#undef HAVE_POLL_H
#define HAVE_POLL_H 1

#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <errno.h>

// Included by <ctype.h> or <bits/types.h> #include <bits/types.h>
#include <time.h> /* timespec definition */
#include <sys/time.h> /* timeval definition */
// Included by <time.h> if _TIME_H is defined #include <bits/time.h> /* timeval definition */
#include <bits/types.h>

#ifdef HAVE_POLL_H
# include <poll.h>
#else
/* According to POSIX.1-2001 */
# include <sys/select.h>
#endif

/* Struct pollfd defined here */
//struct pollfd {
//  int   fd;         /* file descriptor */
//  short events;     /* requested events */
//  short revents;    /* returned events */
//};

/* Struct fdset defined here */
/*
typedef struct
__fd_mask __fds_bits[__FD_SETSIZE / __NFDBITS];
# define __FDS_BITS(set) ((set)->__fds_bits)
} fd_set;
gcc -E: 
typedef long int __fd_mask;
__fd_mask fds_bits[256 / (8 * (int) sizeof (__fd_mask))
*/

int main(void)
{
  int i, j, nfds = 0, nfound;
  int stime, etime;
  time_t *currtime = 0;
  char ans[2] = " ";
  char c[2] = " ";

  enum
  {
    DELAY = -1,
    POLL = 0,
    SELECT = 1
  } ispoll;

  /* poll stuff */
  struct pollfd fds[3];
  int timeout = 5;

  /* select stuff */
  int fd[3];
  fd_set readfds, writefds, exceptfds;
  struct timeval timevalue = {5,0};

  printf("Program test_poll+select\n");

  printf("Test poll or select [p,s]: p? ");
  int key_stroke = 0;

  for (i = 0; ((char)key_stroke != '\n')  && (i < 2); i++)
    {
      key_stroke = getchar();
      ans[i] = (char)key_stroke;
    }
  ans[1] = '\0';

  if( ans[0] != '\n')
    printf("ans = %s\n", ans);

  printf ("Number of file descriptors [0(delay), 1, 2, 3]: 0? ");
  c[0] = (char)getchar();
  if (c[0] != '\n') 
    {
      c[1] = '\0';
      nfds = strtol(c, NULL, 10);
    }
  else
    c[0] = '\0';

  printf( "nfds=%d\n", nfds);

  if (nfds == 0)
    ispoll = DELAY;
  else if (strcmp(ans,"s") != 0)
    ispoll = POLL;
  else
    ispoll = SELECT;

  switch (ispoll)
    {
    case DELAY:
      printf("\nDELAY test\n");
      printf("\nInput data\n");
      printf("timeout=%d seconds.\n", timeout);

      printf("\nOutput data\n");
      if (strcmp(ans,"s") != 0)
	{
	  stime = (int)time(currtime);
	  nfound = poll(fds, 0, timeout*1000);
	  etime = (int)time(currtime);
	  printf("POLL timeout delay= %d(%d) seconds.\n", timeout, etime-stime);
	}
      else
	{
	  stime = (int)time(currtime);
	  nfound = select(0, NULL, NULL, NULL, &timevalue);
	  etime = (int)time(currtime);
	  printf("SELECT timeout delay= %d(%d) seconds.\n", (int)timevalue.tv_sec, etime-stime);
	}
      break;
      return 0;

    case POLL:
      printf("\nPOLL test\n");
      for(i = 0; i <= 2; ++i)
	{
	  fds[i].fd = i;
	  fds[i].revents = 0;
	}
      fds[0].events = POLLIN;
      fds[1].events = POLLOUT;
      fds[2].events = POLLIN | POLLOUT;

      printf("#define POLLIN          001             /* There is data to read.  */\n");
      printf("#define POLLPRI         002             /* There is urgent data to read.  */\n");
      printf("#define POLLOUT         004             /* Writing now will not block.  */\n");
      printf("#define POLLERR         010             /* Error condition.  */\n");
      printf("#define POLLHUP         020             /* Hung up.  */\n");
      printf("#define POLLNVAL        040             /* Invalid polling request.  */\n");

      printf("\nInput data\n");
      printf("timeout=%d seconds.\n", timeout);

      for (j=0; j < nfds; ++j)
	printf("fds[%d].{fd,events,revents}={%d,%d,%d}\n", j, fds[j].fd, fds[j].events, fds[j].revents);

      stime = (int)time(currtime);
      nfound = poll(fds, (unsigned int)nfds, timeout*1000);
      etime = (int)time(currtime);

      printf("\nOutput data\n");
      printf("nfound=%d\n", nfound);
      for (j=0; j < nfds; ++j)
	{
	  printf( "fds[%d].{fd,events,revents}={%d,%d,%d}\n", j, fds[j].fd, fds[j].events, fds[j].revents);

	  if (nfound == -1)
	    {
	      perror("Poll error");
	      printf("error=%s, revents[%d]=%d\n", strerror(errno), j, fds[j].revents);
	      printf("Timed out %d(%d) seconds.\n", timeout, etime-stime);
	    }
	  else if (nfound == 0)
	    printf("Timed out %d(%d) seconds.\n", timeout, etime-stime);
	  else
	    printf("Data is available now, delay=%d\n", etime-stime);
	}
      break;
      return 0;

    case SELECT:
      printf("\nSELECT test\n");

      for(i = 0; i <= 2; ++i)
	  fd[i] = i;

      FD_ZERO(&readfds);
      FD_ZERO(&writefds);
      FD_ZERO(&exceptfds);
      FD_SET(fd[0], &readfds);
      FD_SET(fd[1], &writefds);
      FD_SET(fd[2], &exceptfds);

      if (nfds == 1)
	{
	  /* Watch stdin (fd 0) to see when it has input. */
	  stime = (int)time(currtime);
	  nfound = select(nfds + 1, &readfds, (fd_set*)0, (fd_set*)0, &timevalue);
	  etime = (int)time(currtime);
	}
      else if (nfds == 2)
	{
	  stime = (int)time(currtime);
	//	nfound = select(nfds + 1, &readfds, &writefds, (fd_set*)0, &timevalue);
	  nfound = select(nfds + 1, &readfds, (fd_set*)0, &exceptfds, &timevalue);
	  etime = (int)time(currtime);
	}
      else
	{
	  stime = (int)time(currtime);
	  nfound = select(nfds + 1, &readfds, &writefds, &exceptfds, &timevalue);
	  etime = (int)time(currtime);
	}

      printf("nfound=%d\n", nfound);
      if (nfound == -1)
	perror("select()");
      else if (nfound)
	printf("Data is available now, delay=%d\n", etime-stime);
      else
	printf("No data within %d(%d) seconds.\n", (int)timevalue.tv_sec, etime-stime);
      break;
      return 0;
    }
  return 0;
}