GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/stdio/fread.c Lines: 0 30 0.0 %
Date: 2017-11-13 Branches: 0 32 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: fread.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 <string.h>
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#include <stdint.h>
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#include <errno.h>
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#include "local.h"
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#define MUL_NO_OVERFLOW	(1UL << (sizeof(size_t) * 4))
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size_t
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fread(void *buf, size_t size, size_t count, FILE *fp)
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{
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	size_t resid;
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	char *p;
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	int r;
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	size_t total;
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	/*
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	 * Extension:  Catch integer overflow
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	 */
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	if ((size >= MUL_NO_OVERFLOW || count >= MUL_NO_OVERFLOW) &&
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	    size > 0 && SIZE_MAX / size < count) {
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		errno = EOVERFLOW;
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		fp->_flags |= __SERR;
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		return (0);
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	}
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	/*
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	 * ANSI and SUSv2 require a return value of 0 if size or count are 0.
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	 */
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	if ((resid = count * size) == 0)
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		return (0);
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	FLOCKFILE(fp);
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	_SET_ORIENTATION(fp, -1);
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	if (fp->_r < 0)
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		fp->_r = 0;
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	total = resid;
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	p = buf;
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	if ((fp->_flags & __SNBF) != 0) {
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		/*
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		 * We know if we're unbuffered that our buffer is empty, so
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		 * we can just read directly. This is much faster than the
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		 * loop below which will perform a series of one byte reads.
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		 */
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		while (resid > 0 && (r = (*fp->_read)(fp->_cookie, p, resid)) > 0) {
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			p += r;
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			resid -= r;
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		}
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		FUNLOCKFILE(fp);
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		return ((total - resid) / size);
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	}
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	while (resid > (r = fp->_r)) {
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		(void)memcpy(p, fp->_p, r);
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		fp->_p += r;
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		/* fp->_r = 0 ... done in __srefill */
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		p += r;
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		resid -= r;
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		if (__srefill(fp)) {
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			/* no more input: return partial result */
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			FUNLOCKFILE(fp);
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			return ((total - resid) / size);
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		}
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	}
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	(void)memcpy(p, fp->_p, resid);
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	fp->_r -= resid;
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	fp->_p += resid;
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	FUNLOCKFILE(fp);
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	return (count);
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}
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DEF_STRONG(fread);