1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
/* An ftello() function that works around platform bugs.
Copyright (C) 2007, 2009-2024 Free Software Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include <stdio.h>
#include <errno.h>
#include "intprops.h"
/* Get lseek. */
#include <unistd.h>
#include "stdio-impl.h"
off_t
ftello (FILE *fp)
#undef ftello
#if !HAVE_FTELLO
# undef ftell
# define ftello ftell
#endif
#if _GL_WINDOWS_64_BIT_OFF_T
# undef ftello
# if HAVE__FTELLI64 /* msvc, mingw64 */
# define ftello _ftelli64
# else /* mingw */
# define ftello ftello64
# endif
#endif
{
#if FTELLO_BROKEN_AFTER_UNGETC /* macOS >= 10.15 */
/* The system's ftello() is completely broken, because it calls __sflush,
which makes side effects on the stream. */
/* Handle non-seekable files first. */
if (fp->_file < 0 || fp->_seek == NULL)
{
errno = ESPIPE;
return -1;
}
/* Determine the current offset, ignoring buffered and pushed-back bytes. */
off_t pos;
if (fp->_flags & __SOFF)
pos = fp->_offset;
else
{
pos = fp->_seek (fp->_cookie, 0, SEEK_CUR);
if (pos < 0)
return -1;
if (fp->_flags & __SOPT)
{
fp->_offset = pos;
fp->_flags |= __SOFF;
}
}
if (fp->_flags & __SRD)
{
/* Now consider buffered and pushed-back bytes from ungetc. */
if (fp->_ub._base != NULL)
/* Considering the buffered bytes, we are at position
pos - fp->_ur.
Considering also the pushed-back bytes, we are at position
pos - fp->_ur - fp->_r. */
pos = pos - fp->_ur - fp->_r;
else
/* Considering the buffered bytes, we are at position
pos - fp->_r. */
pos = pos - fp->_r;
if (pos < 0)
{
errno = EIO;
return -1;
}
}
else if ((fp->_flags & __SWR) && fp->_p != NULL)
{
/* Consider the buffered bytes. */
off_t buffered = fp->_p - fp->_bf._base;
/* Compute pos + buffered, with overflow check. */
off_t sum;
if (! INT_ADD_OK (pos, buffered, &sum))
{
errno = EOVERFLOW;
return -1;
}
pos = sum;
}
return pos;
#else
# if LSEEK_PIPE_BROKEN
/* mingw gives bogus answers rather than failure on non-seekable files. */
if (lseek (fileno (fp), 0, SEEK_CUR) == -1)
return -1;
# endif
# if FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE /* Solaris */
/* The Solaris stdio leaves the _IOREAD flag set after reading from a file
reaches EOF and the program then starts writing to the file. ftello
gets confused by this. */
if (fp_->_flag & _IOWRT)
{
off_t pos;
/* Call ftello nevertheless, for the side effects that it does on fp. */
ftello (fp);
/* Compute the file position ourselves. */
pos = lseek (fileno (fp), (off_t) 0, SEEK_CUR);
if (pos >= 0)
{
if ((fp_->_flag & _IONBF) == 0 && fp_->_base != NULL)
pos += fp_->_ptr - fp_->_base;
}
return pos;
}
# endif
# if defined __SL64 && defined __SCLE /* Cygwin */
if ((fp->_flags & __SL64) == 0)
{
/* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
mode; but has an ftello that requires 64-bit mode. */
FILE *tmp = fopen ("/dev/null", "r");
if (!tmp)
return -1;
fp->_flags |= __SL64;
fp->_seek64 = tmp->_seek64;
fclose (tmp);
}
# endif
return ftello (fp);
#endif
}
|
