mcs/class/corlib/System.Reflection/Binder.cs

   1 // System.Reflection.Binder
   2 //
   3 // Authors:
   4 //      Sean MacIsaac (macisaac@ximian.com)
   5 //      Paolo Molaro (lupus@ximian.com)
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //
   8 // (C) Ximian, Inc. 2001 - 2003
   9 // (c) Copyright 2004 Novell, Inc. (http://www.novell.com)
  10
  11 //
  12 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Globalization;
  35 using System.Runtime.InteropServices;
  36
  37 namespace System.Reflection
  38 {
  39         [ComVisible (true)]
  40         [Serializable]
  41         [ClassInterface(ClassInterfaceType.AutoDual)]
  42         public abstract class Binder
  43         {
  44                 protected Binder () {}
  45
  46                 public abstract FieldInfo BindToField (BindingFlags bindingAttr, FieldInfo[] match, object value, CultureInfo culture);
  47                 public abstract MethodBase BindToMethod (BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] names, out object state);
  48                 public abstract object ChangeType (object value, Type type, CultureInfo culture);
  49                 public abstract void ReorderArgumentArray( ref object[] args, object state);
  50                 public abstract MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers);
  51                 public abstract PropertyInfo SelectProperty( BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers);
  52
  53                 static Binder default_binder = new Default ();
  54
  55                 internal static Binder DefaultBinder {
  56                         get {
  57                                 return default_binder;
  58                         }
  59                 }
  60
  61                 internal static bool ConvertArgs (Binder binder, object[] args, ParameterInfo[] pinfo, CultureInfo culture) {
  62                         if (args == null) {
  63                                 if ( pinfo.Length == 0)
  64                                         return true;
  65                                 else
  66                                         throw new TargetParameterCountException ();
  67                         }
  68                         if (pinfo.Length != args.Length)
  69                                 throw new TargetParameterCountException ();
  70                         for (int i = 0; i < args.Length; ++i) {
  71                                 object v = binder.ChangeType (args [i], pinfo[i].ParameterType, culture);
  72                                 if ((v == null) && (args [i] != null))
  73                                         return false;
  74                                 args [i] = v;
  75                         }
  76                         return true;
  77                 }
  78
  79                 internal static int GetDerivedLevel (Type type)
  80                 {
  81                         Type searchType = type;
  82                         int level = 1;
  83
  84                         while (searchType.BaseType != null)
  85                         {
  86                                 level++;
  87                                 searchType = searchType.BaseType;
  88                         }
  89
  90                         return level;
  91                 }
  92
  93                 internal static MethodBase FindMostDerivedMatch (MethodBase [] match)
  94                 {
  95                         int highLevel = 0;
  96                         int matchId = -1;
  97                         int count = match.Length;
  98
  99                         for (int current = 0; current < count; current++)
 100                         {
 101                                 MethodBase m = match [current];
 102                                 int level = GetDerivedLevel (m.DeclaringType);
 103                                 if (level == highLevel)
 104                                         throw new AmbiguousMatchException ();
 105                                 // If the argument types differ we
 106                                 // have an ambigous match, as well
 107                                 if (matchId >= 0) {
 108                                         ParameterInfo[] p1 = m.GetParameters ();
 109                                         ParameterInfo[] p2 = match [matchId].GetParameters ();
 110                                         bool equal = true;
 111
 112                                         if (p1.Length != p2.Length)
 113                                                 equal = false;
 114                                         else {
 115                                                 int i;
 116
 117                                                 for (i = 0; i < p1.Length; ++i) {
 118                                                         if (p1 [i].ParameterType != p2 [i].ParameterType) {
 119                                                                 equal = false;
 120                                                                 break;
 121                                                         }
 122                                                 }
 123                                         }
 124
 125                                         if (!equal)
 126                                                 throw new AmbiguousMatchException ();
 127                                 }
 128
 129                                 if (level > highLevel)
 130                                 {
 131                                         highLevel = level;
 132                                         matchId = current;
 133                                 }
 134                         }
 135
 136                         return match[matchId];
 137                 }
 138
 139                 internal sealed class Default : Binder {
 140                         public override FieldInfo BindToField (BindingFlags bindingAttr, FieldInfo[] match, object value, CultureInfo culture)
 141                         {
 142                                 if (match == null)
 143                                         throw new ArgumentNullException ("match");
 144                                 foreach (FieldInfo f in match) {
