intervals.c 68.4 KB
Newer Older
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1
/* Code for doing intervals.
2
   Copyright (C) 1993, 1994, 1995, 1997, 1998, 2002 Free Software Foundation, Inc.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
3 4 5 6 7

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
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)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
9 10 11 12 13 14 15 16 17
any later version.

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
along with GNU Emacs; see the file COPYING.  If not, write to
18 19
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41


/* 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.

*/


42
#include <config.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
Lisp_Object merge_properties_sticky ();
56 57
static INTERVAL reproduce_tree P_ ((INTERVAL, INTERVAL));
static INTERVAL reproduce_tree_obj P_ ((INTERVAL, Lisp_Object));
Joseph Arceneaux's avatar
Joseph Arceneaux committed
58

59
/* Utility functions for intervals.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
60 61


62
/* Create the root interval of some object, a buffer or string.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
63 64 65 66 67

INTERVAL
create_root_interval (parent)
     Lisp_Object parent;
{
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
      BUF_INTERVALS (XBUFFER (parent)) = new;
79
      new->position = 1;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
80
    }
81
  else if (STRINGP (parent))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
82
    {
83
      new->total_length = SCHARS (parent);
84
      STRING_SET_INTERVALS (parent, new);
85
      new->position = 0;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
86 87
    }

88
  SET_INTERVAL_OBJECT (new, parent);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106

  return new;
}

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

void
copy_properties (source, target)
     register INTERVAL source, target;
{
  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
107 108
   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
109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139

static void
merge_properties (source, target)
     register INTERVAL source, target;
{
  register Lisp_Object o, sym, val;

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

  MERGE_INTERVAL_CACHE (source, target);

  o = source->plist;
  while (! EQ (o, Qnil))
    {
      sym = Fcar (o);
      val = Fmemq (sym, target->plist);

      if (NILP (val))
	{
	  o = Fcdr (o);
	  val = Fcar (o);
	  target->plist = Fcons (sym, Fcons (val, target->plist));
	  o = Fcdr (o);
	}
      else
	o = Fcdr (Fcdr (o));
    }
}

/* Return 1 if the two intervals have the same properties,
140
   0 otherwise.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
141 142 143 144 145 146

int
intervals_equal (i0, i1)
     INTERVAL i0, i1;
{
  register Lisp_Object i0_cdr, i0_sym, i1_val;
Andreas Schwab's avatar
Andreas Schwab committed
147
  register int i1_len;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
148 149 150 151

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

152 153 154
  if (DEFAULT_INTERVAL_P (i0) || DEFAULT_INTERVAL_P (i1))
    return 0;

Joseph Arceneaux's avatar
Joseph Arceneaux committed
155 156 157 158 159 160 161
  i1_len = XFASTINT (Flength (i1->plist));
  if (i1_len & 0x1)		/* Paranoia -- plists are always even */
    abort ();
  i1_len /= 2;
  i0_cdr = i0->plist;
  while (!NILP (i0_cdr))
    {
162
      /* Lengths of the two plists were unequal.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
163 164 165 166 167 168
      if (i1_len == 0)
	return 0;

      i0_sym = Fcar (i0_cdr);
      i1_val = Fmemq (i0_sym, i1->plist);

169
      /* i0 has something i1 doesn't.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
170 171 172
      if (EQ (i1_val, Qnil))
	return 0;

173
      /* i0 and i1 both have sym, but it has different values in each.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
174
      i0_cdr = Fcdr (i0_cdr);
175
      if (! EQ (Fcar (Fcdr (i1_val)), Fcar (i0_cdr)))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
176 177 178 179 180 181
	return 0;

      i0_cdr = Fcdr (i0_cdr);
      i1_len--;
    }

182
  /* Lengths of the two plists were unequal.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
183 184 185 186 187 188 189
  if (i1_len > 0)
    return 0;

  return 1;
}


190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213
/* 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
traverse_intervals_noorder (tree, function, arg)
     INTERVAL tree;
     void (* function) P_ ((INTERVAL, Lisp_Object));
     Lisp_Object arg;
{
  /* 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
214
/* Traverse an interval tree TREE, performing FUNCTION on each node.
215
   Pass FUNCTION two args: an interval, and ARG.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
216 217

void
218
traverse_intervals (tree, position, function, arg)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
219
     INTERVAL tree;
220
     int position;
221
     void (* function) P_ ((INTERVAL, Lisp_Object));
222
     Lisp_Object arg;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
223
{
224 225
  while (!NULL_INTERVAL_P (tree))
    {
226
      traverse_intervals (tree->left, position, function, arg);
227 228 229
      position += LEFT_TOTAL_LENGTH (tree);
      tree->position = position;
      (*function) (tree, arg);
230
      position += LENGTH (tree); tree = tree->right;
231
    }
Joseph Arceneaux's avatar
Joseph Arceneaux committed
232 233 234
}

