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/* open for MMIXware.

   Copyright (C) 2001 Hans-Peter Nilsson

   Permission to use, copy, modify, and distribute this software is

   freely granted, provided that the above copyright notice, this notice

   and the following disclaimer are preserved with no changes.

   THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR

   IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

   PURPOSE.  */

#include <fcntl.h>

#include <_ansi.h>

#include <sys/types.h>

#include <sys/stat.h>

#include "sys/syscall.h"

#include <errno.h>

/* Let's keep the filehandle array here, since this is a primary

   initializer of it.  */

unsigned char _MMIX_allocated_filehandle[32] =

 {

   1,

   1,

   1,

   0, 0, 0, 0, 0,

   0, 0, 0, 0, 0, 0, 0, 0,

   0, 0, 0, 0, 0, 0, 0, 0,

   0, 0, 0, 0, 0, 0, 0, 0

 };

int

_open (const char *path,

       int flags, ...)

{

  long fileno;

  unsigned char mode;

  long fffile = 0;

  long ret;

  for (fileno = 0;

       fileno < (sizeof (_MMIX_allocated_filehandle) /

                 sizeof (_MMIX_allocated_filehandle[0]));

       fileno++)

    if (_MMIX_allocated_filehandle[fileno] == 0)

      break;

  if (fileno == (sizeof (_MMIX_allocated_filehandle) /

                 sizeof (_MMIX_allocated_filehandle[0])))

    {

      errno = EMFILE;

      return -1;

    }

  /* We map this to a fopen call.  The flags parameter is stymied because

     we don't support more other than these flags.  */

  if (flags & ~(O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_APPEND | O_TRUNC))

    {

      UNIMPLEMENTED (("path: %s, flags: %d", path, flags));

      errno = ENOSYS;

      return -1;

    }

  if ((flags & O_ACCMODE) == O_RDONLY)

    mode = BinaryRead;

  else if ((flags & (O_WRONLY | O_APPEND)) == (O_WRONLY | O_APPEND))

    {

      mode = BinaryReadWrite;

      fffile = 1;

    }

  else if ((flags & (O_RDWR | O_APPEND)) == (O_RDWR | O_APPEND))

    {

      mode = BinaryReadWrite;

      fffile = 1;

    }

  else if ((flags & (O_WRONLY | O_CREAT)) == (O_WRONLY | O_CREAT)

           || (flags & (O_WRONLY | O_TRUNC)) == (O_WRONLY | O_TRUNC))

    mode = BinaryWrite;

  else if ((flags & (O_RDWR | O_CREAT)) == (O_RDWR | O_CREAT))

    mode = BinaryReadWrite;

  else if (flags & O_RDWR)

    mode = BinaryReadWrite;

  else

    {

      errno = EINVAL;

      return -1;

    }

  ret = TRAP3f (SYS_Fopen, fileno, path, mode);

  if (ret < 0)

    {

      /* It's totally unknown what the error was.  We'll just take our

         chances and assume ENOENT.  */

      errno = ENOENT;

      return -1;

    }

  _MMIX_allocated_filehandle[fileno] = 1;

  if (fffile)

    {

      TRAP2f (SYS_Fseek, fileno, -1);

    }

  return fileno;

}