shared source/sscli20/jscript/engine/runtime.cs

   1 // ==++==
   2 //
   3 //
   4 //    Copyright (c) 2006 Microsoft Corporation.  All rights reserved.
   5 //
   6 //    The use and distribution terms for this software are contained in the file
   7 //    named license.txt, which can be found in the root of this distribution.
   8 //    By using this software in any fashion, you are agreeing to be bound by the
   9 //    terms of this license.
  10 //
  11 //    You must not remove this notice, or any other, from this software.
  12 //
  13 //
  14 // ==--==
  15
  16 namespace Microsoft.JScript {
  17   using System;
  18   using System.Threading;
  19   using System.Reflection;
  20   using System.Reflection.Emit;
  21   using System.Security;
  22   using System.Security.Permissions;
  23   using Microsoft.JScript.Vsa;
  24
  25   public static class Runtime {
  26     // *** VS58565 - JSEE: Remove all uses of IDebugObject::GetManagedObject from the code ***
  27     // JSEE does a funceval to this method to compare if to value types are equal.
  28     public static new bool Equals(Object v1, Object v2){
  29       Equality e = new Equality((int)JSToken.Equal);
  30       return e.EvaluateEquality(v1, v2);
  31     }
  32
  33
  34     //
  35     public static Int64 DoubleToInt64(double val) {
  36       if (Double.IsNaN(val)) { // Take care of NaN case first as it isn't ordered.
  37         return 0;
  38       }
  39       if (Int64.MinValue <= val && val <= Int64.MaxValue) {
  40         return (Int64)val;
  41       }
  42
  43       // Remove cases where IEEERemainder will return NaN.
  44       if (Double.IsInfinity(val))
  45         return 0;
  46
  47       // Definition of IEEERemandier returns:
  48       //  A number equal to x-(y*Q), where Q is the quotient of x/y rounded to the nearest
  49       //    integer (if x/y falls halfway between two integers, the even integer is returned).
  50       //
  51       // We use y = 2^64 = UInt64.MaxValue+1. The resulting remainder may range from -2^63
  52       // to 2^63. i.e. x = (2^64+2^63) gives Q = 2 and result -2^63, x = -(2^64+2^63) gives
  53       // Q = -2 and result 2^63. To fit into Int64, we translate 2^63 by -2^64 to get -2^63
  54       // which is Int64.MinValue.
  55       double rem = Math.IEEERemainder(Math.Sign(val) * Math.Floor(Math.Abs(val)), (double)UInt64.MaxValue+1.0);
  56       if (rem == (double)Int64.MaxValue+1.0) {
  57         return Int64.MinValue;
  58       }
  59       return (Int64)rem;
  60     }
  61
  62
  63     private const Decimal DecimalTwoToThe64 = (Decimal)UInt64.MaxValue+1;
  64
  65     public static Int64 UncheckedDecimalToInt64(Decimal val) {
  66       // ToInteger
  67       val = Decimal.Truncate(val);
  68
  69       // Ensure value is in range.
  70       if (val < Int64.MinValue || Int64.MaxValue <  val) {
  71         val = Decimal.Remainder(val, DecimalTwoToThe64);
  72         if (val < Int64.MinValue)
  73           val += DecimalTwoToThe64;
  74         else if (val > Int64.MaxValue)
  75           val -= DecimalTwoToThe64;
  76       }
  77
  78       // Checked coercion is guaranteed to succeed
  79       Debug.Assert(Int64.MinValue <= val && val <= Int64.MaxValue);
  80       return (Int64)val;
  81     }
  82
  83
  84     // RUNTIME TYPEREFERENCES
  85     private static TypeReferences _typeRefs;
  86     internal static TypeReferences TypeRefs {
  87       get {
  88         TypeReferences typeRefs = Runtime._typeRefs;
  89         if (typeRefs == null)
  90           typeRefs = Runtime._typeRefs = new TypeReferences(typeof(Runtime).Module);
  91         return typeRefs;
  92       }
  93     }
  94
  95     // ASSEMBLY AND MODULE BUILDER FOR FIELDACCESSOR AND METHODINVOKER THUNKS
  96     private static ModuleBuilder _thunkModuleBuilder;
  97     internal static  ModuleBuilder ThunkModuleBuilder {
  98       get {
  99         ModuleBuilder moduleBuilder = Runtime._thunkModuleBuilder;
 100         if (null == moduleBuilder)
 101           moduleBuilder = Runtime._thunkModuleBuilder = CreateThunkModuleBuilder();
 102         return moduleBuilder;
 103       }
 104     }
 105
 106     [ReflectionPermission(SecurityAction.Assert, ReflectionEmit = true), FileIOPermission(SecurityAction.Assert, Unrestricted = true)]
 107     private static ModuleBuilder CreateThunkModuleBuilder() {
 108       AssemblyName name = new AssemblyName();
 109       name.Name = "JScript Thunk Assembly";
 110       AssemblyBuilder assembly = Thread.GetDomain().DefineDynamicAssembly(name, AssemblyBuilderAccess.Run);
 111       ModuleBuilder module = assembly.DefineDynamicModule("JScript Thunk Module");
 112       module.SetCustomAttribute(new CustomAttributeBuilder(typeof(SecurityTransparentAttribute).GetConstructor(new Type[0]), new Object[0]));
 113       return module;
 114     }
 115   }
 116 }