src/character.h

   1 /* Header for multibyte character handler.
   2    Copyright (C) 1995, 1997, 1998 Electrotechnical Laboratory, JAPAN.
   3    Licensed to the Free Software Foundation.
   4    Copyright (C) 2001, 2002
   5      National Institute of Advanced Industrial Science and Technology (AIST)
   6      Registration Number H13PRO009
   7
   8 This file is part of GNU Emacs.
   9
  10 GNU Emacs is free software; you can redistribute it and/or modify
  11 it under the terms of the GNU General Public License as published by
  12 the Free Software Foundation; either version 2, or (at your option)
  13 any later version.
  14
  15 GNU Emacs is distributed in the hope that it will be useful,
  16 but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 GNU General Public License for more details.
  19
  20 You should have received a copy of the GNU General Public License
  21 along with GNU Emacs; see the file COPYING.  If not, write to
  22 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 Boston, MA 02111-1307, USA.  */
  24
  25 #ifndef EMACS_CHARACTER_H
  26 #define EMACS_CHARACTER_H
  27
  28 /* character code       1st byte   byte sequence
  29    --------------       --------   -------------
  30         0-7F            00..7F     0xxxxxxx
  31        80-7FF           C2..DF     110xxxxx 10xxxxxx
  32       800-FFFF          E0..EF     1110xxxx 10xxxxxx 10xxxxxx
  33     10000-1FFFFF        F0..F7     11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
  34    200000-3FFF7F        F8         11111000 1000xxxx 10xxxxxx 10xxxxxx 10xxxxxx
  35       invalid           F9..FF
  36
  37    raw-8-bit
  38    3FFF80-3FFFFF        C0..C1     1100000x 10xxxxxx
  39 */
  40
  41 /* Maximum character code ((1 << CHARACTERBITS) - 1).  */
  42 #define MAX_CHAR  0x3FFFFF
  43
  44 /* Maximum Unicode character code.  */
  45 #define MAX_UNICODE_CHAR 0x10FFFF
  46
  47 /* Maximum N-byte character codes.  */
  48 #define MAX_1_BYTE_CHAR 0x7F
  49 #define MAX_2_BYTE_CHAR 0x7FF
  50 #define MAX_3_BYTE_CHAR 0xFFFF
  51 #define MAX_4_BYTE_CHAR 0x1FFFFF
  52 #define MAX_5_BYTE_CHAR 0x3FFF7F
  53
  54 /* Leading code range of Latin-1 chars.  */
  55 #define LEADING_CODE_LATIN_1_MIN 0xC2
  56 #define LEADING_CODE_LATIN_1_MAX 0xC3
  57
  58 /* Nonzero iff C is a character that corresponds to a raw 8-bit
  59    byte.  */
  60 #define CHAR_BYTE8_P(c) ((c) > MAX_5_BYTE_CHAR)
  61
  62 /* Return the character code for raw 8-bit byte BYTE.  */
  63 #define BYTE8_TO_CHAR(byte) ((byte) + 0x3FFF00)
  64
  65 /* Return the raw 8-bit byte for character C.  */
  66 #define CHAR_TO_BYTE8(c)        \
  67   (CHAR_BYTE8_P (c)             \
  68    ? (c) - 0x3FFF00             \
  69    : multibyte_char_to_unibyte (c, Qnil))
  70
  71 /* Nonzero iff BYTE is the 1st byte of a multibyte form of a character
  72    that corresponds to a raw 8-bit byte.  */
  73 #define CHAR_BYTE8_HEAD_P(byte) ((byte) == 0xC0 || (byte) == 0xC1)
  74
  75 /* Mapping table from unibyte chars to multibyte chars.  */
  76 extern int unibyte_to_multibyte_table[256];
  77
  78 /* Convert the unibyte character C to the corresponding multibyte
  79    character.  If C can't be converted, return C.  */
  80 #define unibyte_char_to_multibyte(c)    \
  81   ((c) < 256 ? unibyte_to_multibyte_table[(c)] : (c))
  82
  83 /* If C is not ASCII, make it unibyte. */
  84 #define MAKE_CHAR_UNIBYTE(c)    \
  85   do {                          \
  86     if (! ASCII_CHAR_P (c))     \
  87       c = CHAR_TO_BYTE8 (c);    \
  88   } while (0)
  89
  90
  91 /* If C is not ASCII, make it multibyte.  It assumes C < 256.  */
  92 #define MAKE_CHAR_MULTIBYTE(c) ((c) = unibyte_to_multibyte_table[(c)])
  93
