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Commit	Line	Data
	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	* 4. Neither the name of the University nor the names of its contributors
	17	* may be used to endorse or promote products derived from this software
	18	* without specific prior written permission.
	19	*
	20	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	* SUCH DAMAGE.
	31	*/
	32
	33	#if defined(LIBC_SCCS) && !defined(lint)
	34	static char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95";
	35	#endif /* LIBC_SCCS and not lint */
	36	#include <sys/cdefs.h>
	37	__FBSDID("$FreeBSD: src/lib/libc/stdio/ftell.c,v 1.27 2007/01/09 00:28:06 imp Exp $");
	38
	39	#include "namespace.h"
	40	#include <sys/types.h>
	41	#include <errno.h>
	42	#include <limits.h>
	43	#include <stdio.h>
	44	#include "un-namespace.h"
	45	#include "local.h"
	46	#include "libc_private.h"
	47
	48	/*
	49	* standard ftell function.
	50	*/
	51	long
	52	ftell(fp)
	53	FILE *fp;
	54	{
	55	off_t rv;
	56
	57	rv = ftello(fp);
	58	if (rv > LONG_MAX) {
	59	errno = EOVERFLOW;
	60	return (-1);
	61	}
	62	return (rv);
	63	}
	64
	65	/*
	66	* ftello: return current offset.
	67	*/
	68	off_t
	69	ftello(fp)
	70	FILE *fp;
	71	{
	72	fpos_t rv;
	73	int ret;
	74
	75	FLOCKFILE(fp);
	76	ret = _ftello(fp, &rv);
	77	FUNLOCKFILE(fp);
	78	if (ret)
	79	return (-1);
	80	if (rv < 0) { /* Unspecified value because of ungetc() at 0 */
	81	errno = ESPIPE;
	82	return (-1);
	83	}
	84	return (rv);
	85	}
	86
	87	int
	88	_ftello(fp, offset)
	89	FILE *fp;
	90	fpos_t *offset;
	91	{
	92	fpos_t pos;
	93	size_t n;
	94
	95	if (fp->_seek == NULL) {
	96	errno = ESPIPE; /* historic practice */
	97	return (1);
	98	}
	99
	100	/*
	101	* Find offset of underlying I/O object, then
	102	* adjust for buffered bytes.
	103	*/
	104	if (__sflush(fp)) /* may adjust seek offset on append stream */
	105	return (1);
	106	if (fp->_flags & __SOFF)
	107	pos = fp->_offset;
	108	else {
	109	pos = _sseek(fp, (fpos_t)0, SEEK_CUR);
	110	if (pos == -1)
	111	return (1);
	112	}
	113	if (fp->_flags & __SRD) {
	114	/*
	115	* Reading. Any unread characters (including
	116	* those from ungetc) cause the position to be
	117	* smaller than that in the underlying object.
	118	*/
	119	if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) {
	120	fp->_flags \|= __SERR;
	121	errno = EIO;
	122	return (1);
	123	}
	124	if (HASUB(fp))
	125	pos -= fp->_r; /* Can be negative at this point. */
	126	} else if ((fp->_flags & __SWR) && fp->_p != NULL) {
	127	/*
	128	* Writing. Any buffered characters cause the
	129	* position to be greater than that in the
	130	* underlying object.
	131	*/
	132	n = fp->_p - fp->_bf._base;
	133	if (pos > OFF_MAX - n) {
	134	errno = EOVERFLOW;
	135	return (1);
	136	}
	137	pos += n;
	138	}
	139	*offset = pos;
	140	return (0);
	141	}