 145                                         if (check_type (value.GetType (), f.FieldType))
 146                                                 return f;
 147                                 }
 148                                 return null;
 149                         }
 150
 151                         //
 152                         // FIXME: There was a MonoTODO, but it does not explain what the problem is
 153                         //
 154                         public override MethodBase BindToMethod (BindingFlags bindingAttr, MethodBase[] match, ref object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] names, out object state)
 155                         {
 156                                 Type[] types;
 157                                 if (args == null)
 158                                         types = Type.EmptyTypes;
 159                                 else {
 160                                         types = new Type [args.Length];
 161                                         for (int i = 0; i < args.Length; ++i) {
 162                                                 if (args [i] != null)
 163                                                         types [i] = args [i].GetType ();
 164                                         }
 165                                 }
 166                                 MethodBase selected = SelectMethod (bindingAttr, match, types, modifiers, true);
 167                                 state = null;
 168                                 if (names != null)
 169                                         ReorderParameters (names, ref args, selected);
 170                                 return selected;
 171                         }
 172
 173                         void ReorderParameters (string [] names, ref object [] args, MethodBase selected)
 174                         {
 175                                 object [] newArgs = new object [args.Length];
 176                                 Array.Copy (args, newArgs, args.Length);
 177                                 ParameterInfo [] plist = selected.GetParameters ();
 178                                 for (int n = 0; n < names.Length; n++)
 179                                         for (int p = 0; p < plist.Length; p++) {
 180                                                 if (names [n] == plist [p].Name) {
 181                                                         newArgs [p] = args [n];
 182                                                         break;
 183                                                 }
 184                                         }
 185                                 Array.Copy (newArgs, args, args.Length);
 186                         }
 187
 188                         static bool IsArrayAssignable (Type object_type, Type target_type)
 189                         {
 190                                 if (object_type.IsArray && target_type.IsArray)
 191                                         return IsArrayAssignable (object_type.GetElementType (), target_type.GetElementType ());
 192
 193                                 if (target_type.IsAssignableFrom (object_type))
 194                                         return true;
 195
 196                                 return false;
 197                         }
 198
 199                         public override object ChangeType (object value, Type type, CultureInfo culture)
 200                         {
 201                                 if (value == null)
 202                                         return null;
 203                                 Type vtype = value.GetType ();
 204                                 if (type.IsByRef)
 205                                         type = type.GetElementType ();
 206                                 if (vtype == type || type.IsInstanceOfType (value))
 207                                         return value;
 208                                 if (vtype.IsArray && type.IsArray){
 209                                         if (IsArrayAssignable (vtype.GetElementType (), type.GetElementType ()))
 210                                                 return value;
 211                                 }
 212
 213                                 if (check_type (vtype, type)) {
 214                                         // These are not supported by Convert
 215                                         if (type.IsEnum)
 216                                                 return Enum.ToObject (type, value);
 217                                         if (vtype == typeof (Char)) {
 218                                                 if (type == typeof (double))
 219                                                         return (double)(char)value;
 220                                                 if (type == typeof (float))
 221                                                         return (float)(char)value;
 222                                         }
 223                                         if (vtype == typeof (IntPtr) && type.IsPointer)
 224                                                 return value;
 225                                         return Convert.ChangeType (value, type);
 226                                 }
 227                                 return null;
 228                         }
 229
 230                         [MonoTODO ("This method does not do anything in Mono")]
 231                         public override void ReorderArgumentArray (ref object[] args, object state)
 232                         {
 233                                 //do nothing until we support named arguments
 234                                 //throw new NotImplementedException ();
 235                         }
 236
 237                         private static bool check_type (Type from, Type to) {
 238                                 if (from == to)
 239                                         return true;
 240
 241                                 if (from == null)
 242                                         return true;
 243
 244                                 if (to.IsByRef != from.IsByRef)
 245                                         return false;
 246
 247                                 if (to.IsInterface)
 248                                         return to.IsAssignableFrom (from);