#if 0
235 236 237 238 239

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

240
/* These functions are temporary, for debugging purposes only.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261

INTERVAL search_interval, found_interval;

void
check_for_interval (i)
     register INTERVAL i;
{
  if (i == search_interval)
    {
      found_interval = i;
      icount++;
    }
}

INTERVAL
search_for_interval (i, tree)
     register INTERVAL i, tree;
{
  icount = 0;
  search_interval = i;
  found_interval = NULL_INTERVAL;
262
  traverse_intervals_noorder (tree, &check_for_interval, Qnil);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283
  return found_interval;
}

static void
inc_interval_count (i)
     INTERVAL i;
{
  icount++;
  if (LENGTH (i) == 0)
    zero_length++;
  if (depth > idepth)
    idepth = depth;
}

int
count_intervals (i)
     register INTERVAL i;
{
  icount = 0;
  idepth = 0;
  zero_length = 0;
284
  traverse_intervals_noorder (i, &inc_interval_count, Qnil);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
285 286 287 288 289 290 291 292 293 294 295

  return icount;
}

static INTERVAL
root_interval (interval)
     INTERVAL interval;
{
  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
*/

311
static INLINE INTERVAL
Joseph Arceneaux's avatar
Joseph Arceneaux committed
312 313 314 315 316
rotate_right (interval)
     INTERVAL interval;
{
  INTERVAL i;
  INTERVAL B = interval->left;
317
  int old_total = interval->total_length;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
318

319
  /* Deal with any Parent of A;  make it point to B.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
320
  if (! ROOT_INTERVAL_P (interval))
321 322
    {
      if (AM_LEFT_CHILD (interval))
323
	INTERVAL_PARENT (interval)->left = B;
324
      else
325
	INTERVAL_PARENT (interval)->right = B;
326
    }
327
  COPY_INTERVAL_PARENT (B, interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
328

329 330 331
  /* Make B the parent of A */
  i = B->right;
  B->right = interval;
332
  SET_INTERVAL_PARENT (interval, B);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
333

334
  /* Make A point to c */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
335 336
  interval->left = i;
  if (! NULL_INTERVAL_P (i))
337
    SET_INTERVAL_PARENT (i, interval);
338

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

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

  return B;
}
347

Joseph Arceneaux's avatar
Joseph Arceneaux committed
348 349 350 351 352 353 354 355 356
/* Assuming that a right child exists, perform the following operation:

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

357
static INLINE INTERVAL
Joseph Arceneaux's avatar
Joseph Arceneaux committed
358 359 360 361 362
rotate_left (interval)
     INTERVAL interval;
{
  INTERVAL i;
  INTERVAL B = interval->right;
363
  int 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.  */
386 387 388 389
  interval->total_length -= B->total_length - RIGHT_TOTAL_LENGTH (interval);

  /* B must have the same total length of A.  */
  B->total_length = old_total;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
390 391 392 393

  return B;
}

394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437
/* Balance an interval tree with the assumption that the subtrees
   themselves are already balanced.  */

static INTERVAL
balance_an_interval (i)
     INTERVAL i;
{
  register int old_diff, new_diff;

  while (1)
    {
      old_diff = LEFT_TOTAL_LENGTH (i) - RIGHT_TOTAL_LENGTH (i);
      if (old_diff > 0)
	{
	  new_diff = i->total_length - i->left->total_length
	    + RIGHT_TOTAL_LENGTH (i->left) - LEFT_TOTAL_LENGTH (i->left);
	  if (abs (new_diff) >= old_diff)
	    break;
	  i = rotate_right (i);
	  balance_an_interval (i->right);
	}
      else if (old_diff < 0)
	{
	  new_diff = i->total_length - i->right->total_length
	    + LEFT_TOTAL_LENGTH (i->right) - RIGHT_TOTAL_LENGTH (i->right);
	  if (abs (new_diff) >= -old_diff)
	    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.  */

static INLINE INTERVAL
balance_possible_root_interval (interval)
     register INTERVAL interval;
{
  Lisp_Object parent;
438
  int have_parent = 0;
439

