src/buffer.h

   1 /* Header file for the buffer manipulation primitives.
   2    Copyright (C) 1985, 1986, 1993, 1994, 1995 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, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20
  21 #ifdef USE_TEXT_PROPERTIES
  22 #define SET_PT(position) (set_point ((position), current_buffer))
  23 #define TEMP_SET_PT(position) (temp_set_point ((position), current_buffer))
  24
  25 #define BUF_SET_PT(buffer, position) (set_point ((position), (buffer)))
  26 #define BUF_TEMP_SET_PT(buffer, position) (temp_set_point ((position), (buffer)))
  27
  28 #else  /* don't support text properties */
  29
  30 #define SET_PT(position) (current_buffer->pt = (position))
  31 #define TEMP_SET_PT(position) (current_buffer->pt = (position))
  32
  33 #define BUF_SET_PT(buffer, position) (buffer->pt = (position))
  34 #define BUF_TEMP_SET_PT(buffer, position) (buffer->pt = (position))
  35 #endif /* don't support text properties */
  36
  37 /* Character position of beginning of buffer.  */
  38 #define BEG (1)
  39
  40 /* Character position of beginning of accessible range of buffer.  */
  41 #define BEGV (current_buffer->begv)
  42
  43 /* Character position of point in buffer.  The "+ 0" makes this
  44    not an l-value, so you can't assign to it.  Use SET_PT instead.  */
  45 #define PT (current_buffer->pt + 0)
  46
  47 /* Character position of gap in buffer.  */
  48 #define GPT (current_buffer->text->gpt)
  49
  50 /* Character position of end of accessible range of buffer.  */
  51 #define ZV (current_buffer->zv)
  52
  53 /* Character position of end of buffer.  */
  54 #define Z (current_buffer->text->z)
  55
  56 /* Is the current buffer narrowed? */
  57 #define NARROWED        ((BEGV != BEG) || (ZV != Z))
  58
  59 /* Modification count.  */
  60 #define MODIFF (current_buffer->text->modiff)
  61
  62 /* Modification count as of last visit or save.  */
  63 #define SAVE_MODIFF (current_buffer->text->save_modiff)
  64
  65 /* Address of beginning of buffer.  */
  66 #define BEG_ADDR (current_buffer->text->beg)
  67
  68 /* Address of beginning of accessible range of buffer.  */
  69 #define BEGV_ADDR (&FETCH_CHAR (current_buffer->begv))
  70
  71 /* Address of point in buffer.  */
  72 #define PT_ADDR (&FETCH_CHAR (current_buffer->pt))
  73
  74 /* Address of beginning of gap in buffer.  */
  75 #define GPT_ADDR (current_buffer->text->beg + current_buffer->text->gpt - 1)
  76
  77 /* Address of end of gap in buffer.  */
  78 #define GAP_END_ADDR (current_buffer->text->beg + current_buffer->text->gpt + current_buffer->text->gap_size - 1)
  79
  80 /* Address of end of accessible range of buffer.  */
  81 #define ZV_ADDR (&FETCH_CHAR (current_buffer->zv))
  82
  83 /* Size of gap.  */
  84 #define GAP_SIZE (current_buffer->text->gap_size)
  85
  86 /* Now similar macros for a specified buffer.
  87    Note that many of these evaluate the buffer argument more than once.  */
  88
  89 /* Character position of beginning of buffer.  */
  90 #define BUF_BEG(buf) (1)
  91
  92 /* Character position of beginning of accessible range of buffer.  */
  93 #define BUF_BEGV(buf) ((buf)->begv)
  94
  95 /* Character position of point in buffer.  */
  96 #define BUF_PT(buf) ((buf)->pt)
  97
  98 /* Character position of gap in buffer.  */
  99 #define BUF_GPT(buf) ((buf)->text->gpt)
 100
 101 /* Character position of end of accessible range of buffer.  */
 102 #define BUF_ZV(buf) ((buf)->zv)
 103
 104 /* Character position of end of buffer.  */
 105 #define BUF_Z(buf) ((buf)->text->z)
 106
 107 /* Is this buffer narrowed? */
 108 #define BUF_NARROWED(buf) ((BUF_BEGV (buf) != BUF_BEG (buf)) \
 109                            || (BUF_ZV (buf) != BUF_Z (buf)))
 110
 111 /* Modification count.  */
 112 #define BUF_MODIFF(buf) ((buf)->text->modiff)
 113
 114 /* Modification count as of last visit or save.  */
 115 #define BUF_SAVE_MODIFF(buf) ((buf)->text->save_modiff)
 116
 117 /* Interval tree of buffer.  */
 118 #define BUF_INTERVALS(buf) ((buf)->text->intervals)
 119
 120 /* Marker chain of buffer.  */
 121 #define BUF_MARKERS(buf) ((buf)->text->markers)
 122
 123 /* Address of beginning of buffer.  */
 124 #define BUF_BEG_ADDR(buf) ((buf)->text->beg)
 125
 126 /* Macro for setting the value of BUF_ZV (BUF) to VALUE,
 127    by varying the end of the accessible region.  */
 128 #define SET_BUF_ZV(buf, value) ((buf)->zv = (value))
 129 #define SET_BUF_PT(buf, value) ((buf)->pt = (value))
 130
 131 /* Size of gap.  */
 132 #define BUF_GAP_SIZE(buf) ((buf)->text->gap_size)
 133
 134 /* Return the address of character at position POS in buffer BUF.
