--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Source/Data/Sql/SqlValueBase.cs	Thu Mar 27 21:46:09 2014 +0400
@@ -0,0 +1,179 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+using BLToolkit.Mapping;
+using BLToolkit.Reflection;
+
+namespace BLToolkit.Data.Sql
+{
+	public abstract class SqlValueBase: IValueContainer
+	{
+		[CLSCompliant(false)]
+		protected      object _value;
+		public virtual object  Value
+		{
+			get
+			{
+				var valueConverter = ValueConverter;
+				return valueConverter == null ? _value : valueConverter(_value);
+			}
+
+			set { _value = value; }
+		}
+
+		#region Value Converter
+
+		internal List<Type> EnumTypes;
+		internal List<int>  TakeValues;
+		internal string     LikeStart, LikeEnd;
+
+		private Converter<object,object> _valueConverter;
+		public  Converter<object,object>  ValueConverter
+		{
+			get
+			{
+				if (_valueConverter == null)
+				{
+					if (EnumTypes != null)
+						foreach (var type in EnumTypes.ToArray())
+							SetEnumConverter(type, Map.DefaultSchema);
+					else if (TakeValues != null)
+						foreach (var take in TakeValues.ToArray())
+							SetTakeConverter(take);
+					else if (LikeStart != null)
+						SetLikeConverter(LikeStart, LikeEnd);
+				}
+
+				return _valueConverter;
+			}
+
+			set { _valueConverter = value; }
+		}
+
+		bool _isEnumConverterSet;
+
+		internal void SetEnumConverter(Type type, MappingSchema ms)
+		{
+			if (!_isEnumConverterSet)
+			{
+				_isEnumConverterSet = true;
+
+				if (EnumTypes == null)
+					EnumTypes = new List<Type>();
+
+				EnumTypes.Add(type);
+
+				SetEnumConverterInternal(type, ms);
+			}
+		}
+
+		internal void SetEnumConverter(MemberAccessor ma, MappingSchema ms)
+		{
+			if (!_isEnumConverterSet)
+			{
+				_isEnumConverterSet = true;
+
+				if (EnumTypes == null)
+					EnumTypes = new List<Type>();
+
+				EnumTypes.Add(ma.Type);
+
+				SetEnumConverterInternal(ma, ms);
+			}
+		}
+
+		void SetEnumConverterInternal(MemberAccessor ma, MappingSchema ms)
+		{
+			if (_valueConverter == null)
+			{
+				_valueConverter = o => ms.MapEnumToValue(o, ma, true);
+			}
+			else
+			{
+				var converter = _valueConverter;
+				_valueConverter = o => ms.MapEnumToValue(converter(o), ma, true);
+			}
+			// update system type in SqlValue :-/
+			var tmp = Value;
+		}
+
+		void SetEnumConverterInternal(Type type, MappingSchema ms)
+		{
+			if (_valueConverter == null)
+			{
+				_valueConverter = o => ms.MapEnumToValue(o, type, true);
+			}
+			else
+			{
+				var converter = _valueConverter;
+				_valueConverter = o => ms.MapEnumToValue(converter(o), type, true);
+			}
+			// update system type in SqlValue :-/
+			var tmp = Value;
+		}
+
+		internal void SetTakeConverter(int take)
+		{
+			if (TakeValues == null)
+				TakeValues = new List<int>();
+
+			TakeValues.Add(take);
+
+			SetTakeConverterInternal(take);
+		}
+
+		void SetTakeConverterInternal(int take)
+		{
+			var conv = _valueConverter;
+
+			if (conv == null)
+				_valueConverter = v => v == null ? null : (object)((int)v + take);
+			else
+				_valueConverter = v => v == null ? null : (object)((int)conv(v) + take);
+		}
+
+		internal void SetLikeConverter(string start, string end)
+		{
+			LikeStart = start;
+			LikeEnd = end;
+			_valueConverter = GetLikeEscaper(start, end);
+		}
+
+		static Converter<object, object> GetLikeEscaper(string start, string end)
+		{
+			return value =>
+			{
+				if (value == null)
+	#if DEBUG
+					value = "";
+	#else
+					throw new SqlException("NULL cannot be used as a LIKE predicate parameter.");
+	#endif
+
+				var text = value.ToString();
+
+				if (text.IndexOfAny(new[] { '%', '_', '[' }) < 0)
+					return start + text + end;
+
+				var sb = new StringBuilder(start, text.Length + start.Length + end.Length);
+
+				foreach (var c in text)
+				{
+					if (c == '%' || c == '_' || c == '[')
+					{
+						sb.Append('[');
+						sb.Append(c);
+						sb.Append(']');
+					}
+					else
+						sb.Append(c);
+				}
+
+				return sb.ToString();
+			};
+		}
+
+		#endregion
+	}
+}