src/buffer.h

   1 /* Header file for the buffer manipulation primitives.
   2    Copyright (C) 1985, 1986, 1990, 1993 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 /* Modification count.  */
  57 #define MODIFF (current_buffer->text.modiff)
  58
  59 /* Address of beginning of buffer.  */
  60 #define BEG_ADDR (current_buffer->text.beg)
  61
  62 /* Address of beginning of accessible range of buffer.  */
  63 #define BEGV_ADDR (&FETCH_CHAR (current_buffer->text.begv))
  64
  65 /* Address of point in buffer.  */
  66 #define PT_ADDR (&FETCH_CHAR (current_buffer->text.pt))
  67
  68 /* Address of beginning of gap in buffer.  */
  69 #define GPT_ADDR (current_buffer->text.beg + current_buffer->text.gpt - 1)
  70
  71 /* Address of end of gap in buffer.  */
  72 #define GAP_END_ADDR (current_buffer->text.beg + current_buffer->text.gpt + current_buffer->text.gap_size - 1)
  73
  74 /* Address of end of accessible range of buffer.  */
  75 #define ZV_ADDR (&FETCH_CHAR (current_buffer->text.zv))
  76
  77 /* Size of gap.  */
  78 #define GAP_SIZE (current_buffer->text.gap_size)
  79
  80 /* Now similar macros for a specified buffer.
  81    Note that many of these evaluate the buffer argument more than once.  */
  82
  83 /* Character position of beginning of buffer.  */
  84 #define BUF_BEG(buf) (1)
  85
  86 /* Character position of beginning of accessible range of buffer.  */
  87 #define BUF_BEGV(buf) ((buf)->text.begv)
  88
  89 /* Character position of point in buffer.  */
  90 #define BUF_PT(buf) ((buf)->text.pt)
  91
  92 /* Character position of gap in buffer.  */
  93 #define BUF_GPT(buf) ((buf)->text.gpt)
  94
  95 /* Character position of end of accessible range of buffer.  */
  96 #define BUF_ZV(buf) ((buf)->text.zv)
  97
  98 /* Character position of end of buffer.  */
  99 #define BUF_Z(buf) ((buf)->text.z)
 100
 101 /* Modification count.  */
 102 #define BUF_MODIFF(buf) ((buf)->text.modiff)
 103
 104 /* Address of beginning of buffer.  */
 105 #define BUF_BEG_ADDR(buf) ((buf)->text.beg)
 106
 107 /* Macro for setting the value of BUF_ZV (BUF) to VALUE,
 108    by varying the end of the accessible region.  */
 109 #define SET_BUF_ZV(buf, value) ((buf)->text.zv = (value))
 110 #define SET_BUF_PT(buf, value) ((buf)->text.pt = (value))
 111
 112 /* Size of gap.  */
 113 #define BUF_GAP_SIZE(buf) ((buf)->text.gap_size)
 114
 115 /* Return the address of character at position POS in buffer BUF.
 116    Note that both arguments can be computed more than once.  */
 117 #define BUF_CHAR_ADDRESS(buf, pos) \
 118 ((buf)->text.beg + (pos) - 1            \
 119  + ((pos) >= (buf)->text.gpt ? (buf)->text.gap_size : 0))
 120
 121 /* Convert the address of a char in the buffer into a character position.  */
 122 #define PTR_CHAR_POS(ptr) \
 123 ((ptr) - (current_buffer)->text.beg                                     \
 124  - (ptr - (current_buffer)->text.beg < (unsigned) GPT ? 0 : GAP_SIZE)   \
 125  + 1)
 126 \f
 127 struct buffer_text
 128   {
 129     unsigned char *beg;         /* Actual address of buffer contents. */
 130     int begv;                   /* Index of beginning of accessible range. */
 131     int pt;                     /* Position of point in buffer. */
 132     int gpt;                    /* Index of gap in buffer. */
 133     int zv;                     /* Index of end of accessible range. */
 134     int z;                      /* Index of end of buffer. */
 135     int gap_size;               /* Size of buffer's gap */
 136     int modiff;                 /* This counts buffer-modification events
 137                                    for this buffer.  It is incremented for
 138                                    each such event, and never otherwise
 139                                    changed.  */
 140   };
 141
 142 struct buffer
 143   {
 144     /* Everything before the `name' slot must be of a non-Lisp_Object type,
 145        and every slot after `name' must be a Lisp_Object.
