/*- * Copyright (c) 1990, 1993 *	The Regents of the University of California.  All rights reserved. * * This code is derived from software contributed to Berkeley by * Chris Torek. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *	This product includes software developed by the University of *	California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors *    may be used to endorse or promote products derived from this software *    without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint)static char rcsid[] = "$OpenBSD: fgets.c,v 1.2 1996/08/19 08:32:33 tholo Exp $";#endif /* LIBC_SCCS and not lint */ #include <stdio.h>#include <string.h>#include "local.h" /* * Read at most n-1 characters from the given file. * Stop when a newline has been read, or the count runs out. * Return first argument, or NULL if no characters were read. */char *fgets(buf, n, fp)	char *buf;	register int n;	register FILE *fp;{	register size_t len;	register char *s;	register unsigned char *p, *t; 	if (n <= 0)		/* sanity check */		return (NULL); 	s = buf;	n--;			/* leave space for NUL */	while (n != 0) {		/*		 * If the buffer is empty, refill it.		 */		if ((len = fp->_r) <= 0) {			if (__srefill(fp)) {				/* EOF/error: stop with partial or no line */				if (s == buf)					return (NULL);				break;			}			len = fp->_r;		}		p = fp->_p; 		/*		 * Scan through at most n bytes of the current buffer,		 * looking for '\n'.  If found, copy up to and including		 * newline, and stop.  Otherwise, copy entire chunk		 * and loop.		 */		if (len > n)			len = n;		t = memchr((void *)p, '\n', len);		if (t != NULL) {			len = ++t - p;			fp->_r -= len;			fp->_p = t;			(void)memcpy((void *)s, (void *)p, len);			s[len] = 0;			return (buf);		}		fp->_r -= len;		fp->_p += len;		(void)memcpy((void *)s, (void *)p, len);		s += len;		n -= len;	}	*s = 0;	return (buf);}