src/buffer.h

   1 /* Header file for the buffer manipulation primitives.
   2    Copyright (C) 1985, 1986, 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 /* 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 \f
 134 struct buffer_text
 135   {
 136     unsigned char *beg;         /* Actual address of buffer contents. */
 137     int begv;                   /* Index of beginning of accessible range. */
 138     int pt;                     /* Position of point in buffer. */
 139     int gpt;                    /* Index of gap in buffer. */
 140     int zv;                     /* Index of end of accessible range. */
 141     int z;                      /* Index of end of buffer. */
 142     int gap_size;               /* Size of buffer's gap */
 143     int modiff;                 /* This counts buffer-modification events
 144                                    for this buffer.  It is incremented for
 145                                    each such event, and never otherwise
 146                                    changed.  */
 147   };
 148
 149 struct buffer
 150   {
 151     /* Everything before the `name' slot must be of a non-Lisp_Object type,
 152        and every slot after `name' must be a Lisp_Object.
 153
 154        Check out mark_buffer (alloc.c) to see why.
 155      */
 156
 157     /* This structure holds the coordinates of the buffer contents.  */
 158     struct buffer_text text;
 159     /* Next buffer, in chain of all buffers including killed buffers.
 160        This chain is used only for garbage collection, in order to
 161        collect killed buffers properly.  */
 162     struct buffer *next;
 163     /* Flags saying which DEFVAR_PER_BUFFER variables
 164        are local to this buffer.  */
 165     int local_var_flags;
 166     /* Value of text.modiff as of when visited file was read or written. */
 167     int save_modified;
 168     /* Set to the modtime of the visited file when read or written.
 169        -1 means visited file was nonexistent.
 170        0 means visited file modtime unknown; in no case complain
 171        about any mismatch on next save attempt.  */
 172     int modtime;
 173     /* the value of text.modiff at the last auto-save. */
 174     int auto_save_modified;
 175     /* The time at which we detected a failure to auto-save,
 176        Or -1 if we didn't have a failure.  */
 177     int auto_save_failure_time;
 178     /* Position in buffer at which display started
 179        the last time this buffer was displayed */
 180     int last_window_start;
 181
 182     /* Properties of this buffer's text -- conditionally compiled. */
 183     DECLARE_INTERVALS
 184
 185     /* This is a special exception -- as this slot should not be
 186        marked by gc_sweep, and as it is not lisp-accessible as
 187        a local variable -- so we regard it as not really being of type
 188        Lisp_Object */
 189     /* the markers that refer to this buffer.
 190        This is actually a single marker ---
 191        successive elements in its marker `chain'
 192        are the other markers referring to this
 193        buffer */
 194     Lisp_Object markers;
 195
 196
 197     /* Everything from here down must be a Lisp_Object */
 198
 199
 200     /* the name of this buffer */
 201     Lisp_Object name;
 202     /* Nuked: buffer number, assigned when buffer made Lisp_Object number;*/
 203     /* the name of the file associated with this buffer */
 204     Lisp_Object filename;
 205     /* Dir for expanding relative pathnames */
 206     Lisp_Object directory;
 207     /* true iff this buffer has been been backed
 208        up (if you write to its associated file
 209        and it hasn't been backed up, then a
 210        backup will be made) */
 211     /* This isn't really used by the C code, so could be deleted.  */
 212     Lisp_Object backed_up;
 213     /* Length of file when last read or saved. */
 214     Lisp_Object save_length;
 215     /* file name used for auto-saving this buffer */
 216     Lisp_Object auto_save_file_name;
 217     /* Non-nil if buffer read-only */
 218     Lisp_Object read_only;
 219     /* "The mark"; no longer allowed to be nil */
 220     Lisp_Object mark;
 221
 222     /* Alist of elements (SYMBOL . VALUE-IN-THIS-BUFFER)
