lib/mbchar.h

   1 /* Multibyte character data type.
   2    Copyright (C) 2001, 2005-2007, 2009-2025 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>.  */
  18
  19 /* A multibyte character is a short subsequence of a char* string,
  20    representing a single 32-bit wide character.
  21
  22    We use multibyte characters instead of 32-bit wide characters because
  23    of the following goals:
  24    1) correct multibyte handling, i.e. operate according to the LC_CTYPE
  25       locale,
  26    2) ease of maintenance, i.e. the maintainer needs not know all details
  27       of the ISO C 99 standard,
  28    3) don't fail grossly if the input is not in the encoding set by the
  29       locale, because often different encodings are in use in the same
  30       countries (ISO-8859-1/UTF-8, EUC-JP/Shift_JIS, ...),
  31    4) fast in the case of ASCII characters.
  32
  33    Multibyte characters are only accessed through the mb* macros.
  34
  35    mb_ptr (mbc)
  36      return a pointer to the beginning of the multibyte sequence.
  37
  38    mb_len (mbc)
  39      returns the number of bytes occupied by the multibyte sequence.
  40      Always > 0.
  41
  42    mb_iseq (mbc, sc)
  43      returns true if mbc is the standard ASCII character sc.
  44
  45    mb_isnul (mbc)
  46      returns true if mbc is the nul character.
  47
  48    mb_cmp (mbc1, mbc2)
  49      returns a positive, zero, or negative value depending on whether mbc1
  50      sorts after, same or before mbc2.
  51
  52    mb_casecmp (mbc1, mbc2)
  53      returns a positive, zero, or negative value depending on whether mbc1
  54      sorts after, same or before mbc2, modulo upper/lowercase conversion.
  55
  56    mb_equal (mbc1, mbc2)
  57      returns true if mbc1 and mbc2 are equal.
  58
  59    mb_caseequal (mbc1, mbc2)
  60      returns true if mbc1 and mbc2 are equal modulo upper/lowercase conversion.
  61
  62    mb_isalnum (mbc)
  63      returns true if mbc is alphanumeric.
  64
  65    mb_isalpha (mbc)
  66      returns true if mbc is alphabetic.
  67
  68    mb_isascii(mbc)
  69      returns true if mbc is plain ASCII.
  70
  71    mb_isblank (mbc)
  72      returns true if mbc is a blank.
  73
  74    mb_iscntrl (mbc)
  75      returns true if mbc is a control character.
  76
  77    mb_isdigit (mbc)
  78      returns true if mbc is a decimal digit.
  79
  80    mb_isgraph (mbc)
  81      returns true if mbc is a graphic character.
  82
  83    mb_islower (mbc)
  84      returns true if mbc is lowercase.
  85
  86    mb_isprint (mbc)
  87      returns true if mbc is a printable character.
  88
  89    mb_ispunct (mbc)
  90      returns true if mbc is a punctuation character.
  91
  92    mb_isspace (mbc)
  93      returns true if mbc is a space character.
  94
  95    mb_isupper (mbc)
  96      returns true if mbc is uppercase.
  97
  98    mb_isxdigit (mbc)
  99      returns true if mbc is a hexadecimal digit.
 100
 101    mb_width (mbc)
 102      returns the number of columns on the output device occupied by mbc.
 103      Always >= 0.
 104
 105    mb_putc (mbc, stream)
 106      outputs mbc on stream, a byte oriented FILE stream opened for output.
 107
 108    mb_setascii (&mbc, sc)
 109      assigns the standard ASCII character sc to mbc.
 110      (Only available if the 'mbfile' module is in use.)
 111
 112    mb_copy (&destmbc, &srcmbc)
 113      copies srcmbc to destmbc.
