xref: /onnv-gate/usr/src/lib/libbc/libc/stdio/common/fseek.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 1986 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate /*      Copyright (c) 1984 AT&T */
28*0Sstevel@tonic-gate /*        All Rights Reserved   */
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 1.3 */
31*0Sstevel@tonic-gate 
32*0Sstevel@tonic-gate /*LINTLIBRARY*/
33*0Sstevel@tonic-gate /*
34*0Sstevel@tonic-gate  * Seek for standard library.  Coordinates with buffering.
35*0Sstevel@tonic-gate  */
36*0Sstevel@tonic-gate #include <stdio.h>
37*0Sstevel@tonic-gate 
38*0Sstevel@tonic-gate extern long lseek();
39*0Sstevel@tonic-gate extern int fflush();
40*0Sstevel@tonic-gate 
41*0Sstevel@tonic-gate int
fseek(iop,offset,ptrname)42*0Sstevel@tonic-gate fseek(iop, offset, ptrname)
43*0Sstevel@tonic-gate register FILE *iop;
44*0Sstevel@tonic-gate long	offset;
45*0Sstevel@tonic-gate int	ptrname;
46*0Sstevel@tonic-gate {
47*0Sstevel@tonic-gate 	register int resync, c;
48*0Sstevel@tonic-gate 	long	p = -1;			/* can't happen? */
49*0Sstevel@tonic-gate 
50*0Sstevel@tonic-gate 	iop->_flag &= ~_IOEOF;
51*0Sstevel@tonic-gate 	if(iop->_flag & _IOREAD) {
52*0Sstevel@tonic-gate 		if(ptrname < 2 && iop->_base && !(iop->_flag&_IONBF)) {
53*0Sstevel@tonic-gate 			c = iop->_cnt;
54*0Sstevel@tonic-gate 			p = offset;
55*0Sstevel@tonic-gate 			if(ptrname == 0) {
56*0Sstevel@tonic-gate 				long curpos = lseek(fileno(iop), 0L, 1);
57*0Sstevel@tonic-gate 				if (curpos == -1)
58*0Sstevel@tonic-gate 					return (-1);
59*0Sstevel@tonic-gate 				p += c - curpos;
60*0Sstevel@tonic-gate 				resync = offset&01;
61*0Sstevel@tonic-gate 			} else {
62*0Sstevel@tonic-gate 				offset -= (long)c;
63*0Sstevel@tonic-gate 				resync = 0;
64*0Sstevel@tonic-gate 			}
65*0Sstevel@tonic-gate 			if(!(iop->_flag&_IORW) && c > 0 && p <= c &&
66*0Sstevel@tonic-gate 					p >= iop->_base - iop->_ptr) {
67*0Sstevel@tonic-gate 				iop->_ptr += (int)p;
68*0Sstevel@tonic-gate 				iop->_cnt -= (int)p;
69*0Sstevel@tonic-gate 				return(0);
70*0Sstevel@tonic-gate 			}
71*0Sstevel@tonic-gate 		} else
72*0Sstevel@tonic-gate 			resync = 0;
73*0Sstevel@tonic-gate 		if(iop->_flag & _IORW) {
74*0Sstevel@tonic-gate 			iop->_ptr = iop->_base;
75*0Sstevel@tonic-gate 			iop->_flag &= ~_IOREAD;
76*0Sstevel@tonic-gate 			resync = 0;
77*0Sstevel@tonic-gate 		}
78*0Sstevel@tonic-gate 		p = lseek(fileno(iop), offset-resync, ptrname);
79*0Sstevel@tonic-gate 		iop->_cnt = 0;
80*0Sstevel@tonic-gate 		if (resync && p != -1)
81*0Sstevel@tonic-gate 			if (getc(iop) == EOF)
82*0Sstevel@tonic-gate 				p = -1;
83*0Sstevel@tonic-gate 	} else if(iop->_flag & (_IOWRT | _IORW)) {
84*0Sstevel@tonic-gate 		p = fflush(iop);
85*0Sstevel@tonic-gate 		iop->_cnt = 0;
86*0Sstevel@tonic-gate 		if(iop->_flag & _IORW) {
87*0Sstevel@tonic-gate 			iop->_flag &= ~_IOWRT;
88*0Sstevel@tonic-gate 			iop->_ptr = iop->_base;
89*0Sstevel@tonic-gate 		}
90*0Sstevel@tonic-gate 		return(lseek(fileno(iop), offset, ptrname) == -1 || p == EOF ?
91*0Sstevel@tonic-gate 		    -1 : 0);
92*0Sstevel@tonic-gate 	}
93*0Sstevel@tonic-gate 	return((p == -1)? -1: 0);
94*0Sstevel@tonic-gate }
95