 146
 147        Check out mark_buffer (alloc.c) to see why.
 148      */
 149
 150     /* This structure holds the coordinates of the buffer contents.  */
 151     struct buffer_text text;
 152     /* Next buffer, in chain of all buffers including killed buffers.
 153        This chain is used only for garbage collection, in order to
 154        collect killed buffers properly.  */
 155     struct buffer *next;
 156     /* Flags saying which DEFVAR_PER_BUFFER variables
 157        are local to this buffer.  */
 158     int local_var_flags;
 159     /* Value of text.modiff as of when visited file was read or written. */
 160     int save_modified;
 161     /* Set to the modtime of the visited file when read or written.
 162        -1 means visited file was nonexistent.
 163        0 means visited file modtime unknown; in no case complain
 164        about any mismatch on next save attempt.  */
 165     int modtime;
 166     /* the value of text.modiff at the last auto-save. */
 167     int auto_save_modified;
 168     /* Position in buffer at which display started
 169        the last time this buffer was displayed */
 170     int last_window_start;
 171
 172     /* Properties of this buffer's text -- conditionally compiled. */
 173     DECLARE_INTERVALS
 174
 175     /* This is a special exception -- as this slot should not be
 176        marked by gc_sweep, and as it is not lisp-accessible as
 177        a local variable -- so we regard it as not really being of type
 178        Lisp_Object */
 179     /* the markers that refer to this buffer.
 180        This is actually a single marker ---
 181        successive elements in its marker `chain'
 182        are the other markers referring to this
 183        buffer */
 184     Lisp_Object markers;
 185
 186
 187     /* Everything from here down must be a Lisp_Object */
 188
 189
 190     /* the name of this buffer */
 191     Lisp_Object name;
 192     /* Nuked: buffer number, assigned when buffer made Lisp_Object number;*/
 193     /* the name of the file associated with this buffer */
 194     Lisp_Object filename;
 195     /* Dir for expanding relative pathnames */
 196     Lisp_Object directory;
 197     /* true iff this buffer has been been backed
 198        up (if you write to its associated file
 199        and it hasn't been backed up, then a
 200        backup will be made) */
 201     /* This isn't really used by the C code, so could be deleted.  */
 202     Lisp_Object backed_up;
 203     /* Length of file when last read or saved. */
 204     Lisp_Object save_length;
 205     /* file name used for auto-saving this buffer */
 206     Lisp_Object auto_save_file_name;
 207     /* Non-nil if buffer read-only */
 208     Lisp_Object read_only;
 209     /* "The mark"; no longer allowed to be nil */
 210     Lisp_Object mark;
 211
 212     /* Alist of elements (SYMBOL . VALUE-IN-THIS-BUFFER)
 213        for all per-buffer variables of this buffer.  */
 214     Lisp_Object local_var_alist;
 215
 216
 217     /* Symbol naming major mode (eg lisp-mode) */
 218     Lisp_Object major_mode;
 219     /* Pretty name of major mode (eg "Lisp") */
 220     Lisp_Object mode_name;
 221     /* Format string for mode line */
 222     Lisp_Object mode_line_format;
 223
 224     /* Keys that are bound local to this buffer */
 225     Lisp_Object keymap;
 226     /* This buffer's local abbrev table */
 227     Lisp_Object abbrev_table;
 228     /* This buffer's syntax table. */
 229     Lisp_Object syntax_table;
 230
