src/buffer.h

   1 /* Header file for the buffer manipulation primitives.
   2    Copyright (C) 1985, 86, 93, 94, 95, 97, 1998 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 /* Accessing the parameters of the current buffer.  */
  23
  24 /* These macros come in pairs, one for the char position
  25    and one for the byte position.  */
  26
  27 /* Position of beginning of buffer.  */
  28 #define BEG (1)
  29 #define BEG_BYTE (1)
  30
  31 /* Position of beginning of accessible range of buffer.  */
  32 #define BEGV (current_buffer->begv)
  33 #define BEGV_BYTE (current_buffer->begv_byte)
  34
  35 /* Position of point in buffer.  The "+ 0" makes this
  36    not an l-value, so you can't assign to it.  Use SET_PT instead.  */
  37 #define PT (current_buffer->pt + 0)
  38 #define PT_BYTE (current_buffer->pt_byte + 0)
  39
  40 /* Position of gap in buffer.  */
  41 #define GPT (current_buffer->text->gpt)
  42 #define GPT_BYTE (current_buffer->text->gpt_byte)
  43
  44 /* Position of end of accessible range of buffer.  */
  45 #define ZV (current_buffer->zv)
  46 #define ZV_BYTE (current_buffer->zv_byte)
  47
  48 /* Position of end of buffer.  */
  49 #define Z (current_buffer->text->z)
  50 #define Z_BYTE (current_buffer->text->z_byte)
  51
  52 /* Macros for the addresses of places in the buffer.  */
  53
  54 /* Address of beginning of buffer.  */
  55 #define BEG_ADDR (current_buffer->text->beg)
  56
  57 /* Address of beginning of accessible range of buffer.  */
  58 #define BEGV_ADDR (BYTE_POS_ADDR (current_buffer->begv_byte))
  59
  60 /* Address of point in buffer.  */
  61 #define PT_ADDR (BYTE_POS_ADDR (current_buffer->pt_byte))
  62
  63 /* Address of beginning of gap in buffer.  */
  64 #define GPT_ADDR (current_buffer->text->beg + current_buffer->text->gpt_byte - 1)
  65
  66 /* Address of end of gap in buffer.  */
  67 #define GAP_END_ADDR (current_buffer->text->beg + current_buffer->text->gpt_byte + current_buffer->text->gap_size - 1)
  68
  69 /* Address of end of accessible range of buffer.  */
  70 #define ZV_ADDR (BYTE_POS_ADDR (current_buffer->zv_byte))
  71
  72 /* Address of end of buffer.  */
  73 #define Z_ADDR (current_buffer->text->beg + current_buffer->text->gap_size + current_buffer->text->z_byte - 1)
  74
  75 /* Size of gap.  */
  76 #define GAP_SIZE (current_buffer->text->gap_size)
  77
  78 /* Is the current buffer narrowed?  */
  79 #define NARROWED        ((BEGV != BEG) || (ZV != Z))
  80
  81 /* Modification count.  */
  82 #define MODIFF (current_buffer->text->modiff)
  83
  84 /* Overlay modification count.  */
  85 #define OVERLAY_MODIFF (current_buffer->text->overlay_modiff)
  86
  87 /* Modification count as of last visit or save.  */
  88 #define SAVE_MODIFF (current_buffer->text->save_modiff)
  89
  90 /* BUFFER_CEILING_OF (resp. BUFFER_FLOOR_OF), when applied to n, return
  91    the max (resp. min) p such that
  92
  93    BYTE_POS_ADDR (p) - BYTE_POS_ADDR (n) == p - n       */
  94
  95 #define BUFFER_CEILING_OF(BYTEPOS) \
  96   (((BYTEPOS) < GPT_BYTE && GPT < ZV ? GPT_BYTE : ZV_BYTE) - 1)
  97 #define BUFFER_FLOOR_OF(BYTEPOS) \
  98   (BEGV <= GPT && GPT_BYTE <= (BYTEPOS) ? GPT_BYTE : BEGV_BYTE)
  99 \f
 100 /* Similar macros to operate on a specified buffer.
