#W# Initial Commit: Avatars Conquest

Scripts/Commands/Generic/Extensions/Compilers/DistinctCompiler.cs

@@ -0,0 +1,249 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Reflection.Emit;
+using System.Text;
+using Server;
+
+namespace Server.Commands.Generic
+{
+	public static class DistinctCompiler
+	{
+		public static IComparer Compile( AssemblyEmitter assembly, Type objectType, Property[] props )
+		{
+			TypeBuilder typeBuilder = assembly.DefineType(
+					"__distinct",
+					TypeAttributes.Public,
+					typeof( object )
+				);
+
+			#region Constructor
+			{
+				ConstructorBuilder ctor = typeBuilder.DefineConstructor(
+						MethodAttributes.Public,
+						CallingConventions.Standard,
+						Type.EmptyTypes
+					);
+
+				ILGenerator il = ctor.GetILGenerator();
+
+				// : base()
+				il.Emit( OpCodes.Ldarg_0 );
+				il.Emit( OpCodes.Call, typeof( object ).GetConstructor( Type.EmptyTypes ) );
+
+				// return;
+				il.Emit( OpCodes.Ret );
+			}
+			#endregion
+
+			#region IComparer
+			typeBuilder.AddInterfaceImplementation( typeof( IComparer ) );
+
+			MethodBuilder compareMethod;
+
+			#region Compare
+			{
+				MethodEmitter emitter = new MethodEmitter( typeBuilder );
+
+				emitter.Define(
+					/*  name  */ "Compare",
+					/*  attr  */ MethodAttributes.Public | MethodAttributes.Virtual,
+					/* return */ typeof( int ),
+					/* params */ new Type[] { typeof( object ), typeof( object ) } );
+
+				LocalBuilder a = emitter.CreateLocal( objectType );
+				LocalBuilder b = emitter.CreateLocal( objectType );
+
+				LocalBuilder v = emitter.CreateLocal( typeof( int ) );
+
+				emitter.LoadArgument( 1 );
+				emitter.CastAs( objectType );
+				emitter.StoreLocal( a );
+
+				emitter.LoadArgument( 2 );
+				emitter.CastAs( objectType );
+				emitter.StoreLocal( b );
+
+				emitter.Load( 0 );
+				emitter.StoreLocal( v );
+
+				Label end = emitter.CreateLabel();
+
+				for ( int i = 0; i < props.Length; ++i )
+				{
+					if ( i > 0 )
+					{
+						emitter.LoadLocal( v );
+						emitter.BranchIfTrue( end ); // if ( v != 0 ) return v;
+					}
+
+					Property prop = props[i];
+
+					emitter.LoadLocal( a );
+					emitter.Chain( prop );
+
+					bool couldCompare =
+					emitter.CompareTo( 1, delegate()
+					{
+						emitter.LoadLocal( b );
+						emitter.Chain( prop );
+					} );
+
+					if ( !couldCompare )
+						throw new InvalidOperationException( "Property is not comparable." );
+
+					emitter.StoreLocal( v );
+				}
+
+				emitter.MarkLabel( end );
+
+				emitter.LoadLocal( v );
+				emitter.Return();
+
+				typeBuilder.DefineMethodOverride(
+						emitter.Method,
+						typeof( IComparer ).GetMethod(
+							"Compare",
+							new Type[]
+								{
+									typeof( object ),
+									typeof( object )
+								}
+						)
+					);
+
+				compareMethod = emitter.Method;
+			}
+			#endregion
+			#endregion
+
+			#region IEqualityComparer
+			typeBuilder.AddInterfaceImplementation( typeof( IEqualityComparer<object> ) );
+
+			#region Equals
+			{
+				MethodEmitter emitter = new MethodEmitter( typeBuilder );
+
+				emitter.Define(
+					/*  name  */ "Equals",
+					/*  attr  */ MethodAttributes.Public | MethodAttributes.Virtual,
+					/* return */ typeof( bool ),
+					/* params */ new Type[] { typeof( object ), typeof( object ) } );
+
+				emitter.Generator.Emit( OpCodes.Ldarg_0 );
+				emitter.Generator.Emit( OpCodes.Ldarg_1 );
+				emitter.Generator.Emit( OpCodes.Ldarg_2 );
+
+				emitter.Generator.Emit( OpCodes.Call, compareMethod );
+
+				emitter.Generator.Emit( OpCodes.Ldc_I4_0 );
+
+				emitter.Generator.Emit( OpCodes.Ceq );
+
+				emitter.Generator.Emit( OpCodes.Ret );
+
+				typeBuilder.DefineMethodOverride(
+						emitter.Method,
+						typeof( IEqualityComparer<object> ).GetMethod(
+							"Equals",
+							new Type[]
+							{
+								typeof( object ),
+								typeof( object )
+							}
+						)
+					);
+			}
+			#endregion
+
+			#region GetHashCode
+			{
+				MethodEmitter emitter = new MethodEmitter( typeBuilder );
+
+				emitter.Define(
+					/*  name  */ "GetHashCode",
+					/*  attr  */ MethodAttributes.Public | MethodAttributes.Virtual,
+					/* return */ typeof( int ),
+					/* params */ new Type[] { typeof( object ) } );
+
+				LocalBuilder obj = emitter.CreateLocal( objectType );
+
+				emitter.LoadArgument( 1 );
+				emitter.CastAs( objectType );
+				emitter.StoreLocal( obj );
+
+				for ( int i = 0; i < props.Length; ++i )
+				{
+					Property prop = props[i];
+
+					emitter.LoadLocal( obj );
+					emitter.Chain( prop );
+
+					Type active = emitter.Active;
+
+					MethodInfo getHashCode = active.GetMethod( "GetHashCode", Type.EmptyTypes );
+
+					if ( getHashCode == null )
+						getHashCode = typeof( object ).GetMethod( "GetHashCode", Type.EmptyTypes );
+
+					if ( active != typeof( int ) )
+					{
+						if ( !active.IsValueType )
+						{
+							LocalBuilder value = emitter.AcquireTemp( active );
+
+							Label valueNotNull = emitter.CreateLabel();
+							Label done = emitter.CreateLabel();
+
+							emitter.StoreLocal( value );
+							emitter.LoadLocal( value );
+
+							emitter.BranchIfTrue( valueNotNull );
+
+							emitter.Load( 0 );
+							emitter.Pop( typeof( int ) );
+
+							emitter.Branch( done );
+
+							emitter.MarkLabel( valueNotNull );
+
+							emitter.LoadLocal( value );
+							emitter.Call( getHashCode );
+
+							emitter.ReleaseTemp( value );
+
+							emitter.MarkLabel( done );
+						}
+						else
+						{
+							emitter.Call( getHashCode );
+						}
+					}
+
+					if ( i > 0 )
+						emitter.Xor();
+				}
+
+				emitter.Return();
+
+				typeBuilder.DefineMethodOverride(
+						emitter.Method,
+						typeof( IEqualityComparer<object> ).GetMethod(
+							"GetHashCode",
+							new Type[]
+							{
+								typeof( object )
+							}
+						)
+					);
+			}
+			#endregion
+			#endregion
+
+			Type comparerType = typeBuilder.CreateType();
+
+			return (IComparer) Activator.CreateInstance( comparerType );
+		}
+	}
+}