ftell.c - vx32 - Local 9vx git repository for patches.
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       ---
       ftell.c (3093B)
       ---
            1 /*-
            2  * Copyright (c) 1990, 1993
            3  *        The Regents of the University of California.  All rights reserved.
            4  *
            5  * This code is derived from software contributed to Berkeley by
            6  * Chris Torek.
            7  *
            8  * Redistribution and use in source and binary forms, with or without
            9  * modification, are permitted provided that the following conditions
           10  * are met:
           11  * 1. Redistributions of source code must retain the above copyright
           12  *    notice, this list of conditions and the following disclaimer.
           13  * 2. Redistributions in binary form must reproduce the above copyright
           14  *    notice, this list of conditions and the following disclaimer in the
           15  *    documentation and/or other materials provided with the distribution.
           16  * 3. All advertising materials mentioning features or use of this software
           17  *    must display the following acknowledgement:
           18  *        This product includes software developed by the University of
           19  *        California, Berkeley and its contributors.
           20  * 4. Neither the name of the University nor the names of its contributors
           21  *    may be used to endorse or promote products derived from this software
           22  *    without specific prior written permission.
           23  *
           24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
           25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
           26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
           27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
           28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
           29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
           30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
           31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
           32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
           33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
           34  * SUCH DAMAGE.
           35  */
           36 
           37 #if defined(LIBC_SCCS) && !defined(lint)
           38 static char rcsid[] = "$OpenBSD: ftell.c,v 1.2 1996/08/19 08:32:47 tholo Exp $";
           39 #endif /* LIBC_SCCS and not lint */
           40 
           41 #include <stdio.h>
           42 #include <errno.h>
           43 #include "local.h"
           44 
           45 /*
           46  * ftell: return current offset.
           47  */
           48 long
           49 ftell(fp)
           50         register FILE *fp;
           51 {
           52         register fpos_t pos;
           53 
           54         if (fp->_seek == NULL) {
           55                 errno = ESPIPE;                        /* historic practice */
           56                 return (-1L);
           57         }
           58 
           59         /*
           60          * Find offset of underlying I/O object, then
           61          * adjust for buffered bytes.
           62          */
           63         __sflush(fp);                /* may adjust seek offset on append stream */
           64         if (fp->_flags & __SOFF)
           65                 pos = fp->_offset;
           66         else {
           67                 pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR);
           68                 if (pos == -1L)
           69                         return (pos);
           70         }
           71         if (fp->_flags & __SRD) {
           72                 /*
           73                  * Reading.  Any unread characters (including
           74                  * those from ungetc) cause the position to be
           75                  * smaller than that in the underlying object.
           76                  */
           77                 pos -= fp->_r;
           78                 if (HASUB(fp))
           79                         pos -= fp->_ur;
           80         } else if (fp->_flags & __SWR && fp->_p != NULL) {
           81                 /*
           82                  * Writing.  Any buffered characters cause the
           83                  * position to be greater than that in the
           84                  * underlying object.
           85                  */
           86                 pos += fp->_p - fp->_bf._base;
           87         }
           88         return (pos);
           89 }