 231     /* Values of several buffer-local variables */
 232     /* tab-width is buffer-local so that redisplay can find it
 233        in buffers that are not current */
 234     Lisp_Object case_fold_search;
 235     Lisp_Object tab_width;
 236     Lisp_Object fill_column;
 237     Lisp_Object left_margin;
 238     /* Function to call when insert space past fill column */
 239     Lisp_Object auto_fill_function;
 240
 241     /* String of length 256 mapping each char to its lower-case version.  */
 242     Lisp_Object downcase_table;
 243     /* String of length 256 mapping each char to its upper-case version.  */
 244     Lisp_Object upcase_table;
 245
 246     /* Non-nil means do not display continuation lines */
 247     Lisp_Object truncate_lines;
 248     /* Non-nil means display ctl chars with uparrow */
 249     Lisp_Object ctl_arrow;
 250     /* Non-nil means do selective display;
 251        See doc string in syms_of_buffer (buffer.c) for details.  */
 252     Lisp_Object selective_display;
 253 #ifndef old
 254     /* Non-nil means show ... at end of line followed by invisible lines.  */
 255     Lisp_Object selective_display_ellipses;
 256 #endif
 257     /* Alist of (FUNCTION . STRING) for each minor mode enabled in buffer. */
 258     Lisp_Object minor_modes;
 259     /* t if "self-insertion" should overwrite; `binary' if it should also
 260        overwrite newlines and tabs - for editing executables and the like.  */
 261     Lisp_Object overwrite_mode;
 262     /* non-nil means abbrev mode is on.  Expand abbrevs automatically. */
 263     Lisp_Object abbrev_mode;
 264     /* Display table to use for text in this buffer. */
 265     Lisp_Object display_table;
 266     /* Translate table for case-folding search.  */
 267     Lisp_Object case_canon_table;
 268     /* Inverse translate (equivalence class) table for case-folding search.  */
 269     Lisp_Object case_eqv_table;
 270     /* Changes in the buffer are recorded here for undo.
 271        t means don't record anything.  */
 272     Lisp_Object undo_list;
 273     /* t means the mark and region are currently active.  */
 274     Lisp_Object mark_active;
 275
 276     /* List of overlays that end at or before the current center,
 277        in order of end-position.  */
 278     Lisp_Object overlays_before;
 279
 280     /* List of overlays that end after  the current center,
 281        in order of start-position.  */
 282     Lisp_Object overlays_after;
 283
 284     /* Position where the overlay lists are centered.  */
 285     Lisp_Object overlay_center;
 286 };
 287 \f
 288 /* This points to the current buffer.  */
 289
 290 extern struct buffer *current_buffer;
 291
 292 /* This structure holds the default values of the buffer-local variables
 293    that have special slots in each buffer.
 294    The default value occupies the same slot in this structure
 295    as an individual buffer's value occupies in that buffer.
 296    Setting the default value also goes through the alist of buffers
 297    and stores into each buffer that does not say it has a local value.  */
 298
 299 extern struct buffer buffer_defaults;
 300
 301 /* This structure marks which slots in a buffer have corresponding
 302    default values in buffer_defaults.
 303    Each such slot has a nonzero value in this structure.
 304    The value has only one nonzero bit.
 305
 306    When a buffer has its own local value for a slot,
 307    the bit for that slot (found in the same slot in this structure)
 308    is turned on in the buffer's local_var_flags slot.
