intervals.c 72.1 KB
Newer Older
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1
/* Code for doing intervals.
2
   Copyright (C) 1993-1995, 1997-1998, 2001-2011  Free Software Foundation, Inc.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
3 4 5

This file is part of GNU Emacs.

6
GNU Emacs is free software: you can redistribute it and/or modify
Joseph Arceneaux's avatar
Joseph Arceneaux committed
7
it under the terms of the GNU General Public License as published by
8 9
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
10 11 12 13 14 15 16

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
17
along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39


/* NOTES:

   Have to ensure that we can't put symbol nil on a plist, or some
   functions may work incorrectly.

   An idea:  Have the owner of the tree keep count of splits and/or
   insertion lengths (in intervals), and balance after every N.

   Need to call *_left_hook when buffer is killed.

   Scan for zero-length, or 0-length to see notes about handling
   zero length interval-markers.

   There are comments around about freeing intervals.  It might be
   faster to explicitly free them (put them on the free list) than
   to GC them.

*/


40
#include <config.h>
41
#include <setjmp.h>
42
#include <intprops.h>
Joseph Arceneaux's avatar
Joseph Arceneaux committed
43 44 45
#include "lisp.h"
#include "intervals.h"
#include "buffer.h"
Richard M. Stallman's avatar
Richard M. Stallman committed
46
#include "puresize.h"
Karl Heuer's avatar
Karl Heuer committed
47
#include "keyboard.h"
Stefan Monnier's avatar
Stefan Monnier committed
48
#include "keymap.h"
Joseph Arceneaux's avatar
Joseph Arceneaux committed
49

50 51 52 53 54
/* Test for membership, allowing for t (actually any non-cons) to mean the
   universal set.  */

#define TMEM(sym, set) (CONSP (set) ? ! NILP (Fmemq (sym, set)) : ! NILP (set))

55 56
static Lisp_Object merge_properties_sticky (Lisp_Object, Lisp_Object);
static INTERVAL merge_interval_right (INTERVAL);
57 58
static INTERVAL reproduce_tree (INTERVAL, INTERVAL);
static INTERVAL reproduce_tree_obj (INTERVAL, Lisp_Object);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
59

60
/* Utility functions for intervals.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
61 62


63
/* Create the root interval of some object, a buffer or string.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
64 65

INTERVAL
66
create_root_interval (Lisp_Object parent)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
67
{
Richard M. Stallman's avatar
Richard M. Stallman committed
68 69 70 71 72
  INTERVAL new;

  CHECK_IMPURE (parent);

  new = make_interval ();
Joseph Arceneaux's avatar
Joseph Arceneaux committed
73

74
  if (BUFFERP (parent))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
75
    {
76 77
      new->total_length = (BUF_Z (XBUFFER (parent))
			   - BUF_BEG (XBUFFER (parent)));
78
      CHECK_TOTAL_LENGTH (new);
79
      BUF_INTERVALS (XBUFFER (parent)) = new;
80
      new->position = BEG;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
81
    }
82
  else if (STRINGP (parent))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
83
    {
84
      new->total_length = SCHARS (parent);
85
      CHECK_TOTAL_LENGTH (new);
86
      STRING_SET_INTERVALS (parent, new);
87
      new->position = 0;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
88 89
    }

90
  SET_INTERVAL_OBJECT (new, parent);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
91 92 93 94 95 96 97

  return new;
}

/* Make the interval TARGET have exactly the properties of SOURCE */

void
98
copy_properties (register INTERVAL source, register INTERVAL target)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
99 100 101 102 103 104 105 106 107
{
  if (DEFAULT_INTERVAL_P (source) && DEFAULT_INTERVAL_P (target))
    return;

  COPY_INTERVAL_CACHE (source, target);
  target->plist = Fcopy_sequence (source->plist);
}

/* Merge the properties of interval SOURCE into the properties
108 109
   of interval TARGET.  That is to say, each property in SOURCE
   is added to TARGET if TARGET has no such property as yet.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
110 111

static void
112
merge_properties (register INTERVAL source, register INTERVAL target)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
113 114 115 116 117 118 119 120 121
{
  register Lisp_Object o, sym, val;

  if (DEFAULT_INTERVAL_P (source) && DEFAULT_INTERVAL_P (target))
    return;

