src/buffer.h

   1 /* Header file for the buffer manipulation primitives.
   2    Copyright (C) 1985, 1986, 1990, 1992 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 lint
  22 #include "undo.h"
  23 #endif /* lint */
  24
  25
  26 #define SET_PT(position) (current_buffer->text.pt = (position))
  27
  28 /* Character position of beginning of buffer.  */
  29 #define BEG (1)
  30
  31 /* Character position of beginning of accessible range of buffer.  */
  32 #define BEGV (current_buffer->text.begv)
  33
  34 /* Character position of point in buffer.  The "+ 0" makes this
  35    not an l-value, so you can't assign to it.  Use SET_PT instead.  */
  36 #define PT (current_buffer->text.pt + 0)
  37
  38 /* Character position of gap in buffer.  */
  39 #define GPT (current_buffer->text.gpt)
  40
  41 /* Character position of end of accessible range of buffer.  */
  42 #define ZV (current_buffer->text.zv)
  43
  44 /* Character position of end of buffer.  */
  45 #define Z (current_buffer->text.z)
  46
  47 /* Modification count.  */
  48 #define MODIFF (current_buffer->text.modiff)
  49
  50 /* Address of beginning of buffer.  */
  51 #define BEG_ADDR (current_buffer->text.beg)
  52
  53 /* Address of beginning of accessible range of buffer.  */
  54 #define BEGV_ADDR (&FETCH_CHAR (current_buffer->text.begv))
  55
  56 /* Address of point in buffer.  */
  57 #define PT_ADDR (&FETCH_CHAR (current_buffer->text.pt))
  58
  59 /* Address of beginning of gap in buffer.  */
  60 #define GPT_ADDR (current_buffer->text.beg + current_buffer->text.gpt - 1)
  61
  62 /* Address of end of gap in buffer.  */
  63 #define GAP_END_ADDR (current_buffer->text.beg + current_buffer->text.gpt + current_buffer->text.gap_size - 1)
  64
  65 /* Address of end of accessible range of buffer.  */
  66 #define ZV_ADDR (&FETCH_CHAR (current_buffer->text.zv))
  67
  68 /* Size of gap.  */
  69 #define GAP_SIZE (current_buffer->text.gap_size)
  70
  71 /* Now similar macros for a specified buffer.
  72    Note that many of these evaluate the buffer argument more than once.  */
  73
  74 #define BUF_SET_PT(buffer, position) (buffer->text.pt = (position))
  75
  76 /* Character position of beginning of buffer.  */
  77 #define BUF_BEG(buf) (1)
  78
  79 /* Character position of beginning of accessible range of buffer.  */
  80 #define BUF_BEGV(buf) ((buf)->text.begv)
  81
  82 /* Character position of point in buffer.  */
  83 #define BUF_PT(buf) ((buf)->text.pt)
  84
  85 /* Character position of gap in buffer.  */
  86 #define BUF_GPT(buf) ((buf)->text.gpt)
  87
  88 /* Character position of end of accessible range of buffer.  */
  89 #define BUF_ZV(buf) ((buf)->text.zv)
  90
  91 /* Character position of end of buffer.  */
  92 #define BUF_Z(buf) ((buf)->text.z)
  93
  94 /* Modification count.  */
  95 #define BUF_MODIFF(buf) ((buf)->text.modiff)
  96
  97 /* Address of beginning of buffer.  */
  98 #define BUF_BEG_ADDR(buf) ((buf)->text.beg)
  99
 100 /* Macro for setting the value of BUF_ZV (BUF) to VALUE,
 101    by varying the end of the accessible region.  */
 102 #define SET_BUF_ZV(buf, value) ((buf)->text.zv = (value))
 103 #define SET_BUF_PT(buf, value) ((buf)->text.pt = (value))
 104
 105 /* Size of gap.  */
 106 #define BUF_GAP_SIZE(buf) ((buf)->text.gap_size)
 107
 108 /* Return the address of character at position POS in buffer BUF.
