1 | /* |
2 | * Copyright © 2022 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): Garret Rieger |
25 | */ |
26 | |
27 | #include "../hb-set.hh" |
28 | #include "../hb-priority-queue.hh" |
29 | #include "../hb-serialize.hh" |
30 | |
31 | #ifndef GRAPH_GRAPH_HH |
32 | #define GRAPH_GRAPH_HH |
33 | |
34 | namespace graph { |
35 | |
36 | /** |
37 | * Represents a serialized table in the form of a graph. |
38 | * Provides methods for modifying and reordering the graph. |
39 | */ |
40 | struct graph_t |
41 | { |
42 | struct vertex_t |
43 | { |
44 | hb_serialize_context_t::object_t obj; |
45 | int64_t distance = 0 ; |
46 | unsigned space = 0 ; |
47 | unsigned start = 0; |
48 | unsigned end = 0; |
49 | unsigned priority = 0; |
50 | private: |
51 | unsigned incoming_edges_ = 0; |
52 | unsigned single_parent = (unsigned) -1; |
53 | hb_hashmap_t<unsigned, unsigned> parents; |
54 | public: |
55 | |
56 | auto parents_iter () const HB_AUTO_RETURN |
57 | ( |
58 | hb_concat ( |
59 | hb_iter (&single_parent, single_parent != (unsigned) -1), |
60 | parents.keys_ref () |
61 | ) |
62 | ) |
63 | |
64 | bool in_error () const |
65 | { |
66 | return parents.in_error (); |
67 | } |
68 | |
69 | bool link_positions_valid (unsigned num_objects, bool removed_nil) |
70 | { |
71 | hb_set_t assigned_bytes; |
72 | for (const auto& l : obj.real_links) |
73 | { |
74 | if (l.objidx >= num_objects |
75 | || (removed_nil && !l.objidx)) |
76 | { |
77 | DEBUG_MSG (SUBSET_REPACK, nullptr, |
78 | "Invalid graph. Invalid object index." ); |
79 | return false; |
80 | } |
81 | |
82 | unsigned start = l.position; |
83 | unsigned end = start + l.width - 1; |
84 | |
85 | if (unlikely (l.width < 2 || l.width > 4)) |
86 | { |
87 | DEBUG_MSG (SUBSET_REPACK, nullptr, |
88 | "Invalid graph. Invalid link width." ); |
89 | return false; |
90 | } |
91 | |
92 | if (unlikely (end >= table_size ())) |
93 | { |
94 | DEBUG_MSG (SUBSET_REPACK, nullptr, |
95 | "Invalid graph. Link position is out of bounds." ); |
96 | return false; |
97 | } |
98 | |
99 | if (unlikely (assigned_bytes.intersects (start, end))) |
100 | { |
101 | DEBUG_MSG (SUBSET_REPACK, nullptr, |
102 | "Invalid graph. Found offsets whose positions overlap." ); |
103 | return false; |
104 | } |
105 | |
106 | assigned_bytes.add_range (start, end); |
107 | } |
108 | |
109 | return !assigned_bytes.in_error (); |
110 | } |
111 | |
112 | void normalize () |
113 | { |
114 | obj.real_links.qsort (); |
115 | for (auto& l : obj.real_links) |
116 | { |
117 | for (unsigned i = 0; i < l.width; i++) |
118 | { |
119 | obj.head[l.position + i] = 0; |
120 | } |
121 | } |
122 | } |
123 | |
124 | bool equals (const vertex_t& other, |
125 | const graph_t& graph, |
126 | const graph_t& other_graph, |
127 | unsigned depth) const |
128 | { |
129 | if (!(as_bytes () == other.as_bytes ())) |
130 | { |
131 | DEBUG_MSG (SUBSET_REPACK, nullptr, |
132 | "vertex [%lu] bytes != [%lu] bytes, depth = %u" , |
133 | (unsigned long) table_size (), |
134 | (unsigned long) other.table_size (), |
135 | depth); |
136 | |
137 | auto a = as_bytes (); |
138 | auto b = other.as_bytes (); |
139 | while (a || b) |
140 | { |
141 | DEBUG_MSG (SUBSET_REPACK, nullptr, |
142 | " 0x%x %s 0x%x" , (unsigned) *a, (*a == *b) ? "==" : "!=" , (unsigned) *b); |
143 | a++; |
144 | b++; |
145 | } |
146 | return false; |
147 | } |
148 | |
149 | return links_equal (obj.real_links, other.obj.real_links, graph, other_graph, depth); |
150 | } |
151 | |
152 | hb_bytes_t as_bytes () const |
153 | { |
154 | return hb_bytes_t (obj.head, table_size ()); |
155 | } |
156 | |
157 | friend void swap (vertex_t& a, vertex_t& b) |
158 | { |
159 | hb_swap (a.obj, b.obj); |
160 | hb_swap (a.distance, b.distance); |
161 | hb_swap (a.space, b.space); |
162 | hb_swap (a.single_parent, b.single_parent); |
163 | hb_swap (a.parents, b.parents); |
164 | hb_swap (a.incoming_edges_, b.incoming_edges_); |
165 | hb_swap (a.start, b.start); |
166 | hb_swap (a.end, b.end); |
167 | hb_swap (a.priority, b.priority); |
168 | } |
169 | |
170 | hb_hashmap_t<unsigned, unsigned> |
171 | position_to_index_map () const |
172 | { |
173 | hb_hashmap_t<unsigned, unsigned> result; |
174 | |
175 | result.alloc (obj.real_links.length); |
176 | for (const auto& l : obj.real_links) { |
177 | result.set (l.position, l.objidx); |
178 | } |
179 | |
180 | return result; |
181 | } |
182 | |
183 | bool is_shared () const |
184 | { |
185 | return parents.get_population () > 1; |
186 | } |
187 | |
188 | unsigned incoming_edges () const |
189 | { |
190 | if (HB_DEBUG_SUBSET_REPACK) |
191 | { |
192 | assert (incoming_edges_ == (single_parent != (unsigned) -1) + |
193 | (parents.values_ref () | hb_reduce (hb_add, 0))); |
