summaryrefslogtreecommitdiff
path: root/lib/ftello.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/ftello.c')
-rw-r--r--lib/ftello.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/lib/ftello.c b/lib/ftello.c
new file mode 100644
index 0000000..fbdc44f
--- /dev/null
+++ b/lib/ftello.c
@@ -0,0 +1,77 @@
+/* An ftello() function that works around platform bugs.
+ Copyright (C) 2007, 2009-2011 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
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 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/>. */
+
+#include <config.h>
+
+/* Specification. */
+#include <stdio.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 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);
+}