  94 /* This is the maximum byte length of multibyte form.  */
  95 #define MAX_MULTIBYTE_LENGTH 5
  96
  97 /* Return a Lisp character whose character code is C. */
  98 #define make_char(c) make_number (c)
  99
 100 /* Nonzero iff C is an ASCII byte.  */
 101 #define ASCII_BYTE_P(c) ((unsigned) (c) < 0x80)
 102
 103 /* Nonzero iff X is a character.  */
 104 #define CHARACTERP(x) (NATNUMP (x) && XFASTINT (x) <= MAX_CHAR)
 105
 106 /* Nonzero iff C is valid as a character code.  GENERICP is not used
 107    now.  */
 108 #define CHAR_VALID_P(c, genericp) ((unsigned) (c) <= MAX_CHAR)
 109
 110 /* Check if Lisp object X is a character or not.  */
 111 #define CHECK_CHARACTER(x)                                              \
 112   do {                                                                  \
 113     if (! CHARACTERP(x)) x = wrong_type_argument (Qcharacterp, (x));    \
 114   } while (0)
 115
 116 /* Nonzero iff C is an ASCII character.  */
 117 #define ASCII_CHAR_P(c) ((unsigned) (c) < 0x80)
 118
 119 /* Nonzero iff C is a character of code less than 0x100.  */
 120 #define SINGLE_BYTE_CHAR_P(c) ((unsigned) (c) < 0x100)
 121
 122 /* Nonzero if character C has a printable glyph.  */
 123 #define CHAR_PRINTABLE_P(c)     \
 124   (((c) >= 32 && ((c) < 127)    \
 125     || ! NILP (CHAR_TABLE_REF (Vprintable_chars, (c)))))
 126
 127 /* Return byte length of multibyte form for character C.  */
 128 #define CHAR_BYTES(c)                   \
 129   ( (c) <= MAX_1_BYTE_CHAR ? 1          \
 130     : (c) <= MAX_2_BYTE_CHAR ? 2        \
 131     : (c) <= MAX_3_BYTE_CHAR ? 3        \
 132     : (c) <= MAX_4_BYTE_CHAR ? 4        \
 133     : (c) <= MAX_5_BYTE_CHAR ? 5        \
 134     : 2)
 135
 136
 137 /* Return the leading code of multibyte form of C.  */
 138 #define CHAR_LEADING_CODE(c)                            \
 139   ((c) <= MAX_1_BYTE_CHAR ? c                           \
 140    : (c) <= MAX_2_BYTE_CHAR ? (0xC0 | ((c) >> 6))       \
 141    : (c) <= MAX_3_BYTE_CHAR ? (0xE0 | ((c) >> 12))      \
 142    : (c) <= MAX_4_BYTE_CHAR ? (0xF0 | ((c) >> 18))      \
 143    : (c) <= MAX_5_BYTE_CHAR ? 0xF8                      \
 144    : (0xC0 | (((c) >> 6) & 0x01)))
 145
 146
 147 /* Store multibyte form of the character C in P.  The caller should
 148    allocate at least MAX_MULTIBYTE_LENGTH bytes area at P in advance.
 149    Returns the length of the multibyte form.  */
 150
 151 #define CHAR_STRING(c, p)                       \
 152   ((unsigned) (c) <= MAX_1_BYTE_CHAR            \
 153    ? ((p)[0] = (c),                             \
 154       1)                                        \
 155    : (unsigned) (c) <= MAX_2_BYTE_CHAR          \
 156    ? ((p)[0] = (0xC0 | ((c) >> 6)),             \
 157       (p)[1] = (0x80 | ((c) & 0x3F)),           \
 158       2)                                        \
 159    : (unsigned) (c) <= MAX_3_BYTE_CHAR          \
 160    ? ((p)[0] = (0xE0 | ((c) >> 12)),            \
 161       (p)[1] = (0x80 | (((c) >> 6) & 0x3F)),    \
 162       (p)[2] = (0x80 | ((c) & 0x3F)),           \
 163       3)                                        \
 164    : char_string (c, p))
 165
 166 /* Store multibyte form of byte B in P.  The caller should allocate at
 167    least MAX_MULTIBYTE_LENGTH bytes area at P in advance.  Returns the
 168    length of the multibyte form.  */
 169
 170 #define BYTE8_STRING(b, p)                      \
 171   ((p)[0] = (0xC0 | (((b) >> 6) & 0x01)),       \
 172    (p)[1] = (0x80 | ((c) & 0x3F)),              \
 173    2)
 174
 175
 176 /* Store multibyte form of the character C in P.  The caller should
 177    allocate at least MAX_MULTIBYTE_LENGTH bytes area at P in advance.