 114
 115    Here are the function prototypes of the macros.
 116
 117    extern const char *  mb_ptr (const mbchar_t mbc);
 118    extern size_t        mb_len (const mbchar_t mbc);
 119    extern bool          mb_iseq (const mbchar_t mbc, char sc);
 120    extern bool          mb_isnul (const mbchar_t mbc);
 121    extern int           mb_cmp (const mbchar_t mbc1, const mbchar_t mbc2);
 122    extern int           mb_casecmp (const mbchar_t mbc1, const mbchar_t mbc2);
 123    extern bool          mb_equal (const mbchar_t mbc1, const mbchar_t mbc2);
 124    extern bool          mb_caseequal (const mbchar_t mbc1, const mbchar_t mbc2);
 125    extern bool          mb_isalnum (const mbchar_t mbc);
 126    extern bool          mb_isalpha (const mbchar_t mbc);
 127    extern bool          mb_isascii (const mbchar_t mbc);
 128    extern bool          mb_isblank (const mbchar_t mbc);
 129    extern bool          mb_iscntrl (const mbchar_t mbc);
 130    extern bool          mb_isdigit (const mbchar_t mbc);
 131    extern bool          mb_isgraph (const mbchar_t mbc);
 132    extern bool          mb_islower (const mbchar_t mbc);
 133    extern bool          mb_isprint (const mbchar_t mbc);
 134    extern bool          mb_ispunct (const mbchar_t mbc);
 135    extern bool          mb_isspace (const mbchar_t mbc);
 136    extern bool          mb_isupper (const mbchar_t mbc);
 137    extern bool          mb_isxdigit (const mbchar_t mbc);
 138    extern int           mb_width (const mbchar_t mbc);
 139    extern void          mb_putc (const mbchar_t mbc, FILE *stream);
 140    extern void          mb_setascii (mbchar_t *new, char sc);
 141    extern void          mb_copy (mbchar_t *new, const mbchar_t *old);
 142  */
 143
 144 #ifndef _MBCHAR_H
 145 #define _MBCHAR_H 1
 146
 147 /* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE.  */
 148 #if !_GL_CONFIG_H_INCLUDED
 149  #error "Please include config.h first."
 150 #endif
 151
 152 #include <string.h>
 153 #include <uchar.h>
 154
 155 _GL_INLINE_HEADER_BEGIN
 156 #ifndef MBCHAR_INLINE
 157 # define MBCHAR_INLINE _GL_INLINE
 158 #endif
 159
 160 #ifdef __cplusplus
 161 extern "C" {
 162 #endif
 163
 164
 165 /* The longest multibyte characters, nowadays, are 4 bytes long.
 166    Regardless of the values of MB_CUR_MAX and MB_LEN_MAX.  */
 167 #define MBCHAR_BUF_SIZE 4
 168
 169 struct mbchar
 170 {
 171   const char *ptr;      /* pointer to current character */
 172   size_t bytes;         /* number of bytes of current character, > 0 */
 173   bool wc_valid;        /* true if wc is a valid 32-bit wide character */
 174   char32_t wc;          /* if wc_valid: the current character */
 175 #if defined GNULIB_MBFILE
 176   char buf[MBCHAR_BUF_SIZE]; /* room for the bytes, used for file input only */
 177 #endif
 178 };
 179
 180 /* EOF (not a real character) is represented with bytes = 0 and
 181    wc_valid = false.  */
 182
 183 typedef struct mbchar mbchar_t;
 184
 185 /* Access the current character.  */
 186 #define mb_ptr(mbc) ((mbc).ptr)
 187 #define mb_len(mbc) ((mbc).bytes)
 188
 189 /* Comparison of characters.  */
 190 #define mb_iseq(mbc, sc) ((mbc).wc_valid && (mbc).wc == (sc))
