1/*
2 * Copyright © 2012,2017 Google, Inc.
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 *
24 * Google Author(s): Behdad Esfahbod
25 */
26
27#ifndef HB_SET_HH
28#define HB_SET_HH
29
30#include "hb.hh"
31
32
33/*
34 * hb_set_t
35 */
36
37/* TODO Keep a free-list so we can free pages that are completely zeroed. At that
38 * point maybe also use a sentinel value for "all-1" pages? */
39
40struct hb_set_t
41{
42 HB_NO_COPY_ASSIGN (hb_set_t);
43 hb_set_t () { init (); }
44 ~hb_set_t () { fini (); }
45
46 struct page_map_t
47 {
48 int cmp (const page_map_t &o) const { return (int) o.major - (int) major; }
49
50 uint32_t major;
51 uint32_t index;
52 };
53
54 struct page_t
55 {
56 void init0 () { v.clear (); }
57 void init1 () { v.clear (0xFF); }
58
59 unsigned int len () const
60 { return ARRAY_LENGTH_CONST (v); }
61
62 bool is_empty () const
63 {
64 for (unsigned int i = 0; i < len (); i++)
65 if (v[i])
66 return false;
67 return true;
68 }
69
70 void add (hb_codepoint_t g) { elt (g) |= mask (g); }
71 void del (hb_codepoint_t g) { elt (g) &= ~mask (g); }
72 bool has (hb_codepoint_t g) const { return !!(elt (g) & mask (g)); }
73
74 void add_range (hb_codepoint_t a, hb_codepoint_t b)
75 {
76 elt_t *la = &elt (a);
77 elt_t *lb = &elt (b);
78 if (la == lb)
79 *la |= (mask (b) << 1) - mask(a);
80 else
81 {
82 *la |= ~(mask (a) - 1);
83 la++;
84
85 memset (la, 0xff, (char *) lb - (char *) la);
86
87 *lb |= ((mask (b) << 1) - 1);
88 }
89 }
90
91 bool is_equal (const page_t *other) const
92 {
93 return 0 == hb_memcmp (&v, &other->v, sizeof (v));
94 }
95
96 unsigned int get_population () const
97 {
98 unsigned int pop = 0;
99 for (unsigned int i = 0; i < len (); i++)
100 pop += hb_popcount (v[i]);
101 return pop;
102 }
103
104 bool next (hb_codepoint_t *codepoint) const
105 {
106 unsigned int m = (*codepoint + 1) & MASK;
107 if (!m)
108 {
109 *codepoint = INVALID;
110 return false;
111 }
112 unsigned int i = m / ELT_BITS;
113 unsigned int j = m & ELT_MASK;
114
115 const elt_t vv = v[i] & ~((elt_t (1) << j) - 1);
116 for (const elt_t *p = &vv; i < len (); p = &v[++i])
117 if (*p)
118 {
119 *codepoint = i * ELT_BITS + elt_get_min (*p);
120 return true;
121 }
122
123 *codepoint = INVALID;
124 return false;
125 }
126 bool previous (hb_codepoint_t *codepoint) const
127 {
128 unsigned int m = (*codepoint - 1) & MASK;
129 if (m == MASK)
130 {
131 *codepoint = INVALID;
132 return false;
133 }
134 unsigned int i = m / ELT_BITS;
135 unsigned int j = m & ELT_MASK;
136
137 const elt_t vv = v[i] & ((elt_t (1) << (j + 1)) - 1);
138 for (const elt_t *p = &vv; (int) i >= 0; p = &v[--i])
139 if (*p)
140 {
141 *codepoint = i * ELT_BITS + elt_get_max (*p);
142 return true;
143 }
144
145 *codepoint = INVALID;
146 return false;
147 }
148 hb_codepoint_t get_min () const
149 {
150 for (unsigned int i = 0; i < len (); i++)
151 if (v[i])
152 return i * ELT_BITS + elt_get_min (v[i]);
153 return INVALID;
154 }
155 hb_codepoint_t get_max () const
156 {
157 for (int i = len () - 1; i >= 0; i--)
158 if (v[i])
159 return i * ELT_BITS + elt_get_max (v[i]);
160 return 0;
161 }
162
163 typedef unsigned long long elt_t;
164 static constexpr unsigned PAGE_BITS = 512;
165 static_assert ((PAGE_BITS & ((PAGE_BITS) - 1)) == 0, "");
166
167 static unsigned int elt_get_min (const elt_t &elt) { return hb_ctz (elt); }
168 static unsigned int elt_get_max (const elt_t &elt) { return hb_bit_storage (elt) - 1; }
169
170 typedef hb_vector_size_t<elt_t, PAGE_BITS / 8> vector_t;
171
172 static constexpr unsigned ELT_BITS = sizeof (elt_t) * 8;
173 static constexpr unsigned ELT_MASK = ELT_BITS - 1;
