src/System.Private.CoreLib/shared/System/Runtime/CompilerServices/RuntimeHelpers.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 using System.Runtime.Serialization;
   6 using Internal.Runtime.CompilerServices;
   7
   8 namespace System.Runtime.CompilerServices
   9 {
  10     public static partial class RuntimeHelpers
  11     {
  12         public delegate void TryCode(object userData);
  13
  14         public delegate void CleanupCode(object userData, bool exceptionThrown);
  15
  16         /// <summary>
  17         /// Slices the specified array using the specified range.
  18         /// </summary>
  19         public static T[] GetSubArray<T>(T[] array, Range range)
  20         {
  21             if (array == null)
  22             {
  23                 ThrowHelper.ThrowArgumentNullException(ExceptionArgument.array);
  24             }
  25
  26             (int offset, int length) = range.GetOffsetAndLength(array.Length);
  27
  28             if (default(T) != null || typeof(T[]) == array.GetType())
  29             {
  30                 // We know the type of the array to be exactly T[].
  31
  32                 if (length == 0)
  33                 {
  34                     return Array.Empty<T>();
  35                 }
  36
  37                 var dest = new T[length];
  38                 Buffer.Memmove(
  39                     ref Unsafe.As<byte, T>(ref dest.GetRawSzArrayData()),
  40                     ref Unsafe.Add(ref Unsafe.As<byte, T>(ref array.GetRawSzArrayData()), offset),
  41                     (uint)length);
  42                 return dest;
  43             }
  44             else
  45             {
  46                 // The array is actually a U[] where U:T.
  47                 T[] dest = (T[])Array.CreateInstance(array.GetType().GetElementType(), length);
  48                 Array.Copy(array, offset, dest, 0, length);
  49                 return dest;
  50             }
  51         }
  52
  53         public static object GetUninitializedObject(Type type)
  54         {
  55             if (type is null)
  56             {
  57                 throw new ArgumentNullException(nameof(type), SR.ArgumentNull_Type);
  58             }
  59
  60             if (!type.IsRuntimeImplemented())
  61             {
  62                 throw new SerializationException(SR.Format(SR.Serialization_InvalidType, type.ToString()));
  63             }
  64
  65             return GetUninitializedObjectInternal(type);
  66         }
  67
  68         public static void PrepareContractedDelegate(Delegate d)
  69         {
  70         }
  71
  72         public static void ProbeForSufficientStack()
  73         {
  74         }
  75
  76         public static void PrepareConstrainedRegions()
  77         {
  78         }
  79
  80         public static void PrepareConstrainedRegionsNoOP()
  81         {
  82         }
  83     }
  84 }