mcs/class/Microsoft.JScript/Microsoft.JScript/StrictEquality.cs

   1 //
   2 // StrictEquality.cs:
   3 //
   4 // Author:
   5 //      Cesar Lopez Nataren (cesar@ciencias.unam.mx)
   6 //
   7 // (C) 2003, Cesar Lopez Nataren
   8 // (C) 2005, Novell Inc. (http://novell.com)
   9 //
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System;
  33 using System.Reflection.Emit;
  34
  35 namespace Microsoft.JScript {
  36
  37         public class StrictEquality : BinaryOp {
  38
  39                 internal StrictEquality (AST parent, AST left, AST right, JSToken op, Location location)
  40                         : base (parent, left, right, op, location)
  41                 {
  42                 }
  43
  44                 public static bool JScriptStrictEquals (object v1, object v2)
  45                 {
  46                         IConvertible ic1 = v1 as IConvertible;
  47                         IConvertible ic2 = v2 as IConvertible;
  48
  49                         TypeCode tc1 = Convert.GetTypeCode (v1, ic1);
  50                         TypeCode tc2 = Convert.GetTypeCode (v2, ic2);
  51
  52                         bool both_numbers = Convert.IsNumberTypeCode (tc1) && Convert.IsNumberTypeCode (tc2);
  53                         if (tc1 != tc2 && !both_numbers)
  54                                 return false;
  55
  56                         switch (tc1) {
  57                         case TypeCode.DBNull:
  58                         case TypeCode.Empty:
  59                                 return true;
  60
  61                         case TypeCode.Boolean:
  62                                 return ic1.ToBoolean (null) == ic2.ToBoolean (null);
  63
  64                         case TypeCode.String:
  65                                 return ic1.ToString (null) == ic2.ToString (null);
  66
  67                         case TypeCode.Object:
  68                                 if (v1 is ScriptFunction && v2 is ScriptFunction)
  69                                         return v1 == v2 || v1.Equals (v2);
  70                                 else
  71                                         return v1 == v2;
  72
  73                         default:
  74                                 if (both_numbers) {
  75                                         double num1;
  76                                         if (Convert.IsFloatTypeCode (tc1))
  77                                                 num1 = ic1.ToDouble (null);
  78                                         else
  79                                                 num1 = (double) ic1.ToInt64 (null);
  80
  81                                         double num2;
  82                                         if (Convert.IsFloatTypeCode (tc2))
  83                                                 num2 = ic2.ToDouble (null);
  84                                         else
  85                                                 num2 = (double) ic2.ToInt64 (null);
  86
  87                                         return num1 == num2;
  88                                 }
  89                                 Console.WriteLine ("StrictEquality, tc1 = {0}, tc2 = {1}", tc1, tc2);
  90                                 break;
  91                         }
  92                         throw new NotImplementedException ();
  93                 }
  94
  95                 internal override bool Resolve (Environment env)
  96                 {
  97                         bool r = true;
  98                         if (left != null)
  99                                 r &= left.Resolve (env);
 100                         if (right != null)
 101                                 r &= right.Resolve (env);
 102                         return r;
 103                 }
 104
 105                 internal override bool Resolve (Environment env, bool no_effect)
 106                 {
 107                         this.no_effect = no_effect;
 108                         return Resolve (env);
 109                 }
 110
 111                 internal override void Emit (EmitContext ec)
 112                 {
 113                         if (left != null) {
 114                                 left.Emit (ec);
 115                                 CodeGenerator.EmitBox (ec.ig, left);
 116                         }
 117                         if (right != null) {
 118                                 right.Emit (ec);
 119                                 CodeGenerator.EmitBox (ec.ig, right);
 120                         }
 121                         ec.ig.Emit (OpCodes.Call, typeof (StrictEquality).GetMethod ("JScriptStrictEquals"));
 122                 }
 123         }
 124 }