 249
 250                                 if (to.IsEnum) {
 251                                         to = Enum.GetUnderlyingType (to);
 252                                         if (from == to)
 253                                                 return true;
 254                                 }
 255
 256                                 if (to.IsGenericType && to.GetGenericTypeDefinition () == typeof (Nullable<>) && to.GetGenericArguments ()[0] == from)
 257                                         return true;
 258
 259                                 TypeCode fromt = Type.GetTypeCode (from);
 260                                 TypeCode tot = Type.GetTypeCode (to);
 261
 262                                 switch (fromt) {
 263                                 case TypeCode.Char:
 264                                         switch (tot) {
 265                                         case TypeCode.UInt16:
 266                                         case TypeCode.UInt32:
 267                                         case TypeCode.Int32:
 268                                         case TypeCode.UInt64:
 269                                         case TypeCode.Int64:
 270                                         case TypeCode.Single:
 271                                         case TypeCode.Double:
 272                                                 return true;
 273                                         }
 274                                         return to == typeof (object);
 275                                 case TypeCode.Byte:
 276                                         switch (tot) {
 277                                         case TypeCode.Char:
 278                                         case TypeCode.UInt16:
 279                                         case TypeCode.Int16:
 280                                         case TypeCode.UInt32:
 281                                         case TypeCode.Int32:
 282                                         case TypeCode.UInt64:
 283                                         case TypeCode.Int64:
 284                                         case TypeCode.Single:
 285                                         case TypeCode.Double:
 286                                                 return true;
 287                                         }
 288                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 289                                 case TypeCode.SByte:
 290                                         switch (tot) {
 291                                         case TypeCode.Int16:
 292                                         case TypeCode.Int32:
 293                                         case TypeCode.Int64:
 294                                         case TypeCode.Single:
 295                                         case TypeCode.Double:
 296                                                 return true;
 297                                         }
 298                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 299                                 case TypeCode.UInt16:
 300                                         switch (tot) {
 301                                         case TypeCode.UInt32:
 302                                         case TypeCode.Int32:
 303                                         case TypeCode.UInt64:
 304                                         case TypeCode.Int64:
 305                                         case TypeCode.Single:
 306                                         case TypeCode.Double:
 307                                                 return true;
 308                                         }
 309                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 310                                 case TypeCode.Int16:
 311                                         switch (tot) {
 312                                         case TypeCode.Int32:
 313                                         case TypeCode.Int64:
 314                                         case TypeCode.Single:
 315                                         case TypeCode.Double:
 316                                                 return true;
 317                                         }
 318                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 319                                 case TypeCode.UInt32:
 320                                         switch (tot) {
 321                                         case TypeCode.UInt64:
 322                                         case TypeCode.Int64:
 323                                         case TypeCode.Single:
 324                                         case TypeCode.Double:
 325                                                 return true;
 326                                         }
 327                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 328                                 case TypeCode.Int32:
 329                                         switch (tot) {
 330                                         case TypeCode.Int64:
 331                                         case TypeCode.Single:
 332                                         case TypeCode.Double:
 333                                                 return true;
 334                                         }
 335                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 336                                 case TypeCode.UInt64:
 337                                 case TypeCode.Int64:
 338                                         switch (tot) {
 339                                         case TypeCode.Single:
 340                                         case TypeCode.Double:
 341                                                 return true;
 342                                         }
 343                                         return to == typeof (object) || (from.IsEnum && to == typeof (Enum));
 344                                 case TypeCode.Single:
 345                                         return tot == TypeCode.Double || to == typeof (object);
 346                                 default:
 347                                         /* TODO: handle valuetype -> byref */
 348                                         if (to == typeof (object) && from.IsValueType)