 109    Note that both arguments can be computed more than once.  */
 110 #define BUF_CHAR_ADDRESS(buf, pos) \
 111 ((buf)->text.beg + (pos) - 1            \
 112  + ((pos) >= (buf)->text.gpt ? (buf)->text.gap_size : 0))
 113
 114 /* Convert the address of a char in the buffer into a character position.  */
 115 #define PTR_CHAR_POS(ptr) \
 116 ((ptr) - (current_buffer)->text.beg                                     \
 117  - (ptr - (current_buffer)->text.beg < (unsigned) GPT ? 0 : GAP_SIZE)   \
 118  + 1)
 119 \f
 120 struct buffer_text
 121   {
 122     unsigned char *beg;         /* Actual address of buffer contents. */
 123     int begv;                   /* Index of beginning of accessible range. */
 124     int pt;                     /* Position of point in buffer. */
 125     int gpt;                    /* Index of gap in buffer. */
 126     int zv;                     /* Index of end of accessible range. */
 127     int z;                      /* Index of end of buffer. */
 128     int gap_size;               /* Size of buffer's gap */
 129     int modiff;                 /* This counts buffer-modification events
 130                                    for this buffer.  It is incremented for
 131                                    each such event, and never otherwise
 132                                    changed.  */
 133   };
 134
 135 struct buffer
 136   {
 137     /* Everything before the `name' slot must be of a non-Lisp_Object type,
 138        and every slot after `name' must be a Lisp_Object.
 139
 140        Check out mark_buffer (alloc.c) to see why.
 141      */
 142
 143     /* This structure holds the coordinates of the buffer contents.  */
 144     struct buffer_text text;
 145     /* Next buffer, in chain of all buffers including killed buffers.
 146        This chain is used only for garbage collection, in order to
 147        collect killed buffers properly.  */
 148     struct buffer *next;
 149     /* Flags saying which DEFVAR_PER_BUFFER variables
 150        are local to this buffer.  */
 151     int local_var_flags;
 152     /* Value of text.modiff as of when visited file was read or written. */
 153     int save_modified;
 154     /* Set to the modtime of the visited file when read or written.
 155        -1 means visited file was nonexistent.
 156        0 means visited file modtime unknown; in no case complain
 157        about any mismatch on next save attempt.  */
 158     int modtime;
 159     /* the value of text.modiff at the last auto-save. */
 160     int auto_save_modified;
 161     /* Position in buffer at which display started
 162        the last time this buffer was displayed */
 163     int last_window_start;
 164
 165     /* This is a special exception -- as this slot should not be
 166        marked by gc_sweep, and as it is not lisp-accessible as
 167        a local variable -- so we regard it as not really being of type
 168        Lisp_Object */
 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
 173        buffer */
 174     Lisp_Object markers;
 175
 176
 177     /* Everything from here down must be a Lisp_Object */
 178
 179
 180     /* the name of this buffer */
 181     Lisp_Object name;
 182     /* Nuked: buffer number, assigned when buffer made Lisp_Object number;*/
 183     /* the name of the file associated with this buffer */
 184     Lisp_Object filename;
 185     /* Dir for expanding relative pathnames */
 186     Lisp_Object directory;
 187     /* true iff this buffer has been been backed
 188        up (if you write to its associated file
 189        and it hasn't been backed up, then a
 190        backup will be made) */
 191     /* This isn't really used by the C code, so could be deleted.  */
 192     Lisp_Object backed_up;
 193     /* Length of file when last read or saved. */
 194     Lisp_Object save_length;
 195     /* file name used for auto-saving this buffer */
