GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/stdio/ungetc.c Lines: 0 56 0.0 %
Date: 2017-11-13 Branches: 0 46 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: ungetc.c,v 1.15 2016/09/21 04:38:56 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 <stdlib.h>
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#include <string.h>
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#include "local.h"
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static int __submore(FILE *);
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/*
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 * Expand the ungetc buffer `in place'.  That is, adjust fp->_p when
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 * the buffer moves, so that it points the same distance from the end,
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 * and move the bytes in the buffer around as necessary so that they
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 * are all at the end (stack-style).
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 */
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static int
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__submore(FILE *fp)
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{
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	int i;
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	unsigned char *p;
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	if (_UB(fp)._base == fp->_ubuf) {
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		/*
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		 * Get a new buffer (rather than expanding the old one).
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		 */
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		if ((p = malloc(BUFSIZ)) == NULL)
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			return (EOF);
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		_UB(fp)._base = p;
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		_UB(fp)._size = BUFSIZ;
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		p += BUFSIZ - sizeof(fp->_ubuf);
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		for (i = sizeof(fp->_ubuf); --i >= 0;)
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			p[i] = fp->_ubuf[i];
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		fp->_p = p;
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		return (0);
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	}
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	i = _UB(fp)._size;
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	p = reallocarray(_UB(fp)._base, i, 2);
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	if (p == NULL)
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		return (EOF);
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	/* no overlap (hence can use memcpy) because we doubled the size */
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	(void)memcpy(p + i, p, i);
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	fp->_p = p + i;
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	_UB(fp)._base = p;
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	_UB(fp)._size = i * 2;
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	return (0);
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}
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int
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ungetc(int c, FILE *fp)
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{
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	if (c == EOF)
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		return (EOF);
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	if (!__sdidinit)
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		__sinit();
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	FLOCKFILE(fp);
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	_SET_ORIENTATION(fp, -1);
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	if ((fp->_flags & __SRD) == 0) {
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		/*
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		 * Not already reading: no good unless reading-and-writing.
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		 * Otherwise, flush any current write stuff.
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		 */
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		if ((fp->_flags & __SRW) == 0) {
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error:			FUNLOCKFILE(fp);
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			return (EOF);
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		}
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		if (fp->_flags & __SWR) {
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			if (__sflush(fp))
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				goto error;
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			fp->_flags &= ~__SWR;
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			fp->_w = 0;
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			fp->_lbfsize = 0;
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		}
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		fp->_flags |= __SRD;
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	}
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	c = (unsigned char)c;
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	/*
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	 * If we are in the middle of ungetc'ing, just continue.
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	 * This may require expanding the current ungetc buffer.
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	 */
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	if (HASUB(fp)) {
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		if (fp->_r >= _UB(fp)._size && __submore(fp))
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			goto error;
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		*--fp->_p = c;
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inc_ret:	fp->_r++;
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		FUNLOCKFILE(fp);
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		return (c);
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	}
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	fp->_flags &= ~__SEOF;
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	/*
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	 * If we can handle this by simply backing up, do so,
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	 * but never replace the original character.
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	 * (This makes sscanf() work when scanning `const' data.)
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	 */
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	if (fp->_bf._base != NULL && fp->_p > fp->_bf._base &&
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	    fp->_p[-1] == c) {
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		fp->_p--;
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		goto inc_ret;
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	}
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	/*
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	 * Create an ungetc buffer.
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	 * Initially, we will use the `reserve' buffer.
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	 */
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	fp->_ur = fp->_r;
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	fp->_up = fp->_p;
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	_UB(fp)._base = fp->_ubuf;
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	_UB(fp)._size = sizeof(fp->_ubuf);
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	fp->_ubuf[sizeof(fp->_ubuf) - 1] = c;
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	fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1];
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	fp->_r = 1;
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	FUNLOCKFILE(fp);
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	return (c);
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}
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DEF_STRONG(ungetc);