 223        for all per-buffer variables of this buffer.  */
 224     Lisp_Object local_var_alist;
 225
 226
 227     /* Symbol naming major mode (eg lisp-mode) */
 228     Lisp_Object major_mode;
 229     /* Pretty name of major mode (eg "Lisp") */
 230     Lisp_Object mode_name;
 231     /* Format string for mode line */
 232     Lisp_Object mode_line_format;
 233
 234     /* Keys that are bound local to this buffer */
 235     Lisp_Object keymap;
 236     /* This buffer's local abbrev table */
 237     Lisp_Object abbrev_table;
 238     /* This buffer's syntax table. */
 239     Lisp_Object syntax_table;
 240
 241     /* Values of several buffer-local variables */
 242     /* tab-width is buffer-local so that redisplay can find it
 243        in buffers that are not current */
 244     Lisp_Object case_fold_search;
 245     Lisp_Object tab_width;
 246     Lisp_Object fill_column;
 247     Lisp_Object left_margin;
 248     /* Function to call when insert space past fill column */
 249     Lisp_Object auto_fill_function;
 250 #ifdef MSDOS
 251     /* nil: text, t: binary.  */
 252     Lisp_Object buffer_file_type;
 253 #endif
 254
 255     /* String of length 256 mapping each char to its lower-case version.  */
 256     Lisp_Object downcase_table;
 257     /* String of length 256 mapping each char to its upper-case version.  */
 258     Lisp_Object upcase_table;
 259
 260     /* Non-nil means do not display continuation lines */
 261     Lisp_Object truncate_lines;
 262     /* Non-nil means display ctl chars with uparrow */
 263     Lisp_Object ctl_arrow;
 264     /* Non-nil means do selective display;
 265        See doc string in syms_of_buffer (buffer.c) for details.  */
 266     Lisp_Object selective_display;
 267 #ifndef old
 268     /* Non-nil means show ... at end of line followed by invisible lines.  */
 269     Lisp_Object selective_display_ellipses;
 270 #endif
 271     /* Alist of (FUNCTION . STRING) for each minor mode enabled in buffer. */
 272     Lisp_Object minor_modes;
 273     /* t if "self-insertion" should overwrite; `binary' if it should also
 274        overwrite newlines and tabs - for editing executables and the like.  */
 275     Lisp_Object overwrite_mode;
 276     /* non-nil means abbrev mode is on.  Expand abbrevs automatically. */
 277     Lisp_Object abbrev_mode;
 278     /* Display table to use for text in this buffer. */
 279     Lisp_Object display_table;
 280     /* Translate table for case-folding search.  */
 281     Lisp_Object case_canon_table;
 282     /* Inverse translate (equivalence class) table for case-folding search.  */
 283     Lisp_Object case_eqv_table;
 284     /* Changes in the buffer are recorded here for undo.
 285        t means don't record anything.  */
 286     Lisp_Object undo_list;
 287     /* t means the mark and region are currently active.  */
 288     Lisp_Object mark_active;
 289
 290     /* List of overlays that end at or before the current center,
 291        in order of end-position.  */
 292     Lisp_Object overlays_before;
 293
 294     /* List of overlays that end after  the current center,
 295        in order of start-position.  */
 296     Lisp_Object overlays_after;
 297
 298     /* Position where the overlay lists are centered.  */
 299     Lisp_Object overlay_center;
 300 };
 301 \f
 302 /* This points to the current buffer.  */
 303
 304 extern struct buffer *current_buffer;
 305
 306 /* This structure holds the default values of the buffer-local variables
 307    that have special slots in each buffer.
 308    The default value occupies the same slot in this structure
 309    as an individual buffer's value occupies in that buffer.
 310    Setting the default value also goes through the alist of buffers
 311    and stores into each buffer that does not say it has a local value.  */
 312
 313 extern struct buffer buffer_defaults;
 314
 315 /* This structure marks which slots in a buffer have corresponding
 316    default values in buffer_defaults.
 317    Each such slot has a nonzero value in this structure.
 318    The value has only one nonzero bit.
 319
 320    When a buffer has its own local value for a slot,
 321    the bit for that slot (found in the same slot in this structure)
 322    is turned on in the buffer's local_var_flags slot.