194 | } |
195 | return incoming_edges_; |
196 | } |
197 | |
198 | void reset_parents () |
199 | { |
200 | incoming_edges_ = 0; |
201 | single_parent = (unsigned) -1; |
202 | parents.reset (); |
203 | } |
204 | |
205 | void add_parent (unsigned parent_index) |
206 | { |
207 | assert (parent_index != (unsigned) -1); |
208 | if (incoming_edges_ == 0) |
209 | { |
210 | single_parent = parent_index; |
211 | incoming_edges_ = 1; |
212 | return; |
213 | } |
214 | else if (single_parent != (unsigned) -1) |
215 | { |
216 | assert (incoming_edges_ == 1); |
217 | if (!parents.set (single_parent, 1)) |
218 | return; |
219 | single_parent = (unsigned) -1; |
220 | } |
221 | |
222 | unsigned *v; |
223 | if (parents.has (parent_index, &v)) |
224 | { |
225 | (*v)++; |
226 | incoming_edges_++; |
227 | } |
228 | else if (parents.set (parent_index, 1)) |
229 | incoming_edges_++; |
230 | } |
231 | |
232 | void remove_parent (unsigned parent_index) |
233 | { |
234 | if (parent_index == single_parent) |
235 | { |
236 | single_parent = (unsigned) -1; |
237 | incoming_edges_--; |
238 | return; |
239 | } |
240 | |
241 | unsigned *v; |
242 | if (parents.has (parent_index, &v)) |
243 | { |
244 | incoming_edges_--; |
245 | if (*v > 1) |
246 | (*v)--; |
247 | else |
248 | parents.del (parent_index); |
249 | |
250 | if (incoming_edges_ == 1) |
251 | { |
252 | single_parent = *parents.keys (); |
253 | parents.reset (); |
254 | } |
255 | } |
256 | } |
257 | |
258 | void remove_real_link (unsigned child_index, const void* offset) |
259 | { |
260 | unsigned count = obj.real_links.length; |
261 | for (unsigned i = 0; i < count; i++) |
262 | { |
263 | auto& link = obj.real_links.arrayZ[i]; |
264 | if (link.objidx != child_index) |
265 | continue; |
266 | |
267 | if ((obj.head + link.position) != offset) |
268 | continue; |
269 | |
270 | obj.real_links.remove_unordered (i); |
271 | return; |
272 | } |
273 | } |
274 | |
275 | bool remap_parents (const hb_vector_t<unsigned>& id_map) |
276 | { |
277 | if (single_parent != (unsigned) -1) |
278 | { |
279 | assert (single_parent < id_map.length); |
280 | single_parent = id_map[single_parent]; |
281 | return true; |
282 | } |
283 | |
284 | hb_hashmap_t<unsigned, unsigned> new_parents; |
285 | new_parents.alloc (parents.get_population ()); |
286 | for (auto _ : parents) |
287 | { |
288 | assert (_.first < id_map.length); |
289 | assert (!new_parents.has (id_map[_.first])); |
290 | new_parents.set (id_map[_.first], _.second); |
291 | } |
292 | |
293 | if (new_parents.in_error ()) |
294 | return false; |
295 | |
296 | parents = std::move (new_parents); |
297 | return true; |
298 | } |
299 | |
300 | void remap_parent (unsigned old_index, unsigned new_index) |
301 | { |
302 | if (single_parent != (unsigned) -1) |
303 | { |
304 | if (single_parent == old_index) |
305 | single_parent = new_index; |
306 | return; |
307 | } |
308 | |
309 | const unsigned *pv; |
310 | if (parents.has (old_index, &pv)) |
311 | { |
312 | unsigned v = *pv; |
313 | parents.set (new_index, v); |
314 | parents.del (old_index); |
315 | } |
316 | } |
317 | |
318 | bool is_leaf () const |
319 | { |
320 | return !obj.real_links.length && !obj.virtual_links.length; |
321 | } |
322 | |
323 | bool raise_priority () |
324 | { |
325 | if (has_max_priority ()) return false; |
326 | priority++; |
327 | return true; |
328 | } |
329 | |
330 | bool has_max_priority () const { |
331 | return priority >= 3; |
332 | } |
333 | |
334 | size_t table_size () const { |
335 | return obj.tail - obj.head; |
336 | } |
337 | |
338 | int64_t modified_distance (unsigned order) const |
339 | { |
340 | // TODO(garretrieger): once priority is high enough, should try |
341 | // setting distance = 0 which will force to sort immediately after |
342 | // it's parent where possible. |
343 | |
344 | int64_t modified_distance = |
345 | hb_min (hb_max(distance + distance_modifier (), 0), 0x7FFFFFFFFFF); |
346 | if (has_max_priority ()) { |
347 | modified_distance = 0; |
348 | } |
349 | return (modified_distance << 18) | (0x003FFFF & order); |
350 | } |
351 | |
352 | int64_t distance_modifier () const |
353 | { |
354 | if (!priority) return 0; |
355 | int64_t table_size = obj.tail - obj.head; |
356 | |
357 | if (priority == 1) |
358 | return -table_size / 2; |
359 | |
360 | return -table_size; |
361 | } |
362 | |
363 | private: |
364 | bool links_equal (const hb_vector_t<hb_serialize_context_t::object_t::link_t>& this_links, |
365 | const hb_vector_t<hb_serialize_context_t::object_t::link_t>& other_links, |
366 | const graph_t& graph, |
367 | const graph_t& other_graph, |
368 | unsigned depth) const |
369 | { |
370 | auto a = this_links.iter (); |
