| 1 | /* $NetBSD: ftello.c,v 1.4 2003/08/07 16:43:26 agc Exp $ */
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| 2 |
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| 3 | /*-
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| 4 | * Copyright (c) 1990, 1993
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| 5 | * The Regents of the University of California. All rights reserved.
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| 6 | *
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| 7 | * This code is derived from software contributed to Berkeley by
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| 8 | * Chris Torek.
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without
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| 11 | * modification, are permitted provided that the following conditions
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| 12 | * are met:
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| 13 | * 1. Redistributions of source code must retain the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | * 3. Neither the name of the University nor the names of its contributors
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| 19 | * may be used to endorse or promote products derived from this software
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| 20 | * without specific prior written permission.
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| 21 | *
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| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 32 | * SUCH DAMAGE.
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| 33 | */
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| 34 | #include <LibConfig.h>
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| 35 | #include <sys/EfiCdefs.h>
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| 36 | #if defined(LIBC_SCCS) && !defined(lint)
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| 37 | __RCSID("$NetBSD: ftello.c,v 1.4 2003/08/07 16:43:26 agc Exp $");
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| 38 | #endif /* LIBC_SCCS and not lint */
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| 39 |
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| 40 | #include "namespace.h"
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| 41 | #include <assert.h>
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| 42 | #include <errno.h>
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| 43 | #include <stdio.h>
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| 44 | #include "reentrant.h"
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| 45 | #include "local.h"
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| 46 |
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| 47 | #ifdef __weak_alias
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| 48 | __weak_alias(ftello, _ftello)
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| 49 | #endif
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| 50 |
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| 51 | /*
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| 52 | * ftell: return current offset.
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| 53 | */
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| 54 | off_t
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| 55 | ftello(FILE *fp)
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| 56 | {
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| 57 | fpos_t pos;
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| 58 |
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| 59 | FLOCKFILE(fp);
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| 60 |
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| 61 | if (fp->_seek == NULL) {
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| 62 | FUNLOCKFILE(fp);
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| 63 | errno = ESPIPE; /* historic practice */
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| 64 | return ((off_t)-1);
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| 65 | }
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| 66 |
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| 67 | /*
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| 68 | * Find offset of underlying I/O object, then
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| 69 | * adjust for buffered bytes.
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| 70 | */
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| 71 | __sflush(fp); /* may adjust seek offset on append stream */
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| 72 | if (fp->_flags & __SOFF)
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| 73 | pos = fp->_offset;
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| 74 | else {
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| 75 | pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR);
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| 76 | if (pos == (fpos_t)-1) {
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| 77 | FUNLOCKFILE(fp);
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| 78 | return (pos);
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| 79 | }
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| 80 | }
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| 81 | if (fp->_flags & __SRD) {
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| 82 | /*
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| 83 | * Reading. Any unread characters (including
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| 84 | * those from ungetc) cause the position to be
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| 85 | * smaller than that in the underlying object.
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| 86 | */
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| 87 | pos -= fp->_r;
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| 88 | if (HASUB(fp))
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| 89 | pos -= fp->_ur;
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| 90 | } else if (fp->_flags & __SWR && fp->_p != NULL) {
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| 91 | /*
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| 92 | * Writing. Any buffered characters cause the
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| 93 | * position to be greater than that in the
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| 94 | * underlying object.
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| 95 | */
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| 96 | pos += fp->_p - fp->_bf._base;
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| 97 | }
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| 98 | FUNLOCKFILE(fp);
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| 99 | return (pos);
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| 100 | }
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