 178    And, advance P to the end of the multibyte form.  */
 179
 180 #define CHAR_STRING_ADVANCE(c, p)               \
 181   do {                                          \
 182     if ((c) <= MAX_1_BYTE_CHAR)                 \
 183       *(p)++ = (c);                             \
 184     else if ((c) <= MAX_2_BYTE_CHAR)            \
 185       *(p)++ = (0xC0 | ((c) >> 6)),             \
 186         *(p)++ = (0x80 | ((c) & 0x3F));         \
 187     else if ((c) <= MAX_3_BYTE_CHAR)            \
 188       *(p)++ = (0xE0 | ((c) >> 12)),            \
 189         *(p)++ = (0x80 | (((c) >> 6) & 0x3F)),  \
 190         *(p)++ = (0x80 | ((c) & 0x3F));         \
 191     else                                        \
 192       (p) += char_string ((c), (p));            \
 193   } while (0)
 194
 195
 196 /* Nonzero iff BYTE starts a non-ASCII character in a multibyte
 197    form.  */
 198 #define LEADING_CODE_P(byte) (((byte) & 0xC0) == 0xC0)
 199
 200 /* Nonzero iff BYTE is a trailing code of a non-ASCII character in a
 201    multibyte form.  */
 202 #define TRAILING_CODE_P(byte) (((byte) & 0xC0) == 0x80)
 203
 204 /* Nonzero iff BYTE starts a character in a multibyte form.
 205    This is equivalent to:
 206         (ASCII_BYTE_P (byte) || LEADING_CODE_P (byte))  */
 207 #define CHAR_HEAD_P(byte) (((byte) & 0xC0) != 0x80)
 208
 209 /* Just kept for backward compatibility.  This macro will be removed
 210    in the future.  */
 211 #define BASE_LEADING_CODE_P LEADING_CODE_P
 212
 213 /* How many bytes a character that starts with BYTE occupies in a
 214    multibyte form.  */
 215 #define BYTES_BY_CHAR_HEAD(byte)        \
 216   (!((byte) & 0x80) ? 1                 \
 217    : !((byte) & 0x20) ? 2               \
 218    : !((byte) & 0x10) ? 3               \
 219    : !((byte) & 0x08) ? 4               \
 220    : 5)
 221
 222
 223 /* Return the length of the multi-byte form at string STR of length
 224    LEN while assuming that STR points a valid multi-byte form.  As
 225    this macro isn't necessary anymore, all callers will be changed to
 226    use BYTES_BY_CHAR_HEAD directly in the future.  */
 227
 228 #define MULTIBYTE_FORM_LENGTH(str, len)         \
 229   BYTES_BY_CHAR_HEAD (*(str))
 230
 231 /* Parse multibyte string STR of length LENGTH and set BYTES to the
 232    byte length of a character at STR while assuming that STR points a
 233    valid multibyte form.  As this macro isn't necessary anymore, all
 234    callers will be changed to use BYTES_BY_CHAR_HEAD directly in the
 235    future.  */
 236
 237 #define PARSE_MULTIBYTE_SEQ(str, length, bytes) \
 238   (bytes) = BYTES_BY_CHAR_HEAD (*(str))
 239
 240 /* The byte length of multibyte form at unibyte string P ending at
 241    PEND.  If STR doesn't point a valid multibyte form, return 0.  */
 242
 243 #define MULTIBYTE_LENGTH(p, pend)                               \
 244   (p >= pend ? 0                                                \
 245    : !((p)[0] & 0x80) ? 1                                       \
 246    : ((p + 1 >= pend) || (((p)[1] & 0xC0) != 0x80)) ? 0         \
 247    : ((p)[0] & 0xE0) == 0xC0 ? 2                                \
 248    : ((p + 2 >= pend) || (((p)[2] & 0xC0) != 0x80)) ? 0         \
 249    : ((p)[0] & 0xF0) == 0xE0 ? 3                                \
 250    : ((p + 3 >= pend) || (((p)[3] & 0xC0) != 0x80)) ? 0         \
 251    : ((p)[0] & 0xF8) == 0xF0 ? 4                                \
 252    : ((p + 4 >= pend) || (((p)[4] & 0xC0) != 0x80)) ? 0         \
 253    : (p)[0] == 0xF8 && ((p)[1] & 0xF0) == 0x80 ? 5              \
 254    : 0)
 255
 256
 257 /* Like MULTIBYTE_LENGTH but don't check the ending address.  */
 258
 259 #define MULTIBYTE_LENGTH_NO_CHECK(p)                    \
