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

*                                                                      *

*               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"

/*	Tell the current location in a given stream

**

**	Written by Kiem-Phong Vo.

*/

#if __STD_C

Sfoff_t sftell(Sfio_t* f)

#else

Sfoff_t sftell(f)

Sfio_t	*f;

#endif

{	

	reg int	mode;

	Sfoff_t	p;

	SFMTXDECL(f);

	SFMTXENTER(f, (Sfoff_t)(-1));

	/* set the stream to the right mode */

	if((mode = f->mode&SF_RDWR) != (int)f->mode && _sfmode(f,mode,0) < 0)

		SFMTXRETURN(f, (Sfoff_t)(-1));

	/* throw away ungetc data */

	if(f->disc == _Sfudisc)

		(void)sfclose((*_Sfstack)(f,NIL(Sfio_t*)));

	if(f->flags&SF_STRING)

		SFMTXRETURN(f, (Sfoff_t)(f->next-f->data));

	/* let sfseek() handle the hard case */

	if(f->extent >= 0 && (f->flags&(SF_SHARE|SF_APPENDWR)) )

		p = sfseek(f,(Sfoff_t)0,SEEK_CUR);

	else	p = f->here + ((f->mode&SF_WRITE) ? f->next-f->data : f->next-f->endb);

	SFMTXRETURN(f,p);

}