1 |
|
|
/* $OpenBSD: ftell.c,v 1.11 2015/08/31 02:53:57 guenther Exp $ */ |
2 |
|
|
/*- |
3 |
|
|
* Copyright (c) 1990, 1993 |
4 |
|
|
* The Regents of the University of California. All rights reserved. |
5 |
|
|
* |
6 |
|
|
* This code is derived from software contributed to Berkeley by |
7 |
|
|
* Chris Torek. |
8 |
|
|
* |
9 |
|
|
* Redistribution and use in source and binary forms, with or without |
10 |
|
|
* modification, are permitted provided that the following conditions |
11 |
|
|
* are met: |
12 |
|
|
* 1. Redistributions of source code must retain the above copyright |
13 |
|
|
* notice, this list of conditions and the following disclaimer. |
14 |
|
|
* 2. Redistributions in binary form must reproduce the above copyright |
15 |
|
|
* notice, this list of conditions and the following disclaimer in the |
16 |
|
|
* documentation and/or other materials provided with the distribution. |
17 |
|
|
* 3. Neither the name of the University nor the names of its contributors |
18 |
|
|
* may be used to endorse or promote products derived from this software |
19 |
|
|
* without specific prior written permission. |
20 |
|
|
* |
21 |
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
22 |
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
23 |
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
24 |
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
25 |
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
26 |
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
27 |
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
28 |
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
29 |
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
30 |
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
31 |
|
|
* SUCH DAMAGE. |
32 |
|
|
*/ |
33 |
|
|
|
34 |
|
|
#include <stdio.h> |
35 |
|
|
#include <errno.h> |
36 |
|
|
#include <limits.h> |
37 |
|
|
#include "local.h" |
38 |
|
|
|
39 |
|
|
/* |
40 |
|
|
* ftello: return current offset. |
41 |
|
|
*/ |
42 |
|
|
off_t |
43 |
|
|
ftello(FILE *fp) |
44 |
|
|
{ |
45 |
|
|
fpos_t pos; |
46 |
|
|
|
47 |
✗✓ |
19574840 |
if (fp->_seek == NULL) { |
48 |
|
|
errno = ESPIPE; /* historic practice */ |
49 |
|
|
pos = -1; |
50 |
|
|
goto out; |
51 |
|
|
} |
52 |
|
|
|
53 |
|
|
/* |
54 |
|
|
* Find offset of underlying I/O object, then |
55 |
|
|
* adjust for buffered bytes. |
56 |
|
|
*/ |
57 |
✗✓ |
9787420 |
FLOCKFILE(fp); |
58 |
|
9787420 |
__sflush(fp); /* may adjust seek offset on append stream */ |
59 |
✓✗ |
9787420 |
if (fp->_flags & __SOFF) |
60 |
|
9787420 |
pos = fp->_offset; |
61 |
|
|
else { |
62 |
|
|
pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR); |
63 |
|
|
if (pos == -1) |
64 |
|
|
goto out; |
65 |
|
|
} |
66 |
✓✓ |
9787420 |
if (fp->_flags & __SRD) { |
67 |
|
|
/* |
68 |
|
|
* Reading. Any unread characters (including |
69 |
|
|
* those from ungetc) cause the position to be |
70 |
|
|
* smaller than that in the underlying object. |
71 |
|
|
*/ |
72 |
|
40 |
pos -= fp->_r; |
73 |
✗✓ |
40 |
if (HASUB(fp)) |
74 |
|
|
pos -= fp->_ur; |
75 |
✗✓✗✗
|
9787380 |
} else if (fp->_flags & __SWR && fp->_p != NULL) { |
76 |
|
|
/* |
77 |
|
|
* Writing. Any buffered characters cause the |
78 |
|
|
* position to be greater than that in the |
79 |
|
|
* underlying object. |
80 |
|
|
*/ |
81 |
|
|
pos += fp->_p - fp->_bf._base; |
82 |
|
|
} |
83 |
✗✓ |
9787420 |
out: FUNLOCKFILE(fp); |
84 |
|
9787420 |
return (pos); |
85 |
|
|
} |
86 |
|
|
DEF_WEAK(ftello); |
87 |
|
|
|
88 |
|
|
long |
89 |
|
|
ftell(FILE *fp) |
90 |
|
|
{ |
91 |
|
19574760 |
off_t offset = ftello(fp); |
92 |
✗✓ |
9787380 |
if (offset > LONG_MAX) { |
93 |
|
|
errno = EOVERFLOW; |
94 |
|
|
return (-1); |
95 |
|
|
} |
96 |
|
9787380 |
return ((long)offset); |
97 |
|
9787380 |
} |
98 |
|
|
DEF_STRONG(ftell); |