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