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     /* Set nonzero whenever the narrowing is changed in this buffer.  */
 230     int clip_changed;
 231
 232     /* If the long line scan cache is enabled (i.e. the buffer-local
 233        variable cache-long-line-scans is non-nil), newline_cache
 234        points to the newline cache, and width_run_cache points to the
 235        width run cache.
 236
 237        The newline cache records which stretches of the buffer are
 238        known *not* to contain newlines, so that they can be skipped
 239        quickly when we search for newlines.
 240
 241        The width run cache records which stretches of the buffer are
 242        known to contain characters whose widths are all the same.  If
 243        the width run cache maps a character to a value > 0, that value is
 244        the character's width; if it maps a character to zero, we don't
 245        know what its width is.  This allows compute_motion to process
 246        such regions very quickly, using algebra instead of inspecting
 247        each character.   See also width_table, below.  */
 248     struct region_cache *newline_cache;
 249     struct region_cache *width_run_cache;
 250
 251     /* Everything from here down must be a Lisp_Object */
 252
 253
 254     /* The name of this buffer.  */
 255     Lisp_Object name;
 256     /* The name of the file visited in this buffer, or nil.  */
 257     Lisp_Object filename;
 258     /* Dir for expanding relative file names.  */
 259     Lisp_Object directory;
 260     /* True iff this buffer has been backed up (if you write to the
 261        visited file and it hasn't been backed up, then a backup will
 262        be made).  */
 263     /* This isn't really used by the C code, so could be deleted.  */
 264     Lisp_Object backed_up;
 265     /* Length of file when last read or saved.
 266        This is not in the  struct buffer_text
 267        because it's not used in indirect buffers at all.  */
 268     Lisp_Object save_length;
 269     /* File name used for auto-saving this buffer.
 270        This is not in the  struct buffer_text
 271        because it's not used in indirect buffers at all.  */
 272     Lisp_Object auto_save_file_name;
 273
 274     /* Non-nil if buffer read-only.  */
 275     Lisp_Object read_only;
 276     /* "The mark".  This is a marker which may
 277        point into this buffer or may point nowhere.  */
 278     Lisp_Object mark;
 279
 280     /* Alist of elements (SYMBOL . VALUE-IN-THIS-BUFFER)
 281        for all per-buffer variables of this buffer.  */
 282     Lisp_Object local_var_alist;
 283
 284     /* Symbol naming major mode (eg, lisp-mode).  */
 285     Lisp_Object major_mode;
 286     /* Pretty name of major mode (eg, "Lisp"). */
 287     Lisp_Object mode_name;
 288     /* Mode line element that controls format of mode line.  */
 289     Lisp_Object mode_line_format;
 290
 291     /* Keys that are bound local to this buffer.  */
 292     Lisp_Object keymap;
 293     /* This buffer's local abbrev table.  */
 294     Lisp_Object abbrev_table;
 295     /* This buffer's syntax table.  */
 296     Lisp_Object syntax_table;
 297
 298     /* Values of several buffer-local variables */
 299     /* tab-width is buffer-local so that redisplay can find it
 300        in buffers that are not current */
 301     Lisp_Object case_fold_search;
 302     Lisp_Object tab_width;
 303     Lisp_Object fill_column;
 304     Lisp_Object left_margin;
 305     /* Function to call when insert space past fill column.  */
 306     Lisp_Object auto_fill_function;
 307     /* nil: text, t: binary.
 308        This value is meaningful only on certain operating systems.  */
 309     Lisp_Object buffer_file_type;
 310
 311     /* Case table for case-conversion in this buffer.
