/* Selective.c provide access to timeval and select.

Copyright (C) 2009-2022 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.

This file is part of GNU Modula-2.

GNU Modula-2 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GNU Modula-2 is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#include <config.h>
#include <m2rts.h>

#define EXPORT(FUNC) m2pim ## _Selective_ ## FUNC
#define M2EXPORT(FUNC) m2pim ## _M2_Selective_ ## FUNC
#define M2LIBNAME "m2pim"

#if defined(HAVE_STDDEF_H)
/* Obtain a definition for NULL.  */
#include <stddef.h>
#endif

#if defined(HAVE_STDIO_H)
/* Obtain a definition for NULL.  */
#include <stdio.h>
#endif

#if defined(HAVE_SYS_TIME_H)
#include <sys/time.h>
#endif

#if defined(HAVE_TIME_H)
/* Obtain a definition for NULL.  */
#include <time.h>
#endif

#if defined(HAVE_STRING_H)
/* Obtain a definition for NULL.  */
#include <string.h>
#endif

#if defined(HAVE_WCHAR_H)
/* Obtain a definition for NULL.  */
#include <wchar.h>
#endif

#if defined(HAVE_STDLIB_H)
/* Obtain a prototype for free and malloc.  */
#include <stdlib.h>
#endif

#if defined(HAVE_SYS_TYPES_H)
#include <sys/types.h>
#endif

#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif

#if !defined(NULL)
#define NULL (void *)0
#endif

#if defined(HAVE_SELECT)
#define FDSET_T fd_set
#else
#define FDSET_T void
#endif

/* Select wrap a call to the C select.  */

#if defined(HAVE_STRUCT_TIMEVAL)
extern "C" int
EXPORT(Select) (int nooffds, fd_set *readfds, fd_set *writefds,
		fd_set *exceptfds, struct timeval *timeout)
{
  return select (nooffds, readfds, writefds, exceptfds, timeout);
}
#else
extern "C" int
EXPORT(Select) (int nooffds, void *readfds, void *writefds, void *exceptfds,
		void *timeout)
{
  return 0;
}
#endif

/* InitTime initializes a timeval structure and returns a pointer to it.  */

#if defined(HAVE_STRUCT_TIMEVAL)
extern "C" struct timeval *
EXPORT(InitTime) (unsigned int sec, unsigned int usec)
{
  struct timeval *t = (struct timeval *)malloc (sizeof (struct timeval));

  t->tv_sec = (long int)sec;
  t->tv_usec = (long int)usec;
  return t;
}

extern "C" void
EXPORT(GetTime) (struct timeval *t, unsigned int *sec, unsigned int *usec)
{
  *sec = (unsigned int)t->tv_sec;
  *usec = (unsigned int)t->tv_usec;
}

extern "C" void
EXPORT(SetTime) (struct timeval *t, unsigned int sec, unsigned int usec)
{
  t->tv_sec = sec;
  t->tv_usec = usec;
}

/* KillTime frees the timeval structure and returns NULL.  */

extern "C" struct timeval *
EXPORT(KillTime) (struct timeval *t)
{
#if defined(HAVE_STDLIB_H)
  free (t);
#endif
  return NULL;
}

/* InitSet returns a pointer to a FD_SET.  */

extern "C" FDSET_T *
EXPORT(InitSet) (void)
{
#if defined(HAVE_STDLIB_H)
  FDSET_T *s = (FDSET_T *)malloc (sizeof (FDSET_T));

  return s;
#else
  return NULL
#endif
}

/* KillSet frees the FD_SET and returns NULL.  */

extern "C" FDSET_T *
EXPORT(KillSet) (FDSET_T *s)
{
#if defined(HAVE_STDLIB_H)
  free (s);
#endif
  return NULL;
}

/* FdZero generate an empty set.  */

extern "C" void
EXPORT(FdZero) (FDSET_T *s)
{
  FD_ZERO (s);
}

/* FS_Set include an element, fd, into set, s.  */

extern "C" void
EXPORT(FdSet) (int fd, FDSET_T *s)
{
  FD_SET (fd, s);
}

/* FdClr exclude an element, fd, from the set, s.  */

extern "C" void
EXPORT(FdClr) (int fd, FDSET_T *s)
{
  FD_CLR (fd, s);
}

/* FdIsSet return TRUE if, fd, is present in set, s.  */

extern "C" int
EXPORT(FdIsSet) (int fd, FDSET_T *s)
{
  return FD_ISSET (fd, s);
}

/* GetTimeOfDay fills in a record, Timeval, filled in with the
   current system time in seconds and microseconds.
   It returns zero (see man 3p gettimeofday).  */

extern "C" int
EXPORT(GetTimeOfDay) (struct timeval *t)
{
  return gettimeofday (t, NULL);
}
#else

extern "C" void *
EXPORT(InitTime) (unsigned int sec, unsigned int usec)
{
  return NULL;
}

extern "C" void *
EXPORT(KillTime) (void *t)
{
  return NULL;
}

extern "C" void
EXPORT(GetTime) (void *t, unsigned int *sec, unsigned int *usec)
{
}

extern "C" void
EXPORT(SetTime) (void *t, unsigned int sec, unsigned int usec)
{
}

extern "C" FDSET_T *
EXPORT(InitSet) (void)
{
  return NULL;
}

extern "C" FDSET_T *
EXPORT(KillSet) (void)
{
  return NULL;
}

extern "C" void
EXPORT(FdZero) (void *s)
{
}

extern "C" void
EXPORT(FdSet) (int fd, void *s)
{
}

extern "C" void
EXPORT(FdClr) (int fd, void *s)
{
}

extern "C" int
EXPORT(FdIsSet) (int fd, void *s)
{
  return 0;
}

extern "C" int
EXPORT(GetTimeOfDay) (void *t)
{
  return -1;
}
#endif

/* MaxFdsPlusOne returns max (a + 1, b + 1).  */

extern "C" int
EXPORT(MaxFdsPlusOne) (int a, int b)
{
  if (a > b)
    return a + 1;
  else
    return b + 1;
}

/* WriteCharRaw writes a single character to the file descriptor.  */

extern "C" void
EXPORT(WriteCharRaw) (int fd, char ch)
{
  write (fd, &ch, 1);
}

/* ReadCharRaw read and return a single char from file descriptor, fd.  */

extern "C" char
EXPORT(ReadCharRaw) (int fd)
{
  char ch;

  read (fd, &ch, 1);
  return ch;
}

/* GNU Modula-2 linking hooks.  */

extern "C" void
M2EXPORT(init) (int, char **, char **)
{
}

extern "C" void
M2EXPORT(fini) (int, char **, char **)
{
}

extern "C" void
M2EXPORT(dep) (void)
{
}

extern "C" void __attribute__((__constructor__))
M2EXPORT(ctor) (void)
{
  m2pim_M2RTS_RegisterModule ("Selective", M2LIBNAME,
			      M2EXPORT(init), M2EXPORT(fini),
			      M2EXPORT(dep));
}