| | 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 | * 3. All advertising materials mentioning features or use of this software |
| | 17 | * must display the following acknowledgement: |
| | 18 | * This product includes software developed by the University of |
| | 19 | * California, Berkeley and its contributors. |
| | 20 | * 4. Neither the name of the University nor the names of its contributors |
| | 21 | * may be used to endorse or promote products derived from this software |
| | 22 | * without specific prior written permission. |
| | 23 | * |
| | 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| | 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| | 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| | 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| | 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| | 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| | 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| | 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| | 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| | 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| | 34 | * SUCH DAMAGE. |
| | 35 | */ |
| | 36 | |
| | 37 | #if defined(LIBC_SCCS) && !defined(lint) |
| | 38 | static char sccsid[] = "@(#)ftell.c 8.2 (Berkeley) 5/4/95"; |
| | 39 | #endif /* LIBC_SCCS and not lint */ |
| | 40 | #include <sys/cdefs.h> |
| | 41 | __FBSDID("$FreeBSD: src/lib/libc/stdio/ftell.c,v 1.26 2002/03/22 21:53:04 obrien Exp $"); |
| | 42 | |
| | 43 | #include "namespace.h" |
| | 44 | #include <sys/types.h> |
| | 45 | #include <errno.h> |
| | 46 | #include <limits.h> |
| | 47 | #include <stdio.h> |
| | 48 | #include "un-namespace.h" |
| | 49 | #include "local.h" |
| | 50 | #include "libc_private.h" |
| | 51 | |
| | 52 | /* |
| | 53 | * standard ftell function. |
| | 54 | */ |
| | 55 | long |
| | 56 | ftell(fp) |
| | 57 | FILE *fp; |
| | 58 | { |
| | 59 | off_t rv; |
| | 60 | |
| | 61 | rv = ftello(fp); |
| | 62 | if (rv > LONG_MAX) { |
| | 63 | errno = EOVERFLOW; |
| | 64 | return (-1); |
| | 65 | } |
| | 66 | return (rv); |
| | 67 | } |
| | 68 | |
| | 69 | /* |
| | 70 | * ftello: return current offset. |
| | 71 | */ |
| | 72 | off_t |
| | 73 | ftello(fp) |
| | 74 | FILE *fp; |
| | 75 | { |
| | 76 | fpos_t rv; |
| | 77 | int ret; |
| | 78 | |
| | 79 | FLOCKFILE(fp); |
| | 80 | ret = _ftello(fp, &rv); |
| | 81 | FUNLOCKFILE(fp); |
| | 82 | if (ret) |
| | 83 | return (-1); |
| | 84 | if (rv < 0) { /* Unspecified value because of ungetc() at 0 */ |
| | 85 | errno = ESPIPE; |
| | 86 | return (-1); |
| | 87 | } |
| | 88 | return (rv); |
| | 89 | } |
| | 90 | |
| | 91 | int |
| | 92 | _ftello(fp, offset) |
| | 93 | FILE *fp; |
| | 94 | fpos_t *offset; |
| | 95 | { |
| | 96 | fpos_t pos; |
| | 97 | size_t n; |
| | 98 | |
| | 99 | if (fp->_seek == NULL) { |
| | 100 | errno = ESPIPE; /* historic practice */ |
| | 101 | return (1); |
| | 102 | } |
| | 103 | |
| | 104 | /* |
| | 105 | * Find offset of underlying I/O object, then |
| | 106 | * adjust for buffered bytes. |
| | 107 | */ |
| | 108 | if (fp->_flags & __SOFF) |
| | 109 | pos = fp->_offset; |
| | 110 | else { |
| | 111 | pos = _sseek(fp, (fpos_t)0, SEEK_CUR); |
| | 112 | if (pos == -1) |
| | 113 | return (1); |
| | 114 | } |
| | 115 | if (fp->_flags & __SRD) { |
| | 116 | /* |
| | 117 | * Reading. Any unread characters (including |
| | 118 | * those from ungetc) cause the position to be |
| | 119 | * smaller than that in the underlying object. |
| | 120 | */ |
| | 121 | if ((pos -= (HASUB(fp) ? fp->_ur : fp->_r)) < 0) { |
| | 122 | fp->_flags |= __SERR; |
| | 123 | errno = EIO; |
| | 124 | return (1); |
| | 125 | } |
| | 126 | if (HASUB(fp)) |
| | 127 | pos -= fp->_r; /* Can be negative at this point. */ |
| | 128 | } else if ((fp->_flags & __SWR) && fp->_p != NULL) { |
| | 129 | /* |
| | 130 | * Writing. Any buffered characters cause the |
| | 131 | * position to be greater than that in the |
| | 132 | * underlying object. |
| | 133 | */ |
| | 134 | n = fp->_p - fp->_bf._base; |
| | 135 | if (pos > OFF_MAX - n) { |
| | 136 | errno = EOVERFLOW; |
| | 137 | return (1); |
| | 138 | } |
| | 139 | pos += n; |
| | 140 | } |
| | 141 | *offset = pos; |
| | 142 | return (0); |
| | 143 | } |
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