/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)flags.c	5.1 (Berkeley) 01/20/91";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/file.h>
#include <stdio.h>
#include <errno.h>

/*
 * Return the (stdio) flags for a given mode.  Store the flags
 * to be passed to an open() syscall through *optr.
 * Return 0 on error.
 */
__sflags(mode, optr)
	register char *mode;
	int *optr;
{
	register int ret, m, o;

	switch (*mode++) {

	case 'r':	/* open for reading */
		ret = __SRD;
		m = O_RDONLY;
		o = 0;
		break;

	case 'w':	/* open for writing */
		ret = __SWR;
		m = O_WRONLY;
		o = O_CREAT | O_TRUNC;
		break;

	case 'a':	/* open for appending */
		ret = __SWR;
		m = O_WRONLY;
		o = O_CREAT | O_APPEND;
		break;

	default:	/* illegal mode */
		errno = EINVAL;
		return (0);
	}

	/* [rwa]\+ or [rwa]b\+ means read and write */
	if (*mode == '+' || (*mode == 'b' && mode[1] == '+')) {
		ret = __SRW;
		m = O_RDWR;
	}
	*optr = m | o;
	return (ret);
}