EasyQtSql_Util.h

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#ifndef EASYQTSQL_UTIL_H
#define EASYQTSQL_UTIL_H

/*
 * The MIT License (MIT)
 * Copyright 2018 Alexey Kramin
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
*/

#ifndef EASY_QT_SQL_MAIN

#include "EasyQtSql_QueryResult.h"

#endif

class Util
{
public:

   template<typename Func>
   static int each(QueryResult &res, Func&& f)
   {
      int rowCount = 0;

      if (res.isActive())
      {
         while (res.next())
         {
            f(res);
            ++rowCount;
         }
      }

      return rowCount;
   }

   template<typename Func>
   static int range(QueryResult &res, int start, int count, Func&& f)
   {
      Q_ASSERT(start >= 0);
      Q_ASSERT(count >= 0);

      int rowCount = 0;

      if (res.isActive())
      {
         //skip items
         for (int i = 0; i < start; ++i)
         {
            if (!res.next())
               return rowCount;
         }

         for (int i = 0; i < count && res.next(); ++i)
         {
            f(res);
            rowCount++;
         }
      }

      return rowCount;
   }

   template<typename Func>
   static int top(QueryResult &res, int topCount, Func&& f)
   {
      return range(res, 0, topCount, f);
   }
   
   template<typename Func>
   static int first(QueryResult &res, Func&& f)
   {
      return top(res, 1, f);
   }

private:
   Util(){}
};

#endif // EASYQTSQL_UTIL_H