371 | auto b = other_links.iter (); |
372 | |
373 | while (a && b) |
374 | { |
375 | const auto& link_a = *a; |
376 | const auto& link_b = *b; |
377 | |
378 | if (link_a.width != link_b.width || |
379 | link_a.is_signed != link_b.is_signed || |
380 | link_a.whence != link_b.whence || |
381 | link_a.position != link_b.position || |
382 | link_a.bias != link_b.bias) |
383 | return false; |
384 | |
385 | if (!graph.vertices_[link_a.objidx].equals ( |
386 | other_graph.vertices_[link_b.objidx], graph, other_graph, depth + 1)) |
387 | return false; |
388 | |
389 | a++; |
390 | b++; |
391 | } |
392 | |
393 | if (bool (a) != bool (b)) |
394 | return false; |
395 | |
396 | return true; |
397 | } |
398 | }; |
399 | |
400 | template <typename T> |
401 | struct vertex_and_table_t |
402 | { |
403 | vertex_and_table_t () : index (0), vertex (nullptr), table (nullptr) |
404 | {} |
405 | |
406 | unsigned index; |
407 | vertex_t* vertex; |
408 | T* table; |
409 | |
410 | operator bool () { |
411 | return table && vertex; |
412 | } |
413 | }; |
414 | |
415 | /* |
416 | * A topological sorting of an object graph. Ordered |
417 | * in reverse serialization order (first object in the |
418 | * serialization is at the end of the list). This matches |
419 | * the 'packed' object stack used internally in the |
420 | * serializer |
421 | */ |
422 | template<typename T> |
423 | graph_t (const T& objects) |
424 | : parents_invalid (true), |
425 | distance_invalid (true), |
426 | positions_invalid (true), |
427 | successful (true), |
428 | buffers () |
429 | { |
430 | num_roots_for_space_.push (1); |
431 | bool removed_nil = false; |
432 | vertices_.alloc (objects.length); |
433 | vertices_scratch_.alloc (objects.length); |
434 | unsigned count = objects.length; |
435 | for (unsigned i = 0; i < count; i++) |
436 | { |
437 | // If this graph came from a serialization buffer object 0 is the |
438 | // nil object. We don't need it for our purposes here so drop it. |
439 | if (i == 0 && !objects.arrayZ[i]) |
440 | { |
441 | removed_nil = true; |
442 | continue; |
443 | } |
444 | |
445 | vertex_t* v = vertices_.push (); |
446 | if (check_success (!vertices_.in_error ())) |
447 | v->obj = *objects.arrayZ[i]; |
448 | |
449 | check_success (v->link_positions_valid (count, removed_nil)); |
450 | |
451 | if (!removed_nil) continue; |
452 | // Fix indices to account for removed nil object. |
453 | for (auto& l : v->obj.all_links_writer ()) { |
454 | l.objidx--; |
455 | } |
456 | } |
457 | } |
458 | |
459 | ~graph_t () |
460 | { |
461 | for (char* b : buffers) |
462 | hb_free (b); |
463 | } |
464 | |
465 | bool operator== (const graph_t& other) const |
466 | { |
467 | return root ().equals (other.root (), *this, other, 0); |
468 | } |
469 | |
470 | // Sorts links of all objects in a consistent manner and zeroes all offsets. |
471 | void normalize () |
472 | { |
473 | for (auto& v : vertices_.writer ()) |
474 | v.normalize (); |
475 | } |
476 | |
477 | bool in_error () const |
478 | { |
479 | return !successful || |
480 | vertices_.in_error () || |
481 | num_roots_for_space_.in_error (); |
482 | } |
483 | |
484 | const vertex_t& root () const |
485 | { |
486 | return vertices_[root_idx ()]; |
487 | } |
488 | |
489 | unsigned root_idx () const |
490 | { |
491 | // Object graphs are in reverse order, the first object is at the end |
492 | // of the vector. Since the graph is topologically sorted it's safe to |
493 | // assume the first object has no incoming edges. |
494 | return vertices_.length - 1; |
495 | } |
496 | |
497 | const hb_serialize_context_t::object_t& object (unsigned i) const |
498 | { |
499 | return vertices_[i].obj; |
500 | } |
501 | |
502 | bool add_buffer (char* buffer) |
503 | { |
504 | buffers.push (buffer); |
505 | return !buffers.in_error (); |
506 | } |
507 | |
508 | /* |
509 | * Adds a 16 bit link from parent_id to child_id |
510 | */ |
511 | template<typename T> |
512 | void add_link (T* offset, |
513 | unsigned parent_id, |
514 | unsigned child_id) |
515 | { |
516 | auto& v = vertices_[parent_id]; |
517 | auto* link = v.obj.real_links.push (); |
518 | link->width = 2; |
519 | link->objidx = child_id; |
520 | link->position = (char*) offset - (char*) v.obj.head; |
521 | vertices_[child_id].add_parent (parent_id); |
522 | } |
523 | |
524 | /* |
525 | * Generates a new topological sorting of graph ordered by the shortest |
526 | * distance to each node if positions are marked as invalid. |
527 | */ |
528 | void sort_shortest_distance_if_needed () |
529 | { |
530 | if (!positions_invalid) return; |
531 | sort_shortest_distance (); |
532 | } |
533 | |
534 | |
535 | /* |
