| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame^] | 1 | /* $OpenBSD: ftell.c,v 1.6 2005/08/08 08:05:36 espie Exp $ */ |
| 2 | /*- |
| 3 | * Copyright (c) 1990, 1993 |
| 4 | * The Regents of the University of California. All rights reserved. |
| 5 | * |
| 6 | * This code is derived from software contributed to Berkeley by |
| 7 | * Chris Torek. |
| 8 | * |
| 9 | * Redistribution and use in source and binary forms, with or without |
| 10 | * modification, are permitted provided that the following conditions |
| 11 | * are met: |
| 12 | * 1. Redistributions of source code must retain the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer. |
| 14 | * 2. Redistributions in binary form must reproduce the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer in the |
| 16 | * documentation and/or other materials provided with the distribution. |
| 17 | * 3. Neither the name of the University nor the names of its contributors |
| 18 | * may be used to endorse or promote products derived from this software |
| 19 | * without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 31 | * SUCH DAMAGE. |
| 32 | */ |
| 33 | |
| 34 | #include <stdio.h> |
| 35 | #include <errno.h> |
| 36 | #include "local.h" |
| 37 | |
| 38 | /* |
| 39 | * ftello: return current offset. |
| 40 | */ |
| 41 | off_t |
| 42 | ftello(FILE *fp) |
| 43 | { |
| 44 | fpos_t pos; |
| 45 | |
| 46 | if (fp->_seek == NULL) { |
| 47 | errno = ESPIPE; /* historic practice */ |
| 48 | return ((off_t)-1); |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * Find offset of underlying I/O object, then |
| 53 | * adjust for buffered bytes. |
| 54 | */ |
| 55 | __sflush(fp); /* may adjust seek offset on append stream */ |
| 56 | if (fp->_flags & __SOFF) |
| 57 | pos = fp->_offset; |
| 58 | else { |
| 59 | pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR); |
| 60 | if (pos == -1L) |
| 61 | return (pos); |
| 62 | } |
| 63 | if (fp->_flags & __SRD) { |
| 64 | /* |
| 65 | * Reading. Any unread characters (including |
| 66 | * those from ungetc) cause the position to be |
| 67 | * smaller than that in the underlying object. |
| 68 | */ |
| 69 | pos -= fp->_r; |
| 70 | if (HASUB(fp)) |
| 71 | pos -= fp->_ur; |
| 72 | } else if (fp->_flags & __SWR && fp->_p != NULL) { |
| 73 | /* |
| 74 | * Writing. Any buffered characters cause the |
| 75 | * position to be greater than that in the |
| 76 | * underlying object. |
| 77 | */ |
| 78 | pos += fp->_p - fp->_bf._base; |
| 79 | } |
| 80 | return (pos); |
| 81 | } |
| 82 | |
| 83 | /* |
| 84 | * ftell() returns a long and sizeof(off_t) != sizeof(long) on all arches |
| 85 | */ |
| 86 | #if defined(__alpha__) && defined(__indr_reference) |
| 87 | __indr_reference(ftello, ftell); |
| 88 | #else |
| 89 | long |
| 90 | ftell(FILE *fp) |
| 91 | { |
| 92 | long pos; |
| 93 | |
| 94 | pos = (long)ftello(fp); |
| 95 | return(pos); |
| 96 | } |
| 97 | #endif |