xref: /freebsd/lib/libc/stdio/fgetws.c (revision 1670a1c2a47d10ecccd001970b859caf93cd3b6e)
1 /*-
2  * Copyright (c) 2002-2004 Tim J. Robbins.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "namespace.h"
31 #include <errno.h>
32 #include <stdio.h>
33 #include <string.h>
34 #include <wchar.h>
35 #include "un-namespace.h"
36 #include "libc_private.h"
37 #include "local.h"
38 #include "mblocal.h"
39 
40 wchar_t *
41 fgetws(wchar_t * __restrict ws, int n, FILE * __restrict fp)
42 {
43 	wchar_t *wsp;
44 	size_t nconv;
45 	const char *src;
46 	unsigned char *nl;
47 
48 	FLOCKFILE(fp);
49 	ORIENT(fp, 1);
50 
51 	if (n <= 0) {
52 		errno = EINVAL;
53 		goto error;
54 	}
55 
56 	if (fp->_r <= 0 && __srefill(fp))
57 		/* EOF */
58 		goto error;
59 	wsp = ws;
60 	do {
61 		src = fp->_p;
62 		nl = memchr(fp->_p, '\n', fp->_r);
63 		nconv = __mbsnrtowcs(wsp, &src,
64 		    nl != NULL ? (nl - fp->_p + 1) : fp->_r,
65 		    n - 1, &fp->_mbstate);
66 		if (nconv == (size_t)-1)
67 			/* Conversion error */
68 			goto error;
69 		if (src == NULL) {
70 			/*
71 			 * We hit a null byte. Increment the character count,
72 			 * since mbsnrtowcs()'s return value doesn't include
73 			 * the terminating null, then resume conversion
74 			 * after the null.
75 			 */
76 			nconv++;
77 			src = memchr(fp->_p, '\0', fp->_r);
78 			src++;
79 		}
80 		fp->_r -= (unsigned char *)src - fp->_p;
81 		fp->_p = (unsigned char *)src;
82 		n -= nconv;
83 		wsp += nconv;
84 	} while (wsp[-1] != L'\n' && n > 1 && (fp->_r > 0 ||
85 	    __srefill(fp) == 0));
86 	if (wsp == ws)
87 		/* EOF */
88 		goto error;
89 	if (!__mbsinit(&fp->_mbstate))
90 		/* Incomplete character */
91 		goto error;
92 	*wsp = L'\0';
93 	FUNLOCKFILE(fp);
94 
95 	return (ws);
96 
97 error:
98 	FUNLOCKFILE(fp);
99 	return (NULL);
100 }
101