536 | * Generates a new topological sorting of graph ordered by the shortest |
537 | * distance to each node. |
538 | */ |
539 | void sort_shortest_distance () |
540 | { |
541 | positions_invalid = true; |
542 | |
543 | if (vertices_.length <= 1) { |
544 | // Graph of 1 or less doesn't need sorting. |
545 | return; |
546 | } |
547 | |
548 | update_distances (); |
549 | |
550 | hb_priority_queue_t queue; |
551 | hb_vector_t<vertex_t> &sorted_graph = vertices_scratch_; |
552 | if (unlikely (!check_success (sorted_graph.resize (vertices_.length)))) return; |
553 | hb_vector_t<unsigned> id_map; |
554 | if (unlikely (!check_success (id_map.resize (vertices_.length)))) return; |
555 | |
556 | hb_vector_t<unsigned> removed_edges; |
557 | if (unlikely (!check_success (removed_edges.resize (vertices_.length)))) return; |
558 | update_parents (); |
559 | |
560 | queue.insert (root ().modified_distance (0), root_idx ()); |
561 | int new_id = root_idx (); |
562 | unsigned order = 1; |
563 | while (!queue.in_error () && !queue.is_empty ()) |
564 | { |
565 | unsigned next_id = queue.pop_minimum().second; |
566 | |
567 | sorted_graph[new_id] = std::move (vertices_[next_id]); |
568 | const vertex_t& next = sorted_graph[new_id]; |
569 | |
570 | if (unlikely (!check_success(new_id >= 0))) { |
571 | // We are out of ids. Which means we've visited a node more than once. |
572 | // This graph contains a cycle which is not allowed. |
573 | DEBUG_MSG (SUBSET_REPACK, nullptr, "Invalid graph. Contains cycle." ); |
574 | return; |
575 | } |
576 | |
577 | id_map[next_id] = new_id--; |
578 | |
579 | for (const auto& link : next.obj.all_links ()) { |
580 | removed_edges[link.objidx]++; |
581 | if (!(vertices_[link.objidx].incoming_edges () - removed_edges[link.objidx])) |
582 | // Add the order that the links were encountered to the priority. |
583 | // This ensures that ties between priorities objects are broken in a consistent |
584 | // way. More specifically this is set up so that if a set of objects have the same |
585 | // distance they'll be added to the topological order in the order that they are |
586 | // referenced from the parent object. |
587 | queue.insert (vertices_[link.objidx].modified_distance (order++), |
588 | link.objidx); |
589 | } |
590 | } |
591 | |
592 | check_success (!queue.in_error ()); |
593 | check_success (!sorted_graph.in_error ()); |
594 | |
595 | check_success (remap_all_obj_indices (id_map, &sorted_graph)); |
596 | vertices_ = std::move (sorted_graph); |
597 | |
598 | if (!check_success (new_id == -1)) |
599 | print_orphaned_nodes (); |
600 | } |
601 | |
602 | /* |
603 | * Finds the set of nodes (placed into roots) that should be assigned unique spaces. |
604 | * More specifically this looks for the top most 24 bit or 32 bit links in the graph. |
605 | * Some special casing is done that is specific to the layout of GSUB/GPOS tables. |
606 | */ |
607 | void find_space_roots (hb_set_t& visited, hb_set_t& roots) |
608 | { |
609 | int root_index = (int) root_idx (); |
610 | for (int i = root_index; i >= 0; i--) |
611 | { |
612 | if (visited.has (i)) continue; |
613 | |
614 | // Only real links can form 32 bit spaces |
615 | for (auto& l : vertices_[i].obj.real_links) |
616 | { |
617 | if (l.is_signed || l.width < 3) |
618 | continue; |
619 | |
620 | if (i == root_index && l.width == 3) |
621 | // Ignore 24bit links from the root node, this skips past the single 24bit |
622 | // pointer to the lookup list. |
623 | continue; |
624 | |
625 | if (l.width == 3) |
626 | { |
627 | // A 24bit offset forms a root, unless there is 32bit offsets somewhere |
628 | // in it's subgraph, then those become the roots instead. This is to make sure |
629 | // that extension subtables beneath a 24bit lookup become the spaces instead |
630 | // of the offset to the lookup. |
631 | hb_set_t sub_roots; |
632 | find_32bit_roots (l.objidx, sub_roots); |
633 | if (sub_roots) { |
634 | for (unsigned sub_root_idx : sub_roots) { |
635 | roots.add (sub_root_idx); |
636 | find_subgraph (sub_root_idx, visited); |
637 | } |
638 | continue; |
639 | } |
640 | } |
641 | |
642 | roots.add (l.objidx); |
643 | find_subgraph (l.objidx, visited); |
644 | } |
645 | } |
646 | } |
647 | |
648 | template <typename T, typename ...Ts> |
649 | vertex_and_table_t<T> as_table (unsigned parent, const void* offset, Ts... ds) |
650 | { |
651 | return as_table_from_index<T> (index_for_offset (parent, offset), std::forward<Ts>(ds)...); |
652 | } |
653 | |
654 | template <typename T, typename ...Ts> |
655 | vertex_and_table_t<T> as_mutable_table (unsigned parent, const void* offset, Ts... ds) |
656 | { |
657 | return as_table_from_index<T> (mutable_index_for_offset (parent, offset), std::forward<Ts>(ds)...); |
