source: Sophya/trunk/Eval/COS/tios.cc@ 2970

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <iostream.h>
#include <fstream.h>

void tread(istream* s);
void tread2(istream* s);
void twrite(ostream* s);

// -----------------------------------------------------
// This test program illustrates the problem with g++
//  (pb with g++ 2.95 3.0) 
// iostream library with seekg(..., ios::end)
// # compile the program 
// csh> g++ -o tios tios.cc
// # Create the test data file tios.dat
// csh> ./tios w
// # Read with seekg(... ios::end) ---> wrong result
// csh> ./tios r 
// # seekg(... ios::beg) works OK 
// csh> ./tios r2
// ----------------------------------------------------

int main(int narg, char ** arg)
{
if (narg < 2) {
  cout << "Usage: tios w/r/r2 \n" 
       << "  w  : Write data file tios.cc \n" 
       << "  r  : Read data file with seekg(ios::end)  -> g++/Linux Pb \n"
       << "  r2 : Read  data file with seekg(ios::beg) g++/Linux OK  \n" << endl;
  exit(0);
  }

istream* is;
ostream* os;
if (arg[1][0] == 'r') {
// is = new ifstream("tios.dat", ios::in | ios::binary);
 is = new ifstream("tios.dat", ios::in );
 if ( arg[1][1] == '2') tread2(is);
 else tread(is);
 delete is;
 }
else {
// os = new ofstream("tios.dat", ios::out | ios::binary);  
 os = new ofstream("tios.dat", ios::out );  
 twrite(os);
 delete(os);
 }

}

void twrite(ostream* s)
{
int i;
int iv;
float fv;
double dv;
for(i=0; i<10; i++) {
  iv = 1000+i*50;
  fv = iv+2.5;
  dv = iv+3.141596;
  s->write((char const*)(&iv), sizeof(int));
  s->write((char const*)(&fv), sizeof(float));
  s->write((char const*)(&dv), sizeof(double));
  cout << "twrite " << i << " IV= " << iv << " FV= " << fv << " DV= " << dv << endl;
  }
}

void tread(istream* s)
{
int i;
int iv;
float fv;
double dv;
long pos;
for(i=0; i<10; i++) {
  pos = s->tellg();
  s->read((char *)(&iv), sizeof(int));
  s->read((char *)(&fv), sizeof(float));
  s->read((char *)(&dv), sizeof(double));
  cout << "tread " << i << " IV= " << iv << " FV= " << fv << " DV= " << dv 
       << " Pos= " << pos << endl;
  }

cout << " ----- Check Output from here ------- " << endl;
for(i=0; i<4; i++) {
  s->seekg(-i*(sizeof(int)+sizeof(float)+sizeof(double)), ios::end);
  pos = s->tellg();
  s->read((char *)(&iv), sizeof(int));
  s->read((char *)(&fv), sizeof(float));
  s->read((char *)(&dv), sizeof(double));
  cout << "Seek-tread-end " << " IV= " << iv << " FV= " << fv << " DV= " << dv 
       << " Pos= " << pos << endl;
}
s->seekg((sizeof(int)+sizeof(float)+sizeof(double)), ios::beg);
pos = s->tellg();
s->read((char *)(&iv), sizeof(int));
s->read((char *)(&fv), sizeof(float));
s->read((char *)(&dv), sizeof(double));
cout << "Seek-tread-begin " << " IV= " << iv << " FV= " << fv << " DV= " << dv 
     << " Pos= " << pos << endl;

}

void tread2(istream* s)
{
int i;
int iv;
float fv;
double dv;
long pos;
for(i=0; i<10; i++) {
  pos = s->tellg();
  s->read((char *)(&iv), sizeof(int));
  s->read((char *)(&fv), sizeof(float));
  s->read((char *)(&dv), sizeof(double));
  cout << "tread2 " << i << " IV= " << iv << " FV= " << fv << " DV= " << dv 
       << " Pos= " << pos << endl;
  }

cout << " ----- Check Output from here ------- " << endl;
for(i=1; i<5; i+=2) {
  s->seekg(i*(sizeof(int)+sizeof(float)+sizeof(double)), ios::beg);
  pos = s->tellg();
  s->read((char *)(&iv), sizeof(int));
  s->read((char *)(&fv), sizeof(float));
  s->read((char *)(&dv), sizeof(double));
  
  cout << "Seek-tread2-begin " << " IV= " << iv << " FV= " << fv 
       << " DV= " << dv << " Pos= " << pos << endl;
 }

s->seekg(0, ios::end);
pos = s->tellg();
cout << "Seek-tread2 s->seekg(0, ios::end); Pos = " << pos ;
pos -= (sizeof(int)+sizeof(float)+sizeof(double));
cout << " ---> Pos= " << pos << endl;
s->seekg(pos, ios::beg);
pos = s->tellg();
s->read((char *)(&iv), sizeof(int));
s->read((char *)(&fv), sizeof(float));
s->read((char *)(&dv), sizeof(double));
i = 9;
cout << "Seek-tread2-begin " << " IV= " << iv << " FV= " << fv << " DV= " << dv 
     << " Pos= " << pos << endl;


}