 135    Note that both arguments can be computed more than once.  */
 136 #define BUF_CHAR_ADDRESS(buf, pos) \
 137 ((buf)->text->beg + (pos) - 1           \
 138  + ((pos) >= (buf)->text->gpt ? (buf)->text->gap_size : 0))
 139
 140 /* Convert the address of a char in the buffer into a character position.  */
 141 #define PTR_CHAR_POS(ptr) \
 142 ((ptr) - (current_buffer)->text->beg                                    \
 143  - (ptr - (current_buffer)->text->beg < (unsigned) GPT ? 0 : GAP_SIZE)  \
 144  + 1)
 145
 146 /* Convert the address of a char in the buffer into a character position.  */
 147 #define BUF_PTR_CHAR_POS(buf, ptr)                      \
 148 ((ptr) - (buf)->text->beg                               \
 149  - (ptr - (buf)->text->beg < (unsigned) BUF_GPT ((buf)) \
 150     ? 0 : BUF_GAP_SIZE ((buf)))                         \
 151  + 1)
 152 \f
 153 struct buffer_text
 154   {
 155     unsigned char *beg;         /* Actual address of buffer contents.  */
 156     int gpt;                    /* Index of gap in buffer.  */
 157     int z;                      /* Index of end of buffer.  */
 158     int gap_size;               /* Size of buffer's gap.  */
 159     int modiff;                 /* This counts buffer-modification events
 160                                    for this buffer.  It is incremented for
 161                                    each such event, and never otherwise
 162                                    changed.  */
 163     int save_modiff;            /* Previous value of modiff, as of last
 164                                    time buffer visited or saved a file.  */
 165
 166     /* Properties of this buffer's text -- conditionally compiled.  */
 167     DECLARE_INTERVALS
 168
 169     /* The markers that refer to this buffer.
 170        This is actually a single marker ---
 171        successive elements in its marker `chain'
 172        are the other markers referring to this buffer.  */
 173     Lisp_Object markers;
 174   };
 175
 176 struct buffer
 177   {
 178     /* Everything before the `name' slot must be of a non-Lisp_Object type,
 179        and every slot after `name' must be a Lisp_Object.
 180
 181        Check out mark_buffer (alloc.c) to see why.  */
 182
 183     EMACS_INT size;
 184
 185     /* Next buffer, in chain of all buffers including killed buffers.
 186        This chain is used only for garbage collection, in order to
 187        collect killed buffers properly.
 188        Note that vectors and most pseudovectors are all on one chain,
 189        but buffers are on a separate chain of their own.  */
 190     struct buffer *next;
 191
 192     /* This structure holds the coordinates of the buffer contents
 193        in ordinary buffers.  In indirect buffers, this is not used.  */
 194     struct buffer_text own_text;
 195
 196     /* This points to the `struct buffer_text' that used for this buffer.
 197        In an ordinary buffer, this is the own_text field above.
 198        In an indirect buffer, this is the own_text field of another buffer.  */
 199     struct buffer_text *text;
 200
 201     /* Position of point in buffer.  */
 202     int pt;
 203     /* Index of beginning of accessible range.  */
 204     int begv;
 205     /* Index of end of accessible range.  */
 206     int zv;
 207
 208     /* In an indirect buffer, this points to the base buffer.
 209        In an ordinary buffer, it is 0.  */
 210     struct buffer *base_buffer;
 211
 212     /* Flags saying which DEFVAR_PER_BUFFER variables
 213        are local to this buffer.  */
 214     int local_var_flags;
 215     /* Set to the modtime of the visited file when read or written.