658 | } |
659 | |
660 | template <typename T, typename ...Ts> |
661 | vertex_and_table_t<T> as_table_from_index (unsigned index, Ts... ds) |
662 | { |
663 | if (index >= vertices_.length) |
664 | return vertex_and_table_t<T> (); |
665 | |
666 | vertex_and_table_t<T> r; |
667 | r.vertex = &vertices_[index]; |
668 | r.table = (T*) r.vertex->obj.head; |
669 | r.index = index; |
670 | if (!r.table) |
671 | return vertex_and_table_t<T> (); |
672 | |
673 | if (!r.table->sanitize (*(r.vertex), std::forward<Ts>(ds)...)) |
674 | return vertex_and_table_t<T> (); |
675 | |
676 | return r; |
677 | } |
678 | |
679 | // Finds the object id of the object pointed to by the offset at 'offset' |
680 | // within object[node_idx]. |
681 | unsigned index_for_offset (unsigned node_idx, const void* offset) const |
682 | { |
683 | const auto& node = object (node_idx); |
684 | if (offset < node.head || offset >= node.tail) return -1; |
685 | |
686 | unsigned count = node.real_links.length; |
687 | for (unsigned i = 0; i < count; i++) |
688 | { |
689 | // Use direct access for increased performance, this is a hot method. |
690 | const auto& link = node.real_links.arrayZ[i]; |
691 | if (offset != node.head + link.position) |
692 | continue; |
693 | return link.objidx; |
694 | } |
695 | |
696 | return -1; |
697 | } |
698 | |
699 | // Finds the object id of the object pointed to by the offset at 'offset' |
700 | // within object[node_idx]. Ensures that the returned object is safe to mutate. |
701 | // That is, if the original child object is shared by parents other than node_idx |
702 | // it will be duplicated and the duplicate will be returned instead. |
703 | unsigned mutable_index_for_offset (unsigned node_idx, const void* offset) |
704 | { |
705 | unsigned child_idx = index_for_offset (node_idx, offset); |
706 | auto& child = vertices_[child_idx]; |
707 | for (unsigned p : child.parents_iter ()) |
708 | { |
709 | if (p != node_idx) { |
710 | return duplicate (node_idx, child_idx); |
711 | } |
712 | } |
713 | |
714 | return child_idx; |
715 | } |
716 | |
717 | |
718 | /* |
719 | * Assign unique space numbers to each connected subgraph of 24 bit and/or 32 bit offset(s). |
720 | * Currently, this is implemented specifically tailored to the structure of a GPOS/GSUB |
721 | * (including with 24bit offsets) table. |
722 | */ |
723 | bool assign_spaces () |
724 | { |
725 | update_parents (); |
726 | |
727 | hb_set_t visited; |
728 | hb_set_t roots; |
729 | find_space_roots (visited, roots); |
730 | |
731 | // Mark everything not in the subgraphs of the roots as visited. This prevents |
732 | // subgraphs from being connected via nodes not in those subgraphs. |
733 | visited.invert (); |
734 | |
735 | if (!roots) return false; |
736 | |
737 | while (roots) |
738 | { |
739 | uint32_t next = HB_SET_VALUE_INVALID; |
740 | if (unlikely (!check_success (!roots.in_error ()))) break; |
741 | if (!roots.next (&next)) break; |
742 | |
743 | hb_set_t connected_roots; |
744 | find_connected_nodes (next, roots, visited, connected_roots); |
745 | if (unlikely (!check_success (!connected_roots.in_error ()))) break; |
746 | |
747 | isolate_subgraph (connected_roots); |
748 | if (unlikely (!check_success (!connected_roots.in_error ()))) break; |
749 | |
750 | unsigned next_space = this->next_space (); |
751 | num_roots_for_space_.push (0); |
752 | for (unsigned root : connected_roots) |
753 | { |
754 | DEBUG_MSG (SUBSET_REPACK, nullptr, "Subgraph %u gets space %u" , root, next_space); |
755 | vertices_[root].space = next_space; |
756 | num_roots_for_space_[next_space] = num_roots_for_space_[next_space] + 1; |
757 | distance_invalid = true; |
758 | positions_invalid = true; |
759 | } |
760 | |
761 | // TODO(grieger): special case for GSUB/GPOS use extension promotions to move 16 bit space |
762 | // into the 32 bit space as needed, instead of using isolation. |
763 | } |
764 | |
765 | |
766 | |
767 | return true; |
768 | } |
769 | |
770 | /* |
771 | * Isolates the subgraph of nodes reachable from root. Any links to nodes in the subgraph |
772 | * that originate from outside of the subgraph will be removed by duplicating the linked to |
773 | * object. |
774 | * |
775 | * Indices stored in roots will be updated if any of the roots are duplicated to new indices. |
776 | */ |
777 | bool isolate_subgraph (hb_set_t& roots) |
778 | { |
779 | update_parents (); |
780 | hb_map_t subgraph; |
781 | |
782 | // incoming edges to root_idx should be all 32 bit in length so we don't need to de-dup these |
783 | // set the subgraph incoming edge count to match all of root_idx's incoming edges |
784 | hb_set_t parents; |