 349                                                 return true;
 350                                         if (to.IsPointer && from == typeof (IntPtr))
 351                                                 return true;
 352
 353                                         return to.IsAssignableFrom (from);
 354                                 }
 355                         }
 356
 357                         private static bool check_arguments (Type[] types, ParameterInfo[] args, bool allowByRefMatch) {
 358                                 for (int i = 0; i < types.Length; ++i) {
 359                                         bool match = check_type (types [i], args [i].ParameterType);
 360                                         if (!match && allowByRefMatch) {
 361                                                 Type param_type = args [i].ParameterType;
 362                                                 if (param_type.IsByRef)
 363                                                         match = check_type (types [i], param_type.GetElementType ());
 364                                         }
 365                                         if (!match)
 366                                                 return false;
 367                                 }
 368                                 return true;
 369                         }
 370
 371                         public override MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase [] match, Type [] types, ParameterModifier [] modifiers)
 372                         {
 373                                 return SelectMethod (bindingAttr, match, types, modifiers,
 374                                         false);
 375                         }
 376
 377                         MethodBase SelectMethod (BindingFlags bindingAttr, MethodBase[] match, Type[] types, ParameterModifier[] modifiers, bool allowByRefMatch)
 378                         {
 379                                 MethodBase m;
 380                                 int i, j;
 381
 382                                 if (match == null)
 383                                         throw new ArgumentNullException ("match");
 384
 385                                 /* first look for an exact match... */
 386                                 for (i = 0; i < match.Length; ++i) {
 387                                         m = match [i];
 388                                         ParameterInfo[] args = m.GetParameters ();
 389                                         if (args.Length != types.Length)
 390                                                 continue;
 391                                         for (j = 0; j < types.Length; ++j) {
 392                                                 if (types [j] != args [j].ParameterType)
 393                                                         break;
 394                                         }
 395                                         if (j == types.Length)
 396                                                 return m;
 397                                 }
 398
 399                                 /* Try methods with ParamArray attribute */
 400                                 bool isdefParamArray = false;
 401                                 Type elementType = null;
 402                                 for (i = 0; i < match.Length; ++i) {
 403                                         m = match [i];
 404                                         ParameterInfo[] args = m.GetParameters ();
 405                                         if (args.Length > types.Length)
 406                                                 continue;
 407                                         else if (args.Length == 0)
 408                                                 continue;
 409                                         isdefParamArray = Attribute.IsDefined (args [args.Length - 1], typeof (ParamArrayAttribute));
 410                                         if (!isdefParamArray)
 411                                                 continue;
 412                                         elementType = args [args.Length - 1].ParameterType.GetElementType ();
 413                                         for (j = 0; j < types.Length; ++j) {
 414                                                 if (j < (args.Length - 1) && types [j] != args [j].ParameterType)
 415                                                         break;
 416                                                 else if (j >= (args.Length - 1) && types [j] != elementType)
 417                                                         break;
 418                                         }
 419                                         if (j == types.Length)
 420                                                 return m;
 421                                 }
 422
 423                                 if ((int)(bindingAttr & BindingFlags.ExactBinding) != 0)
 424                                         return null;
 425
 426                                 MethodBase result = null;
 427                                 for (i = 0; i < match.Length; ++i) {
 428                                         m = match [i];
 429                                         ParameterInfo[] args = m.GetParameters ();
 430                                         if (args.Length != types.Length)
 431                                                 continue;
 432                                         if (!check_arguments (types, args, allowByRefMatch))
 433                                                 continue;
 434
 435                                         if (result != null)
 436                                                 result = GetBetterMethod (result, m, types);
 437                                         else
 438                                                 result = m;
 439                                 }
 440
 441                                 return result;
 442                         }
 443
 444                         MethodBase GetBetterMethod (MethodBase m1, MethodBase m2, Type [] types)
 445                         {
 446                                 if (m1.IsGenericMethodDefinition &&
 447                                     !m2.IsGenericMethodDefinition)
