/* An ftello() function that works around platform bugs.
- Copyright (C) 2007, 2009-2011 Free Software Foundation, Inc.
+ Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
+ 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>
# 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 LSEEK_PIPE_BROKEN
+#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
+# endif
-#if FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE /* Solaris */
+# 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. */
}
return pos;
}
-#endif
+# endif
-#if defined __SL64 && defined __SCLE /* Cygwin */
+# 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
fp->_seek64 = tmp->_seek64;
fclose (tmp);
}
-#endif
+# endif
+
return ftello (fp);
+
+#endif
}