785 | for (unsigned root_idx : roots) |
786 | { |
787 | subgraph.set (root_idx, wide_parents (root_idx, parents)); |
788 | find_subgraph (root_idx, subgraph); |
789 | } |
790 | if (subgraph.in_error ()) |
791 | return false; |
792 | |
793 | unsigned original_root_idx = root_idx (); |
794 | hb_map_t index_map; |
795 | bool made_changes = false; |
796 | for (auto entry : subgraph.iter ()) |
797 | { |
798 | assert (entry.first < vertices_.length); |
799 | const auto& node = vertices_[entry.first]; |
800 | unsigned subgraph_incoming_edges = entry.second; |
801 | |
802 | if (subgraph_incoming_edges < node.incoming_edges ()) |
803 | { |
804 | // Only de-dup objects with incoming links from outside the subgraph. |
805 | made_changes = true; |
806 | duplicate_subgraph (entry.first, index_map); |
807 | } |
808 | } |
809 | |
810 | if (in_error ()) |
811 | return false; |
812 | |
813 | if (!made_changes) |
814 | return false; |
815 | |
816 | if (original_root_idx != root_idx () |
817 | && parents.has (original_root_idx)) |
818 | { |
819 | // If the root idx has changed since parents was determined, update root idx in parents |
820 | parents.add (root_idx ()); |
821 | parents.del (original_root_idx); |
822 | } |
823 | |
824 | auto new_subgraph = |
825 | + subgraph.keys () |
826 | | hb_map([&] (uint32_t node_idx) { |
827 | const uint32_t *v; |
828 | if (index_map.has (node_idx, &v)) return *v; |
829 | return node_idx; |
830 | }) |
831 | ; |
832 | |
833 | remap_obj_indices (index_map, new_subgraph); |
834 | remap_obj_indices (index_map, parents.iter (), true); |
835 | |
836 | // Update roots set with new indices as needed. |
837 | for (auto next : roots) |
838 | { |
839 | const uint32_t *v; |
840 | if (index_map.has (next, &v)) |
841 | { |
842 | roots.del (next); |
843 | roots.add (*v); |
844 | } |
845 | } |
846 | |
847 | return true; |
848 | } |
849 | |
850 | void find_subgraph (unsigned node_idx, hb_map_t& subgraph) |
851 | { |
852 | for (const auto& link : vertices_[node_idx].obj.all_links ()) |
853 | { |
854 | hb_codepoint_t *v; |
855 | if (subgraph.has (link.objidx, &v)) |
856 | { |
857 | (*v)++; |
858 | continue; |
859 | } |
860 | subgraph.set (link.objidx, 1); |
861 | find_subgraph (link.objidx, subgraph); |
862 | } |
863 | } |
864 | |
865 | void find_subgraph (unsigned node_idx, hb_set_t& subgraph) |
866 | { |
867 | if (subgraph.has (node_idx)) return; |
868 | subgraph.add (node_idx); |
869 | for (const auto& link : vertices_[node_idx].obj.all_links ()) |
870 | find_subgraph (link.objidx, subgraph); |
871 | } |
872 | |
873 | size_t find_subgraph_size (unsigned node_idx, hb_set_t& subgraph, unsigned max_depth = -1) |
874 | { |
875 | if (subgraph.has (node_idx)) return 0; |
876 | subgraph.add (node_idx); |
877 | |
878 | const auto& o = vertices_[node_idx].obj; |
879 | size_t size = o.tail - o.head; |
880 | if (max_depth == 0) |
881 | return size; |
882 | |
883 | for (const auto& link : o.all_links ()) |
884 | size += find_subgraph_size (link.objidx, subgraph, max_depth - 1); |
885 | return size; |
886 | } |
887 | |
888 | /* |
889 | * Finds the topmost children of 32bit offsets in the subgraph starting |
890 | * at node_idx. Found indices are placed into 'found'. |
891 | */ |
892 | void find_32bit_roots (unsigned node_idx, hb_set_t& found) |
893 | { |
894 | for (const auto& link : vertices_[node_idx].obj.all_links ()) |
895 | { |
896 | if (!link.is_signed && link.width == 4) { |
897 | found.add (link.objidx); |
898 | continue; |
899 | } |
900 | find_32bit_roots (link.objidx, found); |
901 | } |
902 | } |
903 | |
904 | /* |
905 | * Moves the child of old_parent_idx pointed to by old_offset to a new |
906 | * vertex at the new_offset. |
907 | */ |
908 | template<typename O> |
909 | void move_child (unsigned old_parent_idx, |
910 | const O* old_offset, |
911 | unsigned new_parent_idx, |
912 | const O* new_offset) |
913 | { |
914 | distance_invalid = true; |
915 | positions_invalid = true; |
916 | |
917 | auto& old_v = vertices_[old_parent_idx]; |
918 | auto& new_v = vertices_[new_parent_idx]; |
919 | |
920 | unsigned child_id = index_for_offset (old_parent_idx, |
921 | old_offset); |
922 | |
923 | auto* new_link = new_v.obj.real_links.push (); |
924 | new_link->width = O::static_size; |
925 | new_link->objidx = child_id; |
926 | new_link->position = (const char*) new_offset - (const char*) new_v.obj.head; |
927 | |
928 | auto& child = vertices_[child_id]; |
929 | child.add_parent (new_parent_idx); |
930 | |
931 | old_v.remove_real_link (child_id, old_offset); |
932 | child.remove_parent (old_parent_idx); |
933 | } |
934 | |
935 | /* |
936 | * duplicates all nodes in the subgraph reachable from node_idx. Does not re-assign |