 101    Note that many of these evaluate the buffer argument more than once.  */
 102
 103 /* Position of beginning of buffer.  */
 104 #define BUF_BEG(buf) (1)
 105 #define BUF_BEG_BYTE(buf) (1)
 106
 107 /* Position of beginning of accessible range of buffer.  */
 108 #define BUF_BEGV(buf) ((buf)->begv)
 109 #define BUF_BEGV_BYTE(buf) ((buf)->begv_byte)
 110
 111 /* Position of point in buffer.  */
 112 #define BUF_PT(buf) ((buf)->pt)
 113 #define BUF_PT_BYTE(buf) ((buf)->pt_byte)
 114
 115 /* Position of gap in buffer.  */
 116 #define BUF_GPT(buf) ((buf)->text->gpt)
 117 #define BUF_GPT_BYTE(buf) ((buf)->text->gpt_byte)
 118
 119 /* Position of end of accessible range of buffer.  */
 120 #define BUF_ZV(buf) ((buf)->zv)
 121 #define BUF_ZV_BYTE(buf) ((buf)->zv_byte)
 122
 123 /* Position of end of buffer.  */
 124 #define BUF_Z(buf) ((buf)->text->z)
 125 #define BUF_Z_BYTE(buf) ((buf)->text->z_byte)
 126
 127 /* Address of beginning of buffer.  */
 128 #define BUF_BEG_ADDR(buf) ((buf)->text->beg)
 129
 130 /* Address of beginning of gap of buffer.  */
 131 #define BUF_GPT_ADDR(buf) ((buf)->text->beg + (buf)->text->gpt_byte - 1)
 132
 133 /* Address of end of buffer.  */
 134 #define BUF_Z_ADDR(buf) ((buf)->text->beg + (buf)->text->gap_size + (buf)->text->z_byte - 1)
 135
 136 /* Address of end of gap in buffer.  */
 137 #define BUF_GAP_END_ADDR(buf) ((buf)->text->beg + (buf)->text->gpt_byte + (buf)->text->gap_size - 1)
 138
 139 /* Size of gap.  */
 140 #define BUF_GAP_SIZE(buf) ((buf)->text->gap_size)
 141
 142 /* Is this buffer narrowed?  */
 143 #define BUF_NARROWED(buf) ((BUF_BEGV (buf) != BUF_BEG (buf)) \
 144                            || (BUF_ZV (buf) != BUF_Z (buf)))
 145
 146 /* Modification count.  */
 147 #define BUF_MODIFF(buf) ((buf)->text->modiff)
 148
 149 /* Modification count as of last visit or save.  */
 150 #define BUF_SAVE_MODIFF(buf) ((buf)->text->save_modiff)
 151
 152 /* Overlay modification count.  */
 153 #define BUF_OVERLAY_MODIFF(buf) ((buf)->text->overlay_modiff)
 154
 155 /* Interval tree of buffer.  */
 156 #define BUF_INTERVALS(buf) ((buf)->text->intervals)
 157
 158 /* Marker chain of buffer.  */
 159 #define BUF_MARKERS(buf) ((buf)->text->markers)
 160 \f
 161 /* Macros to set PT in the current buffer, or another buffer..  */
 162
 163 #ifdef USE_TEXT_PROPERTIES
 164 #define SET_PT(position) (set_point (current_buffer, (position)))
 165 #define TEMP_SET_PT(position) (temp_set_point (current_buffer, (position)))
 166
 167 #define SET_PT_BOTH(position, byte) \
 168   (set_point_both (current_buffer, (position), (byte)))
 169 #define TEMP_SET_PT_BOTH(position, byte) \
 170   (temp_set_point_both (current_buffer, (position), (byte)))
 171
 172 #define BUF_SET_PT(buffer, position) \
 173   (set_point ((buffer), (position)))
 174 #define BUF_TEMP_SET_PT(buffer, position) \
 175   (temp_set_point ((buffer), (position)))
 176
 177 extern void set_point P_ ((struct buffer *, int));
 178 extern INLINE void temp_set_point P_ ((struct buffer *, int));
 179 extern void set_point_both P_ ((struct buffer *, int, int));
 180 extern INLINE void temp_set_point_both P_ ((struct buffer *, int, int));
 181
 182 #else  /* don't support text properties */
 183
 184 #define SET_PT(position) (current_buffer->pt = (position))
 185 #define TEMP_SET_PT(position) (current_buffer->pt = (position))
 186
 187 #define SET_PT_BOTH(position, byte)             \
 188    (current_buffer->pt = (position),            \
 189     current_buffer->pt_byte = (byte))
 190
 191 #define TEMP_SET_PT_BOTH(position, byte)        \
 192    (current_buffer->pt = (position),            \
 193     current_buffer->pt_byte = (byte))
 194
 195 #define BUF_SET_PT(buffer, position) (buffer->pt = (position))
 196 #define BUF_TEMP_SET_PT(buffer, position) (buffer->pt = (position))
 197 #endif /* don't support text properties */
 198 \f
 199 /* Macros for setting the BEGV, ZV or PT of a given buffer.