 216        -1 means visited file was nonexistent.
 217        0 means visited file modtime unknown; in no case complain
 218        about any mismatch on next save attempt.  */
 219     int modtime;
 220     /* the value of text->modiff at the last auto-save.  */
 221     int auto_save_modified;
 222     /* The time at which we detected a failure to auto-save,
 223        Or -1 if we didn't have a failure.  */
 224     int auto_save_failure_time;
 225     /* Position in buffer at which display started
 226        the last time this buffer was displayed.  */
 227     int last_window_start;
 228
 229     /* If the long line scan cache is enabled (i.e. the buffer-local
 230        variable cache-long-line-scans is non-nil), newline_cache
 231        points to the newline cache, and width_run_cache points to the
 232        width run cache.
 233
 234        The newline cache records which stretches of the buffer are
 235        known *not* to contain newlines, so that they can be skipped
 236        quickly when we search for newlines.
 237
 238        The width run cache records which stretches of the buffer are
 239        known to contain characters whose widths are all the same.  If
 240        the width run cache maps a character to a value > 0, that value is
 241        the character's width; if it maps a character to zero, we don't
 242        know what its width is.  This allows compute_motion to process
 243        such regions very quickly, using algebra instead of inspecting
 244        each character.   See also width_table, below.  */
 245     struct region_cache *newline_cache;
 246     struct region_cache *width_run_cache;
 247
 248     /* Everything from here down must be a Lisp_Object */
 249
 250
 251     /* The name of this buffer.  */
 252     Lisp_Object name;
 253     /* The name of the file visited in this buffer, or nil.  */
 254     Lisp_Object filename;
 255     /* Dir for expanding relative file names.  */
 256     Lisp_Object directory;
 257     /* True iff this buffer has been backed up (if you write to the
 258        visited file and it hasn't been backed up, then a backup will
 259        be made).  */
 260     /* This isn't really used by the C code, so could be deleted.  */
 261     Lisp_Object backed_up;
 262     /* Length of file when last read or saved.
 263        This is not in the  struct buffer_text
 264        because it's not used in indirect buffers at all.  */
 265     Lisp_Object save_length;
 266     /* File name used for auto-saving this buffer.
 267        This is not in the  struct buffer_text
 268        because it's not used in indirect buffers at all.  */
 269     Lisp_Object auto_save_file_name;
 270
 271     /* Non-nil if buffer read-only.  */
 272     Lisp_Object read_only;
 273     /* "The mark".  This is a marker which may
 274        point into this buffer or may point nowhere.  */
 275     Lisp_Object mark;
 276
 277     /* Alist of elements (SYMBOL . VALUE-IN-THIS-BUFFER)
 278        for all per-buffer variables of this buffer.  */
 279     Lisp_Object local_var_alist;
 280
 281     /* Symbol naming major mode (eg, lisp-mode).  */
 282     Lisp_Object major_mode;
 283     /* Pretty name of major mode (eg, "Lisp"). */
 284     Lisp_Object mode_name;
 285     /* Mode line element that controls format of mode line.  */
 286     Lisp_Object mode_line_format;
 287
 288     /* Keys that are bound local to this buffer.  */
 289     Lisp_Object keymap;
 290     /* This buffer's local abbrev table.  */
 291     Lisp_Object abbrev_table;
 292     /* This buffer's syntax table.  */
 293     Lisp_Object syntax_table;
 294
 295     /* Values of several buffer-local variables */
 296     /* tab-width is buffer-local so that redisplay can find it
 297        in buffers that are not current */
 298     Lisp_Object case_fold_search;
 299     Lisp_Object tab_width;
 300     Lisp_Object fill_column;
 301     Lisp_Object left_margin;
 302     /* Function to call when insert space past fill column.  */
 303     Lisp_Object auto_fill_function;
 304     /* nil: text, t: binary.