174 static constexpr unsigned BITS = sizeof (vector_t) * 8;
175 static constexpr unsigned MASK = BITS - 1;
176 static_assert ((unsigned) PAGE_BITS == (unsigned) BITS, "");
177
178 elt_t &elt (hb_codepoint_t g) { return v[(g & MASK) / ELT_BITS]; }
179 elt_t const &elt (hb_codepoint_t g) const { return v[(g & MASK) / ELT_BITS]; }
180 elt_t mask (hb_codepoint_t g) const { return elt_t (1) << (g & ELT_MASK); }
181
182 vector_t v;
183 };
184 static_assert (page_t::PAGE_BITS == sizeof (page_t) * 8, "");
185
186 hb_object_header_t header;
187 bool successful; /* Allocations successful */
188 mutable unsigned int population;
189 hb_vector_t<page_map_t> page_map;
190 hb_vector_t<page_t> pages;
191
192 void init_shallow ()
193 {
194 successful = true;
195 population = 0;
196 page_map.init ();
197 pages.init ();
198 }
199 void init ()
200 {
201 hb_object_init (this);
202 init_shallow ();
203 }
204 void fini_shallow ()
205 {
206 population = 0;
207 page_map.fini ();
208 pages.fini ();
209 }
210 void fini ()
211 {
212 hb_object_fini (this);
213 fini_shallow ();
214 }
215
216 bool in_error () const { return !successful; }
217
218 bool resize (unsigned int count)
219 {
220 if (unlikely (!successful)) return false;
221 if (!pages.resize (count) || !page_map.resize (count))
222 {
223 pages.resize (page_map.length);
224 successful = false;
225 return false;
226 }
227 return true;
228 }
229
230 void clear ()
231 {
232 if (unlikely (hb_object_is_immutable (this)))
233 return;
234 successful = true;
235 population = 0;
236 page_map.resize (0);
237 pages.resize (0);
238 }
239 bool is_empty () const
240 {
241 unsigned int count = pages.length;
242 for (unsigned int i = 0; i < count; i++)
243 if (!pages[i].is_empty ())
244 return false;
245 return true;
246 }
247
248 void dirty () { population = (unsigned int) -1; }
249
250 void add (hb_codepoint_t g)
251 {
252 if (unlikely (!successful)) return;
253 if (unlikely (g == INVALID)) return;
254 dirty ();
255 page_t *page = page_for_insert (g); if (unlikely (!page)) return;
256 page->add (g);
257 }
258 bool add_range (hb_codepoint_t a, hb_codepoint_t b)
259 {
260 if (unlikely (!successful)) return true; /* https://github.com/harfbuzz/harfbuzz/issues/657 */
261 if (unlikely (a > b || a == INVALID || b == INVALID)) return false;
262 dirty ();
263 unsigned int ma = get_major (a);
264 unsigned int mb = get_major (b);
265 if (ma == mb)
266 {
267 page_t *page = page_for_insert (a); if (unlikely (!page)) return false;
268 page->add_range (a, b);
269 }
270 else
271 {
272 page_t *page = page_for_insert (a); if (unlikely (!page)) return false;
273 page->add_range (a, major_start (ma + 1) - 1);
274
275 for (unsigned int m = ma + 1; m < mb; m++)
276 {
277 page = page_for_insert (major_start (m)); if (unlikely (!page)) return false;
278 page->init1 ();
279 }
280
281 page = page_for_insert (b); if (unlikely (!page)) return false;
282 page->add_range (major_start (mb), b);
283 }
284 return true;
285 }
286
287 template <typename T>
288 void add_array (const T *array, unsigned int count, unsigned int stride=sizeof(T))
289 {
290 if (unlikely (!successful)) return;
291 if (!count) return;
292 dirty ();
293 hb_codepoint_t g = *array;
294 while (count)
295 {
296 unsigned int m = get_major (g);
297 page_t *page = page_for_insert (g); if (unlikely (!page)) return;
298 unsigned int start = major_start (m);
299 unsigned int end = major_start (m + 1);
300 do
301 {
302 page->add (g);
303
304 array = (const T *) ((const char *) array + stride);
305 count--;
306 }
307 while (count && (g = *array, start <= g && g < end));
308 }
309 }
310
311 /* Might return false if array looks unsorted.
