// posix.cc -- Helper functions for POSIX-flavored OSs.

/* Copyright (C) 2000  Free Software Foundation

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

#include <config.h>

#include "posix.h"

#include <errno.h>

#if defined (ECOS)
extern "C" unsigned long long _clock (void);
#endif

// gettimeofday implementation.
void
_Jv_gettimeofday (struct timeval *tv)
{
#if defined (HAVE_GETTIMEOFDAY)
  gettimeofday (tv, NULL);
#elif defined (HAVE_TIME)
  tv->tv_sec = time (NULL);
  tv->tv_usec = 0;
#elif defined (HAVE_FTIME)
  struct timeb t;
  ftime (&t);
  tv->tv_sec = t.time;
  tv->tv_usec = t.millitm * 1000;
#elif defined (ECOS)
  // FIXME.
  tv->tv_sec = _clock () / 1000;
  tv->tv_usec = 0;
#else
  // In the absence of any function, time remains forever fixed.
  tv->tv_sec = 23;
  tv->tv_usec = 0;
#endif
}

// A wrapper for select() which ignores EINTR.
int
_Jv_select (int n, fd_set *readfds, fd_set  *writefds,
	    fd_set *exceptfds, struct timeval *timeout)
{
#ifdef HAVE_SELECT
  // If we have a timeout, compute the absolute ending time.
  struct timeval end, delay;
  if (timeout)
    {
      _Jv_gettimeofday (&end);
      end.tv_usec += timeout->tv_usec;
      if (end.tv_usec >= 1000000)
	{
	  ++end.tv_sec;
	  end.tv_usec -= 1000000;
	}
      end.tv_sec += timeout->tv_sec;
      delay = *timeout;
    }
  else
    {
      // Placate compiler.
      delay.tv_sec = delay.tv_usec = 0;
    }

  while (1)
    {
      int r = select (n, readfds, writefds, exceptfds,
		      timeout ? &delay : NULL);
      if (r != -1 || errno != EINTR)
	return r;

      struct timeval after;
      if (timeout)
	{
	  _Jv_gettimeofday (&after);
	  // Now compute new timeout argument.
	  delay.tv_usec = end.tv_usec - after.tv_usec;
	  delay.tv_sec = end.tv_sec - after.tv_sec;
	  if (delay.tv_usec < 0)
	    {
	      --delay.tv_sec;
	      delay.tv_usec += 1000000;
	    }
	  if (delay.tv_sec < 0)
	    {
	      // We assume that the user wants a valid select() call
	      // more than precise timing.  So if we get a series of
	      // EINTR we just keep trying with delay 0 until we get a
	      // valid result.
	      delay.tv_sec = 0;
	    }
	}
    }
#else /* HAVE_SELECT */
  return 0;
#endif
}