/////////////////////////////////////////////////////////////////////////////
// copy.cpp - demonstrate performance implications of copy
//
// Jim Fawcett, ELE591/791 - Intelligent Systems, Summer 2000
/////////////////////////////////////////////////////////////////////////////

#include <iostream>
#include "..\timer.h"
using namespace std;

/////////////////////////////////////////////////////////////////////////////
// defining a big object

struct bigArg { char ch[10000]; };

/////////////////////////////////////////////////////////////////////////////
// passing big object by value

void copyVal(bigArg  a) { 

  static bool first = true;
  if(first) {
    cout << "\n  copyVal(bigArg a)";
    first = false;
  }
  char ch = a.ch[0]; ch = a.ch[99]; 
}

/////////////////////////////////////////////////////////////////////////////
// passing big object by reference

void copyRef(bigArg &a) { 
  
  static bool first = true;
  if(first) {
    cout << "\n  copyRef(bigArg &a)";
    first = false;
  }
  char ch = a.ch[0]; ch = a.ch[99]; 
}

//

/////////////////////////////////////////////////////////////////////////////
// function to time function calls

template<class U, class V> 
clock_t timeFunction(U(*pFunc)(V v), V v, int N) {

  timer t;
  t.start();
  int i;
  for(i=0; i<N; i++)
    pFunc(v);
  t.stop();

  cout << "\n  type of argument is " << typeid(v).name();
  cout << "\n  sizeof(argument) = "  << sizeof(v);

  cout << "\n  time to call function " << N << " times = " 
       << t.elapsed() << " milliseconds" << endl;
  
  return t.elapsed();
}

/////////////////////////////////////////////////////////////////////////////
// test stub

void main() {

  cout << "\n  Demo Performance - pass by value vs pass by reference "
       << "\n =======================================================\n";

  const int N = 100000;

  bigArg arg;

  clock_t Ttest = timeFunction<void,bigArg>(copyVal, arg, N);
  
  bigArg &argRef = arg;
  
  Ttest = timeFunction<void,bigArg&>(copyRef, argRef, N);

  cout << "\n  sizeof(bigArg&) = " << sizeof(&arg);
  
  cout << "\n\n";
}