 305        This value is meaningful only on certain operating systems.  */
 306     Lisp_Object buffer_file_type;
 307
 308     /* String of length 256 mapping each char to its lower-case version.  */
 309     Lisp_Object downcase_table;
 310     /* String of length 256 mapping each char to its upper-case version.  */
 311     Lisp_Object upcase_table;
 312     /* Translate table for case-folding search.  */
 313     Lisp_Object case_canon_table;
 314     /* Inverse translate (equivalence class) table for case-folding search.  */
 315     Lisp_Object case_eqv_table;
 316
 317     /* Non-nil means do not display continuation lines.  */
 318     Lisp_Object truncate_lines;
 319     /* Non-nil means display ctl chars with uparrow.  */
 320     Lisp_Object ctl_arrow;
 321     /* Non-nil means do selective display;
 322        see doc string in syms_of_buffer (buffer.c) for details.  */
 323     Lisp_Object selective_display;
 324 #ifndef old
 325     /* Non-nil means show ... at end of line followed by invisible lines.  */
 326     Lisp_Object selective_display_ellipses;
 327 #endif
 328     /* Alist of (FUNCTION . STRING) for each minor mode enabled in buffer.  */
 329     Lisp_Object minor_modes;
 330     /* t if "self-insertion" should overwrite; `binary' if it should also
 331        overwrite newlines and tabs - for editing executables and the like.  */
 332     Lisp_Object overwrite_mode;
 333     /* non-nil means abbrev mode is on.  Expand abbrevs automatically.  */
 334     Lisp_Object abbrev_mode;
 335     /* Display table to use for text in this buffer.  */
 336     Lisp_Object display_table;
 337     /* t means the mark and region are currently active.  */
 338     Lisp_Object mark_active;
 339
 340     /* Changes in the buffer are recorded here for undo.
 341        t means don't record anything.
 342        This information belongs to the base buffer of an indirect buffer,
 343        But we can't store it in the  struct buffer_text
 344        because local variables have to be right in the  struct buffer.
 345        So we copy it around in set_buffer_internal.  */
 346     Lisp_Object undo_list;
 347
 348     /* List of overlays that end at or before the current center,
 349        in order of end-position.  */
 350     Lisp_Object overlays_before;
 351
 352     /* List of overlays that end after  the current center,
 353        in order of start-position.  */
 354     Lisp_Object overlays_after;
 355
 356     /* Position where the overlay lists are centered.  */
 357     Lisp_Object overlay_center;
 358
 359     /* Lisp of symbols naming the file format used for visited file. */
 360     Lisp_Object file_format;
 361
 362     /* True if the newline position cache and width run cache are
 363        enabled.  See search.c and indent.c.  */
 364     Lisp_Object cache_long_line_scans;
 365
 366     /* If the width run cache is enabled, this table contains the
 367        character widths width_run_cache (see above) assumes.  When we
 368        do a thorough redisplay, we compare this against the buffer's
 369        current display table to see whether the display table has
 370        affected the widths of any characters.  If it has, we
 371        invalidate the width run cache, and re-initialize width_table.  */
 372     Lisp_Object width_table;
 373
 374     /* In an indirect buffer, or a buffer that is the base of an
 375        indirect buffer, this holds a marker that records
 376        PT for this buffer when the buffer is not current.  */
 377     Lisp_Object pt_marker;
 378
 379     /* In an indirect buffer, or a buffer that is the base of an
 380        indirect buffer, this holds a marker that records
 381        BEGV for this buffer when the buffer is not current.  */
 382     Lisp_Object begv_marker;
 383
 384     /* In an indirect buffer, or a buffer that is the base of an
 385        indirect buffer, this holds a marker that records
 386        ZV for this buffer when the buffer is not current.  */
 387     Lisp_Object zv_marker;
 388
 389     /* This holds the point value before the last scroll operation.
 390        Explicitly setting point sets this to nil.  */
 391     Lisp_Object point_before_scroll;
 392
 393     /* Truename of the visited file, or nil.  */
 394     Lisp_Object file_truename;
 395
 396     /* Invisibility spec of this buffer.
 397        t => any non-nil `invisible' property means invisible.
 398        A list => `invisible' property means invisible
 399                  if it is memq in that list.  */
 400     Lisp_Object invisibility_spec;
 401   };
 402 \f
 403 /* This points to the current buffer.  */
 404
 405 extern struct buffer *current_buffer;
 406
 407 /* This structure holds the default values of the buffer-local variables
 408    that have special slots in each buffer.
 409    The default value occupies the same slot in this structure
 410    as an individual buffer's value occupies in that buffer.
 411    Setting the default value also goes through the alist of buffers
 412    and stores into each buffer that does not say it has a local value.  */
 413
 414 extern struct buffer buffer_defaults;
 415
 416 /* This structure marks which slots in a buffer have corresponding
 417    default values in buffer_defaults.