  MERGE_INTERVAL_CACHE (source, target);

  o = source->plist;
122
  while (CONSP (o))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
123
    {
124
      sym = XCAR (o);
125 126 127 128 129 130 131 132 133 134 135
      o = XCDR (o);
      CHECK_CONS (o);

      val = target->plist;
      while (CONSP (val) && !EQ (XCAR (val), sym))
	{
	  val = XCDR (val);
	  if (!CONSP (val))
	    break;
	  val = XCDR (val);
	}
Joseph Arceneaux's avatar
Joseph Arceneaux committed
136 137 138

      if (NILP (val))
	{
139
	  val = XCAR (o);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
140 141
	  target->plist = Fcons (sym, Fcons (val, target->plist));
	}
142
      o = XCDR (o);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
143 144 145 146
    }
}

/* Return 1 if the two intervals have the same properties,
147
   0 otherwise.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
148 149

int
150
intervals_equal (INTERVAL i0, INTERVAL i1)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
151
{
152 153
  register Lisp_Object i0_cdr, i0_sym;
  register Lisp_Object i1_cdr, i1_val;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
154 155 156 157

  if (DEFAULT_INTERVAL_P (i0) && DEFAULT_INTERVAL_P (i1))
    return 1;

158 159 160
  if (DEFAULT_INTERVAL_P (i0) || DEFAULT_INTERVAL_P (i1))
    return 0;

Joseph Arceneaux's avatar
Joseph Arceneaux committed
161
  i0_cdr = i0->plist;
162 163
  i1_cdr = i1->plist;
  while (CONSP (i0_cdr) && CONSP (i1_cdr))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
164
    {
165
      i0_sym = XCAR (i0_cdr);
166 167 168 169 170 171 172 173 174 175 176
      i0_cdr = XCDR (i0_cdr);
      if (!CONSP (i0_cdr))
	return 0;		/* abort (); */
      i1_val = i1->plist;
      while (CONSP (i1_val) && !EQ (XCAR (i1_val), i0_sym))
	{
	  i1_val = XCDR (i1_val);
	  if (!CONSP (i1_val))
	    return 0;		/* abort (); */
	  i1_val = XCDR (i1_val);
	}
Joseph Arceneaux's avatar
Joseph Arceneaux committed
177

178
      /* i0 has something i1 doesn't.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
179 180 181
      if (EQ (i1_val, Qnil))
	return 0;

182
      /* i0 and i1 both have sym, but it has different values in each.  */
183 184 185
      if (!CONSP (i1_val)
	  || (i1_val = XCDR (i1_val), !CONSP (i1_val))
	  || !EQ (XCAR (i1_val), XCAR (i0_cdr)))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
186 187
	return 0;

188
      i0_cdr = XCDR (i0_cdr);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
189

190 191 192 193 194
      i1_cdr = XCDR (i1_cdr);
      if (!CONSP (i1_cdr))
	return 0;		/* abort (); */
      i1_cdr = XCDR (i1_cdr);
    }
Joseph Arceneaux's avatar
Joseph Arceneaux committed
195

196 197
  /* Lengths of the two plists were equal.  */
  return (NILP (i0_cdr) && NILP (i1_cdr));
Joseph Arceneaux's avatar
Joseph Arceneaux committed
198 199 200
}


201 202 203 204 205
/* Traverse an interval tree TREE, performing FUNCTION on each node.
   No guarantee is made about the order of traversal.
   Pass FUNCTION two args: an interval, and ARG.  */

void
206
traverse_intervals_noorder (INTERVAL tree, void (*function) (INTERVAL, Lisp_Object), Lisp_Object arg)
207 208 209 210 211 212 213 214 215 216 217 218 219 220 221
{
  /* Minimize stack usage.  */
  while (!NULL_INTERVAL_P (tree))
    {
      (*function) (tree, arg);
      if (NULL_INTERVAL_P (tree->right))
	tree = tree->left;
      else
	{
	  traverse_intervals_noorder (tree->left, function, arg);
	  tree = tree->right;
	}
    }
}

Joseph Arceneaux's avatar
Joseph Arceneaux committed
222
/* Traverse an interval tree TREE, performing FUNCTION on each node.
223
   Pass FUNCTION two args: an interval, and ARG.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
224 225

void
226
traverse_intervals (INTERVAL tree, ptrdiff_t position,
227
		    void (*function) (INTERVAL, Lisp_Object), Lisp_Object arg)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
228
{
229 230
  while (!NULL_INTERVAL_P (tree))
    {
231
      traverse_intervals (tree->left, position, function, arg);
232 233 234
      position += LEFT_TOTAL_LENGTH (tree);
      tree->position = position;
      (*function) (tree, arg);
235
      position += LENGTH (tree); tree = tree->right;
236
    }
Joseph Arceneaux's avatar
Joseph Arceneaux committed
237 238 239
}

