xref: /titanic_51/usr/src/lib/libast/common/sfio/sfgetm.c (revision 78b2cb9a814f49b9599bf830034a12338259e0c9)
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 /*	Read an unsigned long value coded portably for a given range.
25 **
26 **	Written by Kiem-Phong Vo
27 */
28 
29 #if __STD_C
30 Sfulong_t sfgetm(reg Sfio_t* f, Sfulong_t m)
31 #else
32 Sfulong_t sfgetm(f, m)
33 reg Sfio_t*	f;
34 Sfulong_t	m;
35 #endif
36 {
37 	Sfulong_t	v;
38 	reg uchar	*s, *ends, c;
39 	reg int		p;
40 
41 	SFMTXSTART(f, (Sfulong_t)(-1));
42 
43 	if(f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0)
44 		SFMTXRETURN(f, (Sfulong_t)(-1));
45 
46 	SFLOCK(f,0);
47 
48 	for(v = 0;; )
49 	{	if(SFRPEEK(f,s,p) <= 0)
50 		{	f->flags |= SF_ERROR;
51 			v = (Sfulong_t)(-1);
52 			goto done;
53 		}
54 		for(ends = s+p; s < ends;)
55 		{	c = *s++;
56 			v = (v << SF_BBITS) | SFBVALUE(c);
57 			if((m >>= SF_BBITS) <= 0)
58 			{	f->next = s;
59 				goto done;
60 			}
61 		}
62 		f->next = s;
63 	}
64 done:
65 	SFOPEN(f,0);
66 	SFMTXRETURN(f, v);
67 }
68