mbrtoc32.c revision 1.6
1 /* $NetBSD: mbrtoc32.c,v 1.6 2024/08/17 21:24:54 riastradh 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 * mbrtoc32(&c32, s, n, ps) 31 * 32 * Decode a Unicode UTF-32 code unit from up to n bytes out of the 33 * multibyte string s, and store it at c32, using multibyte 34 * encoding state ps. A UTF-32 code unit is also a Unicode scalar 35 * value, which is any Unicode code point except a surrogate. 36 * 37 * Return the number of bytes consumed on success, or 0 if the 38 * code unit is NUL, or (size_t)-2 if the input is incomplete, or 39 * (size_t)-1 on error with errno set to EILSEQ. 40 * 41 * In the case of incomplete input, the decoding state so far 42 * after processing s[0], s[1], ..., s[n - 1] is saved in ps, so 43 * subsequent calls to mbrtoc32 will pick up n bytes later into 44 * the input stream. 45 * 46 * References: 47 * 48 * The Unicode Standard, Version 15.0 -- Core Specification, The 49 * Unicode Consortium, Sec. 3.8 `Surrogates', p. 119. 50 * https://www.unicode.org/versions/Unicode15.0.0/UnicodeStandard-15.0.pdf 51 * https://web.archive.org/web/20240718101254/https://www.unicode.org/versions/Unicode15.0.0/UnicodeStandard-15.0.pdf 52 */ 53 54 #include <sys/cdefs.h> 55 __RCSID("$NetBSD: mbrtoc32.c,v 1.6 2024/08/17 21:24:54 riastradh Exp $"); 56 57 #include "namespace.h" 58 59 #include <sys/param.h> /* MIN */ 60 #include <sys/types.h> /* broken citrus_*.h */ 61 #include <sys/queue.h> /* broken citrus_*.h */ 62 63 #include <assert.h> 64 #include <errno.h> 65 #include <langinfo.h> 66 #include <limits.h> 67 #include <locale.h> 68 #include <paths.h> 69 #include <stdalign.h> 70 #include <stddef.h> 71 #include <stdlib.h> 72 #include <string.h> 73 #include <uchar.h> 74 #include <wchar.h> 75 76 #include "citrus_types.h" /* broken citrus_iconv.h */ 77 #include "citrus_module.h" /* broken citrus_iconv.h */ 78 #include "citrus_hash.h" /* broken citrus_iconv.h */ 79 #include "citrus_iconv.h" 80 #include "setlocale_local.h" 81 82 #include "mbrtoc32.h" 83 84 __CTASSERT(sizeof(struct mbrtoc32state) <= sizeof(mbstate_t)); 85 __CTASSERT(alignof(struct mbrtoc32state) <= alignof(mbstate_t)); 86 87 #ifdef __weak_alias 88 __weak_alias(mbrtoc32,_mbrtoc32) 89 __weak_alias(mbrtoc32_l,_mbrtoc32_l) 90 #endif 91 92 size_t 93 mbrtoc32(char32_t *restrict pc32, const char *restrict s, size_t n, 94 mbstate_t *restrict ps) 95 { 96 97 return mbrtoc32_l(pc32, s, n, ps, _current_locale()); 98 } 99 100 size_t 101 mbrtoc32_l(char32_t *restrict pc32, const char *restrict s, size_t n, 102 mbstate_t *restrict ps, locale_t restrict loc) 103 { 104 static mbstate_t psbuf; 105 struct mbrtoc32state *S; 106 struct _citrus_iconv *iconv = NULL; 107 size_t len; 108 char32_t c32; 109 int error, errno_save; 110 111 /* 112 * Save errno in case _citrus_iconv_* clobbers it. 113 */ 114 errno_save = errno; 115 116 /* 117 * `If ps is a null pointer, each function uses its own 118 * internal mbstate_t object instead, which is initialized at 119 * program startup to the initial conversion state; the 120 * functions are not required to avoid data races with other 121 * calls to the same function in this case. The 122 * implementation behaves as if no library function calls 123 * these functions with a null pointer for ps.' 124 */ 125 if (ps == NULL) 126 ps = &psbuf; 127 128 /* 129 * `If s is a null pointer, the mbrtoc32 function is equivalent 130 * to the call: 131 * 132 * mbrtoc32(NULL, "", 1, ps) 133 * 134 * In this case, the values of the parameters pc32 and n are 135 * ignored.' 