/* _fopen.c (emx+gcc) -- Copyright (c) 1990-1993 by Eberhard Mattes */

#include <sys/emx.h>
#include <stdio.h>
#include <io.h>
#include <fcntl.h>
#include <errno.h>

FILE *_fopen (FILE *dst, const char *fname, const char *mode, int shflag)
{
  char ok, bt;
  int omode;

  switch (*mode)
    {
    case 'r':
      dst->flags = _IOREAD;
      omode = O_RDONLY;
      break;
    case 'w':
      dst->flags = _IOWRT;
      omode = O_WRONLY|O_CREAT|O_TRUNC;
      break;
    case 'a':
      dst->flags = _IOWRT;
      omode = O_WRONLY|O_CREAT|O_APPEND;
      break;
    default:
      errno = EINVAL;
      return (NULL);
    }
  ++mode; ok = TRUE; bt = FALSE;
  while (*mode != 0 && ok)
    {
      switch (*mode)
        {
        case 't':
          if (bt)
            ok = FALSE;
          else
            {
              bt = TRUE;
              omode |= O_TEXT;
            }
          break;
        case 'b':
          if (bt)
            ok = FALSE;
          else
            {
              bt = TRUE;
              omode |= O_BINARY;
            }
          break;
        case '+':
          if (dst->flags & _IORW)
            ok = FALSE;
          else
            {
              omode &= ~(O_RDONLY|O_WRONLY);
              omode |= O_RDWR;
              dst->flags &= ~(_IOREAD|_IOWRT);
              dst->flags |= _IORW;
            }
          break;
        default:
          ok = FALSE; break;
        }
      if (ok) ++mode;
    }
  dst->handle = sopen (fname, omode, shflag, 0644);
  if (dst->handle < 0)
    return (NULL);
  dst->ptr = NULL;
  dst->buffer = NULL;
  dst->rcount = 0;
  dst->wcount = 0;
  dst->tmpidx = 0;
  dst->flags |= _IOOPEN | _IOBUFNONE;
  dst->flush = _flushstream;
  return (dst);
}