/* Filename:  sortemp.cpp

   Author:  Br. David Carlson

   Date:  June 13, 1998

   Last Revised:  November 23, 2001

   This program sorts the emp.dat file that is created with the makeemp
   program.  This sort program will not work for large files, as it
   uses an array to try to hold all of the data at once.  Note that the
   sorting is done based on employee names, last name and then first name.

   Tested with:
      Microsoft Visual C++ 6.0
      Microsoft Visual C++ .NET
      g++ under Linux
*/

#include <fstream>   // needed for files
#include "emparray.h"


/* Given:  InFile     A binary file stream, already opened for input.
   Task:   To read a sequence of employee data from the InFile,
           storing it in EmpArray.
   Return: EmpArray   The array of employee data.
           EmpCount   The number of employees just entered.
           In the function name return OKFlag or 
           TooMuchDataFlag to indicate how this function ended.
*/
int LoadArray(fstream & InFile, EmpArrayType EmpArray, int & EmpCount)
   {
   EmployeeType Employee;
   int RecordSize;

   EmpCount = 0;
   RecordSize = sizeof(Employee);
   InFile.read(reinterpret_cast <char *> (&Employee), RecordSize);

   while ((! InFile.fail()) && (EmpCount < EmpMax))
      {
      EmpArray[EmpCount] = Employee;
      EmpCount++;
      InFile.read(reinterpret_cast <char *> (&Employee), RecordSize);
      }

   if (InFile.fail())
      return OKFlag;
   else   // array ran out of room
      return TooMuchDataFlag;
   }


/* Given:  OutFile    A binary file stream, already opened for output.
           EmpArray   The array of employee data, from index 0 to 
                      EmpCount - 1.
           EmpCount   The number of employee records in EmpArray.
   Task:   To write the employee records contained in EmpArray to OutFile.
   Return: OutFile    The modified file stream.
*/
void WriteToFile(fstream & OutFile, EmpArrayType EmpArray, int EmpCount)
   {
   int RecordSize, k;

   RecordSize = sizeof(EmployeeType);

   for (k = 0; k < EmpCount; k++)
      OutFile.write(reinterpret_cast <char *> (&EmpArray[k]), RecordSize);
   }


int main(void)
   {
   EmpArrayType EmpArray;
   int Flag, EmpCount;
   fstream EmpFile, NewFile;

   EmpFile.open("emp.dat", ios::in | ios::binary);
   if (EmpFile.fail())
      {
      cerr << "Could not open file emp.dat for input" << endl;
      exit(1);
      }

   Flag = LoadArray(EmpFile, EmpArray, EmpCount);
   EmpFile.close();

   if (Flag == TooMuchDataFlag)
      cout << endl << endl << "The data would not fit in the array"
         << endl;
   else
      {
      SelectionSort(EmpArray, EmpCount);

      NewFile.open("emp.dat", ios::out | ios::binary);
      if (NewFile.fail())
         {
         cerr << "Could not open file emp.dat for output" << endl;
         exit(1);
         }

      WriteToFile(NewFile, EmpArray, EmpCount);
      NewFile.close();

      cout << endl << "Sorting completed.  Press ENTER:" << endl;
      cin.get();
      }

   return 0;
   }