136 */ 137 if (s == NULL) { 138 pc32 = NULL; 139 s = ""; 140 n = 1; 141 } 142 143 /* 144 * Get the private conversion state. 145 */ 146 S = (struct mbrtoc32state *)(void *)ps; 147 148 /* 149 * If input length is zero, the result is always incomplete by 150 * definition. Don't bother with iconv -- we'd have to 151 * disentangle truncated outputs. 152 */ 153 if (n == 0) { 154 len = (size_t)-2; 155 goto out; 156 } 157 158 /* 159 * Reset the destination buffer if this is the initial state. 160 */ 161 if (S->dstleft == 0) 162 S->dstleft = sizeof(S->dstbuf); 163 164 /* 165 * Open an iconv handle to convert locale-dependent multibyte 166 * input to UTF-32LE. 167 */ 168 if ((error = _citrus_iconv_open(&iconv, _PATH_ICONV, 169 nl_langinfo_l(CODESET, loc), "utf-32le")) != 0) { 170 errno = EIO; /* XXX? */ 171 len = (size_t)-1; 172 goto out; 173 } 174 175 /* 176 * Try to iconv a minimal prefix. If we succeed, set len to 177 * the length consumed and goto ok. 178 */ 179 for (len = 0; len < MIN(n, sizeof(S->srcbuf) - S->nsrc);) { 180 const char *src = S->srcbuf; 181 size_t srcleft; 182 char *dst = S->dstbuf + sizeof(S->dstbuf) - S->dstleft; 183 size_t inval; 184 185 S->srcbuf[S->nsrc++] = s[len++]; 186 srcleft = S->nsrc; 187 188 error = _citrus_iconv_convert(iconv, 189 &src, &srcleft, 190 &dst, &S->dstleft, 191 _CITRUS_ICONV_F_HIDE_INVALID, &inval); 192 if (error != EINVAL) { 193 if (error == 0) 194 break; 195 errno = error; 196 len = (size_t)-1; 197 goto out; 198 } 199 } 200 201 /* 202 * If it is still incomplete after trying the whole input 203 * buffer, return (size_t)-2 and let the caller try again. 204 */ 205 if (error) { 206 len = (size_t)-2; 207 goto out; 208 } 209 210 /* 211 * Successfully converted a minimal byte sequence, which should 212 * produce exactly one UTF-32 code unit, encoded in 213 * little-endian, representing a code point. Get the code 214 * point. 215 */ 216 c32 = le32dec(S->dstbuf); 217 218 /* 219 * Reject surrogate code points. We only deal in scalar 220 * values. 221 * 222 * XXX Is this necessary? Won't iconv take care of it for us? 223 */ 224 if (c32 >= 0xd800 && c32 <= 0xdfff) { 225 errno = EILSEQ; 226 len = (size_t)-1; 227 goto out; 228 } 229 230 /* 231 * Non-surrogate code point -- scalar value. Yield it. 232 */ 233 if (pc32) 234 *pc32 = c32; 235 236 /* 237 * If we got the null scalar value, return zero length, as the 238 * contract requires. 239 */ 240 if (c32 == 0) 241 len = 0; 242 243 /* 244 * Make sure we preserve errno on success. 245 */ 246 errno = errno_save; 247 248 out: if (len != (size_t)-2) { 249 S->nsrc = 0; 250 memset(S, 0, sizeof(*S)); /* paranoia */ 251 } 252 errno_save = errno; 253 _citrus_iconv_close(iconv); 254 errno = errno_save; 255 return len; 256 } 257
Indexes created Thu Sep 25 16:09:42 GMT 2025