mcs/class/System.Data/Mono.Data.SqlExpressions/ArithmeticExpressions.cs

   1 //
   2 // ArithmeticExpressions.cs
   3 //
   4 // Author:
   5 //   Juraj Skripsky (juraj@hotfeet.ch)
   6 //
   7 // (C) 2004 HotFeet GmbH (http://www.hotfeet.ch)
   8 //
   9
  10 //
  11 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System;
  34 using System.Collections;
  35 using System.Data;
  36
  37 namespace Mono.Data.SqlExpressions {
  38         internal class Negative : UnaryExpression {
  39                 public Negative (IExpression e) : base (e) {}
  40
  41                 override public object Eval (DataRow row)
  42                 {
  43                         return Numeric.Negative ((IConvertible)expr.Eval (row));
  44                 }
  45         }
  46
  47         internal class ArithmeticOperation : BinaryOpExpression {
  48                 public ArithmeticOperation (Operation op, IExpression e1, IExpression e2) : base (op, e1, e2) {}
  49
  50                 override public object Eval (DataRow row)
  51                 {
  52                         object obj1 = expr1.Eval (row);
  53                         object obj2 = expr2.Eval (row);
  54
  55                         if (op == Operation.ADD && (obj1 is string || obj2 is string))
  56                                 return (obj1 != null ? obj1.ToString () : String.Empty) + (obj2 != null ? obj2.ToString () : String.Empty);
  57
  58                         IConvertible o1 = (IConvertible)obj1;
  59                         IConvertible o2 = (IConvertible)obj2;
  60
  61                         switch (op) {
  62                         case Operation.ADD:
  63                                 return Numeric.Add (o1, o2);
  64                         case Operation.SUB:
  65                                 return Numeric.Subtract (o1, o2);
  66                         case Operation.MUL:
  67                                 return Numeric.Multiply (o1, o2);
  68                         case Operation.DIV:
  69                                 return Numeric.Divide (o1, o2);
  70                         case Operation.MOD:
  71                                 return Numeric.Modulo (o1, o2);
  72                         default:
  73                                 return 0;
  74                         }
  75                 }
  76         }
  77 }