312 * Used for faster rejection of corrupt data. */
313 template <typename T>
314 bool add_sorted_array (const T *array, unsigned int count, unsigned int stride=sizeof(T))
315 {
316 if (unlikely (!successful)) return true; /* https://github.com/harfbuzz/harfbuzz/issues/657 */
317 if (!count) return true;
318 dirty ();
319 hb_codepoint_t g = *array;
320 hb_codepoint_t last_g = g;
321 while (count)
322 {
323 unsigned int m = get_major (g);
324 page_t *page = page_for_insert (g); if (unlikely (!page)) return false;
325 unsigned int end = major_start (m + 1);
326 do
327 {
328 /* If we try harder we can change the following comparison to <=;
329 * Not sure if it's worth it. */
330 if (g < last_g) return false;
331 last_g = g;
332 page->add (g);
333
334 array = (const T *) ((const char *) array + stride);
335 count--;
336 }
337 while (count && (g = *array, g < end));
338 }
339 return true;
340 }
341
342 void del (hb_codepoint_t g)
343 {
344 /* TODO perform op even if !successful. */
345 if (unlikely (!successful)) return;
346 page_t *page = page_for (g);
347 if (!page)
348 return;
349 dirty ();
350 page->del (g);
351 }
352 void del_range (hb_codepoint_t a, hb_codepoint_t b)
353 {
354 /* TODO perform op even if !successful. */
355 /* TODO Optimize, like add_range(). */
356 if (unlikely (!successful)) return;
357 for (unsigned int i = a; i < b + 1; i++)
358 del (i);
359 }
360 bool has (hb_codepoint_t g) const
361 {
362 const page_t *page = page_for (g);
363 if (!page)
364 return false;
365 return page->has (g);
366 }
367 bool intersects (hb_codepoint_t first,
368 hb_codepoint_t last) const
369 {
370 hb_codepoint_t c = first - 1;
371 return next (&c) && c <= last;
372 }
373 void set (const hb_set_t *other)
374 {
375 if (unlikely (!successful)) return;
376 unsigned int count = other->pages.length;
377 if (!resize (count))
378 return;
379 population = other->population;
380 memcpy ((void *) pages, (const void *) other->pages, count * pages.item_size);
381 memcpy ((void *) page_map, (const void *) other->page_map, count * page_map.item_size);
382 }
383
384 bool is_equal (const hb_set_t *other) const
385 {
386 if (get_population () != other->get_population ())
387 return false;
388
389 unsigned int na = pages.length;
390 unsigned int nb = other->pages.length;
391
392 unsigned int a = 0, b = 0;
393 for (; a < na && b < nb; )
394 {
395 if (page_at (a).is_empty ()) { a++; continue; }
396 if (other->page_at (b).is_empty ()) { b++; continue; }
397 if (page_map[a].major != other->page_map[b].major ||
398 !page_at (a).is_equal (&other->page_at (b)))
399 return false;
400 a++;
401 b++;
402 }
403 for (; a < na; a++)
404 if (!page_at (a).is_empty ()) { return false; }
405 for (; b < nb; b++)
406 if (!other->page_at (b).is_empty ()) { return false; }
407
408 return true;
409 }
410
411 bool is_subset (const hb_set_t *larger_set) const
412 {
413 if (get_population () > larger_set->get_population ())
414 return false;
415
416 /* TODO Optimize to use pages. */
417 hb_codepoint_t c = INVALID;
418 while (next (&c))
419 if (!larger_set->has (c))
420 return false;
421
422 return true;
423 }
424
425 template <class Op>
426 void process (const hb_set_t *other)
427 {
428 if (unlikely (!successful)) return;
429
430 dirty ();
431
432 unsigned int na = pages.length;
433 unsigned int nb = other->pages.length;
434 unsigned int next_page = na;
435
436 unsigned int count = 0, newCount = 0;
437 unsigned int a = 0, b = 0;
438 for (; a < na && b < nb; )
439 {
440 if (page_map[a].major == other->page_map[b].major)
441 {
442 count++;
443 a++;
444 b++;
445 }
