BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / libc / stdio / ftell.c

diff --git a/usr/src/lib/libc/stdio/ftell.c b/usr/src/lib/libc/stdio/ftell.c
index 04c15a8..168a4ea 100644 (file)
--- a/usr/src/lib/libc/stdio/ftell.c
+++ b/usr/src/lib/libc/stdio/ftell.c
@@ -1,35 +1,88 @@
-#if defined(LIBC_SCCS) && !defined(lint)
-static char sccsid[] = "@(#)ftell.c    5.2 (Berkeley) 3/9/86";
-#endif LIBC_SCCS and not lint
-
-/*
- * Return file offset.
- * Coordinates with buffering.
+/*-
+ * Copyright (c) 1990 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. 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>
-long   lseek();
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)ftell.c    5.4 (Berkeley) 2/5/91";
+#endif /* LIBC_SCCS and not lint */

 
 

+#include <stdio.h>
+#include <errno.h>
+#include "local.h"

 
 

-long ftell(iop)
-register FILE *iop;
+/*
+ * ftell: return current offset.
+ */
+long
+ftell(fp)
+       register const FILE *fp;

 {
 {

-       register long tres;
-       register adjust;
+       register fpos_t pos;
+
+       if (fp->_seek == NULL) {
+               errno = ESPIPE;                 /* historic practice */
+               return (-1L);
+       }

 
 

-       if (iop->_cnt < 0)
-               iop->_cnt = 0;
-       if (iop->_flag&_IOREAD)
-               adjust = - iop->_cnt;
-       else if (iop->_flag&(_IOWRT|_IORW)) {
-               adjust = 0;
-               if (iop->_flag&_IOWRT && iop->_base && (iop->_flag&_IONBF)==0)
-                       adjust = iop->_ptr - iop->_base;
-       } else
-               return(-1);
-       tres = lseek(fileno(iop), 0L, 1);
-       if (tres<0)
-               return(tres);
-       tres += adjust;
-       return(tres);
+       /*
+        * Find offset of underlying I/O object, then
+        * adjust for buffered bytes.
+        */
+       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);

 }
 }