#if 0
240 241 242 243 244

static int icount;
static int idepth;
static int zero_length;

245
/* These functions are temporary, for debugging purposes only.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
246 247 248 249

INTERVAL search_interval, found_interval;

void
Andreas Schwab's avatar
Andreas Schwab committed
250
check_for_interval (INTERVAL i)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
251 252 253 254 255 256 257 258 259
{
  if (i == search_interval)
    {
      found_interval = i;
      icount++;
    }
}

INTERVAL
Andreas Schwab's avatar
Andreas Schwab committed
260
search_for_interval (INTERVAL i, INTERVAL tree)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
261 262 263 264
{
  icount = 0;
  search_interval = i;
  found_interval = NULL_INTERVAL;
265
  traverse_intervals_noorder (tree, &check_for_interval, Qnil);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
266 267 268 269
  return found_interval;
}

static void
Andreas Schwab's avatar
Andreas Schwab committed
270
inc_interval_count (INTERVAL i)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
271 272 273 274 275 276 277 278 279
{
  icount++;
  if (LENGTH (i) == 0)
    zero_length++;
  if (depth > idepth)
    idepth = depth;
}

int
Andreas Schwab's avatar
Andreas Schwab committed
280
count_intervals (INTERVAL i)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
281 282 283 284
{
  icount = 0;
  idepth = 0;
  zero_length = 0;
285
  traverse_intervals_noorder (i, &inc_interval_count, Qnil);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
286 287 288 289 290

  return icount;
}

static INTERVAL
Andreas Schwab's avatar
Andreas Schwab committed
291
root_interval (INTERVAL interval)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
292 293 294 295
{
  register INTERVAL i = interval;

  while (! ROOT_INTERVAL_P (i))
296
    i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
297 298 299 300 301 302 303 304 305 306 307 308 309 310

  return i;
}
#endif

/* Assuming that a left child exists, perform the following operation:

     A		  B
    / \		 / \
   B       =>       A
  / \		   / \
     c		  c
*/

Paul Eggert's avatar
Paul Eggert committed
311
static inline INTERVAL
312
rotate_right (INTERVAL interval)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
313 314 315
{
  INTERVAL i;
  INTERVAL B = interval->left;
316
  ptrdiff_t old_total = interval->total_length;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
317

318
  /* Deal with any Parent of A;  make it point to B.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
319
  if (! ROOT_INTERVAL_P (interval))
320 321
    {
      if (AM_LEFT_CHILD (interval))
322
	INTERVAL_PARENT (interval)->left = B;
323
      else
324
	INTERVAL_PARENT (interval)->right = B;
325
    }
326
  COPY_INTERVAL_PARENT (B, interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
327

328 329 330
  /* Make B the parent of A */
  i = B->right;
  B->right = interval;
331
  SET_INTERVAL_PARENT (interval, B);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
332

333
  /* Make A point to c */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
334 335
  interval->left = i;
  if (! NULL_INTERVAL_P (i))
336
    SET_INTERVAL_PARENT (i, interval);
337

338
  /* A's total length is decreased by the length of B and its left child.  */
339
  interval->total_length -= B->total_length - LEFT_TOTAL_LENGTH (interval);
340
  CHECK_TOTAL_LENGTH (interval);
341 342 343

  /* B must have the same total length of A.  */
  B->total_length = old_total;
344
  CHECK_TOTAL_LENGTH (B);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
345 346 347

  return B;
}
348

Joseph Arceneaux's avatar
Joseph Arceneaux committed
349 350
/* Assuming that a right child exists, perform the following operation:

Juanma Barranquero's avatar
Juanma Barranquero committed
351 352
    A               B
   / \	           / \
Joseph Arceneaux's avatar
Joseph Arceneaux committed
353
      B	   =>     A
Juanma Barranquero's avatar
Juanma Barranquero committed
354
     / \         / \
Joseph Arceneaux's avatar
Joseph Arceneaux committed
355 356 357
    c               c
*/

Paul Eggert's avatar
Paul Eggert committed
358
static inline INTERVAL
359
rotate_left (INTERVAL interval)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
360 361 362
{
  INTERVAL i;
  INTERVAL B = interval->right;
363
  ptrdiff_t old_total = interval->total_length;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
364

