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/*-
* 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include "un-namespace.h"
#include "local.h"
#include "libc_private.h"
/*
* standard ftell function.
*/
long
ftell(FILE *fp)
{
off_t rv;
rv = ftello(fp);
if (rv > LONG_MAX) {
errno = EOVERFLOW;
return (-1);
}
return (rv);
}
/*
* ftello: return current offset.
*/
off_t
ftello(FILE *fp)
{
fpos_t rv;
int ret;
FLOCKFILE(fp);
ret = _ftello(fp, &rv);
FUNLOCKFILE(fp);
if (ret)
return (-1);
if (rv < 0) { /* Unspecified value because of ungetc() at 0 */
errno = ESPIPE;
return (-1);
}
return (rv);
}
int
_ftello(FILE *fp, fpos_t *offset)
{
fpos_t pos;
size_t n;
if (fp->_seek == NULL) {
errno = ESPIPE; /* historic practice */
return (1);
}
/*
* Find offset of underlying I/O object, then
* adjust for buffered bytes.
*/
if (!(fp->_flags & __SRD) && (fp->_flags & __SWR) &&
fp->_p != NULL && fp->_p - fp->_bf._base > 0 &&
((fp->_flags & __SAPP) || (fp->_flags2 & __S2OAP))) {
pos = _sseek(fp, (fpos_t)0, SEEK_END);
if (pos == -1)
return (1);
} else if (fp->_flags & __SOFF)
pos = fp->_offset;
else {
pos = _sseek(fp, (fpos_t)0, SEEK_CUR);
if (pos == -1)
return (1);
}
if (fp->_flags & __SRD) {
/*
* Reading. Any unread characters (including
* those from ungetc) cause the position to be
* smaller than that in the underlying object.
*/
if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) {
fp->_flags |= __SERR;
errno = EIO;
return (1);
}
if (HASUB(fp))
pos -= fp->_r; /* Can be negative at this point. */
} else if ((fp->_flags & __SWR) && fp->_p != NULL &&
(n = fp->_p - fp->_bf._base) > 0) {
/*
* Writing. Any buffered characters cause the
* position to be greater than that in the
* underlying object.
*/
if (pos > OFF_MAX - n) {
errno = EOVERFLOW;
return (1);
}
pos += n;
}
*offset = pos;
return (0);
}
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