 323
 324    If a slot in this structure is zero, then even though there may
 325    be a Lisp-level local variable for the slot, it has no default value,
 326    and the corresponding slot in buffer_defaults is not used.  */
 327
 328 extern struct buffer buffer_local_flags;
 329
 330 /* For each buffer slot, this points to the Lisp symbol name
 331    for that slot in the current buffer.  It is 0 for slots
 332    that don't have such names.  */
 333
 334 extern struct buffer buffer_local_symbols;
 335
 336 /* This structure holds the required types for the values in the
 337    buffer-local slots.  If a slot contains Qnil, then the
 338    corresponding buffer slot may contain a value of any type.  If a
 339    slot contains an integer, then prospective values' tags must be
 340    equal to that integer.  When a tag does not match, the function
 341    buffer_slot_type_mismatch will signal an error.  The value Qnil may
 342    always be safely stored in any slot.  */
 343 extern struct buffer buffer_local_types;
 344 \f
 345 /* Point in the current buffer.  This is an obsolete alias
 346    and should be eliminated.  */
 347 #define point (current_buffer->text.pt + 0)
 348
 349 /* Return character at position n.  No range checking.  */
 350 #define FETCH_CHAR(n) *(((n)>= GPT ? GAP_SIZE : 0) + (n) + BEG_ADDR - 1)
 351
 352 /* BUFFER_CEILING_OF (resp. BUFFER_FLOOR_OF), when applied to n, return
 353    the max (resp. min) p such that
 354
 355    &FETCH_CHAR (p) - &FETCH_CHAR (n) == p - n       */
 356
 357 #define BUFFER_CEILING_OF(n) (((n) < GPT && GPT < ZV ? GPT : ZV) - 1)
 358 #define BUFFER_FLOOR_OF(n) (BEGV <= GPT && GPT <= (n) ? GPT : BEGV)
 359
 360 extern void reset_buffer ();
 361
 362 extern Lisp_Object Fbuffer_name ();
 363 extern Lisp_Object Fget_file_buffer ();
 364
 365 /* Functions to call before and after each text change. */
 366 extern Lisp_Object Vbefore_change_function;
 367 extern Lisp_Object Vafter_change_function;
 368 extern Lisp_Object Vfirst_change_hook;
 369 extern Lisp_Object Qfirst_change_hook;
 370
 371 extern Lisp_Object Vdeactivate_mark;
 372 extern Lisp_Object Vtransient_mark_mode;
 373 \f
 374 /* Overlays */
 375
 376 /* Overlays are ordinary Lisp objects, and users can alter their contents.
 377    Therefore, we cannot assume that they remain valid--we must check.  */
 378
 379 /* 1 if the OV is a cons cell whose car is a cons cell.  */
 380 #define OVERLAY_VALID(OV) (OVERLAYP (OV))
 381
 382 /* Return the marker that stands for where OV starts in the buffer.  */
 383 #define OVERLAY_START(OV) (XCONS (XCONS ((OV))->car)->car)
 384
 385 /* Return the marker that stands for where OV ends in the buffer.  */
 386 #define OVERLAY_END(OV) (XCONS (XCONS ((OV))->car)->cdr)
 387
 388 /* Return the actual buffer position for the marker P,
 389    if it is a marker and points into the current buffer.
 390    Otherwise, zero.  */
 391
 392 #define OVERLAY_POSITION(P)                                     \
 393  ((MARKERP ((P)) && XMARKER ((P))->buffer == current_buffer)    \
 394   ? marker_position ((P)) : 0)
 395
 396 /* Allocation of buffer text.  */
 397
 398 #ifdef REL_ALLOC
 399 #define BUFFER_ALLOC(data,size) ((unsigned char *) r_alloc (&data, (size)))
 400 #define BUFFER_REALLOC(data,size) ((unsigned char *) r_re_alloc (&data, (size)))
 401 #define BUFFER_FREE(data) (r_alloc_free (&data))
 402 #define R_ALLOC_DECLARE(var,data) (r_alloc_declare (&var, (data)))
 403 #else
 404 #define BUFFER_ALLOC(data,size) (data = (unsigned char *) malloc ((size)))
 405 #define BUFFER_REALLOC(data,size) ((unsigned char *) realloc ((data), (size)))
 406 #define BUFFER_FREE(data) (free ((data)))
 407 #define R_ALLOC_DECLARE(var,data)
 408 #endif