System.Data.Select.Eval C# (CSharp) Метод

        private int Eval(BinaryNode expr, DataRow row, DataRowVersion version)
        {
            if (expr._op == Operators.And)
            {
                int lResult = Eval((BinaryNode)expr._left, row, version);
                if (lResult != 0)
                    return lResult;
                int rResult = Eval((BinaryNode)expr._right, row, version);
                if (rResult != 0)
                    return rResult;
                return 0;
            }

            long c = 0;
            object vLeft = expr._left.Eval(row, version);
            if (expr._op != Operators.Is && expr._op != Operators.IsNot)
            {
                object vRight = expr._right.Eval(row, version);
                bool isLConst = (expr._left is ConstNode);
                bool isRConst = (expr._right is ConstNode);

                if ((vLeft == DBNull.Value) || (expr._left.IsSqlColumn && DataStorage.IsObjectSqlNull(vLeft)))
                    return -1;
                if ((vRight == DBNull.Value) || (expr._right.IsSqlColumn && DataStorage.IsObjectSqlNull(vRight)))
                    return 1;

                StorageType leftType = DataStorage.GetStorageType(vLeft.GetType());
                if (StorageType.Char == leftType)
                {
                    if ((isRConst) || (!expr._right.IsSqlColumn))
                        vRight = Convert.ToChar(vRight, _table.FormatProvider);
                    else
                        vRight = SqlConvert.ChangeType2(vRight, StorageType.Char, typeof(char), _table.FormatProvider);
                }

                StorageType rightType = DataStorage.GetStorageType(vRight.GetType());
                StorageType resultType;
                if (expr._left.IsSqlColumn || expr._right.IsSqlColumn)
                {
                    resultType = expr.ResultSqlType(leftType, rightType, isLConst, isRConst, expr._op);
                }
                else
                {
                    resultType = expr.ResultType(leftType, rightType, isLConst, isRConst, expr._op);
                }
                if (StorageType.Empty == resultType)
                {
                    expr.SetTypeMismatchError(expr._op, vLeft.GetType(), vRight.GetType());
                }

                // if comparing a Guid column value against a string literal
                // use InvariantCulture instead of DataTable.Locale because in the Danish related cultures
                // sorting a Guid as a string has different results than in Invariant and English related cultures.
                // This fix is restricted to DataTable.Select("GuidColumn = 'string literal'") types of queries
                NameNode namedNode = null;
                System.Globalization.CompareInfo comparer =
                    ((isLConst && !isRConst && (leftType == StorageType.String) && (rightType == StorageType.Guid) && (null != (namedNode = expr._right as NameNode)) && (namedNode._column.DataType == typeof(Guid))) ||
                     (isRConst && !isLConst && (rightType == StorageType.String) && (leftType == StorageType.Guid) && (null != (namedNode = expr._left as NameNode)) && (namedNode._column.DataType == typeof(Guid))))
                     ? System.Globalization.CultureInfo.InvariantCulture.CompareInfo : null;

                c = expr.BinaryCompare(vLeft, vRight, resultType, expr._op, comparer);
            }
            switch (expr._op)
            {
                case Operators.EqualTo: c = (c == 0 ? 0 : c < 0 ? -1 : 1); break;
                case Operators.GreaterThen: c = (c > 0 ? 0 : -1); break;
                case Operators.LessThen: c = (c < 0 ? 0 : 1); break;
                case Operators.GreaterOrEqual: c = (c >= 0 ? 0 : -1); break;
                case Operators.LessOrEqual: c = (c <= 0 ? 0 : 1); break;
                case Operators.Is: c = (vLeft == DBNull.Value ? 0 : -1); break;
                case Operators.IsNot: c = (vLeft != DBNull.Value ? 0 : 1); break;
                default: Debug.Assert(true, "Unsupported Binary Search Operator!"); break;
            }
            return (int)c;
        }