 309
 310    If a slot in this structure is zero, then even though there may
 311    be a Lisp-level local variable for the slot, it has no default value,
 312    and the corresponding slot in buffer_defaults is not used.  */
 313
 314 extern struct buffer buffer_local_flags;
 315
 316 /* For each buffer slot, this points to the Lisp symbol name
 317    for that slot in the current buffer.  It is 0 for slots
 318    that don't have such names.  */
 319
 320 extern struct buffer buffer_local_symbols;
 321
 322 /* This structure holds the required types for the values in the
 323    buffer-local slots.  If a slot contains Qnil, then the
 324    corresponding buffer slot may contain a value of any type.  If a
 325    slot contains an integer, then prospective values' tags must be
 326    equal to that integer.  When a tag does not match, the function
 327    buffer_slot_type_mismatch will signal an error.  The value Qnil may
 328    always be safely stored in any slot.  */
 329 extern struct buffer buffer_local_types;
 330 \f
 331 /* Point in the current buffer.  This is an obsolete alias
 332    and should be eliminated.  */
 333 #define point (current_buffer->text.pt + 0)
 334
 335 /* Return character at position n.  No range checking.  */
 336 #define FETCH_CHAR(n) *(((n)>= GPT ? GAP_SIZE : 0) + (n) + BEG_ADDR - 1)
 337
 338 /* BUFFER_CEILING_OF (resp. BUFFER_FLOOR_OF), when applied to n, return
 339    the max (resp. min) p such that
 340
 341    &FETCH_CHAR (p) - &FETCH_CHAR (n) == p - n       */
 342
 343 #define BUFFER_CEILING_OF(n) (((n) < GPT && GPT < ZV ? GPT : ZV) - 1)
 344 #define BUFFER_FLOOR_OF(n) (BEGV <= GPT && GPT <= (n) ? GPT : BEGV)
 345
 346 extern void reset_buffer ();
 347
 348 extern Lisp_Object Fbuffer_name ();
 349 extern Lisp_Object Fget_file_buffer ();
 350
 351 /* Functions to call before and after each text change. */
 352 extern Lisp_Object Vbefore_change_function;
 353 extern Lisp_Object Vafter_change_function;
 354 extern Lisp_Object Vfirst_change_hook;
 355 extern Lisp_Object Qfirst_change_hook;
 356
 357 extern Lisp_Object Vdeactivate_mark;
 358 extern Lisp_Object Vtransient_mark_mode;
 359 \f
 360 /* Overlays */
 361
 362 /* Overlays are ordinary Lisp objects, and users can alter their contents.
 363    Therefore, we cannot assume that they remain valid--we must check.  */
 364
 365 /* 1 if the OV is a cons cell whose car is a cons cell.  */
 366 #define OVERLAY_VALID(OV) (CONSP ((OV)) && CONSP (XCONS ((OV))->car))
 367
 368 /* Return the marker that stands for where OV starts in the buffer.  */
 369 #define OVERLAY_START(OV) (XCONS (XCONS ((OV))->car)->car)
 370
 371 /* Return the marker that stands for where OV ends in the buffer.  */
 372 #define OVERLAY_END(OV) (XCONS (XCONS ((OV))->car)->cdr)
 373
 374 /* Return the actual buffer position for the marker P,
 375    if it is a marker and points into the current buffer.
 376    Otherwise, zero.  */
 377
 378 #define OVERLAY_POSITION(P)                                     \
 379  ((MARKERP ((P)) && XMARKER ((P))->buffer == current_buffer)    \
 380   ? marker_position ((P)) : 0)
 381
 382
 383 /* Allocation of buffer text.  */
 384
 385 #ifdef REL_ALLOC
 386 #define BUFFER_ALLOC(data,size) ((unsigned char *) r_alloc (&data, (size)))
 387 #define BUFFER_REALLOC(data,size) ((unsigned char *) r_re_alloc (&data, (size)))
 388 #define BUFFER_FREE(data) (r_alloc_free (&data))
 389 #define R_ALLOC_DECLARE(var,data) (r_alloc_declare (&var, (data)))
 390 #else
 391 #define BUFFER_ALLOC(data,size) (data = (unsigned char *) malloc ((size)))
 392 #define BUFFER_REALLOC(data,size) ((unsigned char *) realloc ((data), (size)))
 393 #define BUFFER_FREE(data) (free ((data)))
 394 #define R_ALLOC_DECLARE(var,data)
 395 #endif