 260   (!((p)[0] & 0x80) ? 1                                 \
 261    : ((p)[1] & 0xC0) != 0x80 ? 0                        \
 262    : ((p)[0] & 0xE0) == 0xC0 ? 2                        \
 263    : ((p)[2] & 0xC0) != 0x80 ? 0                        \
 264    : ((p)[0] & 0xF0) == 0xE0 ? 3                        \
 265    : ((p)[3] & 0xC0) != 0x80 ? 0                        \
 266    : ((p)[0] & 0xF8) == 0xF0 ? 4                        \
 267    : ((p)[4] & 0xC0) != 0x80 ? 0                        \
 268    : (p)[0] == 0xF8 && ((p)[1] & 0xF0) == 0x80 ? 5      \
 269    : 0)
 270
 271
 272 /* Return the character code of character whose multibyte form is at
 273    P.  The argument LEN is ignored.  It will be removed in the
 274    future.  */
 275
 276 #define STRING_CHAR(p, len)                                     \
 277   (!((p)[0] & 0x80)                                             \
 278    ? (p)[0]                                                     \
 279    : ! ((p)[0] & 0x20)                                          \
 280    ? (((((p)[0] & 0x1F) << 6)                                   \
 281        | ((p)[1] & 0x3F))                                       \
 282       + (((unsigned char) (p)[0]) < 0xC2 ? 0x3FFF80 : 0))       \
 283    : ! ((p)[0] & 0x10)                                          \
 284    ? ((((p)[0] & 0x0F) << 12)                                   \
 285       | (((p)[1] & 0x3F) << 6)                                  \
 286       | ((p)[2] & 0x3F))                                        \
 287    : string_char ((p), NULL, NULL))
 288
 289
 290 /* Like STRING_CHAR but set ACTUAL_LEN to the length of multibyte
 291    form.  The argument LEN is ignored.  It will be removed in the
 292    future.  */
 293
 294 #define STRING_CHAR_AND_LENGTH(p, len, actual_len)              \
 295   (!((p)[0] & 0x80)                                             \
 296    ? ((actual_len) = 1, (p)[0])                                 \
 297    : ! ((p)[0] & 0x20)                                          \
 298    ? ((actual_len) = 2,                                         \
 299       (((((p)[0] & 0x1F) << 6)                                  \
 300         | ((p)[1] & 0x3F))                                      \
 301        + (((unsigned char) (p)[0]) < 0xC2 ? 0x3FFF80 : 0)))     \
 302    : ! ((p)[0] & 0x10)                                          \
 303    ? ((actual_len) = 3,                                         \
 304       ((((p)[0] & 0x0F) << 12)                                  \
 305        | (((p)[1] & 0x3F) << 6)                                 \
 306        | ((p)[2] & 0x3F)))                                      \
 307    : string_char ((p), NULL, &actual_len))
 308
 309
 310 /* Like STRING_CHAR but advacen P to the end of multibyte form.  */
 311
 312 #define STRING_CHAR_ADVANCE(p)                                  \
 313   (!((p)[0] & 0x80)                                             \
 314    ? *(p)++                                                     \
 315    : ! ((p)[0] & 0x20)                                          \
 316    ? ((p) += 2,                                                 \
 317       ((((p)[-2] & 0x1F) << 6)                                  \
 318        | ((p)[-1] & 0x3F)                                       \
 319        | (((unsigned char) (p)[-2]) < 0xC2 ? 0x3FFF80 : 0)))    \
 320    : ! ((p)[0] & 0x10)                                          \
 321    ? ((p) += 3,                                                 \
 322       ((((p)[-3] & 0x0F) << 12)                                 \
 323        | (((p)[-2] & 0x3F) << 6)                                \
 324        | ((p)[-1] & 0x3F)))                                     \
 325    : string_char ((p), &(p), NULL))
