New module 'freadahead'.

1 files changed, 62 insertions, 0 deletions

diff --git a/lib/freadahead.c b/lib/freadahead.c
new file mode 100644
index 0000000000..4d52f633ae
--- /dev/null
+++ b/lib/freadahead.c
@@ -0,0 +1,62 @@
+/* Retrieve information about a FILE stream.
+   Copyright (C) 2007 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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "freadahead.h"
+
+size_t
+freadahead (FILE *fp)
+{
+#if defined _IO_ferror_unlocked     /* GNU libc, BeOS */
+  if (fp->_IO_write_ptr > fp->_IO_write_base)
+    return 0;
+  return fp->_IO_read_end - fp->_IO_read_ptr;
+#elif defined __sferror             /* FreeBSD, NetBSD, OpenBSD, MacOS X, Cygwin */
+  if ((fp->_flags & __SWR) != 0 || fp->_r < 0)
+    return 0;
+  return fp->_r;
+#elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */
+# if defined __sun && defined _LP64 /* Solaris/{SPARC,AMD64} 64-bit */
+#  define fp_ ((struct { unsigned char *_ptr; \
+			 unsigned char *_base; \
+			 unsigned char *_end; \
+			 long _cnt; \
+			 int _file; \
+			 unsigned int _flag; \
+		       } *) fp)
+  if ((fp_->_flag & _IOWRT) != 0)
+    return 0;
+  return fp_->_cnt;
+# else
+  if ((fp->_flag & _IOWRT) != 0)
+    return 0;
+  return fp->_cnt;
+# endif
+#elif defined __UCLIBC__            /* uClibc */
+# ifdef __STDIO_BUFFERS
+  if (fp->__modeflags & __FLAG_WRITING)
+    return 0;
+  return fp->__bufread - fp->__bufpos;
+# else
+  return 0;
+# endif
+#else
+ #error "Please port gnulib freadahead.c to your platform! Look at the definition of fflush, fread on your system, then report this to bug-gnulib."
+#endif
+}