/***********************************************************************

*                                                                      *

*               This software is part of the ast package               *

*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

*                      and is licensed under the                       *

*                 Eclipse Public License, Version 1.0                  *

*                    by AT&T Intellectual Property                     *

*                                                                      *

*                A copy of the License is available at                 *

*          http://www.eclipse.org/org/documents/epl-v10.html           *

*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

*                                                                      *

*              Information and Software Systems Research               *

*                            AT&T Research                             *

*                           Florham Park NJ                            *

*                                                                      *

*                 Glenn Fowler <gsf@research.att.com>                  *

*                  David Korn <dgk@research.att.com>                   *

*                   Phong Vo <kpv@research.att.com>                    *

*                                                                      *

***********************************************************************/

#include	"sfhdr.h"

/*	Set some control flags or file descript for the stream

**

**	Written by Kiem-Phong Vo.

*/

#if __STD_C

int sfset(Sfio_t* f, int flags, int set)

#else

int sfset(f,flags,set)

Sfio_t*		f;

int		flags;

int		set;

#endif

{

	reg int	oflags, tflags, rv;

	SFMTXDECL(f);

	SFMTXENTER(f,0);

	if(flags == 0 && set == 0)

		SFMTXRETURN(f, (f->flags&SF_FLAGS));

	if((oflags = (f->mode&SF_RDWR)) != (int)f->mode)

	{	/* avoid sfsetbuf() isatty() call if user sets (SF_LINE|SF_WCWIDTH) */

		if(set && (flags & (SF_LINE|SF_WCWIDTH)) && !(f->flags & (SF_LINE|SF_WCWIDTH)))

		{	tflags = (SF_LINE|SF_WCWIDTH);

			f->flags |= tflags;

		}

		else	tflags = 0;

		rv = _sfmode(f,oflags,0);

		if(tflags)

			f->flags &= ~tflags;

		if(rv < 0)

			SFMTXRETURN(f, 0);

	}

	if(flags == 0)

		SFMTXRETURN(f, (f->flags&SF_FLAGS));

	SFLOCK(f,0);

	/* preserve at least one rd/wr flag */

	oflags = f->flags;

	if(!(f->bits&SF_BOTH) || (flags&SF_RDWR) == SF_RDWR )

		flags &= ~SF_RDWR;

	/* set the flag */

	if(set)

		f->flags |=  (flags&SF_SETS);

	else	f->flags &= ~(flags&SF_SETS);

	/* must have at least one of read/write */

	if(!(f->flags&SF_RDWR))

		f->flags |= (oflags&SF_RDWR);

	if(f->extent < 0)

		f->flags &= ~SF_APPENDWR;

	/* turn to appropriate mode as necessary */

	if((flags &= SF_RDWR) )

	{	if(!set)

		{	if(flags == SF_READ)

				flags = SF_WRITE;

			else	flags = SF_READ;

		}

		if((flags == SF_WRITE && !(f->mode&SF_WRITE)) ||

		   (flags == SF_READ && !(f->mode&(SF_READ|SF_SYNCED))) )

			(void)_sfmode(f,flags,1);

	}

	/* if not shared or unseekable, public means nothing */

	if(!(f->flags&SF_SHARE) || f->extent < 0)

		f->flags &= ~SF_PUBLIC;

	SFOPEN(f,0);

	SFMTXRETURN(f, (oflags&SF_FLAGS));

}