440
  if (!INTERVAL_HAS_OBJECT (interval) && !INTERVAL_HAS_PARENT (interval))
441 442
    return interval;

443 444 445 446 447
  if (INTERVAL_HAS_OBJECT (interval))
    {
      have_parent = 1;
      GET_INTERVAL_OBJECT (parent, interval);
    }
448 449
  interval = balance_an_interval (interval);

450 451 452 453 454
  if (have_parent)
    {
      if (BUFFERP (parent))
	BUF_INTERVALS (XBUFFER (parent)) = interval;
      else if (STRINGP (parent))
455
	STRING_SET_INTERVALS (parent, interval);
456
    }
457 458 459 460 461 462 463 464 465 466 467 468 469

  return interval;
}

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

static INTERVAL
balance_intervals_internal (tree)
     register INTERVAL tree;
{
  /* Balance within each side.  */
  if (tree->left)
470
    balance_intervals_internal (tree->left);
471
  if (tree->right)
472
    balance_intervals_internal (tree->right);
473 474 475 476 477 478 479 480 481 482 483 484 485 486 487
  return balance_an_interval (tree);
}

/* Advertised interface to balance intervals.  */

INTERVAL
balance_intervals (tree)
     INTERVAL tree;
{
  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
Joseph Arceneaux's avatar
Joseph Arceneaux committed
502
split_interval_right (interval, offset)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
503
     INTERVAL interval;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
504
     int offset;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
505 506 507
{
  INTERVAL new = make_interval ();
  int position = interval->position;
508
  int new_length = LENGTH (interval) - offset;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
509

510
  new->position = position + offset;
511
  SET_INTERVAL_PARENT (new, interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
512

513
  if (NULL_RIGHT_CHILD (interval))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
514 515 516 517
    {
      interval->right = new;
      new->total_length = new_length;
    }
518 519 520 521
  else
    {
      /* Insert the new node between INTERVAL and its right child.  */
      new->right = interval->right;
522
      SET_INTERVAL_PARENT (interval->right, new);
523 524 525 526 527
      interval->right = new;
      new->total_length = new_length + new->right->total_length;
      balance_an_interval (new);
    }
  
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
Joseph Arceneaux's avatar
Joseph Arceneaux committed
547
split_interval_left (interval, offset)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
548
     INTERVAL interval;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
549
     int offset;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
550 551
{
  INTERVAL new = make_interval ();
552
  int new_length = offset;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
553 554

  new->position = interval->position;
555
  interval->position = interval->position + offset;
556
  SET_INTERVAL_PARENT (new, interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
557 558 559 560 561 562

  if (NULL_LEFT_CHILD (interval))
    {
      interval->left = new;
      new->total_length = new_length;
    }
563 564 565 566
  else
    {
      /* Insert the new node between INTERVAL and its left child.  */
      new->left = interval->left;
567
      SET_INTERVAL_PARENT (new->left, new);
568 569 570 571 572
      interval->left = new;
      new->total_length = new_length + new->left->total_length;
      balance_an_interval (new);
    }
  
573
  balance_possible_root_interval (interval);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
574 575 576 577

  return new;
}

578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594
/* 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!  */

int
interval_start_pos (source)
     INTERVAL source;
{
  Lisp_Object parent;

  if (NULL_INTERVAL_P (source))
    return 0;

595 596
  if (! INTERVAL_HAS_OBJECT (source))
    return 0;
597
  GET_INTERVAL_OBJECT (parent, source);
598 599 600 601 602
  if (BUFFERP (parent))
    return BUF_BEG (XBUFFER (parent));
  return 0;
}

Joseph Arceneaux's avatar
Joseph Arceneaux committed
603
/* Find the interval containing text position POSITION in the text
604
   represented by the interval tree TREE.  POSITION is a buffer
605 606 607
   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
608