365
  /* Deal with any parent of A;  make it point to B.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
366
  if (! ROOT_INTERVAL_P (interval))
367 368
    {
      if (AM_LEFT_CHILD (interval))
369
	INTERVAL_PARENT (interval)->left = B;
370
      else
371
	INTERVAL_PARENT (interval)->right = B;
372
    }
373
  COPY_INTERVAL_PARENT (B, interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
374 375

  /* Make B the parent of A */
376 377
  i = B->left;
  B->left = interval;
378
  SET_INTERVAL_PARENT (interval, B);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
379 380 381 382

  /* Make A point to c */
  interval->right = i;
  if (! NULL_INTERVAL_P (i))
383
    SET_INTERVAL_PARENT (i, interval);
384

385
  /* A's total length is decreased by the length of B and its right child.  */
386
  interval->total_length -= B->total_length - RIGHT_TOTAL_LENGTH (interval);
387
  CHECK_TOTAL_LENGTH (interval);
388 389 390

  /* B must have the same total length of A.  */
  B->total_length = old_total;
391
  CHECK_TOTAL_LENGTH (B);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
392 393 394 395

  return B;
}

396 397 398 399
/* Balance an interval tree with the assumption that the subtrees
   themselves are already balanced.  */

static INTERVAL
400
balance_an_interval (INTERVAL i)
401
{
402
  register ptrdiff_t old_diff, new_diff;
403 404 405 406 407 408

  while (1)
    {
      old_diff = LEFT_TOTAL_LENGTH (i) - RIGHT_TOTAL_LENGTH (i);
      if (old_diff > 0)
	{
409
	  /* Since the left child is longer, there must be one.  */
410 411
	  new_diff = i->total_length - i->left->total_length
	    + RIGHT_TOTAL_LENGTH (i->left) - LEFT_TOTAL_LENGTH (i->left);
Eli Zaretskii's avatar
Eli Zaretskii committed
412
	  if (eabs (new_diff) >= old_diff)
413 414 415 416 417 418
	    break;
	  i = rotate_right (i);
	  balance_an_interval (i->right);
	}
      else if (old_diff < 0)
	{
419
	  /* Since the right child is longer, there must be one.  */
420 421
	  new_diff = i->total_length - i->right->total_length
	    + LEFT_TOTAL_LENGTH (i->right) - RIGHT_TOTAL_LENGTH (i->right);
Eli Zaretskii's avatar
Eli Zaretskii committed
422
	  if (eabs (new_diff) >= -old_diff)
423 424 425 426 427 428 429 430 431 432 433 434 435
	    break;
	  i = rotate_left (i);
	  balance_an_interval (i->left);
	}
      else
	break;
    }
  return i;
}

/* Balance INTERVAL, potentially stuffing it back into its parent
   Lisp Object.  */

Paul Eggert's avatar
Paul Eggert committed
436
static inline INTERVAL
437
balance_possible_root_interval (register INTERVAL interval)
438 439
{
  Lisp_Object parent;
440
  int have_parent = 0;
441

442
  if (!INTERVAL_HAS_OBJECT (interval) && !INTERVAL_HAS_PARENT (interval))
443 444
    return interval;

445 446 447 448 449
  if (INTERVAL_HAS_OBJECT (interval))
    {
      have_parent = 1;
      GET_INTERVAL_OBJECT (parent, interval);
    }
450 451
  interval = balance_an_interval (interval);

452 453 454 455 456
  if (have_parent)
    {
      if (BUFFERP (parent))
	BUF_INTERVALS (XBUFFER (parent)) = interval;
      else if (STRINGP (parent))
457
	STRING_SET_INTERVALS (parent, interval);
458
    }
459 460 461 462 463 464 465 466

  return interval;
}

/* Balance the interval tree TREE.  Balancing is by weight
   (the amount of text).  */

static INTERVAL
467
balance_intervals_internal (register INTERVAL tree)
468 469 470
{
  /* Balance within each side.  */
  if (tree->left)
471
    balance_intervals_internal (tree->left);
472
  if (tree->right)
473
    balance_intervals_internal (tree->right);
474 475 476 477 478 479
  return balance_an_interval (tree);
}