937 | * links. index_map is updated with mappings from old id to new id. If a duplication has already |
938 | * been performed for a given index, then it will be skipped. |
939 | */ |
940 | void duplicate_subgraph (unsigned node_idx, hb_map_t& index_map) |
941 | { |
942 | if (index_map.has (node_idx)) |
943 | return; |
944 | |
945 | unsigned clone_idx = duplicate (node_idx); |
946 | if (!check_success (clone_idx != (unsigned) -1)) |
947 | return; |
948 | |
949 | index_map.set (node_idx, clone_idx); |
950 | for (const auto& l : object (node_idx).all_links ()) { |
951 | duplicate_subgraph (l.objidx, index_map); |
952 | } |
953 | } |
954 | |
955 | /* |
956 | * Creates a copy of node_idx and returns it's new index. |
957 | */ |
958 | unsigned duplicate (unsigned node_idx) |
959 | { |
960 | positions_invalid = true; |
961 | distance_invalid = true; |
962 | |
963 | auto* clone = vertices_.push (); |
964 | auto& child = vertices_[node_idx]; |
965 | if (vertices_.in_error ()) { |
966 | return -1; |
967 | } |
968 | |
969 | clone->obj.head = child.obj.head; |
970 | clone->obj.tail = child.obj.tail; |
971 | clone->distance = child.distance; |
972 | clone->space = child.space; |
973 | clone->reset_parents (); |
974 | |
975 | unsigned clone_idx = vertices_.length - 2; |
976 | for (const auto& l : child.obj.real_links) |
977 | { |
978 | clone->obj.real_links.push (l); |
979 | vertices_[l.objidx].add_parent (clone_idx); |
980 | } |
981 | for (const auto& l : child.obj.virtual_links) |
982 | { |
983 | clone->obj.virtual_links.push (l); |
984 | vertices_[l.objidx].add_parent (clone_idx); |
985 | } |
986 | |
987 | check_success (!clone->obj.real_links.in_error ()); |
988 | check_success (!clone->obj.virtual_links.in_error ()); |
989 | |
990 | // The last object is the root of the graph, so swap back the root to the end. |
991 | // The root's obj idx does change, however since it's root nothing else refers to it. |
992 | // all other obj idx's will be unaffected. |
993 | hb_swap (vertices_[vertices_.length - 2], *clone); |
994 | |
995 | // Since the root moved, update the parents arrays of all children on the root. |
996 | for (const auto& l : root ().obj.all_links ()) |
997 | vertices_[l.objidx].remap_parent (root_idx () - 1, root_idx ()); |
998 | |
999 | return clone_idx; |
1000 | } |
1001 | |
1002 | /* |
1003 | * Creates a copy of child and re-assigns the link from |
1004 | * parent to the clone. The copy is a shallow copy, objects |
1005 | * linked from child are not duplicated. |
1006 | */ |
1007 | unsigned duplicate_if_shared (unsigned parent_idx, unsigned child_idx) |
1008 | { |
1009 | unsigned new_idx = duplicate (parent_idx, child_idx); |
1010 | if (new_idx == (unsigned) -1) return child_idx; |
1011 | return new_idx; |
1012 | } |
1013 | |
1014 | |
1015 | /* |
1016 | * Creates a copy of child and re-assigns the link from |
1017 | * parent to the clone. The copy is a shallow copy, objects |
1018 | * linked from child are not duplicated. |
1019 | */ |
1020 | unsigned duplicate (unsigned parent_idx, unsigned child_idx) |
1021 | { |
1022 | update_parents (); |
1023 | |
1024 | unsigned links_to_child = 0; |
1025 | for (const auto& l : vertices_[parent_idx].obj.all_links ()) |
1026 | { |
1027 | if (l.objidx == child_idx) links_to_child++; |
1028 | } |
1029 | |
1030 | if (vertices_[child_idx].incoming_edges () <= links_to_child) |
1031 | { |
1032 | // Can't duplicate this node, doing so would orphan the original one as all remaining links |
1033 | // to child are from parent. |
1034 | DEBUG_MSG (SUBSET_REPACK, nullptr, " Not duplicating %u => %u" , |
1035 | parent_idx, child_idx); |
1036 | return -1; |
1037 | } |
1038 | |
1039 | DEBUG_MSG (SUBSET_REPACK, nullptr, " Duplicating %u => %u" , |
1040 | parent_idx, child_idx); |
1041 | |
1042 | unsigned clone_idx = duplicate (child_idx); |
1043 | if (clone_idx == (unsigned) -1) return false; |
1044 | // duplicate shifts the root node idx, so if parent_idx was root update it. |
1045 | if (parent_idx == clone_idx) parent_idx++; |
1046 | |
1047 | auto& parent = vertices_[parent_idx]; |
1048 | for (auto& l : parent.obj.all_links_writer ()) |
1049 | { |
1050 | if (l.objidx != child_idx) |
1051 | continue; |
1052 | |
1053 | reassign_link (l, parent_idx, clone_idx); |
1054 | } |
1055 | |
1056 | return clone_idx; |
1057 | } |
1058 | |
1059 | |
1060 | /* |
1061 | * Adds a new node to the graph, not connected to anything. |
1062 | */ |
1063 | unsigned new_node (char* head, char* tail) |
1064 | { |
1065 | positions_invalid = true; |
1066 | distance_invalid = true; |
1067 | |
1068 | auto* clone = vertices_.push (); |
1069 | if (vertices_.in_error ()) { |
1070 | return -1; |