Joseph Arceneaux's avatar
Joseph Arceneaux committed
609 610
   The `position' field, which is a cache of an interval's position,
   is updated in the interval found.  Other functions (e.g., next_interval)
611
   will update this cache based on the result of find_interval.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
612

613
INTERVAL
Joseph Arceneaux's avatar
Joseph Arceneaux committed
614 615 616 617
find_interval (tree, position)
     register INTERVAL tree;
     register int position;
{
618 619
  /* The distance from the left edge of the subtree at TREE
                    to POSITION.  */
620
  register int relative_position;
Joseph Arceneaux's avatar
Joseph Arceneaux committed
621 622 623 624

  if (NULL_INTERVAL_P (tree))
    return NULL_INTERVAL;

625
  relative_position = position;
626 627 628 629 630 631 632
  if (INTERVAL_HAS_OBJECT (tree))
    {
      Lisp_Object parent;
      GET_INTERVAL_OBJECT (parent, tree);
      if (BUFFERP (parent))
	relative_position -= BUF_BEG (XBUFFER (parent));
    }
633

634
  if (relative_position > TOTAL_LENGTH (tree))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
635 636
    abort ();			/* Paranoia */

637 638
  if (!handling_signal)
    tree = balance_possible_root_interval (tree);
639

Joseph Arceneaux's avatar
Joseph Arceneaux committed
640 641
  while (1)
    {
642
      if (relative_position < LEFT_TOTAL_LENGTH (tree))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
643 644 645
	{
	  tree = tree->left;
	}
646 647 648
      else if (! NULL_RIGHT_CHILD (tree)
	       && relative_position >= (TOTAL_LENGTH (tree)
					- RIGHT_TOTAL_LENGTH (tree)))
Joseph Arceneaux's avatar
Joseph Arceneaux committed
649 650 651 652 653 654 655
	{
	  relative_position -= (TOTAL_LENGTH (tree)
				- RIGHT_TOTAL_LENGTH (tree));
	  tree = tree->right;
	}
      else
	{
656 657 658
	  tree->position
	    = (position - relative_position /* the left edge of *tree */
	       + LEFT_TOTAL_LENGTH (tree)); /* the left edge of this interval */
659

Joseph Arceneaux's avatar
Joseph Arceneaux committed
660 661 662 663 664 665
	  return tree;
	}
    }
}

/* Find the succeeding interval (lexicographically) to INTERVAL.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
666
   Sets the `position' field based on that of INTERVAL (see
667
   find_interval).  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693

INTERVAL
next_interval (interval)
     register INTERVAL interval;
{
  register INTERVAL i = interval;
  register int next_position;

  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))
	{
694
	  i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
695 696 697 698
	  i->position = next_position;
	  return i;
	}

699
      i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
700 701 702 703 704 705
    }

  return NULL_INTERVAL;
}

/* Find the preceding interval (lexicographically) to INTERVAL.
Joseph Arceneaux's avatar
Joseph Arceneaux committed
706
   Sets the `position' field based on that of INTERVAL (see
707
   find_interval).  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732

INTERVAL
previous_interval (interval)
     register INTERVAL interval;
{
  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))
	{
733
	  i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
734 735 736 737

	  i->position = interval->position - LENGTH (i);
	  return i;
	}
738
      i = INTERVAL_PARENT (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
739 740 741 742
    }

  return NULL_INTERVAL;
}
743 744

/* Find the interval containing POS given some non-NULL INTERVAL
745
   in the same tree.  Note that we need to update interval->position
746 747 748
   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.  */
749 750 751 752 753 754 755 756 757 758 759 760 761
INTERVAL
update_interval (i, pos)
     register INTERVAL i;
     int pos;
{
  if (NULL_INTERVAL_P (i))
    return NULL_INTERVAL;