446 else if (page_map[a].major < other->page_map[b].major)
447 {
448 if (Op::passthru_left)
449 count++;
450 a++;
451 }
452 else
453 {
454 if (Op::passthru_right)
455 count++;
456 b++;
457 }
458 }
459 if (Op::passthru_left)
460 count += na - a;
461 if (Op::passthru_right)
462 count += nb - b;
463
464 if (count > pages.length)
465 if (!resize (count))
466 return;
467 newCount = count;
468
469 /* Process in-place backward. */
470 a = na;
471 b = nb;
472 for (; a && b; )
473 {
474 if (page_map[a - 1].major == other->page_map[b - 1].major)
475 {
476 a--;
477 b--;
478 count--;
479 page_map[count] = page_map[a];
480 Op::process (page_at (count).v, page_at (a).v, other->page_at (b).v);
481 }
482 else if (page_map[a - 1].major > other->page_map[b - 1].major)
483 {
484 a--;
485 if (Op::passthru_left)
486 {
487 count--;
488 page_map[count] = page_map[a];
489 }
490 }
491 else
492 {
493 b--;
494 if (Op::passthru_right)
495 {
496 count--;
497 page_map[count].major = other->page_map[b].major;
498 page_map[count].index = next_page++;
499 page_at (count).v = other->page_at (b).v;
500 }
501 }
502 }
503 if (Op::passthru_left)
504 while (a)
505 {
506 a--;
507 count--;
508 page_map[count] = page_map [a];
509 }
510 if (Op::passthru_right)
511 while (b)
512 {
513 b--;
514 count--;
515 page_map[count].major = other->page_map[b].major;
516 page_map[count].index = next_page++;
517 page_at (count).v = other->page_at (b).v;
518 }
519 assert (!count);
520 if (pages.length > newCount)
521 resize (newCount);
522 }
523
524 void union_ (const hb_set_t *other)
525 {
526 process<HbOpOr> (other);
527 }
528 void intersect (const hb_set_t *other)
529 {
530 process<HbOpAnd> (other);
531 }
532 void subtract (const hb_set_t *other)
533 {
534 process<HbOpMinus> (other);
535 }
536 void symmetric_difference (const hb_set_t *other)
537 {
538 process<HbOpXor> (other);
539 }
540 bool next (hb_codepoint_t *codepoint) const
541 {
542 if (unlikely (*codepoint == INVALID)) {
543 *codepoint = get_min ();
544 return *codepoint != INVALID;
545 }
546
547 page_map_t map = {get_major (*codepoint), 0};
548 unsigned int i;
549 page_map.bfind (map, &i, HB_BFIND_NOT_FOUND_STORE_CLOSEST);
550 if (i < page_map.length && page_map[i].major == map.major)
551 {
552 if (pages[page_map[i].index].next (codepoint))
553 {
554 *codepoint += page_map[i].major * page_t::PAGE_BITS;
555 return true;
556 }
557 i++;
558 }
559 for (; i < page_map.length; i++)
560 {
561 hb_codepoint_t m = pages[page_map[i].index].get_min ();
562 if (m != INVALID)
563 {
564 *codepoint = page_map[i].major * page_t::PAGE_BITS + m;
565 return true;
566 }
567 }
568 *codepoint = INVALID;
569 return false;
570 }
571 bool previous (hb_codepoint_t *codepoint) const
572 {
573 if (unlikely (*codepoint == INVALID)) {
574 *codepoint = get_max ();
575 return *codepoint != INVALID;
576 }
577
578 page_map_t map = {get_major (*codepoint), 0};
579 unsigned int i;
580 page_map.bfind (map, &i, HB_BFIND_NOT_FOUND_STORE_CLOSEST);
581 if (i < page_map.length && page_map[i].major == map.major)
582 {
583 if (pages[page_map[i].index].previous (codepoint))
584 {
585 *codepoint += page_map[i].major * page_t::PAGE_BITS;
586 return true;
587 }
588 }
589 i--;
590 for (; (int) i >= 0; i--)
591 {
592 hb_codepoint_t m = pages[page_map[i].index].get_max ();
593 if (m != INVALID)
594 {
595 *codepoint = page_map[i].major * page_t::PAGE_BITS + m;
596 return true;
597 }
598 }
599 *codepoint = INVALID;
600 return false;
601 }
602 bool next_range (hb_codepoint_t *first, hb_codepoint_t *last) const
603 {
604 hb_codepoint_t i;
605
606 i = *last;
607 if (!next (&i))
608 {
