2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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 * 4. 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.
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
32 * @(#)fgetln.c 8.2 (Berkeley) 1/2/94
33 * $FreeBSD: src/lib/libc/stdio/fgetln.c,v 1.11 2007/01/09 00:28:06 imp Exp $
34 * $DragonFly: src/lib/libc/stdio/fgetln.c,v 1.7 2005/11/20 11:07:30 swildner Exp $
37 #include "namespace.h"
41 #include "un-namespace.h"
43 #include "libc_private.h"
45 #include "priv_stdio.h"
48 * Expand the line buffer. Return -1 on error.
50 * The `new size' does not account for a terminating '\0',
55 __slbexpand(FILE *fp, size_t newsize)
62 if (fp->_lb._size >= newsize)
64 if ((p = realloc(fp->_lb._base, newsize)) == NULL)
67 fp->_lb._size = newsize;
72 * Get an input line. The returned pointer often (but not always)
73 * points into a stdio buffer. Fgetln does not alter the text of
74 * the returned line (which is thus not a C string because it will
75 * not necessarily end with '\0'), but does allow callers to modify
76 * it if they wish. Thus, we set __SMOD in case the caller does.
79 fgetln(FILE *fp, size_t *lenp)
87 /* make sure there is input */
88 if (fp->pub._r <= 0 && __srefill(fp)) {
94 /* look for a newline in the input */
95 if ((p = memchr((void *)fp->pub._p, '\n', (size_t)fp->pub._r)) != NULL) {
99 * Found one. Flag buffer as modified to keep fseek from
100 * `optimising' a backward seek, in case the user stomps on
103 p++; /* advance over it */
104 ret = (char *)fp->pub._p;
105 *lenp = len = p - fp->pub._p;
106 fp->pub._flags |= __SMOD;
114 * We have to copy the current buffered data to the line buffer.
115 * As a bonus, though, we can leave off the __SMOD.
117 * OPTIMISTIC is length that we (optimistically) expect will
118 * accomodate the `rest' of the string, on each trip through the
121 #define OPTIMISTIC 80
123 for (len = fp->pub._r, off = 0;; len += fp->pub._r) {
127 * Make sure there is room for more bytes. Copy data from
128 * file buffer to line buffer, refill file and look for
129 * newline. The loop stops only when we find a newline.
131 if (__slbexpand(fp, len + OPTIMISTIC))
133 memcpy((void *)(fp->_lb._base + off), (void *)fp->pub._p,
137 break; /* EOF or error: return partial line */
138 if ((p = memchr((void *)fp->pub._p, '\n', (size_t)fp->pub._r))
142 /* got it: finish up the line (like code above) */
144 diff = p - fp->pub._p;
146 if (__slbexpand(fp, len))
148 memcpy((void *)(fp->_lb._base + off), (void *)fp->pub._p, diff);
155 fp->_lb._base[len] = 0;
158 return ((char *)fp->_lb._base);
163 return (NULL); /* ??? */