 200
 201    SET_BUF_PT* seet to be redundant.  Get rid of them?
 202
 203    The ..._BOTH macros take both a charpos and a bytepos,
 204    which must correspond to each other.
 205
 206    The macros without ..._BOTH take just a charpos,
 207    and compute the bytepos from it.  */
 208
 209 #define SET_BUF_BEGV(buf, charpos)                               \
 210   ((buf)->begv_byte = buf_charpos_to_bytepos ((buf), (charpos)), \
 211    (buf)->begv = (charpos))
 212
 213 #define SET_BUF_ZV(buf, charpos)                                \
 214   ((buf)->zv_byte = buf_charpos_to_bytepos ((buf), (charpos)),  \
 215    (buf)->zv = (charpos))
 216
 217 #define SET_BUF_BEGV_BOTH(buf, charpos, byte)           \
 218   ((buf)->begv = (charpos),                             \
 219    (buf)->begv_byte = (byte))
 220
 221 #define SET_BUF_ZV_BOTH(buf, charpos, byte)             \
 222   ((buf)->zv = (charpos),                               \
 223    (buf)->zv_byte = (byte))
 224
 225 #define SET_BUF_PT_BOTH(buf, charpos, byte)             \
 226   ((buf)->pt = (charpos),                               \
 227    (buf)->pt_byte = (byte))
 228 \f
 229 /* Macros to access a character or byte in the current buffer,
 230    or convert between a byte position and an address.
 231    These macros do not check that the position is in range.  */
 232
 233 /* Access a Lisp position value in POS,
 234    and store the charpos in CHARPOS and the bypepos in BYPEPOS.  */
 235
 236 #define DECODE_POSITION(charpos, bytepos, pos)                  \
 237 if (1)                                                          \
 238   {                                                             \
 239     Lisp_Object __pos = (pos);                                  \
 240     if (NUMBERP (__pos))                                        \
 241       {                                                         \
 242         charpos = __pos;                                        \
 243         bytepos = buf_charpos_to_bytepos (current_buffer, __pos);  \
 244       }                                                         \
 245     else if (MARKERP (__pos))                                   \
 246       {                                                         \
 247         charpos = marker_position (__pos);                      \
 248         bytepos = marker_byte_position (__pos);                 \
 249       }                                                         \
 250     else                                                        \
 251       wrong_type_argument (Qinteger_or_marker_p, __pos);        \
 252   }                                                             \
 253 else
 254
 255 /* Return the address of byte position N in current buffer.  */
 256
 257 #define BYTE_POS_ADDR(n) \
 258   (((n) >= GPT_BYTE ? GAP_SIZE : 0) + (n) + BEG_ADDR - 1)
 259
 260 /* Return the address of char position N.  */
 261
 262 #define CHAR_POS_ADDR(n)                        \
 263   (((n) >= GPT ? GAP_SIZE : 0)                  \
 264    + buf_charpos_to_bytepos (current_buffer, n) \
 265    + BEG_ADDR - 1)
 266
 267 /* Convert a character position to a byte position.  */
 268
 269 #define CHAR_TO_BYTE(charpos)                   \
 270   (buf_charpos_to_bytepos (current_buffer, charpos))
 271
 272 /* Convert a byte position to a character position.  */
 273
 274 #define BYTE_TO_CHAR(bytepos)                   \
 275   (buf_bytepos_to_charpos (current_buffer, bytepos))
 276
 277 /* Convert PTR, the address of a byte in the buffer, into a byte position.  */
 278
 279 #define PTR_BYTE_POS(ptr) \
 280 ((ptr) - (current_buffer)->text->beg                                        \
 281  - (ptr - (current_buffer)->text->beg < (unsigned) GPT_BYTE ? 0 : GAP_SIZE) \
 282  + 1)
 283
 284 /* Return character at position POS.  */
 285
 286 #define FETCH_CHAR(pos)                                 \
 287   (!NILP (current_buffer->enable_multibyte_characters)  \
 288    ? FETCH_MULTIBYTE_CHAR ((pos))                       \
 289    : FETCH_BYTE ((pos)))
 290
 291 /* Return the byte at byte position N.  */
 292
 293 #define FETCH_BYTE(n) *(BYTE_POS_ADDR ((n)))
 294
 295 /* Variables used locally in FETCH_MULTIBYTE_CHAR.  */
 296 extern unsigned char *_fetch_multibyte_char_p;
 297 extern int _fetch_multibyte_char_len;
 298
 299 /* Return character code of multi-byte form at position POS.  If POS
 300    doesn't point the head of valid multi-byte form, only the byte at
 301    POS is returned.  No range checking.  */
 302
 303 #define FETCH_MULTIBYTE_CHAR(pos)                                       \
 304   (_fetch_multibyte_char_p = (((pos) >= GPT_BYTE ? GAP_SIZE : 0)        \
 305                                + (pos) + BEG_ADDR - 1),                 \
 306    _fetch_multibyte_char_len                                            \
 307       = ((pos) >= GPT_BYTE ? ZV_BYTE : GPT_BYTE) - (pos),               \
 308    STRING_CHAR (_fetch_multibyte_char_p, _fetch_multibyte_char_len))
 309 \f
 310 /* Macros for accessing a character or byte,
 311    or converting between byte positions and addresses,
 312    in a specified buffer.  */
 313
 314 /* Return the address of character at byte position POS in buffer BUF.
