portability.h

关于Q元LDPC码的C++仿真程序

#ifndef PORTABILITY
#define PORTABILITY

#ifdef VISUAL_C
   #include <stdlib.h>
   #include <time.h>
   #include <float.h>
#else
   #include <strings.h>
   #include <unistd.h>
   #include <stdlib.h>
   #include <time.h>
   #include <math.h>
#endif


/************************************************************************
 *
 *	VISUAL_C utilities
 *
 ************************************************************************/

#ifdef VISUAL_C


inline char* CharTime(void)
{
   time_t tt = time(NULL);
   return ctime(&tt);
}  


inline double atanh(double x)
{  
   return 0.5 * log((x-1)/(x+1));
}


inline long min(long l1, long l2)
{
	return (l1 < l2) ? l1 : l2;
}



inline void bzero(void *x, int len)
{
	char *str_x = (char *)x;

	for (int i=0; i<len; i++)
		*str_x++ = 0;
}



inline void bcopy(void *from, void *to, int len)
{
	char *str_to = (char*)to;
	char *str_from = (char*)from;

	if (*str_to > *str_from) 
	{
		str_to += len-1;
		str_from += len-1;
		for (int i = 0; i < len; i++)
			*str_to-- = *str_from--;
	}
	else 
	{
		for (int i = 0; i < len; i++)
			*str_to++ = *str_from++;
	}
}


inline BOOLEAN isfinite(double &d)
{
   switch(_fpclass(d))
      {
         case _FPCLASS_SNAN:
         case _FPCLASS_QNAN:
         case _FPCLASS_NINF:
         case _FPCLASS_PINF:
            return FALSE;
            break;
         default:
            return TRUE;
      }
}




inline double clip(double &d, double MAXVAL = INF)
{
   switch(_fpclass(d))
      {
         case _FPCLASS_SNAN:
         case _FPCLASS_QNAN:
            d = 0;  // not a number 
            break;
         case _FPCLASS_NINF:
            d = -MAXVAL;
            break;
         case _FPCLASS_PINF:
            d = MAXVAL;
            break;
         default:
            if (d > MAXVAL) 
               d = MAXVAL;
            else if (d < -MAXVAL)
               d = -MAXVAL;
//            else if (fabs(d) < EPSILON)
//               d = 0;
            break;  
      }
  return d;
}


#endif

/************************************************************************
 *
 *  Unix requirements 
 *
 ************************************************************************/

#ifndef VISUAL_C

inline char* CharTime(void)
{
   time_t tt = time(NULL);
   return ctime(&tt);
}



inline double min(double x, double y)
{
  return (x < y) ? x : y;
}



inline long min(long x, long y)
{
  return (x < y) ? x : y;
}



inline int min(int x, int y)
{
  return (x < y) ? x : y;
}

#endif


/************************************************************************
 *
 *  Mixed
 *
 ************************************************************************/

inline unsigned int RandomSeed()
{
#ifdef VISUAL_C
   return (unsigned)time( NULL ) ;
#else
   return time(NULL);
#endif
}


inline void my_srand(unsigned int seed)
{
#ifdef VISUAL_C
   srand( seed );
#else
   srand48( seed );
#endif
}



inline double my_rand()
{
#ifdef VISUAL_C
    return (double)rand() / (double)(RAND_MAX + 1);
#else
    return drand48();
#endif
}



inline double Q(double x)
{
#ifndef VISUAL_C
  return 0.5 * erfc( x / sqrt(2.) );
#else
  return -x;
#endif
}



/************************************************************************
 *
 *  Linux
 *
 ************************************************************************/

#ifdef LINUX_C


inline BOOLEAN isfinite(double d)
{
   if (isnan(d))
      return FALSE;
   else
   {
      switch(isinf(d))
         {
         case -1:
         case 1:
            return FALSE;
            break;
         default:
            return TRUE;
            break;
         }
   }
}



inline double clip(double &d, double MAXVAL = INF)
{
   if (isnan(d))
      d = 0;
   else
   {
      switch(isinf(d))
         {
         case -1:
            d = -MAXVAL;
            break;
         case 1:
            d = MAXVAL;
            break;
         default:
            if (d > MAXVAL) 
               d = MAXVAL;
            else if (d < -MAXVAL)
               d = -MAXVAL;
            break;  
         }
   }
  return d;
}

#endif

#endif