 196     Lisp_Object auto_save_file_name;
 197     /* Non-nil if buffer read-only */
 198     Lisp_Object read_only;
 199     /* "The mark"; no longer allowed to be nil */
 200     Lisp_Object mark;
 201
 202     /* Alist of elements (SYMBOL . VALUE-IN-THIS-BUFFER)
 203        for all per-buffer variables of this buffer.  */
 204     Lisp_Object local_var_alist;
 205
 206
 207     /* Symbol naming major mode (eg lisp-mode) */
 208     Lisp_Object major_mode;
 209     /* Pretty name of major mode (eg "Lisp") */
 210     Lisp_Object mode_name;
 211     /* Format string for mode line */
 212     Lisp_Object mode_line_format;
 213
 214     /* Keys that are bound local to this buffer */
 215     Lisp_Object keymap;
 216     /* This buffer's local abbrev table */
 217     Lisp_Object abbrev_table;
 218     /* This buffer's syntax table. */
 219     Lisp_Object syntax_table;
 220
 221     /* Values of several buffer-local variables */
 222     /* tab-width is buffer-local so that redisplay can find it
 223        in buffers that are not current */
 224     Lisp_Object case_fold_search;
 225     Lisp_Object tab_width;
 226     Lisp_Object fill_column;
 227     Lisp_Object left_margin;
 228     /* Function to call when insert space past fill column */
 229     Lisp_Object auto_fill_function;
 230
 231     /* String of length 256 mapping each char to its lower-case version.  */
 232     Lisp_Object downcase_table;
 233     /* String of length 256 mapping each char to its upper-case version.  */
 234     Lisp_Object upcase_table;
 235
 236     /* Non-nil means do not display continuation lines */
 237     Lisp_Object truncate_lines;
 238     /* Non-nil means display ctl chars with uparrow */
 239     Lisp_Object ctl_arrow;
 240     /* Non-nil means do selective display;
 241        See doc string in syms_of_buffer (buffer.c) for details.  */
 242     Lisp_Object selective_display;
 243 #ifndef old
 244     /* Non-nil means show ... at end of line followed by invisible lines.  */
 245     Lisp_Object selective_display_ellipses;
 246 #endif
 247     /* Alist of (FUNCTION . STRING) for each minor mode enabled in buffer. */
 248     Lisp_Object minor_modes;
 249     /* t if "self-insertion" should overwrite */
 250     Lisp_Object overwrite_mode;
 251     /* non-nil means abbrev mode is on.  Expand abbrevs automatically. */
 252     Lisp_Object abbrev_mode;
 253     /* Display table to use for text in this buffer. */
 254     Lisp_Object display_table;
 255     /* Translate table for case-folding search.  */
 256     Lisp_Object case_canon_table;
 257     /* Inverse translate (equivalence class) table for case-folding search.  */
 258     Lisp_Object case_eqv_table;
 259     /* Changes in the buffer are recorded here for undo.
 260        t means don't record anything.  */
 261     Lisp_Object undo_list;
 262
 263     /* List of fields in this buffer.  */
 264     Lisp_Object fieldlist;
 265 };
 266
 267 extern struct buffer *current_buffer;
 268
 269 /* This structure holds the default values of the buffer-local variables
 270    defined with DefBufferLispVar, that have special slots in each buffer.
 271    The default value occupies the same slot in this structure
 272    as an individual buffer's value occupies in that buffer.
 273    Setting the default value also goes through the alist of buffers
 274    and stores into each buffer that does not say it has a local value.  */
 275
 276 extern struct buffer buffer_defaults;
 277
 278 /* This structure marks which slots in a buffer have corresponding
 279    default values in buffer_defaults.
 280    Each such slot has a nonzero value in this structure.
 281    The value has only one nonzero bit.
 282
 283    When a buffer has its own local value for a slot,
 284    the bit for that slot (found in the same slot in this structure)
 285    is turned on in the buffer's local_var_flags slot.
