src/buffer.h

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