1 files changed, 97 insertions, 0 deletions
diff --git a/libc/stdio/ftell.c b/libc/stdio/ftell.c
new file mode 100644
index 0000000..b7d449e
--- /dev/null
+++ b/libc/stdio/ftell.c
@@ -0,0 +1,97 @@
+/*	$OpenBSD: ftell.c,v 1.6 2005/08/08 08:05:36 espie Exp $ */
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include "local.h"
+
+/*
+ * ftello: return current offset.
+ */
+off_t
+ftello(FILE *fp)
+{
+	fpos_t pos;
+
+	if (fp->_seek == NULL) {
+		errno = ESPIPE;			/* historic practice */
+		return ((off_t)-1);
+	}
+
+	/*
+	 * Find offset of underlying I/O object, then
+	 * adjust for buffered bytes.
+	 */
+	__sflush(fp);		/* may adjust seek offset on append stream */
+	if (fp->_flags & __SOFF)
+		pos = fp->_offset;
+	else {
+		pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR);
+		if (pos == -1L)
+			return (pos);
+	}
+	if (fp->_flags & __SRD) {
+		/*
+		 * Reading.  Any unread characters (including
+		 * those from ungetc) cause the position to be
+		 * smaller than that in the underlying object.
+		 */
+		pos -= fp->_r;
+		if (HASUB(fp))
+			pos -= fp->_ur;
+	} else if (fp->_flags & __SWR && fp->_p != NULL) {
+		/*
+		 * Writing.  Any buffered characters cause the
+		 * position to be greater than that in the
+		 * underlying object.
+		 */
+		pos += fp->_p - fp->_bf._base;
+	}
+	return (pos);
+}
+
+/*
+ * ftell() returns a long and sizeof(off_t) != sizeof(long) on all arches
+ */
+#if defined(__alpha__) && defined(__indr_reference)
+__indr_reference(ftello, ftell);
+#else
+long
+ftell(FILE *fp)
+{
+	long pos;
+
+	pos = (long)ftello(fp);
+	return(pos);
+}
+#endif