libc/stdio/fgets.c

/*-
 * 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. 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 sccsid[] = "@(#)fgets.c     8.2 (Berkeley) 12/22/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "namespace.h"
#include <stdio.h>
#include <string.h>
#include "un-namespace.h"
#include "local.h"
#include "libc_private.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(char * __restrict buf, int n, FILE * __restrict fp)
{
        size_t len;
        char *s;
        unsigned char *p, *t;

        if (n <= 0)             /* sanity check */
                return (NULL);

        FLOCKFILE(fp);
        ORIENT(fp, -1);
        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) {
                                        FUNLOCKFILE(fp);
                                        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;
                        FUNLOCKFILE(fp);
                        return (buf);
                }
                fp->_r -= len;
                fp->_p += len;
                (void)memcpy((void *)s, (void *)p, len);
                s += len;
                n -= len;
        }
        *s = 0;
        FUNLOCKFILE(fp);
        return (buf);
}
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. Neither the name of the University nor the names of its contributors
17	* may be used to endorse or promote products derived from this software
18	* without specific prior written permission.
19	*
20	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30	* SUCH DAMAGE.
31	*/
32
33	#if defined(LIBC_SCCS) && !defined(lint)
34	static char sccsid[] = "@(#)fgets.c 8.2 (Berkeley) 12/22/93";
35	#endif /* LIBC_SCCS and not lint */
36	#include <sys/cdefs.h>
37	__FBSDID("$FreeBSD$");
38
39	#include "namespace.h"
40	#include <stdio.h>
41	#include <string.h>
42	#include "un-namespace.h"
43	#include "local.h"
44	#include "libc_private.h"
45
46	/*
47	* Read at most n-1 characters from the given file.
48	* Stop when a newline has been read, or the count runs out.
49	* Return first argument, or NULL if no characters were read.
50	*/
51	char *
52	fgets(char * __restrict buf, int n, FILE * __restrict fp)
53	{
54	size_t len;
55	char *s;
56	unsigned char p, t;
57
58	if (n <= 0) /* sanity check */
59	return (NULL);
60
61	FLOCKFILE(fp);
62	ORIENT(fp, -1);
63	s = buf;
64	n--; /* leave space for NUL */
65	while (n != 0) {
66	/*
67	* If the buffer is empty, refill it.
68	*/
69	if ((len = fp->_r) <= 0) {
70	if (__srefill(fp)) {
71	/* EOF/error: stop with partial or no line */
72	if (s == buf) {
73	FUNLOCKFILE(fp);
74	return (NULL);
75	}
76	break;
77	}
78	len = fp->_r;
79	}
80	p = fp->_p;
81
82	/*
83	* Scan through at most n bytes of the current buffer,
84	* looking for '\n'. If found, copy up to and including
85	* newline, and stop. Otherwise, copy entire chunk
86	* and loop.
87	*/
88	if (len > n)
89	len = n;
90	t = memchr((void *)p, '\n', len);
91	if (t != NULL) {
92	len = ++t - p;
93	fp->_r -= len;
94	fp->_p = t;
95	(void)memcpy((void )s, (void )p, len);
96	s[len] = 0;
97	FUNLOCKFILE(fp);
98	return (buf);
99	}
100	fp->_r -= len;
101	fp->_p += len;
102	(void)memcpy((void )s, (void )p, len);
103	s += len;
104	n -= len;
105	}
106	*s = 0;
107	FUNLOCKFILE(fp);
108	return (buf);
109	}