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/* $OpenBSD: ftell.c,v 1.11 2015/08/31 02:53:57 guenther Exp $ */ |
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/*- |
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* Copyright (c) 1990, 1993 |
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* The Regents of the University of California. All rights reserved. |
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* |
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* This code is derived from software contributed to Berkeley by |
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* Chris Torek. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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#include <stdio.h> |
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#include <errno.h> |
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#include <limits.h> |
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#include "local.h" |
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/* |
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* ftello: return current offset. |
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*/ |
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off_t |
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ftello(FILE *fp) |
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{ |
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fpos_t pos; |
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✗✓ |
2104 |
if (fp->_seek == NULL) { |
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errno = ESPIPE; /* historic practice */ |
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pos = -1; |
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goto out; |
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} |
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/* |
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* Find offset of underlying I/O object, then |
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* adjust for buffered bytes. |
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*/ |
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✗✓ |
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FLOCKFILE(fp); |
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__sflush(fp); /* may adjust seek offset on append stream */ |
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✓✗ |
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if (fp->_flags & __SOFF) |
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pos = fp->_offset; |
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else { |
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pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR); |
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if (pos == -1) |
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goto out; |
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} |
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✗✓ |
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if (fp->_flags & __SRD) { |
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/* |
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* Reading. Any unread characters (including |
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* those from ungetc) cause the position to be |
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* smaller than that in the underlying object. |
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*/ |
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pos -= fp->_r; |
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if (HASUB(fp)) |
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pos -= fp->_ur; |
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✗✓✗✗
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} else if (fp->_flags & __SWR && fp->_p != NULL) { |
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/* |
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* Writing. Any buffered characters cause the |
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* position to be greater than that in the |
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* underlying object. |
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*/ |
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pos += fp->_p - fp->_bf._base; |
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} |
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✗✓ |
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out: FUNLOCKFILE(fp); |
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return (pos); |
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} |
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DEF_WEAK(ftello); |
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long |
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ftell(FILE *fp) |
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{ |
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2104 |
off_t offset = ftello(fp); |
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✗✓ |
1052 |
if (offset > LONG_MAX) { |
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errno = EOVERFLOW; |
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return (-1); |
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} |
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return ((long)offset); |
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} |
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DEF_STRONG(ftell); |