/* Advertised interface to balance intervals.  */

INTERVAL
480
balance_intervals (INTERVAL tree)
481 482 483 484 485 486 487
{
  if (tree == NULL_INTERVAL)
    return NULL_INTERVAL;

  return balance_intervals_internal (tree);
}

488 489 490 491
/* Split INTERVAL into two pieces, starting the second piece at
   character position OFFSET (counting from 0), relative to INTERVAL.
   INTERVAL becomes the left-hand piece, and the right-hand piece
   (second, lexicographically) is returned.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
492 493 494 495 496

   The size and position fields of the two intervals are set based upon
   those of the original interval.  The property list of the new interval
   is reset, thus it is up to the caller to do the right thing with the
   result.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
497 498

   Note that this does not change the position of INTERVAL;  if it is a root,
499
   it is still a root after this operation.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
500 501

INTERVAL
502
split_interval_right (INTERVAL interval, ptrdiff_t offset)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
503 504
{
  INTERVAL new = make_interval ();
505 506
  ptrdiff_t position = interval->position;
  ptrdiff_t new_length = LENGTH (interval) - offset;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
507

508
  new->position = position + offset;
509
  SET_INTERVAL_PARENT (new, interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
510

511
  if (NULL_RIGHT_CHILD (interval))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
512 513 514
    {
      interval->right = new;
      new->total_length = new_length;
515
      CHECK_TOTAL_LENGTH (new);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
516
    }
517 518 519 520
  else
    {
      /* Insert the new node between INTERVAL and its right child.  */
      new->right = interval->right;
521
      SET_INTERVAL_PARENT (interval->right, new);
522 523
      interval->right = new;
      new->total_length = new_length + new->right->total_length;
524
      CHECK_TOTAL_LENGTH (new);
525 526
      balance_an_interval (new);
    }
Juanma Barranquero's avatar
Juanma Barranquero committed
527

528 529
  balance_possible_root_interval (interval);

Joseph Arceneaux's avatar
Joseph Arceneaux committed
530 531 532
  return new;
}

533 534 535 536
/* Split INTERVAL into two pieces, starting the second piece at
   character position OFFSET (counting from 0), relative to INTERVAL.
   INTERVAL becomes the right-hand piece, and the left-hand piece
   (first, lexicographically) is returned.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
537

Joseph Arceneaux's avatar
Joseph Arceneaux committed
538 539 540 541 542 543
   The size and position fields of the two intervals are set based upon
   those of the original interval.  The property list of the new interval
   is reset, thus it is up to the caller to do the right thing with the
   result.

   Note that this does not change the position of INTERVAL;  if it is a root,
544
   it is still a root after this operation.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
545 546

INTERVAL
547
split_interval_left (INTERVAL interval, ptrdiff_t offset)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
548 549
{
  INTERVAL new = make_interval ();
550
  ptrdiff_t new_length = offset;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
551 552

  new->position = interval->position;
553
  interval->position = interval->position + offset;
554
  SET_INTERVAL_PARENT (new, interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
555 556 557 558 559

  if (NULL_LEFT_CHILD (interval))
    {
      interval->left = new;
      new->total_length = new_length;
560
      CHECK_TOTAL_LENGTH (new);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
561
    }
562 563 564 565
  else
    {
      /* Insert the new node between INTERVAL and its left child.  */
      new->left = interval->left;
566
      SET_INTERVAL_PARENT (new->left, new);
567 568
      interval->left = new;
      new->total_length = new_length + new->left->total_length;
569
      CHECK_TOTAL_LENGTH (new);
570 571
      balance_an_interval (new);
    }
Juanma Barranquero's avatar
Juanma Barranquero committed
572

573
  balance_possible_root_interval (interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
574 575 576 577

  return new;
}

578 579 580 581 582 583 584 585
/* Return the proper position for the first character
   described by the interval tree SOURCE.
   This is 1 if the parent is a buffer,
   0 if the parent is a string or if there is no parent.

   Don't use this function on an interval which is the child
   of another interval!  */

586
static int
587
interval_start_pos (INTERVAL source)
588 589 590 591 592 593
{
  Lisp_Object parent;

  if (NULL_INTERVAL_P (source))
    return 0;

594 595
  if (! INTERVAL_HAS_OBJECT (source))
    return 0;
596
  GET_INTERVAL_OBJECT (parent, source);
597 598 599 600 601
  if (BUFFERP (parent))
    return BUF_BEG (XBUFFER (parent));
  return 0;
}

Joseph Arceneaux's avatar
Joseph Arceneaux committed
602
/* Find the interval containing text position POSITION in the text
603
   represented by the interval tree TREE.  POSITION is a buffer
604 605 606
   position (starting from 1) or a string index (starting from 0).
   If POSITION is at the end of the buffer or string,
   return the interval containing the last character.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
607