 312        This char-table maps each char into its lower-case version.  */
 313     Lisp_Object downcase_table;
 314     /* Char-table mapping each char to its upper-case version.  */
 315     Lisp_Object upcase_table;
 316     /* Char-table for conversion for case-folding search.  */
 317     Lisp_Object case_canon_table;
 318     /* Char-table of equivalences for case-folding search.  */
 319     Lisp_Object case_eqv_table;
 320
 321     /* Non-nil means do not display continuation lines.  */
 322     Lisp_Object truncate_lines;
 323     /* Non-nil means display ctl chars with uparrow.  */
 324     Lisp_Object ctl_arrow;
 325     /* Non-nil means do selective display;
 326        see doc string in syms_of_buffer (buffer.c) for details.  */
 327     Lisp_Object selective_display;
 328 #ifndef old
 329     /* Non-nil means show ... at end of line followed by invisible lines.  */
 330     Lisp_Object selective_display_ellipses;
 331 #endif
 332     /* Alist of (FUNCTION . STRING) for each minor mode enabled in buffer.  */
 333     Lisp_Object minor_modes;
 334     /* t if "self-insertion" should overwrite; `binary' if it should also
 335        overwrite newlines and tabs - for editing executables and the like.  */
 336     Lisp_Object overwrite_mode;
 337     /* non-nil means abbrev mode is on.  Expand abbrevs automatically.  */
 338     Lisp_Object abbrev_mode;
 339     /* Display table to use for text in this buffer.  */
 340     Lisp_Object display_table;
 341     /* t means the mark and region are currently active.  */
 342     Lisp_Object mark_active;
 343
 344     /* Changes in the buffer are recorded here for undo.
 345        t means don't record anything.
 346        This information belongs to the base buffer of an indirect buffer,
 347        But we can't store it in the  struct buffer_text
 348        because local variables have to be right in the  struct buffer.
 349        So we copy it around in set_buffer_internal.  */
 350     Lisp_Object undo_list;
 351
 352     /* List of overlays that end at or before the current center,
 353        in order of end-position.  */
 354     Lisp_Object overlays_before;
 355
 356     /* List of overlays that end after  the current center,
 357        in order of start-position.  */
 358     Lisp_Object overlays_after;
 359
 360     /* Position where the overlay lists are centered.  */
 361     Lisp_Object overlay_center;
 362
 363     /* Lisp of symbols naming the file format used for visited file. */
 364     Lisp_Object file_format;
 365
 366     /* True if the newline position cache and width run cache are
 367        enabled.  See search.c and indent.c.  */
 368     Lisp_Object cache_long_line_scans;
 369
 370     /* If the width run cache is enabled, this table contains the
 371        character widths width_run_cache (see above) assumes.  When we
 372        do a thorough redisplay, we compare this against the buffer's
 373        current display table to see whether the display table has
 374        affected the widths of any characters.  If it has, we
 375        invalidate the width run cache, and re-initialize width_table.  */
 376     Lisp_Object width_table;
 377
 378     /* In an indirect buffer, or a buffer that is the base of an
 379        indirect buffer, this holds a marker that records
 380        PT for this buffer when the buffer is not current.  */
 381     Lisp_Object pt_marker;
 382
 383     /* In an indirect buffer, or a buffer that is the base of an
 384        indirect buffer, this holds a marker that records
 385        BEGV for this buffer when the buffer is not current.  */
 386     Lisp_Object begv_marker;
 387
 388     /* In an indirect buffer, or a buffer that is the base of an
 389        indirect buffer, this holds a marker that records
 390        ZV for this buffer when the buffer is not current.  */
 391     Lisp_Object zv_marker;
 392
 393     /* This holds the point value before the last scroll operation.
 394        Explicitly setting point sets this to nil.  */
 395     Lisp_Object point_before_scroll;
 396
 397     /* Truename of the visited file, or nil.  */
 398     Lisp_Object file_truename;
 399
 400     /* Invisibility spec of this buffer.
 401        t => any non-nil `invisible' property means invisible.
 402        A list => `invisible' property means invisible
 403                  if it is memq in that list.  */
 404     Lisp_Object invisibility_spec;
 405   };
 406 \f
 407 /* This points to the current buffer.  */
 408
 409 extern struct buffer *current_buffer;
 410
 411 /* This structure holds the default values of the buffer-local variables
 412    that have special slots in each buffer.
 413    The default value occupies the same slot in this structure
 414    as an individual buffer's value occupies in that buffer.
 415    Setting the default value also goes through the alist of buffers
 416    and stores into each buffer that does not say it has a local value.  */
 417
 418 extern struct buffer buffer_defaults;
 419
 420 /* This structure marks which slots in a buffer have corresponding
 421    default values in buffer_defaults.
 422    Each such slot has a nonzero value in this structure.
 423    The value has only one nonzero bit.
 424
 425    When a buffer has its own local value for a slot,
 426    the bit for that slot (found in the same slot in this structure)
 427    is turned on in the buffer's local_var_flags slot.
