ftell.c revision 92986
11573Srgrimes/*- 21573Srgrimes * Copyright (c) 1990, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * This code is derived from software contributed to Berkeley by 61573Srgrimes * Chris Torek. 71573Srgrimes * 81573Srgrimes * Redistribution and use in source and binary forms, with or without 91573Srgrimes * modification, are permitted provided that the following conditions 101573Srgrimes * are met: 111573Srgrimes * 1. Redistributions of source code must retain the above copyright 121573Srgrimes * notice, this list of conditions and the following disclaimer. 131573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141573Srgrimes * notice, this list of conditions and the following disclaimer in the 151573Srgrimes * documentation and/or other materials provided with the distribution. 161573Srgrimes * 3. All advertising materials mentioning features or use of this software 171573Srgrimes * must display the following acknowledgement: 181573Srgrimes * This product includes software developed by the University of 191573Srgrimes * California, Berkeley and its contributors. 201573Srgrimes * 4. Neither the name of the University nor the names of its contributors 211573Srgrimes * may be used to endorse or promote products derived from this software 221573Srgrimes * without specific prior written permission. 231573Srgrimes * 241573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 251573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 261573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 271573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 281573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 291573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 301573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 311573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 321573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 331573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 341573Srgrimes * SUCH DAMAGE. 351573Srgrimes */ 361573Srgrimes 371573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 3823663Speterstatic char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95"; 391573Srgrimes#endif /* LIBC_SCCS and not lint */ 4092986Sobrien#include <sys/cdefs.h> 4192986Sobrien__FBSDID("$FreeBSD: head/lib/libc/stdio/ftell.c 92986 2002-03-22 21:53:29Z obrien $"); 421573Srgrimes 4371579Sdeischen#include "namespace.h" 4443782Sdt#include <sys/types.h> 4582588Sache#include <errno.h> 4682588Sache#include <limits.h> 471573Srgrimes#include <stdio.h> 4871579Sdeischen#include "un-namespace.h" 491573Srgrimes#include "local.h" 5035129Sjb#include "libc_private.h" 511573Srgrimes 521573Srgrimes/* 5343782Sdt * standard ftell function. 541573Srgrimes */ 551573Srgrimeslong 561573Srgrimesftell(fp) 5792889Sobrien FILE *fp; 581573Srgrimes{ 5992889Sobrien off_t rv; 6082588Sache 6143782Sdt rv = ftello(fp); 6282588Sache if (rv > LONG_MAX) { 6343782Sdt errno = EOVERFLOW; 6443782Sdt return (-1); 6543782Sdt } 6643782Sdt return (rv); 6743782Sdt} 6843782Sdt 6943782Sdt/* 7043782Sdt * ftello: return current offset. 7143782Sdt */ 7243782Sdtoff_t 7343782Sdtftello(fp) 7492889Sobrien FILE *fp; 7543782Sdt{ 7682709Sache fpos_t rv; 7782709Sache int ret; 7882668Sache 7982668Sache FLOCKFILE(fp); 8082709Sache ret = _ftello(fp, &rv); 8182668Sache FUNLOCKFILE(fp); 8282709Sache if (ret) 8382709Sache return (-1); 8482736Sache if (rv < 0) { /* Unspecified value because of ungetc() at 0 */ 8582736Sache errno = ESPIPE; 8682736Sache return (-1); 8782736Sache } 8882668Sache return (rv); 8982668Sache} 9082668Sache 9182709Sacheint 9282709Sache_ftello(fp, offset) 9392889Sobrien FILE *fp; 9482709Sache fpos_t *offset; 9582668Sache{ 9692889Sobrien fpos_t pos; 9782588Sache size_t n; 981573Srgrimes 991573Srgrimes if (fp->_seek == NULL) { 1001573Srgrimes errno = ESPIPE; /* historic practice */ 10182709Sache return (1); 1021573Srgrimes } 1031573Srgrimes 1041573Srgrimes /* 1051573Srgrimes * Find offset of underlying I/O object, then 1061573Srgrimes * adjust for buffered bytes. 1071573Srgrimes */ 10882734Sache if (fp->_flags & __SOFF) 1091573Srgrimes pos = fp->_offset; 11082734Sache else { 11182807Sache pos = _sseek(fp, (fpos_t)0, SEEK_CUR); 11282668Sache if (pos == -1) 11382709Sache return (1); 1141573Srgrimes } 1151573Srgrimes if (fp->_flags & __SRD) { 1161573Srgrimes /* 1171573Srgrimes * Reading. Any unread characters (including 1181573Srgrimes * those from ungetc) cause the position to be 1191573Srgrimes * smaller than that in the underlying object. 1201573Srgrimes */ 12182709Sache if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) { 12282734Sache fp->_flags |= __SERR; 12382734Sache errno = EIO; 12482734Sache return (1); 12582588Sache } 12682709Sache if (HASUB(fp)) 12782709Sache pos -= fp->_r; /* Can be negative at this point. */ 12882588Sache } else if ((fp->_flags & __SWR) && fp->_p != NULL) { 1291573Srgrimes /* 1301573Srgrimes * Writing. Any buffered characters cause the 1311573Srgrimes * position to be greater than that in the 1321573Srgrimes * underlying object. 1331573Srgrimes */ 13482588Sache n = fp->_p - fp->_bf._base; 13582588Sache if (pos > OFF_MAX - n) { 13682588Sache errno = EOVERFLOW; 13782709Sache return (1); 13882588Sache } 13982588Sache pos += n; 1401573Srgrimes } 14182709Sache *offset = pos; 14282709Sache return (0); 1431573Srgrimes} 144