xref: /titanic_41/usr/src/lib/libast/common/sfio/sftell.c (revision 67e96bdfbca5b789a8c03fa34eaaa6c9aec7a629)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *           Copyright (c) 1985-2007 AT&T Knowledge Ventures            *
5 *                      and is licensed under the                       *
6 *                  Common Public License, Version 1.0                  *
7 *                      by AT&T Knowledge Ventures                      *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #include	"sfhdr.h"
23 
24 /*	Tell the current location in a given stream
25 **
26 **	Written by Kiem-Phong Vo.
27 */
28 
29 #if __STD_C
30 Sfoff_t sftell(reg Sfio_t* f)
31 #else
32 Sfoff_t sftell(f)
33 reg Sfio_t	*f;
34 #endif
35 {
36 	reg int	mode;
37 	Sfoff_t	p;
38 
39 	SFMTXSTART(f, (Sfoff_t)(-1));
40 
41 	/* set the stream to the right mode */
42 	if((mode = f->mode&SF_RDWR) != (int)f->mode && _sfmode(f,mode,0) < 0)
43 		SFMTXRETURN(f, (Sfoff_t)(-1));
44 
45 	/* throw away ungetc data */
46 	if(f->disc == _Sfudisc)
47 		(void)sfclose((*_Sfstack)(f,NIL(Sfio_t*)));
48 
49 	if(f->flags&SF_STRING)
50 		SFMTXRETURN(f, (Sfoff_t)(f->next-f->data));
51 
52 	/* let sfseek() handle the hard case */
53 	if(f->extent >= 0 && (f->flags&(SF_SHARE|SF_APPENDWR)) )
54 		p = sfseek(f,(Sfoff_t)0,SEEK_CUR);
55 	else	p = f->here + ((f->mode&SF_WRITE) ? f->next-f->data : f->next-f->endb);
56 
57 	SFMTXRETURN(f,p);
58 }
59