 286
 287    If a slot in this structure is zero, then even though there may
 288    be a DefBufferLispVar for the slot, there is no default valuefeor it;
 289    and the corresponding slot in buffer_defaults is not used.  */
 290
 291 extern struct buffer buffer_local_flags;
 292
 293 /* For each buffer slot, this points to the Lisp symbol name
 294    for that slot in the current buffer.  It is 0 for slots
 295    that don't have such names.  */
 296
 297 extern struct buffer buffer_local_symbols;
 298
 299 /* This structure holds the required types for the values in the
 300    buffer-local slots.  If a slot contains Qnil, then the
 301    corresponding buffer slot may contain a value of any type.  If a
 302    slot contains an integer, then prospective values' tags must be
 303    equal to that integer.  When a tag does not match, the function
 304    buffer_slot_type_mismatch will signal an error.  The value Qnil may
 305    always be safely stored in any slot.  */
 306 struct buffer buffer_local_types;
 307
 308 /* Point in the current buffer. */
 309
 310 #define point (current_buffer->text.pt + 0)
 311
 312 /* Return character at position n.  No range checking */
 313 #define FETCH_CHAR(n) *(((n)>= GPT ? GAP_SIZE : 0) + (n) + BEG_ADDR - 1)
 314
 315 /* BUFFER_CEILING_OF (resp. BUFFER_FLOOR_OF), when applied to n, return
 316    the max (resp. min) p such that
 317
 318    &FETCH_CHAR (p) - &FETCH_CHAR (n) == p - n       */
 319
 320 #define BUFFER_CEILING_OF(n) (((n) < GPT && GPT < ZV ? GPT : ZV) - 1)
 321 #define BUFFER_FLOOR_OF(n) (BEGV <= GPT && GPT <= (n) ? GPT : BEGV)
 322
 323 extern void reset_buffer ();
 324
 325 /* Functions to call before and after each text change. */
 326 extern Lisp_Object Vbefore_change_function;
 327 extern Lisp_Object Vafter_change_function;
 328 extern Lisp_Object Vfirst_change_function;
 329
 330 /* Fields.
 331
 332 A field is like a marker but it defines a region rather than a
 333 point.  Like a marker, a field is asocated with a buffer.
 334 The field mechanism uses the marker mechanism in the
 335 sense that its start and end points are maintained as markers
 336 updated in the usual way as the buffer changes.
 337
 338 A field can be protected or unprotected.  If it is protected,
 339 no modifications can be made that affect the field in its buffer,
 340 when protected field checking is enabled.
 341
 342 Each field also contains an alist, in which you can store
 343 whatever you like.  */
 344
 345 /* Slots in a field:  */
 346
 347 #define FIELD_BUFFER(f) (XVECTOR(f)->contents[1])
 348 #define FIELD_START_MARKER(f) (XVECTOR(f)->contents[2])
 349 #define FIELD_END_MARKER(f) (XVECTOR(f)->contents[3])
 350 #define FIELD_PROTECTED_FLAG(f) (XVECTOR(f)->contents[4])
 351 #define FIELD_ALIST(f) (XVECTOR(f)->contents[5])
 352
 353 /* Allocation of buffer data. */
 354 #ifdef REL_ALLOC
 355 #define BUFFER_ALLOC(data,size) ((unsigned char *) r_alloc (&data, (size)))
 356 #define BUFFER_REALLOC(data,size) ((unsigned char *) r_re_alloc (&data, (size)))
 357 #define BUFFER_FREE(data) (r_alloc_free (&data))
 358 #define R_ALLOC_DECLARE(var,data) (r_alloc_declare (&var, (data)))
 359 #else
 360 #define BUFFER_ALLOC(data,size) (data = (unsigned char *) malloc ((size)))
 361 #define BUFFER_REALLOC(data,size) ((unsigned char *) realloc ((data), (size)))
 362 #define BUFFER_FREE(data) (free ((data)))
 363 #define R_ALLOC_DECLARE(var,data)
 364 #endif
 365
 366 /* A search buffer, with a fastmap allocated and ready to go.  */
 367 extern struct re_pattern_buffer searchbuf;