 326
 327
 328 /* Fetch the "next" character from Lisp string STRING at byte position
 329    BYTEIDX, character position CHARIDX.  Store it into OUTPUT.
 330
 331    All the args must be side-effect-free.
 332    BYTEIDX and CHARIDX must be lvalues;
 333    we increment them past the character fetched.  */
 334
 335 #define FETCH_STRING_CHAR_ADVANCE(OUTPUT, STRING, CHARIDX, BYTEIDX)     \
 336   if (1)                                                                \
 337     {                                                                   \
 338       CHARIDX++;                                                        \
 339       if (STRING_MULTIBYTE (STRING))                                    \
 340         {                                                               \
 341           unsigned char *ptr = &XSTRING (STRING)->data[BYTEIDX];        \
 342           int len;                                                      \
 343                                                                         \
 344           OUTPUT = STRING_CHAR_AND_LENGTH (ptr, 0, len);                \
 345           BYTEIDX += len;                                               \
 346         }                                                               \
 347       else                                                              \
 348         OUTPUT = XSTRING (STRING)->data[BYTEIDX++];                     \
 349     }                                                                   \
 350   else
 351
 352 /* Like FETCH_STRING_CHAR_ADVANCE */
 353
 354 #define FETCH_STRING_CHAR_AS_MULTIBYTE_ADVANCE(OUTPUT, STRING, CHARIDX, BYTEIDX) \
 355   if (1)                                                                      \
 356     {                                                                         \
 357       CHARIDX++;                                                              \
 358       if (STRING_MULTIBYTE (STRING))                                          \
 359         {                                                                     \
 360           unsigned char *ptr = &XSTRING (STRING)->data[BYTEIDX];              \
 361           int len;                                                            \
 362                                                                               \
 363           OUTPUT = STRING_CHAR_AND_LENGTH (ptr, 0, len);                      \
 364           BYTEIDX += len;                                                     \
 365         }                                                                     \
 366       else                                                                    \
 367         {                                                                     \
 368           OUTPUT = XSTRING (STRING)->data[BYTEIDX++];                         \
 369           MAKE_CHAR_MULTIBYTE (OUTPUT);                                       \
 370         }                                                                     \
 371     }                                                                         \
 372   else
 373
 374
 375 /* Like FETCH_STRING_CHAR_ADVANCE but assumes STRING is multibyte.  */
 376
 377 #define FETCH_STRING_CHAR_ADVANCE_NO_CHECK(OUTPUT, STRING, CHARIDX, BYTEIDX) \
 378   if (1)                                                                     \
 379     {                                                                        \
 380       unsigned char *ptr = &XSTRING (STRING)->data[BYTEIDX];                 \
 381       int len;                                                               \
 382                                                                              \
 383       OUTPUT = STRING_CHAR_AND_LENGTH (ptr, 0, len);                         \
 384       BYTEIDX += len;                                                        \
 385       CHARIDX++;                                                             \
 386     }                                                                        \
 387   else
 388
 389
 390 /* Like FETCH_STRING_CHAR_ADVANCE but fetch character from the current
 391    buffer.  */
 392
 393 #define FETCH_CHAR_ADVANCE(OUTPUT, CHARIDX, BYTEIDX)            \
 394   if (1)                                                        \
 395     {                                                           \
 396       CHARIDX++;                                                \
 397       if (!NILP (current_buffer->enable_multibyte_characters))  \
 398         {                                                       \
 399           unsigned char *ptr = BYTE_POS_ADDR (BYTEIDX);         \
 400           int len;                                              \
 401                                                                 \
 402           OUTPUT= STRING_CHAR_AND_LENGTH (ptr, 0, len);         \
 403           BYTEIDX += len;                                       \
 404         }                                                       \
 405       else                                                      \
 406         {                                                       \
 407           OUTPUT = *(BYTE_POS_ADDR (BYTEIDX));                  \
 408           BYTEIDX++;                                            \
