/**
 * @File : exo_04.cxx
 *
 * nsFctShell::FileCopy()  
 *
 * donneTailleMorceau
 **/
#include <string>
#include <exception>
#include <fcntl.h>          // O_RDONLY


#include "CExc.h"
#include "nsSysteme.h"      // Open(), Read(), Close()

using namespace nsSysteme;  // Open(), Read(), Close()
using namespace std;

int main (int argc, char * argv []) {
   try {
    if (2 != argc)
        throw CExc ("main()",string ("Usage : ") +
		    argv [0] + " <fichier> ");

    char c;
    int  fD;
    fD = Open(argv[1],O_RDONLY);
    Read(fD,&c,sizeof(char));
    cout << "Lecture caractere:  '" << c << "' " << endl; 
    int n;
    Read(fD,&n,sizeof(int));
	cout << "Lecture entier:  " << n <<flush;
	cout<< " et lecture d'autant de caracteres: "<<endl <<"' " << flush; 
	   
	/************************************************************************************/
	/*____________________Variante trop gourmande en memoire____________________________*/
	/*   
	  
    char Tab[n];    // 0,...,n=> n+1 espaces reserves
    Read(fD,Tab,n);
    for(int i=0;i<n;++i)	
    		cout <<Tab[i];
    
    cout<< flush;
    cout << "et enfin lecture du reste: '" << flush;
    while(Read(fD,&c,sizeof(char))) {
		cout << c << flush;
    }
	*/
	/************************************************************************************/
	/*____Variante lecture d'une taille variable par des morceaux de taille fixe________*/  
	   
	   
	   const int AReserver= 512;
	   char Tab[AReserver+1];
	   size_t NbLus;
	   
	   while (n>AReserver)
	   {
		   n-=AReserver; 
		   NbLus=Read(fD, Tab, AReserver);
		   Tab[NbLus]='\0';
		   cout << Tab;
		   
	   }
	   NbLus=Read(fD, Tab, n);
	   Tab[NbLus]='\0';
	   cout << Tab;
	   cout<< "  '"<<endl;
	   cout << "et enfin lecture du reste: '" << flush;
	   
	   
	   while((NbLus=Read(fD, Tab, AReserver))>0)
	   {
		   Tab[NbLus]='\0';
		   cout << Tab;
	   }
	   cout << flush;
	   
    /************************************************************************************/
   
    cout << "' "<< endl<<"et le traitement est fini, au revoir.\n";
    Close(fD);
    return 0;
   }
   catch (const CExc & Exc) {
        cerr <<Exc<< endl;
        return errno;
   }
   catch (const exception & Exc) {
        cerr << "Exception : " << Exc.what () << endl;
        return 1;
   }
   catch (...) {
        cerr << "Exception inconnue recue dans la fonction main()" 
             << endl;
        return 1;
   }

} // main()