103 lines
3.1 KiB
C
103 lines
3.1 KiB
C
|
/* $NetBSD: ftello.c,v 1.4 2003/08/07 16:43:26 agc 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 <sys/cdefs.h>
|
||
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
||
|
|
__RCSID("$NetBSD: ftello.c,v 1.4 2003/08/07 16:43:26 agc Exp $");
|
||
|
|
#endif /* LIBC_SCCS and not lint */
|
||
|
|
|
||
|
|
#include "namespace.h"
|
||
|
|
#include <assert.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include "reentrant.h"
|
||
|
|
#include "local.h"
|
||
|
|
|
||
|
|
#ifdef __weak_alias
|
||
|
|
__weak_alias(ftello, _ftello)
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* ftell: return current offset.
|
||
|
|
*/
|
||
|
|
off_t
|
||
|
|
ftello(fp)
|
||
|
|
FILE *fp;
|
||
|
|
{
|
||
|
|
fpos_t pos;
|
||
|
|
|
||
|
|
|
||
|
|
FLOCKFILE(fp);
|
||
|
|
|
||
|
|
if (fp->_seek == NULL) {
|
||
|
|
FUNLOCKFILE(fp);
|
||
|
|
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 == (fpos_t)-1) {
|
||
|
|
FUNLOCKFILE(fp);
|
||
|
|
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;
|
||
|
|
}
|
||
|
|
FUNLOCKFILE(fp);
|
||
|
|
return (pos);
|
||
|
|
}
|