  while (1) 
    {
      if (pos < i->position) 
	{
	  /* Move left. */
762 763 764 765 766 767
	  if (pos >= i->position - TOTAL_LENGTH (i->left)) 
	    {
	      i->left->position = i->position - TOTAL_LENGTH (i->left)
		+ LEFT_TOTAL_LENGTH (i->left);
	      i = i->left;		/* Move to the left child */
	    }
768 769
	  else if (NULL_PARENT (i)) 
	    error ("Point before start of properties");
770
	  else  
771
	      i = INTERVAL_PARENT (i);
772 773 774 775 776
	  continue;
	}
      else if (pos >= INTERVAL_LAST_POS (i))
	{
	  /* Move right. */
777 778 779 780 781 782
	  if (pos < INTERVAL_LAST_POS (i) + TOTAL_LENGTH (i->right)) 
	    {
	      i->right->position = INTERVAL_LAST_POS (i) +
		LEFT_TOTAL_LENGTH (i->right);
	      i = i->right;		/* Move to the right child */
	    }
783 784 785
	  else if (NULL_PARENT (i)) 
	    error ("Point after end of properties");
	  else 
786
	      i = INTERVAL_PARENT (i);
787 788 789 790 791 792 793
	  continue;
	}
      else 
	return i;
    }
}

Joseph Arceneaux's avatar
Joseph Arceneaux committed
794

Joseph Arceneaux's avatar
Joseph Arceneaux committed
795
#if 0
Joseph Arceneaux's avatar
Joseph Arceneaux committed
796 797 798 799 800 801 802 803 804
/* 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
805
   and check the hungry bits of both.  Then add the length going back up
806
   to the root.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843

static INTERVAL
adjust_intervals_for_insertion (tree, position, length)
     INTERVAL tree;
     int position, length;
{
  register int relative_position;
  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;
	  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;
	  this = this->right;
	}
      else
	{
	  /* If we are to use zero-length intervals as buffer pointers,
844
	     then this code will have to change.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
845 846 847 848 849 850 851
	  this->total_length += length;
	  this->position = LEFT_TOTAL_LENGTH (this)
	                   + position - relative_position + 1;
	  return tree;
	}
    }
}
Joseph Arceneaux's avatar
Joseph Arceneaux committed
852 853 854 855
#endif

/* Effect an adjustment corresponding to the addition of LENGTH characters
   of text.  Do this by finding the interval containing POSITION in the
856
   interval tree TREE, and then adjusting all of its ancestors by adding
Joseph Arceneaux's avatar
Joseph Arceneaux committed
857 858 859 860 861 862
   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
863
   If both intervals are "sticky", then make them belong to the left-most
Joseph Arceneaux's avatar
Joseph Arceneaux committed
864
   interval.  Another possibility would be to create a new interval for
865
   this text, and make it have the merged properties of both ends.  */
Joseph Arceneaux's avatar
Joseph Arceneaux committed
866 867 868 869 870 871 872

static INTERVAL
adjust_intervals_for_insertion (tree, position, length)
     INTERVAL tree;
     int position, length;
{
  register INTERVAL i;
873 874
  register INTERVAL temp;
  int eobp = 0;
875 876
  Lisp_Object parent;
  int offset;
877
  
Joseph Arceneaux's avatar
Joseph Arceneaux committed
878 879 880
  if (TOTAL_LENGTH (tree) == 0)	/* Paranoia */
    abort ();

881
  GET_INTERVAL_OBJECT (parent, tree);
882 883
  offset = (BUFFERP (parent) ? BUF_BEG (XBUFFER (parent)) : 0);

884 885
  /* If inserting at point-max of a buffer, that position will be out
     of range.  Remember that buffer positions are 1-based.  */
886 887 888 889 890
  if (position >= TOTAL_LENGTH (tree) + offset)
    {
      position = TOTAL_LENGTH (tree) + offset;
      eobp = 1;
    }
Joseph Arceneaux's avatar
Joseph Arceneaux committed
891 892

  i = find_interval (tree, position);
893

894 895
  /* If in middle of an interval which is not sticky either way,
     we must not just give its properties to the insertion.
896 897 898 899 900 901 902 903 904 905
     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))
906
    {
907 908 909
      Lisp_Object tail;
      Lisp_Object front, rear;

910 911 912 913 914 915 916 917 918 919 920
      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;
	}
921
      front = textget (i->plist, Qfront_sticky);
922 923 924 925 926 927
      if (! CONSP (front) && ! NILP (front))
	{
	  /* All properties are sticky.  We don't split the interval.  */
	  tail = Qnil;
	  goto check_done;
	}
928

929 930 931
      /* 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)))
932
	{
933
	  Lisp_Object prop, tmp;
934
	  prop = XCAR (tail);
935