 191 #define mb_isnul(mbc) ((mbc).wc_valid && (mbc).wc == 0)
 192 #define mb_cmp(mbc1, mbc2) \
 193   ((mbc1).wc_valid                                                      \
 194    ? ((mbc2).wc_valid                                                   \
 195       ? _GL_CMP ((mbc1).wc, (mbc2).wc)                                  \
 196       : -1)                                                             \
 197    : ((mbc2).wc_valid                                                   \
 198       ? 1                                                               \
 199       : (mbc1).bytes == (mbc2).bytes                                    \
 200         ? memcmp ((mbc1).ptr, (mbc2).ptr, (mbc1).bytes)                 \
 201         : (mbc1).bytes < (mbc2).bytes                                   \
 202           ? (memcmp ((mbc1).ptr, (mbc2).ptr, (mbc1).bytes) > 0 ? 1 : -1) \
 203           : (memcmp ((mbc1).ptr, (mbc2).ptr, (mbc2).bytes) >= 0 ? 1 : -1)))
 204 #define mb_casecmp(mbc1, mbc2) \
 205   ((mbc1).wc_valid                                                      \
 206    ? ((mbc2).wc_valid                                                   \
 207       ? _GL_CMP (c32tolower ((mbc1).wc), c32tolower ((mbc2).wc))        \
 208       : -1)                                                             \
 209    : ((mbc2).wc_valid                                                   \
 210       ? 1                                                               \
 211       : (mbc1).bytes == (mbc2).bytes                                    \
 212         ? memcmp ((mbc1).ptr, (mbc2).ptr, (mbc1).bytes)                 \
 213         : (mbc1).bytes < (mbc2).bytes                                   \
 214           ? (memcmp ((mbc1).ptr, (mbc2).ptr, (mbc1).bytes) > 0 ? 1 : -1) \
 215           : (memcmp ((mbc1).ptr, (mbc2).ptr, (mbc2).bytes) >= 0 ? 1 : -1)))
 216 #define mb_equal(mbc1, mbc2) \
 217   ((mbc1).wc_valid && (mbc2).wc_valid                                   \
 218    ? (mbc1).wc == (mbc2).wc                                             \
 219    : (mbc1).bytes == (mbc2).bytes                                       \
 220      && memcmp ((mbc1).ptr, (mbc2).ptr, (mbc1).bytes) == 0)
 221 #define mb_caseequal(mbc1, mbc2) \
 222   ((mbc1).wc_valid && (mbc2).wc_valid                                   \
 223    ? c32tolower ((mbc1).wc) == c32tolower ((mbc2).wc)                   \
 224    : (mbc1).bytes == (mbc2).bytes                                       \
 225      && memcmp ((mbc1).ptr, (mbc2).ptr, (mbc1).bytes) == 0)
 226
 227 /* <ctype.h>, <wctype.h> classification.  */
 228 #define mb_isascii(mbc) \
 229   ((mbc).wc_valid && (mbc).wc >= 0 && (mbc).wc <= 127)
 230 #define mb_isalnum(mbc) ((mbc).wc_valid && c32isalnum ((mbc).wc))
 231 #define mb_isalpha(mbc) ((mbc).wc_valid && c32isalpha ((mbc).wc))
 232 #define mb_isblank(mbc) ((mbc).wc_valid && c32isblank ((mbc).wc))
 233 #define mb_iscntrl(mbc) ((mbc).wc_valid && c32iscntrl ((mbc).wc))
 234 #define mb_isdigit(mbc) ((mbc).wc_valid && c32isdigit ((mbc).wc))
 235 #define mb_isgraph(mbc) ((mbc).wc_valid && c32isgraph ((mbc).wc))
 236 #define mb_islower(mbc) ((mbc).wc_valid && c32islower ((mbc).wc))
 237 #define mb_isprint(mbc) ((mbc).wc_valid && c32isprint ((mbc).wc))
