#if NET_4_0
//
// SimpleConcurrentBag.cs
//
// Author:
// Jrmie "Garuma" Laval <jeremie.laval@gmail.com>
//
// Copyright (c) 2009 Jrmie "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.Threading;
namespace System.Threading.Tasks{
internal class SimpleConcurrentBag<T>
{
readonly IDequeOperations<T>[] deques;
readonly bool unique;
int index = -1;
[ThreadStatic]
int stealIndex;
public SimpleConcurrentBag (int num)
{
deques = new CyclicDeque<T>[num];
for (int i = 0; i < deques.Length; i++) {
deques[i] = new CyclicDeque<T> ();
}
unique = num <= 1;
}
public int GetNextIndex ()
{
return Interlocked.Increment (ref index);
}
public bool TryTake (int index, out T value)
{
value = default (T);
return deques[index].PopBottom (out value) == PopResult.Succeed;
}
public bool TrySteal (int index, out T value)
{
value = default (T);
if (unique)
return false;
const int roundThreshold = 3;
for (int round = 0; round < roundThreshold; ++round) {
if (stealIndex == index)
stealIndex = (stealIndex + 1) % deques.Length;
if (deques[(stealIndex = (stealIndex + 1) % deques.Length)].PopTop (out value) == PopResult.Succeed)
return true;
}
return false;
}
public void Add (int index, T value)
{
deques[index].PushBottom (value);
}
}
}
#endif
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