 315    Note that both arguments can be computed more than once.  */
 316
 317 #define BUF_BYTE_ADDRESS(buf, pos) \
 318 ((buf)->text->beg + (pos) - 1           \
 319  + ((pos) >= (buf)->text->gpt_byte ? (buf)->text->gap_size : 0))
 320
 321 /* Return the address of character at char position POS in buffer BUF.
 322    Note that both arguments can be computed more than once.  */
 323
 324 #define BUF_CHAR_ADDRESS(buf, pos) \
 325 ((buf)->text->beg + buf_charpos_to_bytepos ((buf), (pos)) - 1   \
 326  + ((pos) >= (buf)->text->gpt ? (buf)->text->gap_size : 0))
 327
 328 /* Convert PTR, the address of a char in buffer BUF,
 329    into a character position.  */
 330
 331 #define BUF_PTR_BYTE_POS(buf, ptr)                              \
 332 ((ptr) - (buf)->text->beg                                       \
 333  - (ptr - (buf)->text->beg < (unsigned) BUF_GPT_BYTE ((buf))    \
 334     ? 0 : BUF_GAP_SIZE ((buf)))                                 \
 335  + 1)
 336
 337 /* Return the character at byte position POS in buffer BUF.   */
 338
 339 #define BUF_FETCH_CHAR(buf, pos)                \
 340   (!NILP (buf->enable_multibyte_characters)     \
 341    ? BUF_FETCH_MULTIBYTE_CHAR ((buf), (pos))    \
 342    : BUF_FETCH_BYTE ((buf), (pos)))
 343
 344 /* Return the byte at byte position N in buffer BUF.   */
 345
 346 #define BUF_FETCH_BYTE(buf, n) \
 347   *(BUF_BYTE_ADDRESS ((buf), (n)))
 348
 349 /* Return character code of multi-byte form at byte position POS in BUF.
 350    If POS doesn't point the head of valid multi-byte form, only the byte at
 351    POS is returned.  No range checking.  */
 352
 353 #define BUF_FETCH_MULTIBYTE_CHAR(buf, pos)                              \
 354   (_fetch_multibyte_char_p                                              \
 355      = (((pos) >= BUF_GPT_BYTE (buf) ? BUF_GAP_SIZE (buf) : 0)          \
 356         + (pos) + BUF_BEG_ADDR (buf) - 1),                              \
 357    _fetch_multibyte_char_len                                            \
 358      = (((pos) >= BUF_GPT_BYTE (buf) ? BUF_ZV_BYTE (buf) : BUF_GPT_BYTE (buf)) \
 359         - (pos)),                                                       \
 360    STRING_CHAR (_fetch_multibyte_char_p, _fetch_multibyte_char_len))
 361 \f
 362 /* Define the actual buffer data structures.  */
 363
 364 /* This data structure describes the actual text contents of a buffer.
