mcs/class/referencesource/System.Core/System/Linq/Parallel/Utils/Util.cs

   1 // ==++==
   2 //
   3 //   Copyright (c) Microsoft Corporation.  All rights reserved.
   4 //
   5 // ==--==
   6 // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
   7 //
   8 // Util.cs
   9 //
  10 // <OWNER>Microsoft</OWNER>
  11 //
  12 // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
  13
  14 using System.Collections.Generic;
  15
  16 namespace System.Linq.Parallel
  17 {
  18     /// <summary>
  19     /// Common miscellaneous utility methods used throughout the code-base.
  20     /// </summary>
  21     internal static class Util
  22     {
  23
  24         //-----------------------------------------------------------------------------------
  25         // Simple helper that returns a constant depending on the sign of the argument. I.e.
  26         // if the argument is negative, the result is -1; if it's positive, the result is 1;
  27         // otherwise, if it's zero, the result is 0.
  28         //
  29
  30         internal static int Sign(int x)
  31         {
  32             return x < 0 ? -1 : x == 0 ? 0 : 1;
  33         }
  34
  35         //-----------------------------------------------------------------------------------
  36         // This is a temporary workaround for a VSWhidbey bug 601998 in the X64 JIT compiler.
  37         // Unlike the X86 JIT, null checks on value types aren't optimized away in Whidbey.
  38         // That means using the GenericComparer<K> infrastructure results in boxing value
  39         // types. This kills performance all over the place. This bug has been fixed in
  40         // Orcas (2.0 SP1), so once we're on the SP1 runtime, this can be removed.
  41         //
  42
  43         internal static Comparer<TKey> GetDefaultComparer<TKey>()
  44         {
  45             if (typeof(TKey) == typeof(int))
  46             {
  47                 return (Comparer<TKey>)(object)s_fastIntComparer;
  48             }
  49             else if (typeof(TKey) == typeof(long))
  50             {
  51                 return (Comparer<TKey>)(object)s_fastLongComparer;
  52             }
  53             else if (typeof(TKey) == typeof(float))
  54             {
  55                 return (Comparer<TKey>)(object)s_fastFloatComparer;
  56             }
  57             else if (typeof(TKey) == typeof(double))
  58             {
  59                 return (Comparer<TKey>)(object)s_fastDoubleComparer;
  60             }
  61             else if (typeof(TKey) == typeof(DateTime))
  62             {
  63                 return (Comparer<TKey>)(object)s_fastDateTimeComparer;
  64             }
  65
  66             return Comparer<TKey>.Default;
  67         }
  68
  69         private static FastIntComparer s_fastIntComparer = new FastIntComparer();
  70
  71         class FastIntComparer : Comparer<int>
  72         {
  73             public override int Compare(int x, int y)
  74             {
  75                 return x.CompareTo(y);
  76             }
  77         }
  78
  79         private static FastLongComparer s_fastLongComparer = new FastLongComparer();
  80
  81         class FastLongComparer : Comparer<long>
  82         {
  83             public override int Compare(long x, long y)
  84             {
  85                 return x.CompareTo(y);
  86             }
  87         }
  88
  89         private static FastFloatComparer s_fastFloatComparer = new FastFloatComparer();
  90
  91         class FastFloatComparer : Comparer<float>
  92         {
  93             public override int Compare(float x, float y)
  94             {
  95                 return x.CompareTo(y);
  96             }
  97         }
  98
  99         private static FastDoubleComparer s_fastDoubleComparer = new FastDoubleComparer();
 100
 101         class FastDoubleComparer : Comparer<double>
 102         {
 103             public override int Compare(double x, double y)
 104             {
 105                 return x.CompareTo(y);
 106             }
 107         }
 108
 109         private static FastDateTimeComparer s_fastDateTimeComparer = new FastDateTimeComparer();
 110
 111         class FastDateTimeComparer : Comparer<DateTime>
 112         {
 113             public override int Compare(DateTime x, DateTime y)
 114             {
 115                 return x.CompareTo(y);
 116             }
 117         }
 118
 119     }
 120 }