include/Expression.h

   1 /***************************************************************************
   2  *   Copyright (C) 2007 by www.databasecache.com                           *
   3  *   Contact: praba_tuty@databasecache.com                                 *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  ***************************************************************************/
  16 #ifndef EXPRESSION_H
  17 #define EXPRESSION_H
  18 #include<os.h>
  19 #include<DataType.h>
  20 #include<Function.h>
  21
  22 class Table;
  23 class TableImpl;
  24 enum ArithOperator {
  25     unKnownOperator = 0,
  26     addition,
  27     subtraction,
  28     multiplication,
  29     division,
  30     modulus
  31 };
  32 class DllExport Expression
  33 {
  34     char fldName[IDENTIFIER_LENGTH];
  35     void *tuple;
  36     void *constVal;
  37     void *calVal;
  38     TableImpl *table;
  39     ArithOperator arOp;
  40     Expression *lhs;
  41     Expression *rhs;
  42     FunctionType fType;
  43     DataType dType;
  44     public:
  45     Expression()
  46     {
  47         table=NULL; arOp = unKnownOperator; lhs=NULL; rhs=NULL;
  48         tuple=NULL; constVal=NULL;
  49         strcpy(fldName,"\0");
  50         calVal = NULL;
  51         fType = UNKNOWN_FUNCTION;
  52     }
  53     ~Expression()
  54     {
  55         if(lhs){ delete lhs; lhs=NULL;}
  56         if(rhs){ delete rhs; rhs=NULL;}
  57     }
  58     void setTable(Table *tbl);
  59     void setTuple(void *tpl);
  60     bool isSingleTerm();
  61     void setDataType(DataType type){dType = type;};
  62     DataType getDataType(){ return dType;};
  63     void setFunctionType(FunctionType type);
  64     FunctionType getFunctionType() {return fType;}
  65     void copyFunctionVal(void *dest,void *src, FunctionType type, int length);
  66     void *evaluateAndGetValPtr(void *lhsResult, void *rhsResult);
  67     void setExpr(Expression* exp1, FunctionType type,Expression* exp2);
  68     void setExpr(char const *name,ArithOperator op,void *cVal );
  69     void setExpr(char const *name);
  70     void setExpr(Expression *exp1, ArithOperator op, Expression *exp2 );
  71     void setExpr(void *cVal,bool flag );
  72     void *evaluate(DataType type,bool &result);
  73     void *evaluateForFunction(DataType type);
  74     void solve(void *opand1, void *opand2, DataType type, ArithOperator arOp);
  75     void convertStrToVal(DataType type);
  76     void freeVal();
  77     void memFree();
  78 };
  79
  80 #endif