 365    It is shared between indirect buffers and their base buffer.  */
 366
 367 struct buffer_text
 368   {
 369     unsigned char *beg;         /* Actual address of buffer contents.  */
 370     int gpt;                    /* Char pos of gap in buffer.  */
 371     int z;                      /* Char pos of end of buffer.  */
 372     int gpt_byte;               /* Byte pos of gap in buffer.  */
 373     int z_byte;                 /* Byte pos of end of buffer.  */
 374     int gap_size;               /* Size of buffer's gap.  */
 375     int modiff;                 /* This counts buffer-modification events
 376                                    for this buffer.  It is incremented for
 377                                    each such event, and never otherwise
 378                                    changed.  */
 379     int save_modiff;            /* Previous value of modiff, as of last
 380                                    time buffer visited or saved a file.  */
 381
 382     int overlay_modiff;         /* Counts modifications to overlays.  */
 383
 384     /* Properties of this buffer's text -- conditionally compiled.  */
 385     DECLARE_INTERVALS
 386
 387     /* The markers that refer to this buffer.
 388        This is actually a single marker ---
 389        successive elements in its marker `chain'
 390        are the other markers referring to this buffer.  */
 391     Lisp_Object markers;
 392   };
 393
 394 /* This is the structure that the buffer Lisp object points to.  */
 395
 396 struct buffer
 397   {
 398     /* Everything before the `name' slot must be of a non-Lisp_Object type,
 399        and every slot after `name' must be a Lisp_Object.
 400
 401        Check out mark_buffer (alloc.c) to see why.  */
 402
 403     EMACS_INT size;
 404
 405     /* Next buffer, in chain of all buffers including killed buffers.
 406        This chain is used only for garbage collection, in order to
 407        collect killed buffers properly.
 408        Note that vectors and most pseudovectors are all on one chain,
 409        but buffers are on a separate chain of their own.  */
 410     struct buffer *next;
 411
 412     /* This structure holds the coordinates of the buffer contents
 413        in ordinary buffers.  In indirect buffers, this is not used.  */
 414     struct buffer_text own_text;
 415
 416     /* This points to the `struct buffer_text' that used for this buffer.
 417        In an ordinary buffer, this is the own_text field above.
 418        In an indirect buffer, this is the own_text field of another buffer.  */
 419     struct buffer_text *text;
 420
 421     /* Char position of point in buffer.  */
 422     int pt;
 423     /* Byte position of point in buffer.  */
 424     int pt_byte;
 425     /* Char position of beginning of accessible range.  */
 426     int begv;
 427     /* Byte position of beginning of accessible range.  */
 428     int begv_byte;
 429     /* Char position of end of accessible range.  */
 430     int zv;
 431     /* Byte position of end of accessible range.  */
 432     int zv_byte;
 433
 434     /* In an indirect buffer, this points to the base buffer.
 435        In an ordinary buffer, it is 0.  */
 436     struct buffer *base_buffer;
 437
 438     /* Flags saying which DEFVAR_PER_BUFFER variables
 439        are local to this buffer.  */
 440     int local_var_flags;
 441     /* Set to the modtime of the visited file when read or written.
 442        -1 means visited file was nonexistent.
 443        0 means visited file modtime unknown; in no case complain
 444        about any mismatch on next save attempt.  */
 445     int modtime;
 446     /* the value of text->modiff at the last auto-save.  */
 447     int auto_save_modified;
 448     /* The time at which we detected a failure to auto-save,
 449        Or -1 if we didn't have a failure.  */
 450     int auto_save_failure_time;
 451     /* Position in buffer at which display started
 452        the last time this buffer was displayed.  */
 453     int last_window_start;
 454
 455     /* Set nonzero whenever the narrowing is changed in this buffer.  */
 456     int clip_changed;
 457
 458     /* If the long line scan cache is enabled (i.e. the buffer-local
 459        variable cache-long-line-scans is non-nil), newline_cache
 460        points to the newline cache, and width_run_cache points to the
 461        width run cache.
 462
 463        The newline cache records which stretches of the buffer are
 464        known *not* to contain newlines, so that they can be skipped
 465        quickly when we search for newlines.
 466
 467        The width run cache records which stretches of the buffer are
 468        known to contain characters whose widths are all the same.  If
 469        the width run cache maps a character to a value > 0, that value is
 470        the character's width; if it maps a character to zero, we don't
 471        know what its width is.  This allows compute_motion to process
 472        such regions very quickly, using algebra instead of inspecting
 473        each character.   See also width_table, below.  */
 474     struct region_cache *newline_cache;
 475     struct region_cache *width_run_cache;
 476
 477     /* Changes in the buffer are recorded here for undo.
 478        t means don't record anything.
