Add support for BigInteger in DoubleType and SingleType

Author: hazzik

src/NHibernate/Type/DoubleType.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Data;
 using System.Data.Common;
+using System.Numerics;
 using NHibernate.Engine;
 using NHibernate.SqlTypes;
 
@@ -22,12 +23,20 @@ public DoubleType(SqlType sqlType) : base(sqlType) {}
 
 		public override object Get(DbDataReader rs, int index, ISessionImplementor session)
 		{
-			return Convert.ToDouble(rs[index]);
+			return rs[index] switch
+			{
+				BigInteger bi => (double) bi,
+				var v => Convert.ToDouble(v)
+			};
 		}
 
 		public override object Get(DbDataReader rs, string name, ISessionImplementor session)
 		{
-			return Convert.ToDouble(rs[name]);
+			return rs[name] switch
+			{
+				BigInteger bi => (double) bi,
+				var v => Convert.ToDouble(v)
+			};
 		}
 
 		/// <summary></summary>

src/NHibernate/Type/SingleType.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Data;
 using System.Data.Common;
+using System.Numerics;
 using NHibernate.Engine;
 using NHibernate.SqlTypes;
 
@@ -35,7 +36,11 @@ public override object Get(DbDataReader rs, int index, ISessionImplementor sessi
 		{
 			try
 			{
-				return Convert.ToSingle(rs[index]);
+				return rs[index] switch
+				{
+					BigInteger bi => (float) bi,
+					var v => Convert.ToSingle(v)
+				};
 			}
 			catch (Exception ex)
 			{
@@ -47,7 +52,11 @@ public override object Get(DbDataReader rs, string name, ISessionImplementor ses
 		{
 			try
 			{
-				return Convert.ToSingle(rs[name]);
+				return rs[name] switch
+				{
+					BigInteger bi => (float) bi,
+					var v => Convert.ToSingle(v)
+				};
 			}
 			catch (Exception ex)
 			{