriteLock();
while (segment >= _buckets.Length)
Array.Resize(ref _buckets, _buckets.Length * 2);
}
finally
{
_slim.ExitWriteLock();
}
if (readLockTaken)
_slim.EnterReadLock();
}
// Reverse integer bits
static ulong ComputeDummyKey(uint key)
{
return (ulong)(((uint)ReverseTable[key & 0xff] << 24) | ((uint)ReverseTable[(key >> 8) & 0xff] << 16) | ((uint)ReverseTable[(key >> 16) & 0xff] << 8) | ReverseTable[(key >> 24) & 0xff]) << 1;
}
// Reverse integer bits and make sure LSB is set
static ulong ComputeRegularKey(uint key)
{
return ComputeDummyKey(key) | 1;
}
// Bucket storage is abstracted in a simple two-layer tree to avoid too much memory resize
Node GetBucket(uint index)
{
if (index >= _buckets.Length)
return null;
return _buckets[index];
}
// Turn v's MSB off
static uint GetParent(uint v)
{
uint t, tt;
// Find MSB position in v
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];
return (uint)(v & ~(1 << pos));
}
Node InitializeBucket(uint b)
{
Node current;
uint parent = GetParent(b);
Node bucket;
if ((bucket = GetBucket(parent)) == null)
bucket = InitializeBucket(parent);
Node dummy = new Node().Init(ComputeDummyKey(b));
if (!ListInsert(dummy, bucket, out current, null))
return current;
return SetBucket(b, dummy);
}
bool InsertInternal(uint key, TKey subKey, T data, Func<T> dataCreator, out Node current)
{
Node node = new Node().Init(ComputeRegularKey(key), subKey, data);
uint b = key % (uint)_size;
Node bucket;
if ((bucket = GetBucket(b)) == null)
bucket = InitializeBucket(b);
if (!ListInsert(node, bucket, out current, dataCreator))
return false;
int csize = _size;
if (Interlocked.Increment(ref _count) / csize > MaxLoad && (csize & 0x40000000) == 0)
Interlocked.CompareExchange(ref _size, 2 * csize, csize);
current = node;
return true;
}
bool ListDelete(Node startPoint, ulong key, TKey subKey, out T data)
{
Node rightNode = null, rightNodeNext = null, leftNode = null;
data = default(T);
Node markedNode = null;
do
{
rightNode = ListSearch(key, subKey, ref leftNode, startPoint);
if (rightNode == _tail || rightNode.Key != key || !_comparer.Equals(subKey, rightNode.SubKey))
return false;
data = rightNode.Data;
rightNodeNext = rightNode.Next;
if (!rightNodeNext.Marked)
{
if (markedNode == null)
markedNode = new Node();
markedNode.Init(rightNodeNext);
if (Interlocked.CompareExchange(ref rightNode.Next, markedNode, rightNodeNext) == rightNodeNext)
break;
}
} while (true);
if (Interlocked.CompareExchange(ref leftNode.Next, rightNodeNext, rightNode) != rightNode)
ListSearch(rightNode.Key, subKey, ref leftNode, startPoint);
return true;
}
bool ListFind(ulong key, TKey subKey, Node startPoint, out Node data)
{
Node rightNode = null, leftNode = null;
data = null;
rightNode = ListSearch(key, subKey, ref leftNode, startPoint);
data = rightNode;
return rightNode != _tail && rightNode.Key == key && _comparer.Equals(subKey, rightNode.SubKey);
}
bool ListInsert(Node newNode, Node startPoint, out Node current, Func<T> dataCreator)
{
ulong key = newNode.Key;
Node rightNode = null, leftNode = null;
do
{
rightNode = current = ListSearch(key, newNode.SubKey, ref leftNode, startPoint);
if (rightNode != _tail && rightNode.Key == key && _comparer.Equals(newNode.SubKey, rightNode.SubKey))
return false;
newNode.Next = rightNode;
if (dataCreator != null)
newNode.Data = dataCreator();
if (Interlocked.CompareExchange(ref leftNode.Next, newNode, rightNode) == rightNode)
return true;
} while (true);
}
Node ListSearch(ulong key, TKey subKey, ref Node left, Node h)
{
Node leftNodeNext = null, rightNode = null;
do
{
Node t = h;
Node tNext = t.Next;
do
{
if (!tNext.Marked)
{
left = t;
leftNodeNext = tNext;
}
t = tNext.Marked ? tNext.Next : tNext;
if (t == _tail)
break;
tNext = t.Next;
} while (tNext.Marked || t.Key < key || (tNext.Key == key && !_comparer.Equals(subKey, t.SubKey)));
rightNode = t;
if (leftNodeNext == rightNode)
{
if (rightNode != _tail && rightNode.Next.Marked)
continue;
return rightNode;
}
if (Interlocked.CompareExchange(ref left.Next, rightNode, leftNodeNext) == leftNodeNext)
{
if (rightNode != _tail && rightNode.Next.Marked)
continue;
return rightNode;
}
} while (true);
}
Node SetBucket(uint index, Node node)
{
try
{
_slim.EnterReadLock();
CheckSegment(index, true);
Interlocked.CompareExchange(ref _buckets[index], node, null);
return _buckets[index];
}
finally
{
_slim.ExitReadLock();
}
}
class Node
{
public T Data;
public ulong Key;
public bool Marked;
public Node Next;
public TKey SubKey;
public Node Init(ulong key, TKey subKey, T data)
{
Key = key;
SubKey = subKey;
Data = data;
Marked = false;
Next = null;
return this;
}
// Used to create dummy node
public Node Init(ulong key)
{
Key = key;
Data = default(T);
Next = null;
Marked = false;
SubKey = default(TKey);
return this;
}
// Used to create marked node
public Node Init(Node wrapped)
{
Marked = true;
Next = wrapped;
Key = 0;
Data = default(T);
SubKey = default(TKey);
return this;
}
}
struct SimpleRwLock
{
const int RwWait = 1;
const int RwWrite = 2;
const int RwRead = 4;
int _rwlock;
public void EnterReadLock()
{
var sw = new SpinWait();
do
{
while ((_rwlock & (RwWrite | RwWait)) > 0)
sw.SpinOnce();
if ((Interlocked.Add(ref _rwlock, RwRead) & (RwWait | RwWait)) == 0)
return;
Interlocked.Add(ref _rwlock, -RwRead);
} while (true);
}
public void ExitReadLock()
{
Interlocked.Add(ref _rwlock, -RwRead);
}
public void EnterWriteLock()
{
var sw = new SpinWait();
do
{
int state = _rwlock;
if (state < RwWrite)
{
if (Interlocked.CompareExchange(ref _rwlock, RwWrite, state) == state)
return;
state = _rwlock;
}
// We register our interest in taking the Write lock (if upgradeable it's already done)
while ((state & RwWait) == 0 && Interlocked.CompareExchange(ref _rwlock, state | RwWait, state) != state)
state = _rwlock;
// Before falling to sleep
while (_rwlock > RwWait)
sw.SpinOnce();
} while (true);
}
public void ExitWriteLock()
{
Interlocked.Add(ref _rwlock, -RwWrite);
}
}
}
}
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