 479        This information belongs to the base buffer of an indirect buffer,
 480        But we can't store it in the  struct buffer_text
 481        because local variables have to be right in the  struct buffer.
 482        So we copy it around in set_buffer_internal.
 483        This comes before `name' because it is marked in a special way.  */
 484     Lisp_Object undo_list;
 485
 486     /* Everything from here down must be a Lisp_Object */
 487
 488
 489     /* The name of this buffer.  */
 490     Lisp_Object name;
 491     /* The name of the file visited in this buffer, or nil.  */
 492     Lisp_Object filename;
 493     /* Dir for expanding relative file names.  */
 494     Lisp_Object directory;
 495     /* True iff this buffer has been backed up (if you write to the
 496        visited file and it hasn't been backed up, then a backup will
 497        be made).  */
 498     /* This isn't really used by the C code, so could be deleted.  */
 499     Lisp_Object backed_up;
 500     /* Length of file when last read or saved.
 501        This is not in the  struct buffer_text
 502        because it's not used in indirect buffers at all.  */
 503     Lisp_Object save_length;
 504     /* File name used for auto-saving this buffer.
 505        This is not in the  struct buffer_text
 506        because it's not used in indirect buffers at all.  */
 507     Lisp_Object auto_save_file_name;
 508
 509     /* Non-nil if buffer read-only.  */
 510     Lisp_Object read_only;
 511     /* "The mark".  This is a marker which may
 512        point into this buffer or may point nowhere.  */
 513     Lisp_Object mark;
 514
 515     /* Alist of elements (SYMBOL . VALUE-IN-THIS-BUFFER)
 516        for all per-buffer variables of this buffer.  */
 517     Lisp_Object local_var_alist;
 518
 519     /* Symbol naming major mode (eg, lisp-mode).  */
 520     Lisp_Object major_mode;
 521     /* Pretty name of major mode (eg, "Lisp"). */
 522     Lisp_Object mode_name;
 523     /* Mode line element that controls format of mode line.  */
 524     Lisp_Object mode_line_format;
 525
 526     /* Keys that are bound local to this buffer.  */
 527     Lisp_Object keymap;
 528     /* This buffer's local abbrev table.  */
 529     Lisp_Object abbrev_table;
 530     /* This buffer's syntax table.  */
 531     Lisp_Object syntax_table;
 532     /* This buffer's category table.  */
 533     Lisp_Object category_table;
 534
 535     /* Values of several buffer-local variables */
 536     /* tab-width is buffer-local so that redisplay can find it
 537        in buffers that are not current */
 538     Lisp_Object case_fold_search;
 539     Lisp_Object tab_width;
 540     Lisp_Object fill_column;
 541     Lisp_Object left_margin;
 542     /* Function to call when insert space past fill column.  */
 543     Lisp_Object auto_fill_function;
 544     /* nil: text, t: binary.
 545        This value is meaningful only on certain operating systems.  */
 546     /* Actually, we don't need this flag any more because end-of-line
 547        is handled correctly according to the buffer-file-coding-system
 548        of the buffer.  Just keeping it for backward compatibility.  */
 549     Lisp_Object buffer_file_type;
 550
 551     /* Case table for case-conversion in this buffer.
