class/System.ServiceModel/Mono.CodeGeneration/CodeCast.cs

   1 //
   2 // Permission is hereby granted, free of charge, to any person obtaining
   3 // a copy of this software and associated documentation files (the
   4 // "Software"), to deal in the Software without restriction, including
   5 // without limitation the rights to use, copy, modify, merge, publish,
   6 // distribute, sublicense, and/or sell copies of the Software, and to
   7 // permit persons to whom the Software is furnished to do so, subject to
   8 // the following conditions:
   9 //
  10 // The above copyright notice and this permission notice shall be
  11 // included in all copies or substantial portions of the Software.
  12 //
  13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  14 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  15 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  16 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  17 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  18 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  19 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  20 //
  21 // Copyright (C) Lluis Sanchez Gual, 2004
  22 //
  23
  24 using System;
  25 using System.Reflection;
  26 using System.Reflection.Emit;
  27 using Mono.CodeGeneration;
  28
  29 namespace Mono.CodeGeneration
  30 {
  31         public class CodeCast: CodeExpression
  32         {
  33                 Type type;
  34                 CodeExpression exp;
  35
  36                 public CodeCast (Type type, CodeExpression exp)
  37                 {
  38                         this.type = type;
  39                         this.exp = exp;
  40                 }
  41
  42                 public override void Generate (ILGenerator gen)
  43                 {
  44                         exp.Generate (gen);
  45
  46                         Type typeObj = exp.GetResultType ();
  47
  48                         if (type.IsAssignableFrom (typeObj)) {
  49                                 if (typeObj.IsValueType)
  50                                         gen.Emit (OpCodes.Box, typeObj);
  51                                 return;
  52                         }
  53                         else if (type.IsValueType && typeObj == typeof(object)) {
  54                                 // Unbox
  55                                 gen.Emit (OpCodes.Unbox, type);
  56                                 CodeGenerationHelper.LoadFromPtr (gen, type);
  57                                 return;
  58                         }
  59                         else if (typeObj.IsAssignableFrom (type)) {
  60                                 // Sub s = (Sub)base
  61                                 gen.Emit (OpCodes.Castclass, type);
  62                                 return;
  63                         }
  64                         else if (CodeGenerationHelper.IsNumber (type) && CodeGenerationHelper.IsNumber (typeObj)) {
  65                                 switch (Type.GetTypeCode (type))
  66                                 {
  67                                         case TypeCode.Byte:
  68                                                 gen.Emit (OpCodes.Conv_U1);
  69                                                 return;
  70                                         case TypeCode.Double:
  71                                                 gen.Emit (OpCodes.Conv_R8);
  72                                                 return;
  73                                         case TypeCode.Int16:
  74                                                 gen.Emit (OpCodes.Conv_I2);
  75                                                 return;
  76                                         case TypeCode.Int32:
  77                                                 gen.Emit (OpCodes.Conv_I4);
  78                                                 return;
  79                                         case TypeCode.Int64:
  80                                                 gen.Emit (OpCodes.Conv_I8);
  81                                                 return;
  82                                         case TypeCode.SByte:
  83                                                 gen.Emit (OpCodes.Conv_I1);
  84                                                 return;
  85                                         case TypeCode.Single:
  86                                                 gen.Emit (OpCodes.Conv_R4);
  87                                                 return;
  88                                         case TypeCode.UInt16:
  89                                                 gen.Emit (OpCodes.Conv_U2);
  90                                                 return;
  91                                         case TypeCode.UInt32:
  92                                                 gen.Emit (OpCodes.Conv_U4);
  93                                                 return;
  94                                         case TypeCode.UInt64:
  95                                                 gen.Emit (OpCodes.Conv_U8);
  96                                                 return;
  97                                 }
  98                         }
  99
 100                         MethodInfo imp = type.GetMethod ("op_Implicit", new Type[] { typeObj });
 101                         if (imp != null) {
 102                                 gen.Emit (OpCodes.Call, imp);
 103                                 return;
 104                         }
 105
 106                         foreach (MethodInfo m in typeObj.GetMember ("op_Explicit"))
 107                                 if (m.ReturnType == type) {
 108                                         gen.Emit (OpCodes.Call, m);
 109                                         return;
 110                                 }
 111
 112                         throw new InvalidOperationException ("Can't cast from " + typeObj + " to " + type);
 113                 }
 114
 115                 public override void PrintCode (CodeWriter cp)
 116                 {
 117                         Type typeObj = exp.GetResultType ();
 118                         if (type.IsAssignableFrom (typeObj)) {
 119                                 exp.PrintCode (cp);
 120                                 return;
 121                         }
 122
 123                         cp.Write ("((" + type.FullName + ") ");
 124                         exp.PrintCode (cp);
 125                         cp.Write (")");
 126                 }
 127
 128                 public override Type GetResultType ()
 129                 {
 130                         return type;
 131                 }
 132         }
 133 }