 428
 429    If a slot in this structure is zero, then even though there may
 430    be a Lisp-level local variable for the slot, it has no default value,
 431    and the corresponding slot in buffer_defaults is not used.  */
 432
 433 extern struct buffer buffer_local_flags;
 434
 435 /* For each buffer slot, this points to the Lisp symbol name
 436    for that slot in the current buffer.  It is 0 for slots
 437    that don't have such names.  */
 438
 439 extern struct buffer buffer_local_symbols;
 440
 441 /* This structure holds the required types for the values in the
 442    buffer-local slots.  If a slot contains Qnil, then the
 443    corresponding buffer slot may contain a value of any type.  If a
 444    slot contains an integer, then prospective values' tags must be
 445    equal to that integer.  When a tag does not match, the function
 446    buffer_slot_type_mismatch will signal an error.  The value Qnil may
 447    always be safely stored in any slot.  */
 448 extern struct buffer buffer_local_types;
 449 \f
 450 /* Point in the current buffer.  This is an obsolete alias
 451    and should be eliminated.  */
 452 #define point (current_buffer->pt + 0)
 453
 454 /* Return character at position n.  No range checking.  */
 455 #define FETCH_CHAR(n) *(((n)>= GPT ? GAP_SIZE : 0) + (n) + BEG_ADDR - 1)
 456
 457 /* BUFFER_CEILING_OF (resp. BUFFER_FLOOR_OF), when applied to n, return
 458    the max (resp. min) p such that
 459
 460    &FETCH_CHAR (p) - &FETCH_CHAR (n) == p - n       */
 461
 462 #define BUFFER_CEILING_OF(n) (((n) < GPT && GPT < ZV ? GPT : ZV) - 1)
 463 #define BUFFER_FLOOR_OF(n) (BEGV <= GPT && GPT <= (n) ? GPT : BEGV)
 464
 465 extern void reset_buffer ();
 466 extern void evaporate_overlays ();
 467
 468 extern Lisp_Object Fbuffer_name ();
 469 extern Lisp_Object Fget_file_buffer ();
 470 extern Lisp_Object Fnext_overlay_change ();
 471 extern Lisp_Object Fdelete_overlay ();
 472
 473 /* Functions to call before and after each text change.  */
 474 extern Lisp_Object Vbefore_change_function;
 475 extern Lisp_Object Vafter_change_function;
 476 extern Lisp_Object Vbefore_change_functions;
 477 extern Lisp_Object Vafter_change_functions;
 478 extern Lisp_Object Vfirst_change_hook;
 479 extern Lisp_Object Qbefore_change_functions;
 480 extern Lisp_Object Qafter_change_functions;
 481 extern Lisp_Object Qfirst_change_hook;
 482
 483 extern Lisp_Object Vdeactivate_mark;
 484 extern Lisp_Object Vtransient_mark_mode;
 485 \f
 486 /* Overlays */
 487
 488 /* 1 if the OV is an overlay object.  */
 489 #define OVERLAY_VALID(OV) (OVERLAYP (OV))
 490
 491 /* Return the marker that stands for where OV starts in the buffer.  */
 492 #define OVERLAY_START(OV) (XOVERLAY (OV)->start)
 493
 494 /* Return the marker that stands for where OV ends in the buffer.  */
 495 #define OVERLAY_END(OV) (XOVERLAY (OV)->end)
 496
 497 /* Return the actual buffer position for the marker P.
 498    We assume you know which buffer it's pointing into.  */
 499
 500 #define OVERLAY_POSITION(P) \
 501  (GC_MARKERP (P) ? marker_position (P) : (abort (), 0))
 502
 503 /* Allocation of buffer text.  */
 504
 505 #ifdef REL_ALLOC
 506 #define BUFFER_ALLOC(data,size) ((unsigned char *) r_alloc (&data, (size)))
 507 #define BUFFER_REALLOC(data,size) ((unsigned char *) r_re_alloc (&data, (size)))
 508 #define BUFFER_FREE(data) (r_alloc_free (&data))
 509 #define R_ALLOC_DECLARE(var,data) (r_alloc_declare (&var, (data)))
 510 #else
 511 #define BUFFER_ALLOC(data,size) (data = (unsigned char *) malloc ((size)))
 512 #define BUFFER_REALLOC(data,size) ((unsigned char *) realloc ((data), (size)))
 513 #define BUFFER_FREE(data) (free ((data)))
 514 #define R_ALLOC_DECLARE(var,data)
 515 #endif