936
	  /* Is this particular property front-sticky?  */
937 938 939
	  if (CONSP (front) && ! NILP (Fmemq (prop, front)))
	    continue;

940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955
	  /* 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.  */
956 957
	}

958
    check_done:
959 960 961 962 963 964 965
      /* If any property is a real problem, split the interval.  */
      if (! NILP (tail))
	{
	  temp = split_interval_right (i, position - i->position);
	  copy_properties (i, temp);
	  i = temp;
	}
966 967
    }

Joseph Arceneaux's avatar
Joseph Arceneaux committed
968
  /* If we are positioned between intervals, check the stickiness of
969 970
     both of them.  We have to do this too, if we are at BEG or Z.  */
  if (position == i->position || eobp)
Joseph Arceneaux's avatar
Joseph Arceneaux committed
971
    {
972 973 974 975 976 977 978 979 980 981 982
      register INTERVAL prev;

      if (position == BEG)
	prev = 0;
      else if (eobp)
	{
	  prev = i;
	  i = 0;
	}
      else
	prev = previous_interval (i);
Joseph Arceneaux's avatar
Joseph Arceneaux committed
983

984 985
      /* Even if we are positioned between intervals, we default
	 to the left one if it exists.  We extend it now and split
Karl Heuer's avatar
Karl Heuer committed
986
	 off a part later, if stickiness demands it.  */
987
      for (temp = prev ? prev : i; temp; temp = INTERVAL_PARENT_OR_NULL (temp))
988 989 990 991
	{
	  temp->total_length += length;
	  temp = balance_possible_root_interval (temp);
	}
992 993
      
      /* If at least one interval has sticky properties,
994 995 996 997 998 999 1000 1001 1002 1003
	 we check the stickiness property by property.

	 Originally, the if condition here was this:
		(END_NONSTICKY_P (prev) || FRONT_STICKY_P (i))
	 But, these macros are now unreliable because of introduction
	 of Vtext_property_default_nonsticky.  So, we always have to
	 check stickiness of properties one by one.  If cache of
	 stickiness is implemented in the future, we may be able to
	 use those macros again.  */
      if (1)
1004
	{
1005
	  Lisp_Object pleft, pright;
1006 1007
	  struct interval newi;

1008 1009
	  pleft = NULL_INTERVAL_P (prev) ? Qnil : prev->plist;
	  pright = NULL_INTERVAL_P (i) ? Qnil : i->plist;
1010 1011
	  newi.plist = merge_properties_sticky (pleft, pright);

1012
	  if (! prev) /* i.e. position == BEG */
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
	    {
	      if (! intervals_equal (i, &newi))
		{
		  i = split_interval_left (i, length);
		  i->plist = newi.plist;
		}
	    }
	  else if (! intervals_equal (prev, &newi))
	    {
	      prev = split_interval_right (prev,
					   position - prev->position);
	      prev->plist = newi.plist;
	      if (! NULL_INTERVAL_P (i)
		  && intervals_equal (prev, i))
		merge_interval_right (prev);
	    }

	  /* We will need to update the cache here later.  */
	}
      else if (! prev && ! NILP (i->plist))
        {
	  /* Just split off a new interval at the left.
	     Since I wasn't front-sticky, the empty plist is ok.  */
	  i = split_interval_left (i, length);
        }
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1038 1039
    }

1040 1041
  /* Otherwise just extend the interval.  */
  else
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1042
    {
1043
      for (temp = i; temp; temp = INTERVAL_PARENT_OR_NULL (temp))
1044 1045 1046 1047
	{
	  temp->total_length += length;
	  temp = balance_possible_root_interval (temp);
	}
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1048
    }
1049
      
Joseph Arceneaux's avatar
Joseph Arceneaux committed
1050 1051
  return tree;
}
1052