 409         }                                                       \
 410     }                                                           \
 411   else
 412
 413
 414 /* Like FETCH_CHAR_ADVANCE but assumes STRING is multibyte.  */
 415
 416 #define FETCH_CHAR_ADVANCE_NO_CHECK(OUTPUT, CHARIDX, BYTEIDX)   \
 417   if (1)                                                        \
 418     {                                                           \
 419       unsigned char *ptr = BYTE_POS_ADDR (BYTEIDX);             \
 420       int len;                                                  \
 421                                                                 \
 422       OUTPUT= STRING_CHAR_AND_LENGTH (ptr, 0, len);             \
 423       BYTEIDX += len;                                           \
 424       CHARIDX++;                                                \
 425     }                                                           \
 426   else
 427
 428
 429 /* Increase the buffer byte position POS_BYTE of the current buffer to
 430    the next character boundary.  No range checking of POS.  */
 431
 432 #define INC_POS(pos_byte)                               \
 433   do {                                                  \
 434     unsigned char *p = BYTE_POS_ADDR (pos_byte);        \
 435     pos_byte += BYTES_BY_CHAR_HEAD (*p);                \
 436   } while (0)
 437
 438
 439 /* Decrease the buffer byte position POS_BYTE of the current buffer to
 440    the previous character boundary.  No range checking of POS.  */
 441
 442 #define DEC_POS(pos_byte)                       \
 443   do {                                          \
 444     unsigned char *p;                           \
 445                                                 \
 446     pos_byte--;                                 \
 447     if (pos_byte < GPT_BYTE)                    \
 448       p = BEG_ADDR + pos_byte - 1;              \
 449     else                                        \
 450       p = BEG_ADDR + GAP_SIZE + pos_byte - 1;   \
 451     while (!CHAR_HEAD_P (*p))                   \
 452       {                                         \
 453         p--;                                    \
 454         pos_byte--;                             \
 455       }                                         \
 456   } while (0)
 457
 458 /* Increment both CHARPOS and BYTEPOS, each in the appropriate way.  */
 459
 460 #define INC_BOTH(charpos, bytepos)                              \
 461   do                                                            \
 462     {                                                           \
 463       (charpos)++;                                              \
 464       if (NILP (current_buffer->enable_multibyte_characters))   \
 465         (bytepos)++;                                            \
 466       else                                                      \
 467         INC_POS ((bytepos));                                    \
 468     }                                                           \
 469   while (0)
 470
 471
 472 /* Decrement both CHARPOS and BYTEPOS, each in the appropriate way.  */
 473
 474 #define DEC_BOTH(charpos, bytepos)                              \
 475   do                                                            \
 476     {                                                           \
 477       (charpos)--;                                              \
 478       if (NILP (current_buffer->enable_multibyte_characters))   \
 479         (bytepos)--;                                            \
 480       else                                                      \
 481         DEC_POS ((bytepos));                                    \
 482     }                                                           \
 483   while (0)
 484
 485
 486 /* Increase the buffer byte position POS_BYTE of the current buffer to
 487    the next character boundary.  This macro relies on the fact that
 488    *GPT_ADDR and *Z_ADDR are always accessible and the values are
 489    '\0'.  No range checking of POS_BYTE.  */
 490
 491 #define BUF_INC_POS(buf, pos_byte)                              \
 492   do {                                                          \
 493     unsigned char *p = BUF_BYTE_ADDRESS (buf, pos_byte);        \
 494     pos_byte += BYTES_BY_CHAR_HEAD (*p);                        \
 495   } while (0)
 496
 497
 498 /* Decrease the buffer byte position POS_BYTE of the current buffer to
 499    the previous character boundary.  No range checking of POS_BYTE.  */
 500
 501 #define BUF_DEC_POS(buf, pos_byte)                                      \
 502   do {                                                                  \
 503     unsigned char *p;                                                   \
 504     pos_byte--;                                                         \
 505     if (pos_byte < BUF_GPT_BYTE (buf))                                  \
 506       p = BUF_BEG_ADDR (buf) + pos_byte - 1;                            \
 507     else                                                                \
 508       p = BUF_BEG_ADDR (buf) + BUF_GAP_SIZE (buf) + pos_byte - 1;       \