 448                                         return m2;
 449                                 if (m2.IsGenericMethodDefinition &&
 450                                     !m1.IsGenericMethodDefinition)
 451                                         return m1;
 452
 453                                 ParameterInfo [] pl1 = m1.GetParameters ();
 454                                 ParameterInfo [] pl2 = m2.GetParameters ();
 455                                 int prev = 0;
 456                                 for (int i = 0; i < pl1.Length; i++) {
 457                                         int cmp = CompareCloserType (pl1 [i].ParameterType, pl2 [i].ParameterType);
 458                                         if (cmp != 0 && prev != 0 && prev != cmp)
 459                                                 throw new AmbiguousMatchException ();
 460                                         if (cmp != 0)
 461                                                 prev = cmp;
 462                                 }
 463                                 if (prev != 0)
 464                                         return prev > 0 ? m2 : m1;
 465
 466                                 Type dt1 = m1.DeclaringType;
 467                                 Type dt2 = m2.DeclaringType;
 468                                 if (dt1 != dt2) {
 469                                         if (dt1.IsSubclassOf(dt2))
 470                                                 return m1;
 471                                         if (dt2.IsSubclassOf(dt1))
 472                                                 return m2;
 473                                 }
 474
 475                                 bool va1 = (m1.CallingConvention & CallingConventions.VarArgs) != 0;
 476                                 bool va2 = (m2.CallingConvention & CallingConventions.VarArgs) != 0;
 477                                 if (va1 && !va2)
 478                                         return m2;
 479                                 if (va2 && !va1)
 480                                         return m1;
 481
 482                                 throw new AmbiguousMatchException ();
 483                         }
 484
 485                         int CompareCloserType (Type t1, Type t2)
 486                         {
 487                                 if (t1 == t2)
 488                                         return 0;
 489                                 if (t1.IsGenericParameter && !t2.IsGenericParameter)
 490                                         return 1; // t2
 491                                 if (!t1.IsGenericParameter && t2.IsGenericParameter)
 492                                         return -1; // t1
 493                                 if (t1.HasElementType && t2.HasElementType)
 494                                         return CompareCloserType (
 495                                                 t1.GetElementType (),
 496                                                 t2.GetElementType ());
 497
 498                                 if (t1.IsSubclassOf (t2))
 499                                         return -1; // t1
 500                                 if (t2.IsSubclassOf (t1))
 501                                         return 1; // t2
 502
 503                                 if (t1.IsInterface && Array.IndexOf (t2.GetInterfaces (), t1) >= 0)
 504                                         return 1; // t2
 505                                 if (t2.IsInterface && Array.IndexOf (t1.GetInterfaces (), t2) >= 0)
 506                                         return -1; // t1
 507
 508                                 // What kind of cases could reach here?
 509                                 return 0;
 510                         }
 511
 512                         public override PropertyInfo SelectProperty (BindingFlags bindingAttr, PropertyInfo[] match, Type returnType, Type[] indexes, ParameterModifier[] modifiers)
 513                         {
 514                                 if (match == null || match.Length == 0)
 515                                         throw new ArgumentException ("No properties provided", "match");
 516
 517                                 bool haveRet = (returnType != null);
 518                                 int idxlen = (indexes != null) ? indexes.Length : -1;
 519                                 PropertyInfo result = null;
 520                                 int i;
 521                                 int best_score = Int32.MaxValue - 1;
 522                                 int fail_score = Int32.MaxValue;
 523                                 int level = 0;
 524
 525                                 for (i = match.Length - 1; i >= 0; i--) {
 526                                         PropertyInfo p = match [i];
 527                                         ParameterInfo[] args = p.GetIndexParameters ();
 528                                         if (idxlen >= 0 && idxlen != args.Length)
 529                                                 continue;
 530
 531                                         if (haveRet && p.PropertyType != returnType)
 532                                                 continue;
 533
 534                                         int score = Int32.MaxValue - 1;
 535                                         if (idxlen > 0) {
 536                                                 score = check_arguments_with_score (indexes, args);
 537                                                 if (score == -1)
 538                                                         continue;
 539                                         }
 540
 541                                         int new_level = GetDerivedLevel (p.DeclaringType);
 542                                         if (result != null) {
 543                                                 if (best_score < score)
 544                                                         continue;
 545
 546                                                 if (best_score == score) {
 547                                                         if (level == new_level) {
 548                                                                 // Keep searching. May be there's something
 549                                                                 // better for us.