1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
/* Any property might be front-sticky on the left, rear-sticky on the left,
   front-sticky on the right, or rear-sticky on the right; the 16 combinations
   can be arranged in a matrix with rows denoting the left conditions and
   columns denoting the right conditions:
      _  __  _
_     FR FR FR FR
FR__   0  1  2  3
 _FR   4  5  6  7
FR     8  9  A  B
  FR   C  D  E  F

   left-props  = '(front-sticky (p8 p9 pa pb pc pd pe pf)
		   rear-nonsticky (p4 p5 p6 p7 p8 p9 pa pb)
		   p0 L p1 L p2 L p3 L p4 L p5 L p6 L p7 L
		   p8 L p9 L pa L pb L pc L pd L pe L pf L)
   right-props = '(front-sticky (p2 p3 p6 p7 pa pb pe pf)
		   rear-nonsticky (p1 p2 p5 p6 p9 pa pd pe)
		   p0 R p1 R p2 R p3 R p4 R p5 R p6 R p7 R
		   p8 R p9 R pa R pb R pc R pd R pe R pf R)

   We inherit from whoever has a sticky side facing us.  If both sides
   do (cases 2, 3, E, and F), then we inherit from whichever side has a
   non-nil value for the current property.  If both sides do, then we take
   from the left.

   When we inherit a property, we get its stickiness as well as its value.
   So, when we merge the above two lists, we expect to get this:

   result      = '(front-sticky (p6 p7 pa pb pc pd pe pf)
		   rear-nonsticky (p6 pa)
		   p0 L p1 L p2 L p3 L p6 R p7 R
		   pa R pb R pc L pd L pe L pf L)

   The optimizable special cases are:
       left rear-nonsticky = nil, right front-sticky = nil (inherit left)
       left rear-nonsticky = t,   right front-sticky = t   (inherit right)
       left rear-nonsticky = t,   right front-sticky = nil (inherit none)
*/

1092 1093 1094 1095
Lisp_Object
merge_properties_sticky (pleft, pright)
     Lisp_Object pleft, pright;
{
1096 1097
  register Lisp_Object props, front, rear;
  Lisp_Object lfront, lrear, rfront, rrear;
1098
  register Lisp_Object tail1, tail2, sym, lval, rval, cat;
1099
  int use_left, use_right;
1100
  int lpresent;
1101

1102 1103 1104 1105 1106 1107 1108 1109
  props = Qnil;
  front = Qnil;
  rear  = Qnil;
  lfront = textget (pleft, Qfront_sticky);
  lrear  = textget (pleft, Qrear_nonsticky);
  rfront = textget (pright, Qfront_sticky);
  rrear  = textget (pright, Qrear_nonsticky);

1110
  /* Go through each element of PRIGHT.  */
1111
  for (tail1 = pright; CONSP (tail1); tail1 = Fcdr (Fcdr (tail1)))
1112
    {
1113 1114
      Lisp_Object tmp;

1115 1116 1117 1118 1119
      sym = Fcar (tail1);

      /* Sticky properties get special treatment.  */
      if (EQ (sym, Qrear_nonsticky) || EQ (sym, Qfront_sticky))
	continue;
1120 1121

      rval = Fcar (Fcdr (tail1));
1122
      for (tail2 = pleft; CONSP (tail2); tail2 = Fcdr (Fcdr (tail2)))
1123 1124 1125
	if (EQ (sym, Fcar (tail2)))
	  break;

1126 1127 1128 1129 1130 1131
      /* Indicate whether the property is explicitly defined on the left.
	 (We know it is defined explicitly on the right
	 because otherwise we don't get here.)  */
      lpresent = ! NILP (tail2);
      lval = (NILP (tail2) ? Qnil : Fcar (Fcdr (tail2)));

1132 1133 1134 1135 1136 1137
      /* Even if lrear or rfront say nothing about the stickiness of
	 SYM, Vtext_property_default_nonsticky may give default
	 stickiness to SYM.  */
      tmp = Fassq (sym, Vtext_property_default_nonsticky);
      use_left = (lpresent
		  && ! (TMEM (sym, lrear)
1138
			|| (CONSP (tmp) && ! NILP (XCDR (tmp)))));
1139 1140
      use_right = (TMEM (sym, rfront)
		   || (CONSP (tmp) && NILP (XCDR (tmp))));
1141 1142
      if (use_left && use_right)
	{
1143 1144 1145 1146
	  if (NILP (lval))
	    use_left = 0;
	  else if (NILP (rval))
	    use_right = 0;
1147 1148
	}
      if (use_left)
1149
	{
1150 1151
	  /* We build props as (value sym ...) rather than (sym value ...)
	     because we plan to nreverse it when we're done.  */