mcs/class/Microsoft.JScript/Microsoft.JScript/Equality.cs

   1 //
   2 // Equality.cs:
   3 //
   4 // Author:
   5 //      Cesar Lopez Nataren (cesar@ciencias.unam.mx)
   6 //
   7 // (C) 2003, 2004 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.Text;
  34 using System.Diagnostics;
  35 using System.Reflection.Emit;
  36
  37 namespace Microsoft.JScript {
  38
  39         public class Equality : BinaryOp {
  40
  41                 internal Equality (AST parent, AST left, AST right, JSToken op, Location location)
  42                         : base (parent, left, right, op, location)
  43                 {
  44                 }
  45
  46                 public Equality (int i)
  47                         : base (null, null, null, (JSToken) i, null)
  48                 {
  49                 }
  50
  51                 [DebuggerStepThroughAttribute]
  52                 [DebuggerHiddenAttribute]
  53                 public bool EvaluateEquality (object v1, object v2)
  54                 {
  55                         IConvertible ic1 = v1 as IConvertible;
  56                         IConvertible ic2 = v2 as IConvertible;
  57
  58                         TypeCode tc1 = Convert.GetTypeCode (v1, ic1);
  59                         TypeCode tc2 = Convert.GetTypeCode (v2, ic2);
  60
  61                         bool both_numbers = Convert.IsNumberTypeCode (tc1) && Convert.IsNumberTypeCode (tc2);
  62                         if ((tc1 == tc2) || both_numbers) {
  63                                 switch (tc1) {
  64                                 case TypeCode.DBNull:
  65                                 case TypeCode.Empty:
  66                                         return true;
  67
  68                                 case TypeCode.Boolean:
  69                                         return ic1.ToBoolean (null) == ic2.ToBoolean (null);
  70
  71                                 case TypeCode.String:
  72                                         return ic1.ToString (null) == ic2.ToString (null);
  73
  74                                 case TypeCode.Object:
  75                                         if (v1 is ScriptFunction && v2 is ScriptFunction)
  76                                                 return v1 == v2 || v1.Equals (v2);
  77                                         else
  78                                                 return v1 == v2;
  79
  80                                 default:
  81                                         if (both_numbers) {
  82                                                 double num1;
  83                                                 if (Convert.IsFloatTypeCode (tc1))
  84                                                         num1 = ic1.ToDouble (null);
  85                                                 else
  86                                                         num1 = (double) ic1.ToInt64 (null);
  87
  88                                                 double num2;
  89                                                 if (Convert.IsFloatTypeCode (tc2))
  90                                                         num2 = ic2.ToDouble (null);
  91                                                 else
  92                                                         num2 = (double) ic2.ToInt64 (null);
  93
  94                                                 return num1 == num2;
  95                                         } else
  96                                                 return false;
  97                                 }
  98                         } else {
  99                                 bool swapped = false;
 100
 101                         redo:
 102                                 switch (tc1) {
 103                                 case TypeCode.DBNull:
 104                                         if (tc2 == TypeCode.Empty)
 105                                                 return true;
 106                                         break;
 107
 108                                 case TypeCode.String:
 109                                         if (Convert.IsNumberTypeCode (tc2))
 110                                                 return EvaluateEquality (Convert.ToNumber (v1), v2);
 111                                         break;
 112
 113                                 case TypeCode.Boolean:
 114                                         return EvaluateEquality (Convert.ToNumber (v1), v2);
 115
 116                                 case TypeCode.Object:
 117                                         if (tc2 == TypeCode.String || Convert.IsNumberTypeCode (tc2))
 118                                                 return EvaluateEquality (Convert.ToPrimitive (v1, null), v2);
 119                                         break;
 120                                 }
 121
 122                                 if (!swapped) {
 123                                         swapped = true;
 124
 125                                         object vt = v1;
 126                                         v1 = v2;
 127                                         v2 = vt;
 128
 129                                         ic1 = v1 as IConvertible;
 130                                         ic2 = v2 as IConvertible;
 131
 132                                         tc1 = Convert.GetTypeCode (v1, ic1);
 133                                         tc2 = Convert.GetTypeCode (v2, ic2);
 134
 135                                         goto redo;
 136                                 } else
 137                                         return false;
 138                         }
 139                 }
 140
 141                 public static bool JScriptEquals (object v1, object v2)
 142                 {
 143                         throw new NotImplementedException ();
 144                 }
 145
 146                 internal override bool Resolve (IdentificationTable context)
 147                 {
 148                         bool r = true;
 149                         if (left != null)
 150                                 r &= left.Resolve (context);
 151                         if (right != null)
 152                                 r &= right.Resolve (context);
 153                         return r;
 154                 }
 155
 156                 internal override bool Resolve (IdentificationTable context, bool no_effect)
 157                 {
 158                         this.no_effect = no_effect;
 159                         return Resolve (context);
 160                 }
 161
 162                 internal override void Emit (EmitContext ec)
 163                 {
 164                         ILGenerator ig = ec.ig;
 165                         LocalBuilder local_builder;
 166
 167                         if (op != JSToken.None) {
 168                                 Type t = typeof (Equality);
 169                                 local_builder = ig.DeclareLocal (t);
 170                                 if (op == JSToken.Equal)
 171                                         ig.Emit (OpCodes.Ldc_I4_S, (byte) 53);
 172                                 else if (op == JSToken.NotEqual)
 173                                         ig.Emit (OpCodes.Ldc_I4_S, (byte) 54);
 174                                 ig.Emit (OpCodes.Newobj, t.GetConstructor (new Type [] { typeof (int) }));
 175                                 ig.Emit (OpCodes.Stloc, local_builder);
 176                                 ig.Emit (OpCodes.Ldloc, local_builder);
 177                         }
 178
 179                         if (left != null) {
 180                                 left.Emit (ec);
 181                                 CodeGenerator.EmitBox (ig, left);
 182                         }
 183                         if (right != null) {
 184                                 right.Emit (ec);
 185                                 CodeGenerator.EmitBox (ig, right);
 186                         }
 187
 188                         if (op == JSToken.Equal || op == JSToken.NotEqual) {
 189                                 ig.Emit (OpCodes.Call, typeof (Equality).GetMethod ("EvaluateEquality"));
 190
 191                                 if (no_effect) {
 192                                         Label t_lbl = ig.DefineLabel ();
 193                                         Label f_lbl = ig.DefineLabel ();
 194
 195                                         if (op == JSToken.Equal)
 196                                                 ig.Emit (OpCodes.Brtrue_S, t_lbl);
 197                                         else if (op == JSToken.NotEqual)
 198                                                 ig.Emit (OpCodes.Brfalse_S, t_lbl);
 199
 200                                         ig.Emit (OpCodes.Ldc_I4_0);
 201                                         ig.Emit (OpCodes.Br_S, f_lbl);
 202                                         ig.MarkLabel (t_lbl);
 203                                         ig.Emit (OpCodes.Ldc_I4_1);
 204                                         ig.MarkLabel (f_lbl);
 205                                         ig.Emit (OpCodes.Pop);
 206                                 }
 207                         }
 208                 }
 209         }
 210 }