 550                                                                 fail_score = score;
 551                                                                 continue;
 552                                                         }
 553
 554                                                         if (level > new_level)
 555                                                                 continue;
 556                                                 }
 557                                         }
 558
 559                                         result = p;
 560                                         best_score = score;
 561                                         level = new_level;
 562                                 }
 563
 564                                 if (fail_score <= best_score)
 565                                         throw new AmbiguousMatchException ();
 566
 567                                 return result;
 568                         }
 569
 570                         static int check_arguments_with_score (Type [] types, ParameterInfo [] args)
 571                         {
 572                                 int worst = -1;
 573
 574                                 for (int i = 0; i < types.Length; ++i) {
 575                                         int res = check_type_with_score (types [i], args [i].ParameterType);
 576                                         if (res == -1)
 577                                                 return -1;
 578
 579                                         if (worst < res)
 580                                                 worst = res;
 581                                 }
 582
 583                                 return worst;
 584                         }
 585
 586                         // 0 -> same type or null and !valuetype
 587                         // 1 -> to == Enum
 588                         // 2 -> value type that don't lose data
 589                         // 3 -> to == IsAssignableFrom
 590                         // 4 -> to == object
 591                         static int check_type_with_score (Type from, Type to)
 592                         {
 593                                 if (from == null)
 594                                         return to.IsValueType ? -1 : 0;
 595
 596                                 if (from == to)
 597                                         return 0;
 598
 599                                 if (to == typeof (object))
 600                                         return 4;
 601
 602                                 TypeCode fromt = Type.GetTypeCode (from);
 603                                 TypeCode tot = Type.GetTypeCode (to);
 604
 605                                 switch (fromt) {
 606                                 case TypeCode.Char:
 607                                         switch (tot) {
 608                                         case TypeCode.UInt16:
 609                                                 return 0;
 610
 611                                         case TypeCode.UInt32:
 612                                         case TypeCode.Int32:
 613                                         case TypeCode.UInt64:
 614                                         case TypeCode.Int64:
 615                                         case TypeCode.Single:
 616                                         case TypeCode.Double:
 617                                                 return 2;
 618                                         }
 619                                         return -1;
 620                                 case TypeCode.Byte:
 621                                         switch (tot) {
 622                                         case TypeCode.Char:
 623                                         case TypeCode.UInt16:
 624                                         case TypeCode.Int16:
 625                                         case TypeCode.UInt32:
 626                                         case TypeCode.Int32:
 627                                         case TypeCode.UInt64:
 628                                         case TypeCode.Int64:
 629                                         case TypeCode.Single:
 630                                         case TypeCode.Double:
 631                                                 return 2;
 632                                         }
 633                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 634                                 case TypeCode.SByte:
 635                                         switch (tot) {
 636                                         case TypeCode.Int16:
 637                                         case TypeCode.Int32:
 638                                         case TypeCode.Int64:
 639                                         case TypeCode.Single:
 640                                         case TypeCode.Double:
 641                                                 return 2;
 642                                         }
 643                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 644                                 case TypeCode.UInt16:
 645                                         switch (tot) {
 646                                         case TypeCode.UInt32:
 647                                         case TypeCode.Int32:
 648                                         case TypeCode.UInt64:
 649                                         case TypeCode.Int64:
 650                                         case TypeCode.Single:
 651                                         case TypeCode.Double:
 652                                                 return 2;
 653                                         }
 654                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 655                                 case TypeCode.Int16:
 656                                         switch (tot) {
 657                                         case TypeCode.Int32:
 658                                         case TypeCode.Int64:
 659                                         case TypeCode.Single:
 660                                         case TypeCode.Double:
 661                                                 return 2;
 662                                         }
 663                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 664                                 case TypeCode.UInt32:
 665                                         switch (tot) {
 666                                         case TypeCode.UInt64:
 667                                         case TypeCode.Int64:
 668                                         case TypeCode.Single:
 669                                         case TypeCode.Double:
 670                                                 return 2;
 671                                         }
 672                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 673                                 case TypeCode.Int32:
 674                                         switch (tot) {
 675                                         case TypeCode.Int64:
 676                                         case TypeCode.Single:
 677                                         case TypeCode.Double:
 678                                                 return 2;
 679                                         }
 680                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 681                                 case TypeCode.UInt64:
 682                                 case TypeCode.Int64:
 683                                         switch (tot) {
 684                                         case TypeCode.Single:
 685                                         case TypeCode.Double:
 686                                                 return 2;
 687                                         }
 688                                         return (from.IsEnum && to == typeof (Enum)) ? 1 : -1;
 689                                 case TypeCode.Single:
 690                                         return tot == TypeCode.Double ? 2 : -1;
 691                                 default:
 692                                         return (to.IsAssignableFrom (from)) ? 3 : -1;
 693                                 }
 694                         }
 695                 }
 696         }
 697 }
 698