 552        This char-table maps each char into its lower-case version.  */
 553     Lisp_Object downcase_table;
 554     /* Char-table mapping each char to its upper-case version.  */
 555     Lisp_Object upcase_table;
 556     /* Char-table for conversion for case-folding search.  */
 557     Lisp_Object case_canon_table;
 558     /* Char-table of equivalences for case-folding search.  */
 559     Lisp_Object case_eqv_table;
 560
 561     /* Non-nil means do not display continuation lines.  */
 562     Lisp_Object truncate_lines;
 563     /* Non-nil means display ctl chars with uparrow.  */
 564     Lisp_Object ctl_arrow;
 565     /* Non-nil means display text from right to left.  */
 566     Lisp_Object direction_reversed;
 567     /* Non-nil means do selective display;
 568        see doc string in syms_of_buffer (buffer.c) for details.  */
 569     Lisp_Object selective_display;
 570 #ifndef old
 571     /* Non-nil means show ... at end of line followed by invisible lines.  */
 572     Lisp_Object selective_display_ellipses;
 573 #endif
 574     /* Alist of (FUNCTION . STRING) for each minor mode enabled in buffer.  */
 575     Lisp_Object minor_modes;
 576     /* t if "self-insertion" should overwrite; `binary' if it should also
 577        overwrite newlines and tabs - for editing executables and the like.  */
 578     Lisp_Object overwrite_mode;
 579     /* non-nil means abbrev mode is on.  Expand abbrevs automatically.  */
 580     Lisp_Object abbrev_mode;
 581     /* Display table to use for text in this buffer.  */
 582     Lisp_Object display_table;
 583     /* t means the mark and region are currently active.  */
 584     Lisp_Object mark_active;
 585
 586     /* List of overlays that end at or before the current center,
 587        in order of end-position.  */
 588     Lisp_Object overlays_before;
 589
 590     /* List of overlays that end after  the current center,
 591        in order of start-position.  */
 592     Lisp_Object overlays_after;
 593
 594     /* Position where the overlay lists are centered.  */
 595     Lisp_Object overlay_center;
 596
 597     /* Non-nil means the buffer contents are regarded as multi-byte
 598        form of characters, not a binary code.  */
 599     Lisp_Object enable_multibyte_characters;
 600
 601     /* Coding system to be used for encoding the buffer contents on
 602        saving.  */
 603     Lisp_Object buffer_file_coding_system;
 604
 605     /* List of symbols naming the file format used for visited file. */
 606     Lisp_Object file_format;
 607
 608     /* True if the newline position cache and width run cache are
 609        enabled.  See search.c and indent.c.  */
 610     Lisp_Object cache_long_line_scans;
 611
 612     /* If the width run cache is enabled, this table contains the
 613        character widths width_run_cache (see above) assumes.  When we
 614        do a thorough redisplay, we compare this against the buffer's
 615        current display table to see whether the display table has
 616        affected the widths of any characters.  If it has, we
 617        invalidate the width run cache, and re-initialize width_table.  */
 618     Lisp_Object width_table;
 619
 620     /* In an indirect buffer, or a buffer that is the base of an
 621        indirect buffer, this holds a marker that records
 622        PT for this buffer when the buffer is not current.  */
 623     Lisp_Object pt_marker;
 624
 625     /* In an indirect buffer, or a buffer that is the base of an
 626        indirect buffer, this holds a marker that records
 627        BEGV for this buffer when the buffer is not current.  */
 628     Lisp_Object begv_marker;
 629
 630     /* In an indirect buffer, or a buffer that is the base of an
 631        indirect buffer, this holds a marker that records
 632        ZV for this buffer when the buffer is not current.  */
 633     Lisp_Object zv_marker;
 634
 635     /* This holds the point value before the last scroll operation.
 636        Explicitly setting point sets this to nil.  */
 637     Lisp_Object point_before_scroll;
 638
 639     /* Truename of the visited file, or nil.  */
 640     Lisp_Object file_truename;
 641
 642     /* Invisibility spec of this buffer.
 643        t => any non-nil `invisible' property means invisible.
 644        A list => `invisible' property means invisible
 645                  if it is memq in that list.  */
 646     Lisp_Object invisibility_spec;
 647
 648     /* This is the last window that was selected with this buffer in it,
 649        or nil if that window no longer displays this buffer.  */
 650     Lisp_Object last_selected_window;
 651
 652     /* Incremented each time the buffer is displayed in a window.  */
 653     Lisp_Object display_count;
 654
 655     /* Time stamp updated each time this buffer is displayed in a window.  */
 656     Lisp_Object display_time;
 657
 658     /* These are so we don't have to recompile everything
 659        the next few times we add a new slot.  */
 660     Lisp_Object extra2, extra3;
 661   };
 662 \f
 663 /* This points to the current buffer.  */
 664
 665 extern struct buffer *current_buffer;
 666
 667 /* This structure holds the default values of the buffer-local variables
 668    that have special slots in each buffer.
 669    The default value occupies the same slot in this structure
 670    as an individual buffer's value occupies in that buffer.
 671    Setting the default value also goes through the alist of buffers
 672    and stores into each buffer that does not say it has a local value.  */
 673
 674 extern struct buffer buffer_defaults;
 675
 676 /* This structure marks which slots in a buffer have corresponding
 677    default values in buffer_defaults.
 678    Each such slot has a nonzero value in this structure.
 679    The value has only one nonzero bit.
 680
 681    When a buffer has its own local value for a slot,
 682    the bit for that slot (found in the same slot in this structure)
 683    is turned on in the buffer's local_var_flags slot.