 238 #define mb_ispunct(mbc) ((mbc).wc_valid && c32ispunct ((mbc).wc))
 239 #define mb_isspace(mbc) ((mbc).wc_valid && c32isspace ((mbc).wc))
 240 #define mb_isupper(mbc) ((mbc).wc_valid && c32isupper ((mbc).wc))
 241 #define mb_isxdigit(mbc) ((mbc).wc_valid && c32isxdigit ((mbc).wc))
 242
 243 /* Extra <wchar.h> function.  */
 244
 245 /* Unprintable characters appear as a small box of width 1.  */
 246 #define MB_UNPRINTABLE_WIDTH 1
 247
 248 MBCHAR_INLINE int
 249 mb_width_aux (char32_t wc)
 250 {
 251   int w = c32width (wc);
 252   /* For unprintable characters, arbitrarily return 0 for control characters
 253      and MB_UNPRINTABLE_WIDTH otherwise.  */
 254   return (w >= 0 ? w : c32iscntrl (wc) ? 0 : MB_UNPRINTABLE_WIDTH);
 255 }
 256
 257 #define mb_width(mbc) \
 258   ((mbc).wc_valid ? mb_width_aux ((mbc).wc) : MB_UNPRINTABLE_WIDTH)
 259
 260 /* Output.  */
 261 #define mb_putc(mbc, stream)  fwrite ((mbc).ptr, 1, (mbc).bytes, (stream))
 262
 263 #if defined GNULIB_MBFILE
 264 /* Assignment.  */
 265 # define mb_setascii(mbc, sc) \
 266    ((mbc)->ptr = (mbc)->buf, (mbc)->bytes = 1, (mbc)->wc_valid = 1, \
 267     (mbc)->wc = (mbc)->buf[0] = (sc))
 268 #endif
 269
 270 /* Copying a character.  */
 271 MBCHAR_INLINE void
 272 mb_copy (mbchar_t *new_mbc, const mbchar_t *old_mbc)
 273 {
 274 #if defined GNULIB_MBFILE
 275   if (old_mbc->ptr == &old_mbc->buf[0])
 276     {
 277       memcpy (&new_mbc->buf[0], &old_mbc->buf[0], old_mbc->bytes);
 278       new_mbc->ptr = &new_mbc->buf[0];
 279     }
 280   else
 281 #endif
 282     new_mbc->ptr = old_mbc->ptr;
 283   new_mbc->bytes = old_mbc->bytes;
 284   if ((new_mbc->wc_valid = old_mbc->wc_valid))
 285     new_mbc->wc = old_mbc->wc;
 286 }
 287
 288
 289 /* is_basic(c) tests whether the single-byte character c is
 290    - in the ISO C "basic character set" or is one of '@', '$', and '`'
 291      which ISO C 23 § 5.2.1.1.(1) guarantees to be single-byte and in
 292      practice are safe to treat as basic in the execution character set,
 293      or
 294    - in the POSIX "portable character set", which
 295      <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap06.html>
 296      equally guarantees to be single-byte.
 297    This is a convenience function, and is in this file only to share code
 298    between mbiter.h, mbuiter.h, and mbfile.h.  */
 299 #if (' ' == 32) && ('!' == 33) && ('"' == 34) && ('#' == 35) \
 300     && ('$' == 36) && ('%' == 37) && ('&' == 38) && ('\'' == 39) \
 301     && ('(' == 40) && (')' == 41) && ('*' == 42) && ('+' == 43) \
 302     && (',' == 44) && ('-' == 45) && ('.' == 46) && ('/' == 47) \
 303     && ('0' == 48) && ('1' == 49) && ('2' == 50) && ('3' == 51) \
 304     && ('4' == 52) && ('5' == 53) && ('6' == 54) && ('7' == 55) \
 305     && ('8' == 56) && ('9' == 57) && (':' == 58) && (';' == 59) \
 306     && ('<' == 60) && ('=' == 61) && ('>' == 62) && ('?' == 63) \
 307     && ('@' == 64) && ('A' == 65) && ('B' == 66) && ('C' == 67) \
 308     && ('D' == 68) && ('E' == 69) && ('F' == 70) && ('G' == 71) \
 309     && ('H' == 72) && ('I' == 73) && ('J' == 74) && ('K' == 75) \
 310     && ('L' == 76) && ('M' == 77) && ('N' == 78) && ('O' == 79) \
