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Commit	Line	Data
	1	/*-
	2	* Copyright (c) 1990, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Chris Torek.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*/
	36
	37	#if defined(LIBC_SCCS) && !defined(lint)
	38	static char sccsid[] = "@(#)fgets.c 8.2 (Berkeley) 12/22/93";
	39	#endif /* LIBC_SCCS and not lint */
	40	#include <sys/cdefs.h>
	41	__FBSDID("$FreeBSD: src/lib/libc/stdio/fgets.c,v 1.13 2002/08/13 09:30:41 tjr Exp $");
	42
	43	#include "namespace.h"
	44	#include <stdio.h>
	45	#include <string.h>
	46	#include "un-namespace.h"
	47	#include "local.h"
	48	#include "libc_private.h"
	49
	50	/*
	51	* Read at most n-1 characters from the given file.
	52	* Stop when a newline has been read, or the count runs out.
	53	* Return first argument, or NULL if no characters were read.
	54	*/
	55	char *
	56	fgets(buf, n, fp)
	57	char *buf;
	58	int n;
	59	FILE *fp;
	60	{
	61	size_t len;
	62	char *s;
	63	unsigned char p, t;
	64
	65	if (n <= 0) /* sanity check */
	66	return (NULL);
	67
	68	FLOCKFILE(fp);
	69	ORIENT(fp, -1);
	70	s = buf;
	71	n--; /* leave space for NUL */
	72	while (n != 0) {
	73	/*
	74	* If the buffer is empty, refill it.
	75	*/
	76	if ((len = fp->_r) <= 0) {
	77	if (__srefill(fp)) {
	78	/* EOF/error: stop with partial or no line */
	79	if (s == buf) {
	80	FUNLOCKFILE(fp);
	81	return (NULL);
	82	}
	83	break;
	84	}
	85	len = fp->_r;
	86	}
	87	p = fp->_p;
	88
	89	/*
	90	* Scan through at most n bytes of the current buffer,
	91	* looking for '\n'. If found, copy up to and including
	92	* newline, and stop. Otherwise, copy entire chunk
	93	* and loop.
	94	*/
	95	if (len > n)
	96	len = n;
	97	t = memchr((void *)p, '\n', len);
	98	if (t != NULL) {
	99	len = ++t - p;
	100	fp->_r -= len;
	101	fp->_p = t;
	102	(void)memcpy((void )s, (void )p, len);
	103	s[len] = 0;
	104	FUNLOCKFILE(fp);
	105	return (buf);
	106	}
	107	fp->_r -= len;
	108	fp->_p += len;
	109	(void)memcpy((void )s, (void )p, len);
	110	s += len;
	111	n -= len;
	112	}
	113	*s = 0;
	114	FUNLOCKFILE(fp);
	115	return (buf);
	116	}