mcs/class/System/System.Collections.Concurrent/ConcurrentBag.cs

   1 //
   2 // ConcurrentBag.cs
   3 //
   4 // Author:
   5 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   6 //
   7 // Copyright (c) 2009 Jérémie "Garuma" Laval
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining a copy
  10 // of this software and associated documentation files (the "Software"), to deal
  11 // in the Software without restriction, including without limitation the rights
  12 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13 // copies of the Software, and to permit persons to whom the Software is
  14 // furnished to do so, subject to the following conditions:
  15 //
  16 // The above copyright notice and this permission notice shall be included in
  17 // all copies or substantial portions of the Software.
  18 //
  19 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25 // THE SOFTWARE.
  26
  27 #if NET_4_0
  28 using System;
  29 using System.Collections;
  30 using System.Collections.Generic;
  31 using System.Diagnostics;
  32 using System.Runtime.InteropServices;
  33
  34 using System.Threading;
  35 using System.Threading.Tasks;
  36
  37 namespace System.Collections.Concurrent
  38 {
  39         [ComVisible (false)]
  40         [DebuggerDisplay ("Count={Count}")]
  41         [DebuggerTypeProxy (typeof (CollectionDebuggerView<>))]
  42         public class ConcurrentBag<T> : IProducerConsumerCollection<T>, IEnumerable<T>, IEnumerable
  43         {
  44                 const int multiplier = 2;
  45                 int size = Environment.ProcessorCount + 1;
  46                 int count;
  47
  48                 CyclicDeque<T>[] container;
  49
  50                 object syncLock = new object ();
  51
  52                 public ConcurrentBag ()
  53                 {
  54                         container = new CyclicDeque<T>[size];
  55                         for (int i = 0; i < container.Length; i++)
  56                                 container[i] = new CyclicDeque<T> ();
  57                 }
  58
  59                 public ConcurrentBag (IEnumerable<T> enumerable) : this ()
  60                 {
  61                         foreach (T item in enumerable)
  62                                 Add (item);
  63                 }
  64
  65                 public bool TryAdd (T item)
  66                 {
  67                         Add (item);
  68
  69                         return true;
  70                 }
  71
  72                 public void Add (T item)
  73                 {
  74                         Interlocked.Increment (ref count);
  75                         GrowIfNecessary ();
  76
  77                         CyclicDeque<T> bag = GetBag ();
  78                         bag.PushBottom (item);
  79                 }
  80
  81                 public bool TryTake (out T item)
  82                 {
  83                         item = default (T);
  84                         CyclicDeque<T> bag = GetBag ();
  85
  86                         if (bag == null || bag.PopBottom (out item) != PopResult.Succeed) {
  87                                 for (int i = 0; i < container.Length; i++) {
  88                                         if (container[i].PopTop (out item) == PopResult.Succeed) {
  89                                                 Interlocked.Decrement (ref count);
  90                                                 return true;
  91                                         }
  92                                 }
  93                         } else {
  94                                 Interlocked.Decrement (ref count);
  95                                 return true;
  96                         }
  97
  98                         return false;
  99                 }
 100
 101                 public int Count {
 102                         get {
 103                                 return count;
 104                         }
 105                 }
 106
 107                 public bool IsEmpty {
 108                         get {
 109                                 return count == 0;
 110                         }
 111                 }
 112
 113                 object System.Collections.ICollection.SyncRoot  {
 114                         get {
 115                                 return this;
 116                         }
 117                 }
 118
 119                 bool System.Collections.ICollection.IsSynchronized  {
 120                         get {
 121                                 return true;
 122                         }
 123                 }
 124
 125                 IEnumerator IEnumerable.GetEnumerator ()
 126                 {
 127                         return GetEnumeratorInternal ();
 128                 }
 129
 130                 IEnumerator<T> IEnumerable<T>.GetEnumerator ()
 131                 {
 132                         return GetEnumeratorInternal ();
 133                 }
 134
 135                 IEnumerator<T> GetEnumeratorInternal ()
 136                 {
 137                         for (int i = 0; i < size; i++) {
 138                                 CyclicDeque<T> bag = container[i];
 139                                 foreach (T item in bag.GetEnumerable ()) {
 140                                         yield return item;
 141                                 }
 142                         }
 143                 }
 144
 145                 void System.Collections.ICollection.CopyTo (Array array, int index)
 146                 {
 147                         T[] a = array as T[];
 148                         if (a == null)
 149                                 return;
 150
 151                         CopyTo (a, index);
 152                 }
 153
 154                 public void CopyTo (T[] array, int index)
 155                 {
 156                         int c = count;
 157                         if (array.Length < c + index)
 158                                 throw new InvalidOperationException ("Array is not big enough");
 159
 160                         CopyTo (array, index, c);
 161                 }
 162
 163                 void CopyTo (T[] array, int index, int num)
 164                 {
 165                         int i = index;
 166
 167                         foreach (T item in this) {
 168                                 if (i >= num)
 169                                         break;
 170
 171                                 array[i++] = item;
 172                         }
 173                 }
 174
 175                 public T[] ToArray ()
 176                 {
 177                         int c = count;
 178                         T[] temp = new T[c];
 179
 180                         CopyTo (temp, 0, c);
 181
 182                         return temp;
 183                 }
 184
 185                 int GetIndex ()
 186                 {
 187                         return Thread.CurrentThread.ManagedThreadId - 1;
 188                 }
 189
 190                 void GrowIfNecessary ()
 191                 {
 192                         int index = GetIndex ();
 193                         int currentSize = size;
 194
 195                         while (index > currentSize - 1) {
 196                                 currentSize = size;
 197                                 Grow (currentSize);
 198                         }
 199                 }
 200
 201                 CyclicDeque<T> GetBag ()
 202                 {
 203                         int i = GetIndex ();
 204
 205                         return i < container.Length ? container[i] : null;
 206                 }
 207
 208                 void Grow (int referenceSize)
 209                 {
 210                         lock (syncLock) {
 211                                 if (referenceSize != size)
 212                                         return;
 213
 214                                 CyclicDeque<T>[] slice = new CyclicDeque<T>[size * multiplier];
 215                                 int i = 0;
 216                                 for (i = 0; i < container.Length; i++)
 217                                         slice[i] = container[i];
 218                                 for (; i < slice.Length; i++)
 219                                         slice[i] = new CyclicDeque<T> ();
 220
 221                                 container = slice;
 222                                 size = slice.Length;
 223                         }
 224                 }
 225         }
 226 }
 227 #endif