Joseph Arceneaux's avatar
Joseph Arceneaux committed
608 609
   The `position' field, which is a cache of an interval's position,
   is updated in the interval found.  Other functions (e.g., next_interval)
610
   will update this cache based on the result of find_interval.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
611

612
INTERVAL
613
find_interval (register INTERVAL tree, register ptrdiff_t position)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
614
{
615 616
  /* The distance from the left edge of the subtree at TREE
                    to POSITION.  */
617
  register ptrdiff_t relative_position;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
618 619 620 621

  if (NULL_INTERVAL_P (tree))
    return NULL_INTERVAL;

622
  relative_position = position;
623 624 625 626 627 628 629
  if (INTERVAL_HAS_OBJECT (tree))
    {
      Lisp_Object parent;
      GET_INTERVAL_OBJECT (parent, tree);
      if (BUFFERP (parent))
	relative_position -= BUF_BEG (XBUFFER (parent));
    }
630

631
  if (relative_position > TOTAL_LENGTH (tree))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
632 633
    abort ();			/* Paranoia */

634 635
  if (!handling_signal)
    tree = balance_possible_root_interval (tree);
636

Joseph Arceneaux's avatar
Joseph Arceneaux committed
637 638
  while (1)
    {
639
      if (relative_position < LEFT_TOTAL_LENGTH (tree))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
640 641 642
	{
	  tree = tree->left;
	}
643 644 645
      else if (! NULL_RIGHT_CHILD (tree)
	       && relative_position >= (TOTAL_LENGTH (tree)
					- RIGHT_TOTAL_LENGTH (tree)))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
646 647 648 649 650 651 652
	{
	  relative_position -= (TOTAL_LENGTH (tree)
				- RIGHT_TOTAL_LENGTH (tree));
	  tree = tree->right;
	}
      else
	{
653
	  tree->position
654 655
	    = (position - relative_position /* left edge of *tree.  */
	       + LEFT_TOTAL_LENGTH (tree)); /* left edge of this interval.  */
656

Joseph Arceneaux's avatar
Joseph Arceneaux committed
657 658 659 660 661 662
	  return tree;
	}
    }
}

/* Find the succeeding interval (lexicographically) to INTERVAL.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
663
   Sets the `position' field based on that of INTERVAL (see
664
   find_interval).  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
665 666

INTERVAL
667
next_interval (register INTERVAL interval)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
668 669
{
  register INTERVAL i = interval;
670
  register ptrdiff_t next_position;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689

  if (NULL_INTERVAL_P (i))
    return NULL_INTERVAL;
  next_position = interval->position + LENGTH (interval);

  if (! NULL_RIGHT_CHILD (i))
    {
      i = i->right;
      while (! NULL_LEFT_CHILD (i))
	i = i->left;

      i->position = next_position;
      return i;
    }

  while (! NULL_PARENT (i))
    {
      if (AM_LEFT_CHILD (i))
	{
690
	  i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
691 692 693 694
	  i->position = next_position;
	  return i;
	}

695
      i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
696 697 698 699 700 701
    }

  return NULL_INTERVAL;
}

/* Find the preceding interval (lexicographically) to INTERVAL.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
702
   Sets the `position' field based on that of INTERVAL (see
703
   find_interval).  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
704 705

INTERVAL
706
previous_interval (register INTERVAL interval)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
{
  register INTERVAL i;

  if (NULL_INTERVAL_P (interval))
    return NULL_INTERVAL;

  if (! NULL_LEFT_CHILD (interval))
    {
      i = interval->left;
      while (! NULL_RIGHT_CHILD (i))
	i = i->right;

      i->position = interval->position - LENGTH (i);
      return i;
    }

  i = interval;
  while (! NULL_PARENT (i))
    {
      if (AM_RIGHT_CHILD (i))
	{
728
	  i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
729 730 731 732

	  i->position = interval->position - LENGTH (i);
	  return i;
	}
733
      i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
734 735 736 737
    }

  return NULL_INTERVAL;
}
738 739

/* Find the interval containing POS given some non-NULL INTERVAL
740
   in the same tree.  Note that we need to update interval->position
741 742 743
   if we go down the tree.
   To speed up the process, we assume that the ->position of
   I and all its parents is already uptodate.  */
744
INTERVAL
745
update_interval (register INTERVAL i, ptrdiff_t pos)
746 747 748 749
{
  if (NULL_INTERVAL_P (i))
    return NULL_INTERVAL;