609 *last = *first = INVALID;
610 return false;
611 }
612
613 /* TODO Speed up. */
614 *last = *first = i;
615 while (next (&i) && i == *last + 1)
616 (*last)++;
617
618 return true;
619 }
620 bool previous_range (hb_codepoint_t *first, hb_codepoint_t *last) const
621 {
622 hb_codepoint_t i;
623
624 i = *first;
625 if (!previous (&i))
626 {
627 *last = *first = INVALID;
628 return false;
629 }
630
631 /* TODO Speed up. */
632 *last = *first = i;
633 while (previous (&i) && i == *first - 1)
634 (*first)--;
635
636 return true;
637 }
638
639 unsigned int get_population () const
640 {
641 if (population != (unsigned int) -1)
642 return population;
643
644 unsigned int pop = 0;
645 unsigned int count = pages.length;
646 for (unsigned int i = 0; i < count; i++)
647 pop += pages[i].get_population ();
648
649 population = pop;
650 return pop;
651 }
652 hb_codepoint_t get_min () const
653 {
654 unsigned int count = pages.length;
655 for (unsigned int i = 0; i < count; i++)
656 if (!page_at (i).is_empty ())
657 return page_map[i].major * page_t::PAGE_BITS + page_at (i).get_min ();
658 return INVALID;
659 }
660 hb_codepoint_t get_max () const
661 {
662 unsigned int count = pages.length;
663 for (int i = count - 1; i >= 0; i++)
664 if (!page_at (i).is_empty ())
665 return page_map[(unsigned) i].major * page_t::PAGE_BITS + page_at (i).get_max ();
666 return INVALID;
667 }
668
669 static constexpr hb_codepoint_t INVALID = HB_SET_VALUE_INVALID;
670
671 /*
672 * Iterator implementation.
673 */
674 struct const_iter_t : hb_sorted_iter_t<const_iter_t, const hb_codepoint_t>
675 {
676 const_iter_t (const hb_set_t &s_) :
677 s (s_), v (INVALID), l (s.get_population () + 1) { __next__ (); }
678
679 typedef hb_codepoint_t __item_type__;
680 hb_codepoint_t __item__ () const { return v; }
681 bool __more__ () const { return v != INVALID; }
682 void __next__ () { s.next (&v); if (l) l--; }
683 void __prev__ () { s.previous (&v); }
684 unsigned __len__ () { return l; }
685
686 protected:
687 const hb_set_t &s;
688 hb_codepoint_t v;
689 unsigned l;
690 };
691 const_iter_t const_iter () const { return const_iter_t (*this); }
692 operator const_iter_t () const { return const_iter (); }
693 typedef const_iter_t iter_t;
694 iter_t iter () const { return const_iter (); }
695
696 protected:
697
698 page_t *page_for_insert (hb_codepoint_t g)
699 {
700 page_map_t map = {get_major (g), pages.length};
701 unsigned int i;
702 if (!page_map.bfind (map, &i, HB_BFIND_NOT_FOUND_STORE_CLOSEST))
703 {
704 if (!resize (pages.length + 1))
705 return nullptr;
706
707 pages[map.index].init0 ();
708 memmove (page_map + i + 1,
709 page_map + i,
710 (page_map.length - 1 - i) * page_map.item_size);
711 page_map[i] = map;
712 }
713 return &pages[page_map[i].index];
714 }
715 page_t *page_for (hb_codepoint_t g)
716 {
717 page_map_t key = {get_major (g)};
718 const page_map_t *found = page_map.bsearch (key);
719 if (found)
720 return &pages[found->index];
721 return nullptr;
722 }
723 const page_t *page_for (hb_codepoint_t g) const
724 {
725 page_map_t key = {get_major (g)};
726 const page_map_t *found = page_map.bsearch (key);
727 if (found)
728 return &pages[found->index];
729 return nullptr;
730 }
731 page_t &page_at (unsigned int i) { return pages[page_map[i].index]; }
732 const page_t &page_at (unsigned int i) const { return pages[page_map[i].index]; }
733 unsigned int get_major (hb_codepoint_t g) const { return g / page_t::PAGE_BITS; }
734 hb_codepoint_t major_start (unsigned int major) const { return major * page_t::PAGE_BITS; }
735};
736
737
738#endif /* HB_SET_HH */
739