1 | /*-␊ |
2 | * Copyright (c) 1990, 1993␊ |
3 | *␉The Regents of the University of California. All rights reserved.␊ |
4 | *␊ |
5 | * This code is derived from software contributed to Berkeley by␊ |
6 | * Chris Torek.␊ |
7 | *␊ |
8 | * Redistribution and use in source and binary forms, with or without␊ |
9 | * modification, are permitted provided that the following conditions␊ |
10 | * are met:␊ |
11 | * 1. Redistributions of source code must retain the above copyright␊ |
12 | * notice, this list of conditions and the following disclaimer.␊ |
13 | * 2. Redistributions in binary form must reproduce the above copyright␊ |
14 | * notice, this list of conditions and the following disclaimer in the␊ |
15 | * documentation and/or other materials provided with the distribution.␊ |
16 | * 4. Neither the name of the University nor the names of its contributors␊ |
17 | * may be used to endorse or promote products derived from this software␊ |
18 | * without specific prior written permission.␊ |
19 | *␊ |
20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND␊ |
21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE␊ |
22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE␊ |
23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE␊ |
24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL␊ |
25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS␊ |
26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)␊ |
27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT␊ |
28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY␊ |
29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF␊ |
30 | * SUCH DAMAGE.␊ |
31 | */␊ |
32 | ␊ |
33 | #if defined(LIBC_SCCS) && !defined(lint)␊ |
34 | static char sccsid[] = "@(#)ftell.c␉8.2 (Berkeley) 5/4/95";␊ |
35 | #endif /* LIBC_SCCS and not lint */␊ |
36 | #include <sys/cdefs.h>␊ |
37 | __FBSDID("$FreeBSD: src/lib/libc/stdio/ftell.c,v 1.27 2007/01/09 00:28:06 imp Exp $");␊ |
38 | ␊ |
39 | #include "namespace.h"␊ |
40 | #include <sys/types.h>␊ |
41 | #include <errno.h>␊ |
42 | #include <limits.h>␊ |
43 | #include <stdio.h>␊ |
44 | #include "un-namespace.h"␊ |
45 | #include "local.h"␊ |
46 | ␊ |
47 | /*␊ |
48 | * standard ftell function.␊ |
49 | */␊ |
50 | long␊ |
51 | ftell(fp)␊ |
52 | ␉FILE *fp;␊ |
53 | {␊ |
54 | ␉off_t rv;␊ |
55 | ␊ |
56 | ␉rv = ftello(fp);␊ |
57 | ␉if (rv > LONG_MAX) {␊ |
58 | ␉␉errno = EOVERFLOW; ␊ |
59 | ␉␉return (-1);␊ |
60 | ␉}␊ |
61 | ␉return (rv);␊ |
62 | }␊ |
63 | ␊ |
64 | /*␊ |
65 | * ftello: return current offset.␊ |
66 | */␊ |
67 | off_t␊ |
68 | ftello(fp)␊ |
69 | ␉FILE *fp;␊ |
70 | {␊ |
71 | ␉fpos_t rv;␊ |
72 | ␉int ret;␊ |
73 | ␊ |
74 | ␉ret = _ftello(fp, &rv);␊ |
75 | ␉if (ret)␊ |
76 | ␉␉return (-1);␊ |
77 | ␉if (rv < 0) { /* Unspecified value because of ungetc() at 0 */␊ |
78 | ␉␉errno = ESPIPE;␊ |
79 | ␉␉return (-1);␊ |
80 | ␉}␊ |
81 | ␉return (rv);␊ |
82 | }␊ |
83 | ␊ |
84 | int␊ |
85 | _ftello(fp, offset)␊ |
86 | ␉FILE *fp;␊ |
87 | ␉fpos_t *offset;␊ |
88 | {␊ |
89 | ␉fpos_t pos;␊ |
90 | ␉size_t n;␊ |
91 | ␊ |
92 | ␉if (fp->_seek == NULL) {␊ |
93 | ␉␉errno = ESPIPE;␉␉/* historic practice */␊ |
94 | ␉␉return (1);␊ |
95 | ␉}␊ |
96 | ␊ |
97 | ␉/*␊ |
98 | ␉ * Find offset of underlying I/O object, then␊ |
99 | ␉ * adjust for buffered bytes.␊ |
100 | ␉ */␊ |
101 | ␉if (__sflush(fp))␉␉/* may adjust seek offset on append stream */␊ |
102 | ␉␉return (1);␊ |
103 | ␉if (fp->_flags & __SOFF)␊ |
104 | ␉␉pos = fp->_offset;␊ |
105 | ␉else {␊ |
106 | ␉␉pos = _sseek(fp, (fpos_t)0, SEEK_CUR);␊ |
107 | ␉␉if (pos == -1)␊ |
108 | ␉␉␉return (1);␊ |
109 | ␉}␊ |
110 | ␉if (fp->_flags & __SRD) {␊ |
111 | ␉␉/*␊ |
112 | ␉␉ * Reading. Any unread characters (including␊ |
113 | ␉␉ * those from ungetc) cause the position to be␊ |
114 | ␉␉ * smaller than that in the underlying object.␊ |
115 | ␉␉ */␊ |
116 | ␉␉if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) {␊ |
117 | ␉␉␉fp->_flags |= __SERR;␊ |
118 | ␉␉␉errno = EIO;␊ |
119 | ␉␉␉return (1);␊ |
120 | ␉␉}␊ |
121 | ␉␉if (HASUB(fp))␊ |
122 | ␉␉␉pos -= fp->_r; /* Can be negative at this point. */␊ |
123 | ␉} else if ((fp->_flags & __SWR) && fp->_p != NULL) {␊ |
124 | ␉␉/*␊ |
125 | ␉␉ * Writing. Any buffered characters cause the␊ |
126 | ␉␉ * position to be greater than that in the␊ |
127 | ␉␉ * underlying object.␊ |
128 | ␉␉ */␊ |
129 | ␉␉n = fp->_p - fp->_bf._base;␊ |
130 | ␉␉if (pos > OFF_MAX - n) {␊ |
131 | errno = EOVERFLOW;␊ |
132 | ␉␉␉return (1);␊ |
133 | ␉␉}␊ |
134 | ␉␉pos += n;␊ |
135 | ␉}␊ |
136 | ␉*offset = pos;␊ |
137 | ␉return (0);␊ |
138 | }␊ |
139 | |