fgetwln.c revision 1.3 
1/*	$NetBSD: fgetwln.c,v 1.3 2009/09/24 20:38:53 roy Exp $	*/
2
3/*-
4 * Copyright (c) 2002-2004 Tim J. Robbins.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30#if defined(LIBC_SCCS) && !defined(lint)
31#if 0
32__FBSDID("$FreeBSD: src/lib/libc/stdio/fgetwln.c,v 1.2 2004/08/06 17:00:09 tjr Exp $");
33#else
34__RCSID("$NetBSD: fgetwln.c,v 1.3 2009/09/24 20:38:53 roy Exp $");
35#endif
36#endif /* LIBC_SCCS and not lint */
37
38#include "namespace.h"
39#include <assert.h>
40#include <errno.h>
41#include <limits.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <wchar.h>
45#include "reentrant.h"
46#include "local.h"
47
48#ifdef __weak_alias
49__weak_alias(fgetwln,_fgetwln)
50#endif
51
52/*
53 * Expand the line buffer.  Return -1 on error.
54#ifdef notdef
55 * The `new size' does not account for a terminating '\0',
56 * so we add 1 here.
57#endif
58 */
59static int
60__slbexpand(FILE *fp, size_t newsize)
61{
62	void *p;
63
64#ifdef notdef
65	++newsize;
66#endif
67	_DIAGASSERT(fp != NULL);
68
69	/* fp->_lb._size is an int ..... */
70	if (newsize > INT_MAX) {
71		errno = EOVERFLOW;
72		return (-1);
73	}
74	if ((size_t)fp->_lb._size >= newsize)
75		return (0);
76	if ((p = realloc(fp->_lb._base, newsize)) == NULL)
77		return (-1);
78	fp->_lb._base = p;
79	fp->_lb._size = newsize;
80	return (0);
81}
82
83wchar_t *
84fgetwln(FILE * __restrict fp, size_t *lenp)
85{
86	wint_t wc;
87	size_t len;
88
89	FLOCKFILE(fp);
90	_SET_ORIENTATION(fp, 1);
91
92	len = 0;
93	while ((wc = __fgetwc_unlock(fp)) != WEOF) {
94#define	GROW	512
95		if (len * sizeof(wchar_t) >= (size_t)fp->_lb._size &&
96		    __slbexpand(fp, (len + GROW) * sizeof(wchar_t)))
97			goto error;
98		*((wchar_t *)(void *)fp->_lb._base + len++) = wc;
99		if (wc == L'\n')
100			break;
101	}
102	if (len == 0)
103		goto error;
104
105	FUNLOCKFILE(fp);
106	*lenp = len;
107	return ((wchar_t *)(void *)fp->_lb._base);
108
109error:
110	FUNLOCKFILE(fp);
111	*lenp = 0;
112	return (NULL);
113}
114