 684
 685    If a slot in this structure is zero, then even though there may
 686    be a Lisp-level local variable for the slot, it has no default value,
 687    and the corresponding slot in buffer_defaults is not used.  */
 688
 689 extern struct buffer buffer_local_flags;
 690
 691 /* For each buffer slot, this points to the Lisp symbol name
 692    for that slot in the current buffer.  It is 0 for slots
 693    that don't have such names.  */
 694
 695 extern struct buffer buffer_local_symbols;
 696
 697 /* This structure holds the required types for the values in the
 698    buffer-local slots.  If a slot contains Qnil, then the
 699    corresponding buffer slot may contain a value of any type.  If a
 700    slot contains an integer, then prospective values' tags must be
 701    equal to that integer (except nil is always allowed).
 702    When a tag does not match, the function
 703    buffer_slot_type_mismatch will signal an error.
 704
 705    If a slot here contains -1, the corresponding variable is read-only.  */
 706
 707 extern struct buffer buffer_local_types;
 708 \f
 709 extern void reset_buffer P_ ((struct buffer *));
 710 extern void evaporate_overlays P_ ((int));
 711 extern int overlays_at P_ ((int, int, Lisp_Object **, int *, int *, int *));
 712 extern int sort_overlays P_ ((Lisp_Object *, int, struct window *));
 713 extern void recenter_overlay_lists P_ ((struct buffer *, int));
 714 extern int overlay_strings P_ ((int, struct window *, unsigned char **));
 715 extern void validate_region P_ ((Lisp_Object *, Lisp_Object *));
 716 extern void set_buffer_internal P_ ((struct buffer *));
 717 extern void set_buffer_internal_1 P_ ((struct buffer *));
 718 extern void set_buffer_temp P_ ((struct buffer *));
 719 extern void record_buffer P_ ((Lisp_Object));
 720 extern void buffer_slot_type_mismatch P_ ((int));
 721 extern void fix_overlays_before P_ ((struct buffer *, int, int));
 722
 723
 724 EXFUN (Fbuffer_name, 1);
 725 EXFUN (Fget_file_buffer, 1);
 726 EXFUN (Fnext_overlay_change, 1);
 727 EXFUN (Fdelete_overlay, 1);
 728
 729 /* Functions to call before and after each text change.  */
 730 extern Lisp_Object Vbefore_change_function;
 731 extern Lisp_Object Vafter_change_function;
 732 extern Lisp_Object Vbefore_change_functions;
 733 extern Lisp_Object Vafter_change_functions;
 734 extern Lisp_Object Vfirst_change_hook;
 735 extern Lisp_Object Qbefore_change_functions;
 736 extern Lisp_Object Qafter_change_functions;
 737 extern Lisp_Object Qfirst_change_hook;
 738
 739 extern Lisp_Object Vdeactivate_mark;
 740 extern Lisp_Object Vtransient_mark_mode;
 741 \f
 742 /* Overlays */
 743
 744 /* 1 if the OV is an overlay object.  */
 745 #define OVERLAY_VALID(OV) (OVERLAYP (OV))
 746
 747 /* Return the marker that stands for where OV starts in the buffer.  */
 748 #define OVERLAY_START(OV) (XOVERLAY (OV)->start)
 749
 750 /* Return the marker that stands for where OV ends in the buffer.  */
 751 #define OVERLAY_END(OV) (XOVERLAY (OV)->end)
 752
 753 /* Return the actual buffer position for the marker P.
 754    We assume you know which buffer it's pointing into.  */
 755
 756 #define OVERLAY_POSITION(P) \
 757  (GC_MARKERP (P) ? marker_position (P) : (abort (), 0))
 758
 759 /* Allocation of buffer text.  */
 760
 761 #ifdef REL_ALLOC
 762 #define BUFFER_ALLOC(data,size) ((unsigned char *) r_alloc (&data, (size)))
 763 #define BUFFER_REALLOC(data,size) ((unsigned char *) r_re_alloc (&data, (size)))
 764 #define BUFFER_FREE(data) (r_alloc_free (&data))
 765 #define R_ALLOC_DECLARE(var,data) (r_alloc_declare (&var, (data)))
 766 #else
 767 #define BUFFER_ALLOC(data,size) (data = (unsigned char *) malloc ((size)))
 768 #define BUFFER_REALLOC(data,size) ((unsigned char *) realloc ((data), (size)))
 769 #define BUFFER_FREE(data) (free ((data)))
 770 #define R_ALLOC_DECLARE(var,data)
 771 #endif