 509     while (!CHAR_HEAD_P (*p))                                           \
 510       {                                                                 \
 511         p--;                                                            \
 512         pos_byte--;                                                     \
 513       }                                                                 \
 514   } while (0)
 515
 516
 517 #define MAYBE_UNIFY_CHAR(c)                                     \
 518   if (c > MAX_UNICODE_CHAR                                      \
 519       && CHAR_TABLE_P (Vchar_unify_table))                      \
 520     {                                                           \
 521       Lisp_Object val;                                          \
 522       int unified;                                              \
 523                                                                 \
 524       val = CHAR_TABLE_REF (Vchar_unify_table, c);              \
 525       if (! NILP (val))                                         \
 526         {                                                       \
 527           if (SYMBOLP (val))                                    \
 528             {                                                   \
 529               Funify_charset (val, Qnil, Qnil);                 \
 530               val = CHAR_TABLE_REF (Vchar_unify_table, c);      \
 531             }                                                   \
 532           if ((unified = XINT (val)) >= 0)                      \
 533             c = unified;                                        \
 534         }                                                       \
 535     }                                                           \
 536   else
 537
 538
 539 /* Return the width of ASCII character C.  The width is measured by
 540    how many columns occupied on the screen when displayed in the
 541    current buffer.  */
 542
 543 #define ASCII_CHAR_WIDTH(c)                                             \
 544   (c < 0x20                                                             \
 545    ? (c == '\t'                                                         \
 546       ? XFASTINT (current_buffer->tab_width)                            \
 547       : (c == '\n' ? 0 : (NILP (current_buffer->ctl_arrow) ? 4 : 2)))   \
 548    : (c < 0x7f                                                          \
 549       ? 1                                                               \
 550       : ((NILP (current_buffer->ctl_arrow) ? 4 : 2))))
 551
 552 /* Return the width of character C.  The width is measured by how many
 553    columns occupied on the screen when displayed in the current
 554    buffer.  */
 555
 556 #define CHAR_WIDTH(c)           \
 557   (ASCII_CHAR_P (c)             \
 558    ? ASCII_CHAR_WIDTH (c)       \
 559    : XINT (CHAR_TABLE_REF (Vchar_width_table, c)))
 560
 561 extern int char_resolve_modifier_mask P_ ((int));
 562 extern int char_string P_ ((int, unsigned char *));
 563 extern int string_char P_ ((const unsigned char *,
 564                             const unsigned char **, int *));
 565
 566 extern int translate_char P_ ((Lisp_Object, int c));
 567 extern int char_printable_p P_ ((int c));
 568 extern void parse_str_as_multibyte P_ ((unsigned char *, int, int *, int *));
 569 extern int parse_str_to_multibyte P_ ((unsigned char *, int));
 570 extern int str_as_multibyte P_ ((unsigned char *, int, int, int *));
 571 extern int str_to_multibyte P_ ((unsigned char *, int, int));
 572 extern int str_as_unibyte P_ ((unsigned char *, int));
 573 extern int strwidth P_ ((unsigned char *, int));
 574 extern int c_string_width P_ ((unsigned char *, int, int, int *, int *));
 575 extern int lisp_string_width P_ ((Lisp_Object, int, int *, int *));
 576
 577 extern Lisp_Object Vprintable_chars;
 578
 579 extern Lisp_Object Qcharacterp, Qauto_fill_chars;
 580 extern Lisp_Object Vtranslation_table_vector;
 581 extern Lisp_Object Vchar_width_table;
 582 extern Lisp_Object Vchar_direction_table;
 583 extern Lisp_Object Vchar_unify_table;
 584
 585 extern Lisp_Object string_escape_byte8 P_ ((Lisp_Object));
 586
 587 /* Return a translation table of id number ID.  */
 588 #define GET_TRANSLATION_TABLE(id) \
 589   (XCDR(XVECTOR(Vtranslation_table_vector)->contents[(id)]))
 590
 591 /* A char-table for characters which may invoke auto-filling.  */
 592 extern Lisp_Object Vauto_fill_chars;
 593
 594 extern Lisp_Object Vchar_script_table;
 595
 596 /* Copy LEN bytes from FROM to TO.  This macro should be used only
 597    when a caller knows that LEN is short and the obvious copy loop is
 598    faster than calling bcopy which has some overhead.  Copying a
 599    multibyte sequence of a character is the typical case.  */
 600
 601 #define BCOPY_SHORT(from, to, len)              \
 602   do {                                          \
 603     int i = len;                                \
 604     unsigned char *from_p = from, *to_p = to;   \
 605     while (i--) *to_p++ = *from_p++;            \
 606   } while (0)
 607
 608 #define DEFSYM(sym, name)       \
 609   do { (sym) = intern ((name)); staticpro (&(sym)); } while (0)
 610
 611 #endif /* EMACS_CHARACTER_H */