 418    Each such slot has a nonzero value in this structure.
 419    The value has only one nonzero bit.
 420
 421    When a buffer has its own local value for a slot,
 422    the bit for that slot (found in the same slot in this structure)
 423    is turned on in the buffer's local_var_flags slot.
 424
 425    If a slot in this structure is zero, then even though there may
 426    be a Lisp-level local variable for the slot, it has no default value,
 427    and the corresponding slot in buffer_defaults is not used.  */
 428
 429 extern struct buffer buffer_local_flags;
 430
 431 /* For each buffer slot, this points to the Lisp symbol name
 432    for that slot in the current buffer.  It is 0 for slots
 433    that don't have such names.  */
 434
 435 extern struct buffer buffer_local_symbols;
 436
 437 /* This structure holds the required types for the values in the
 438    buffer-local slots.  If a slot contains Qnil, then the
 439    corresponding buffer slot may contain a value of any type.  If a
 440    slot contains an integer, then prospective values' tags must be
 441    equal to that integer.  When a tag does not match, the function
 442    buffer_slot_type_mismatch will signal an error.  The value Qnil may
 443    always be safely stored in any slot.  */
 444 extern struct buffer buffer_local_types;
 445 \f
 446 /* Point in the current buffer.  This is an obsolete alias
 447    and should be eliminated.  */
 448 #define point (current_buffer->pt + 0)
 449
 450 /* Return character at position n.  No range checking.  */
 451 #define FETCH_CHAR(n) *(((n)>= GPT ? GAP_SIZE : 0) + (n) + BEG_ADDR - 1)
 452
 453 /* BUFFER_CEILING_OF (resp. BUFFER_FLOOR_OF), when applied to n, return
 454    the max (resp. min) p such that
 455
 456    &FETCH_CHAR (p) - &FETCH_CHAR (n) == p - n       */
 457
 458 #define BUFFER_CEILING_OF(n) (((n) < GPT && GPT < ZV ? GPT : ZV) - 1)
 459 #define BUFFER_FLOOR_OF(n) (BEGV <= GPT && GPT <= (n) ? GPT : BEGV)
 460
 461 extern void reset_buffer ();
 462 extern void evaporate_overlays ();
 463
 464 extern Lisp_Object Fbuffer_name ();
 465 extern Lisp_Object Fget_file_buffer ();
 466 extern Lisp_Object Fnext_overlay_change ();
 467
 468 /* Functions to call before and after each text change.  */
 469 extern Lisp_Object Vbefore_change_function;
 470 extern Lisp_Object Vafter_change_function;
 471 extern Lisp_Object Vbefore_change_functions;
 472 extern Lisp_Object Vafter_change_functions;
 473 extern Lisp_Object Vfirst_change_hook;
 474 extern Lisp_Object Qfirst_change_hook;
 475
 476 extern Lisp_Object Vdeactivate_mark;
 477 extern Lisp_Object Vtransient_mark_mode;
 478 \f
 479 /* Overlays */
 480
 481 /* 1 if the OV is an overlay object.  */
 482 #define OVERLAY_VALID(OV) (OVERLAYP (OV))
 483
 484 /* Return the marker that stands for where OV starts in the buffer.  */
 485 #define OVERLAY_START(OV) (XOVERLAY (OV)->start)
 486
 487 /* Return the marker that stands for where OV ends in the buffer.  */
 488 #define OVERLAY_END(OV) (XOVERLAY (OV)->end)
 489
 490 /* Return the actual buffer position for the marker P.
 491    We assume you know which buffer it's pointing into.  */
 492
 493 #define OVERLAY_POSITION(P) \
 494  (GC_MARKERP (P) ? marker_position (P) : (abort (), 0))
 495
 496 /* Allocation of buffer text.  */
 497
 498 #ifdef REL_ALLOC
 499 #define BUFFER_ALLOC(data,size) ((unsigned char *) r_alloc (&data, (size)))
 500 #define BUFFER_REALLOC(data,size) ((unsigned char *) r_re_alloc (&data, (size)))
 501 #define BUFFER_FREE(data) (r_alloc_free (&data))
 502 #define R_ALLOC_DECLARE(var,data) (r_alloc_declare (&var, (data)))
 503 #else
 504 #define BUFFER_ALLOC(data,size) (data = (unsigned char *) malloc ((size)))
 505 #define BUFFER_REALLOC(data,size) ((unsigned char *) realloc ((data), (size)))
 506 #define BUFFER_FREE(data) (free ((data)))
 507 #define R_ALLOC_DECLARE(var,data)
 508 #endif