Juanma Barranquero's avatar
Juanma Barranquero committed
750
  while (1)
751
    {
Juanma Barranquero's avatar
Juanma Barranquero committed
752
      if (pos < i->position)
753 754
	{
	  /* Move left. */
Juanma Barranquero's avatar
Juanma Barranquero committed
755
	  if (pos >= i->position - TOTAL_LENGTH (i->left))
756 757 758 759 760
	    {
	      i->left->position = i->position - TOTAL_LENGTH (i->left)
		+ LEFT_TOTAL_LENGTH (i->left);
	      i = i->left;		/* Move to the left child */
	    }
Juanma Barranquero's avatar
Juanma Barranquero committed
761
	  else if (NULL_PARENT (i))
762
	    error ("Point before start of properties");
Juanma Barranquero's avatar
Juanma Barranquero committed
763
	  else
764
	      i = INTERVAL_PARENT (i);
765 766 767 768 769
	  continue;
	}
      else if (pos >= INTERVAL_LAST_POS (i))
	{
	  /* Move right. */
Juanma Barranquero's avatar
Juanma Barranquero committed
770
	  if (pos < INTERVAL_LAST_POS (i) + TOTAL_LENGTH (i->right))
771
	    {
772 773
	      i->right->position = INTERVAL_LAST_POS (i)
	        + LEFT_TOTAL_LENGTH (i->right);
774 775
	      i = i->right;		/* Move to the right child */
	    }
Juanma Barranquero's avatar
Juanma Barranquero committed
776
	  else if (NULL_PARENT (i))
777
	    error ("Point %"pI"d after end of properties", pos);
Juanma Barranquero's avatar
Juanma Barranquero committed
778
	  else
779
            i = INTERVAL_PARENT (i);
780 781
	  continue;
	}
Juanma Barranquero's avatar
Juanma Barranquero committed
782
      else
783 784 785 786
	return i;
    }
}

Joseph Arceneaux's avatar
Joseph Arceneaux committed
787

Joseph Arceneaux's avatar
Joseph Arceneaux committed
788
#if 0
Joseph Arceneaux's avatar
Joseph Arceneaux committed
789 790 791 792 793 794 795 796 797
/* Traverse a path down the interval tree TREE to the interval
   containing POSITION, adjusting all nodes on the path for
   an addition of LENGTH characters.  Insertion between two intervals
   (i.e., point == i->position, where i is second interval) means
   text goes into second interval.

   Modifications are needed to handle the hungry bits -- after simply
   finding the interval at position (don't add length going down),
   if it's the beginning of the interval, get the previous interval
Karl Heuer's avatar
Karl Heuer committed
798
   and check the hungry bits of both.  Then add the length going back up
799
   to the root.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
800 801

static INTERVAL
802 803
adjust_intervals_for_insertion (INTERVAL tree, ptrdiff_t position,
				ptrdiff_t length)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
804
{
805
  register ptrdiff_t relative_position;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822
  register INTERVAL this;

  if (TOTAL_LENGTH (tree) == 0)	/* Paranoia */
    abort ();

  /* If inserting at point-max of a buffer, that position
     will be out of range */
  if (position > TOTAL_LENGTH (tree))
    position = TOTAL_LENGTH (tree);
  relative_position = position;
  this = tree;

  while (1)
    {
      if (relative_position <= LEFT_TOTAL_LENGTH (this))
	{
	  this->total_length += length;
823
	  CHECK_TOTAL_LENGTH (this);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
824 825 826 827 828 829 830 831
	  this = this->left;
	}
      else if (relative_position > (TOTAL_LENGTH (this)
				    - RIGHT_TOTAL_LENGTH (this)))
	{
	  relative_position -= (TOTAL_LENGTH (this)
				- RIGHT_TOTAL_LENGTH (this));
	  this->total_length += length;
832
	  CHECK_TOTAL_LENGTH (this);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
833 834 835 836 837
	  this = this->right;
	}
      else
	{
	  /* If we are to use zero-length intervals as buffer pointers,
838
	     then this code will have to change.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
839
	  this->total_length += length;
840
	  CHECK_TOTAL_LENGTH (this);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
841 842 843 844 845 846
	  this->position = LEFT_TOTAL_LENGTH (this)
	                   + position - relative_position + 1;
	  return tree;
	}
    }
}
Joseph Arceneaux's avatar
Joseph Arceneaux committed
847 848 849 850
#endif

/* Effect an adjustment corresponding to the addition of LENGTH characters
   of text.  Do this by finding the interval containing POSITION in the
851
   interval tree TREE, and then adjusting all of its ancestors by adding
Joseph Arceneaux's avatar
Joseph Arceneaux committed
852 853 854 855 856 857
   LENGTH to them.

