2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
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11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)fgetln.c 8.2 (Berkeley) 1/2/94";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include "namespace.h"
47 #include "un-namespace.h"
48 #include "libc_private.h"
52 * Expand the line buffer. Return -1 on error.
54 * The `new size' does not account for a terminating '\0',
59 __slbexpand(FILE *fp, size_t newsize)
66 if (fp->_lb._size >= newsize)
68 if (newsize > INT_MAX) {
72 if ((p = realloc(fp->_lb._base, newsize)) == NULL)
75 fp->_lb._size = newsize;
80 * Get an input line. The returned pointer often (but not always)
81 * points into a stdio buffer. Fgetln does not alter the text of
82 * the returned line (which is thus not a C string because it will
83 * not necessarily end with '\0'), but does allow callers to modify
84 * it if they wish. Thus, we set __SMOD in case the caller does.
87 fgetln(FILE *fp, size_t *lenp)
94 FLOCKFILE_CANCELSAFE(fp);
96 /* make sure there is input */
97 if (fp->_r <= 0 && __srefill(fp)) {
103 /* look for a newline in the input */
104 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) {
106 * Found one. Flag buffer as modified to keep fseek from
107 * `optimising' a backward seek, in case the user stomps on
110 p++; /* advance over it */
111 ret = (char *)fp->_p;
112 *lenp = len = p - fp->_p;
113 fp->_flags |= __SMOD;
120 * We have to copy the current buffered data to the line buffer.
121 * As a bonus, though, we can leave off the __SMOD.
123 * OPTIMISTIC is length that we (optimistically) expect will
124 * accommodate the `rest' of the string, on each trip through the
127 #define OPTIMISTIC 80
129 for (len = fp->_r, off = 0;; len += fp->_r) {
133 * Make sure there is room for more bytes. Copy data from
134 * file buffer to line buffer, refill file and look for
135 * newline. The loop stops only when we find a newline.
137 if (__slbexpand(fp, len + OPTIMISTIC))
139 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
147 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL)
150 /* got it: finish up the line (like code above) */
154 if (__slbexpand(fp, len))
156 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p,
164 fp->_lb._base[len] = '\0';
166 ret = (char *)fp->_lb._base;
168 FUNLOCKFILE_CANCELSAFE();
173 fp->_flags |= __SERR;