1 /* $NetBSD: c32rtomb.c,v 1.6 2024/08/21 18:36:11 rillig Exp $ */
2
3 /*-
4 * Copyright (c) 2024 The NetBSD Foundation, Inc.
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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /*
30 * c32rtomb(s, c32, ps)
31 *
32 * Encode the Unicode UTF-32 code unit c32, which must not be a
33 * surrogate code point, into the multibyte buffer s under the
34 * current locale, using multibyte encoding state ps. A UTF-32
35 * code unit is also a Unicode scalar value, which is any Unicode
36 * code point except a surrogate.
37 *
38 * Return the number of bytes stored on success, or (size_t)-1 on
39 * error with errno set to EILSEQ.
40 *
41 * At most MB_CUR_MAX bytes will be stored.
42 *
43 * References:
44 *
45 * The Unicode Standard, Version 15.0 -- Core Specification, The
46 * Unicode Consortium, Sec. 3.8 `Surrogates', p. 118.
47 * https://www.unicode.org/versions/Unicode15.0.0/UnicodeStandard-15.0.pdf#page=144
48 * https://web.archive.org/web/20240718101254/https://www.unicode.org/versions/Unicode15.0.0/UnicodeStandard-15.0.pdf#page=144
49 */
50
51 #include <sys/cdefs.h>
52 __RCSID("$NetBSD: c32rtomb.c,v 1.6 2024/08/21 18:36:11 rillig Exp $");
53
54 #include "namespace.h"
55
56 #include <sys/types.h> /* broken citrus_*.h */
57 #include <sys/queue.h> /* broken citrus_*.h */
58
59 #include <assert.h>
60 #include <errno.h>
61 #include <langinfo.h>
62 #include <limits.h>
63 #include <locale.h>
64 #include <paths.h>
65 #include <stddef.h>
66 #include <stdlib.h>
67 #include <uchar.h>
68 #include <wchar.h>
69
70 #include "citrus_types.h" /* broken citrus_iconv.h */
71 #include "citrus_module.h" /* broken citrus_iconv.h */
72 #include "citrus_hash.h" /* broken citrus_iconv.h */
73 #include "citrus_iconv.h"
74 #include "setlocale_local.h"
75
76 #ifdef __weak_alias
__weak_alias(c32rtomb,_c32rtomb)77 __weak_alias(c32rtomb,_c32rtomb)
78 __weak_alias(c32rtomb_l,_c32rtomb_l)
79 #endif
80
81 size_t
82 c32rtomb(char *restrict s, char32_t c32, mbstate_t *restrict ps)
83 {
84
85 return c32rtomb_l(s, c32, ps, _current_locale());
86 }
87
88 size_t
c32rtomb_l(char * restrict s,char32_t c32,mbstate_t * restrict ps,locale_t loc)89 c32rtomb_l(char *restrict s, char32_t c32, mbstate_t *restrict ps,
90 locale_t loc)
91 {
92 static mbstate_t psbuf;
93 struct _citrus_iconv *iconv = NULL;
94 char buf[2*MB_LEN_MAX]; /* [shift from init, wc] [shift to init] */
95 char utf32le[4];
96 const char *src;
97 char *dst;
98 size_t srcleft, dstleft, inval;
99 mbstate_t mbrtowcstate = {0};
100 wchar_t wc;
101 size_t wc_len;
102 size_t len;
103 int error, errno_save;
104
105 /*
106 * Save errno in case _citrus_iconv_* clobbers it.
107 */
108 errno_save = errno;
109
110 /*
111 * `If ps is a null pointer, each function uses its own
112 * internal mbstate_t object instead, which is initialized at
113 * program startup to the initial conversion state; the
114 * functions are not required to avoid data races with other
115 * calls to the same function in this case. The
116 * implementation behaves as if no library function calls
117 * these functions with a null pointer for ps.'
118 */
119 if (ps == NULL)
120 ps = &psbuf;
121
122 /*
123 * `If s is a null pointer, the c32rtomb function is equivalent
124 * to the call
125 *
126 * c32rtomb(buf, L'\0', ps)
127 *
128 * where buf is an internal buffer.'
129 */
130 if (s == NULL) {
131 s = buf;
132 c32 = L'\0';
133 }
134
135 /*
136 * Reject surrogate code points. We only deal in scalar
137 * values.
138 *
139 * XXX Is this necessary? Won't iconv take care of it for us?
140 */
141 if (c32 >= 0xd800 && c32 <= 0xdfff) {
142 errno = EILSEQ;
143 len = (size_t)-1;
144 goto out;
145 }
146
147 /*
148 * Open an iconv handle to convert UTF-32LE to locale-dependent
149 * multibyte output.
150 */
151 if ((error = _citrus_iconv_open(&iconv, _PATH_ICONV, "utf-32le",
152 nl_langinfo_l(CODESET, loc))) != 0) {
153 errno = EIO; /* XXX? */
154 len = (size_t)-1;
155 goto out;
156 }
157
158 /*
159 * Convert from UTF-32LE to a multibyte sequence.
160 */
161 le32enc(utf32le, c32);
162 src = utf32le;
163 srcleft = sizeof(utf32le);
164 dst = buf;
165 dstleft = MB_CUR_MAX;
166 error = _citrus_iconv_convert(iconv, &src, &srcleft, &dst, &dstleft,
167 _CITRUS_ICONV_F_HIDE_INVALID, &inval);
168 if (error) { /* can't be incomplete, must be error */
169 errno = error;
170 len = (size_t)-1;
171 goto out;
172 }
173 _DIAGASSERT(srcleft == 0);
174 _DIAGASSERT(dstleft <= MB_CUR_MAX);
175
176 /*
177 * If we didn't produce any output, that means the scalar value
178 * c32 can't be encoded in the current locale, so treat it as
179 * EILSEQ.
180 */
181 len = MB_CUR_MAX - dstleft;
182 if (len == 0) {
183 errno = EILSEQ;
184 len = (size_t)-1;
185 goto out;
186 }
187
188 /*
189 * Now get a wide character out of the buffer. We don't care
190 * how much it consumes other than for a diagnostic assertion.
191 * It had better return exactly one wide character, because we
192 * are only allowed to encode one wide character's worth of
193 * multibyte output (possibly including a shift sequence).
194 *
195 * XXX What about combining characters?
196 */
197 wc_len = mbrtowc_l(&wc, buf, len, &mbrtowcstate, loc);
198 switch (wc_len) {
199 case (size_t)-1: /* error, with errno set */
200 len = (size_t)-1;
201 goto out;
202 case 0: /* decoded NUL */
203 wc = 0; /* paranoia */
204 len = wc_len;
205 break;
206 default: /* decoded wc */
207 _DIAGASSERT(wc_len <= len);
208 }
209
210 /*
211 * Now put the wide character out, using the caller's
212 * conversion state so that we don't output unnecessary shift
213 * sequences.
214 */
215 len = wcrtomb_l(s, wc, ps, loc);
216 if (len == (size_t)-1) /* error, with errno set */
217 goto out;
218
219 /*
220 * Make sure we preserve errno on success.
221 */
222 errno = errno_save;
223
224 out: errno_save = errno;
225 _citrus_iconv_close(iconv);
226 errno = errno_save;
227 return len;
228 }
229