   If POSITION is the first character of an interval, meaning that point
   is actually between the two intervals, make the new text belong to
   the interval which is "sticky".

Joseph Arceneaux's avatar
Joseph Arceneaux committed
858
   If both intervals are "sticky", then make them belong to the left-most
Joseph Arceneaux's avatar
Joseph Arceneaux committed
859
   interval.  Another possibility would be to create a new interval for
860
   this text, and make it have the merged properties of both ends.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
861 862

static INTERVAL
863
adjust_intervals_for_insertion (INTERVAL tree,
864
				ptrdiff_t position, ptrdiff_t length)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
865 866
{
  register INTERVAL i;
867 868
  register INTERVAL temp;
  int eobp = 0;
869
  Lisp_Object parent;
870
  ptrdiff_t offset;
Juanma Barranquero's avatar
Juanma Barranquero committed
871

Joseph Arceneaux's avatar
Joseph Arceneaux committed
872 873 874
  if (TOTAL_LENGTH (tree) == 0)	/* Paranoia */
    abort ();

875
  GET_INTERVAL_OBJECT (parent, tree);
876 877
  offset = (BUFFERP (parent) ? BUF_BEG (XBUFFER (parent)) : 0);

878 879
  /* If inserting at point-max of a buffer, that position will be out
     of range.  Remember that buffer positions are 1-based.  */
880 881 882 883 884
  if (position >= TOTAL_LENGTH (tree) + offset)
    {
      position = TOTAL_LENGTH (tree) + offset;
      eobp = 1;
    }
Joseph Arceneaux's avatar
Joseph Arceneaux committed
885 886

  i = find_interval (tree, position);
887

888 889
  /* If in middle of an interval which is not sticky either way,
     we must not just give its properties to the insertion.
890 891 892 893 894 895 896 897 898 899
     So split this interval at the insertion point.

     Originally, the if condition here was this:
	(! (position == i->position || eobp)
	 && END_NONSTICKY_P (i)
	 && FRONT_NONSTICKY_P (i))
     But, these macros are now unreliable because of introduction of
     Vtext_property_default_nonsticky.  So, we always check properties
     one by one if POSITION is in middle of an interval.  */
  if (! (position == i->position || eobp))
900
    {
901 902 903
      Lisp_Object tail;
      Lisp_Object front, rear;

904 905 906 907 908 909 910 911 912 913 914
      tail = i->plist;

      /* Properties font-sticky and rear-nonsticky override
         Vtext_property_default_nonsticky.  So, if they are t, we can
         skip one by one checking of properties.  */
      rear = textget (i->plist, Qrear_nonsticky);
      if (! CONSP (rear) && ! NILP (rear))
	{
	  /* All properties are nonsticky.  We split the interval.  */
	  goto check_done;
	}
915
      front = textget (i->plist, Qfront_sticky);
916 917 918 919 920 921
      if (! CONSP (front) && ! NILP (front))
	{
	  /* All properties are sticky.  We don't split the interval.  */
	  tail = Qnil;
	  goto check_done;
	}
922

923 924 925
      /* Does any actual property pose an actual problem?  We break
         the loop if we find a nonsticky property.  */
      for (; CONSP (tail); tail = Fcdr (XCDR (tail)))
926
	{
927
	  Lisp_Object prop, tmp;
928
	  prop = XCAR (tail);
929

930
	  /* Is this particular property front-sticky?  */
931 932 933
	  if (CONSP (front) && ! NILP (Fmemq (prop, front)))
	    continue;

934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949
	  /* Is this particular property rear-nonsticky?  */
	  if (CONSP (rear) && ! NILP (Fmemq (prop, rear)))
	    break;

	  /* Is this particular property recorded as sticky or
             nonsticky in Vtext_property_default_nonsticky?  */
	  tmp = Fassq (prop, Vtext_property_default_nonsticky);
	  if (CONSP (tmp))
	    {
	      if (NILP (tmp))
		continue;
	      break;
	    }

	  /* By default, a text property is rear-sticky, thus we
	     continue the loop.  */
950 951
	}