 311     && ('P' == 80) && ('Q' == 81) && ('R' == 82) && ('S' == 83) \
 312     && ('T' == 84) && ('U' == 85) && ('V' == 86) && ('W' == 87) \
 313     && ('X' == 88) && ('Y' == 89) && ('Z' == 90) && ('[' == 91) \
 314     && ('\\' == 92) && (']' == 93) && ('^' == 94) && ('_' == 95) \
 315     && ('`' == 96) && ('a' == 97) && ('b' == 98) && ('c' == 99) \
 316     && ('d' == 100) && ('e' == 101) && ('f' == 102) && ('g' == 103) \
 317     && ('h' == 104) && ('i' == 105) && ('j' == 106) && ('k' == 107) \
 318     && ('l' == 108) && ('m' == 109) && ('n' == 110) && ('o' == 111) \
 319     && ('p' == 112) && ('q' == 113) && ('r' == 114) && ('s' == 115) \
 320     && ('t' == 116) && ('u' == 117) && ('v' == 118) && ('w' == 119) \
 321     && ('x' == 120) && ('y' == 121) && ('z' == 122) && ('{' == 123) \
 322     && ('|' == 124) && ('}' == 125) && ('~' == 126)
 323 /* The character set is ISO-646, not EBCDIC. */
 324 # define IS_BASIC_ASCII 1
 325
 326 /* All locale encodings (see localcharset.h) map the characters 0x00..0x7F
 327    to U+0000..U+007F, like ASCII, except for
 328      CP864      different mapping of '%'
 329      SHIFT_JIS  different mappings of 0x5C, 0x7E
 330      JOHAB      different mapping of 0x5C
 331    However, these characters in the range 0x20..0x7E are in the ISO C
 332    "basic character set" and in the POSIX "portable character set", which
 333    ISO C and POSIX guarantee to be single-byte.  Thus, locales with these
 334    encodings are not POSIX compliant.  And they are most likely not in use
 335    any more (as of 2023).  */
 336 # define is_basic(c) ((unsigned char) (c) < 0x80)
 337
 338 #else
 339
 340 MBCHAR_INLINE bool
 341 is_basic (char c)
 342 {
 343   switch (c)
 344     {
 345     case '\0':
 346     case '\007': case '\010':
 347     case '\t': case '\n': case '\v': case '\f': case '\r':
 348     case ' ': case '!': case '"': case '#': case '$': case '%':
 349     case '&': case '\'': case '(': case ')': case '*':
 350     case '+': case ',': case '-': case '.': case '/':
 351     case '0': case '1': case '2': case '3': case '4':
 352     case '5': case '6': case '7': case '8': case '9':
 353     case ':': case ';': case '<': case '=': case '>':
 354     case '?': case '@':
 355     case 'A': case 'B': case 'C': case 'D': case 'E':
 356     case 'F': case 'G': case 'H': case 'I': case 'J':
 357     case 'K': case 'L': case 'M': case 'N': case 'O':
 358     case 'P': case 'Q': case 'R': case 'S': case 'T':
 359     case 'U': case 'V': case 'W': case 'X': case 'Y':
 360     case 'Z':
 361     case '[': case '\\': case ']': case '^': case '_': case '`':
 362     case 'a': case 'b': case 'c': case 'd': case 'e':
 363     case 'f': case 'g': case 'h': case 'i': case 'j':
 364     case 'k': case 'l': case 'm': case 'n': case 'o':
 365     case 'p': case 'q': case 'r': case 's': case 't':
 366     case 'u': case 'v': case 'w': case 'x': case 'y':
 367     case 'z': case '{': case '|': case '}': case '~':
 368       return 1;
 369     default:
 370       return 0;
 371     }
 372 }
 373
 374 #endif
 375
 376
 377 #ifdef __cplusplus
 378 }
 379 #endif
 380
 381 _GL_INLINE_HEADER_END
 382
 383 #endif /* _MBCHAR_H */