1071 | } |
1072 | |
1073 | clone->obj.head = head; |
1074 | clone->obj.tail = tail; |
1075 | clone->distance = 0; |
1076 | clone->space = 0; |
1077 | |
1078 | unsigned clone_idx = vertices_.length - 2; |
1079 | |
1080 | // The last object is the root of the graph, so swap back the root to the end. |
1081 | // The root's obj idx does change, however since it's root nothing else refers to it. |
1082 | // all other obj idx's will be unaffected. |
1083 | hb_swap (vertices_[vertices_.length - 2], *clone); |
1084 | |
1085 | // Since the root moved, update the parents arrays of all children on the root. |
1086 | for (const auto& l : root ().obj.all_links ()) |
1087 | vertices_[l.objidx].remap_parent (root_idx () - 1, root_idx ()); |
1088 | |
1089 | return clone_idx; |
1090 | } |
1091 | |
1092 | /* |
1093 | * Raises the sorting priority of all children. |
1094 | */ |
1095 | bool raise_childrens_priority (unsigned parent_idx) |
1096 | { |
1097 | DEBUG_MSG (SUBSET_REPACK, nullptr, " Raising priority of all children of %u" , |
1098 | parent_idx); |
1099 | // This operation doesn't change ordering until a sort is run, so no need |
1100 | // to invalidate positions. It does not change graph structure so no need |
1101 | // to update distances or edge counts. |
1102 | auto& parent = vertices_[parent_idx].obj; |
1103 | bool made_change = false; |
1104 | for (auto& l : parent.all_links_writer ()) |
1105 | made_change |= vertices_[l.objidx].raise_priority (); |
1106 | return made_change; |
1107 | } |
1108 | |
1109 | bool is_fully_connected () |
1110 | { |
1111 | update_parents(); |
1112 | |
1113 | if (root().incoming_edges ()) |
1114 | // Root cannot have parents. |
1115 | return false; |
1116 | |
1117 | for (unsigned i = 0; i < root_idx (); i++) |
1118 | { |
1119 | if (!vertices_[i].incoming_edges ()) |
1120 | return false; |
1121 | } |
1122 | return true; |
1123 | } |
1124 | |
1125 | #if 0 |
1126 | /* |
1127 | * Saves the current graph to a packed binary format which the repacker fuzzer takes |
1128 | * as a seed. |
1129 | */ |
1130 | void save_fuzzer_seed (hb_tag_t tag) const |
1131 | { |
1132 | FILE* f = fopen ("./repacker_fuzzer_seed" , "w" ); |
1133 | fwrite ((void*) &tag, sizeof (tag), 1, f); |
1134 | |
1135 | uint16_t num_objects = vertices_.length; |
1136 | fwrite ((void*) &num_objects, sizeof (num_objects), 1, f); |
1137 | |
1138 | for (const auto& v : vertices_) |
1139 | { |
1140 | uint16_t blob_size = v.table_size (); |
1141 | fwrite ((void*) &blob_size, sizeof (blob_size), 1, f); |
1142 | fwrite ((const void*) v.obj.head, blob_size, 1, f); |
1143 | } |
1144 | |
1145 | uint16_t link_count = 0; |
1146 | for (const auto& v : vertices_) |
1147 | link_count += v.obj.real_links.length; |
1148 | |
1149 | fwrite ((void*) &link_count, sizeof (link_count), 1, f); |
1150 | |
1151 | typedef struct |
1152 | { |
1153 | uint16_t parent; |
1154 | uint16_t child; |
1155 | uint16_t position; |
1156 | uint8_t width; |
1157 | } link_t; |
1158 | |
1159 | for (unsigned i = 0; i < vertices_.length; i++) |
1160 | { |
1161 | for (const auto& l : vertices_[i].obj.real_links) |
1162 | { |
1163 | link_t link { |
1164 | (uint16_t) i, (uint16_t) l.objidx, |
1165 | (uint16_t) l.position, (uint8_t) l.width |
1166 | }; |
1167 | fwrite ((void*) &link, sizeof (link), 1, f); |
1168 | } |
1169 | } |
1170 | |
1171 | fclose (f); |
1172 | } |
1173 | #endif |
1174 | |
1175 | void print_orphaned_nodes () |
1176 | { |
1177 | if (!DEBUG_ENABLED(SUBSET_REPACK)) return; |
1178 | |
1179 | DEBUG_MSG (SUBSET_REPACK, nullptr, "Graph is not fully connected." ); |
1180 | parents_invalid = true; |
1181 | update_parents(); |
1182 | |
1183 | if (root().incoming_edges ()) { |
1184 | DEBUG_MSG (SUBSET_REPACK, nullptr, "Root node has incoming edges." ); |
1185 | } |
1186 | |
1187 | for (unsigned i = 0; i < root_idx (); i++) |
1188 | { |
1189 | const auto& v = vertices_[i]; |
1190 | if (!v.incoming_edges ()) |
1191 | DEBUG_MSG (SUBSET_REPACK, nullptr, "Node %u is orphaned." , i); |
1192 | } |
1193 | } |
1194 | |
1195 | unsigned num_roots_for_space (unsigned space) const |
1196 | { |
1197 | return num_roots_for_space_[space]; |
1198 | } |
1199 | |
1200 | unsigned next_space () const |
1201 | { |
1202 | return num_roots_for_space_.length; |
1203 | } |
1204 | |
1205 | void move_to_new_space (const hb_set_t& indices) |
1206 | { |
1207 | num_roots_for_space_.push (0); |
1208 | unsigned new_space = num_roots_for_space_.length - 1; |
1209 | |
1210 | for (unsigned index : indices) { |
1211 | auto& node = vertices_[index]; |
1212 | num_roots_for_space_[node.space] = num_roots_for_space_[node.space] - 1; |
1213 | num_roots_for_space_[new_space] = num_roots_for_space_[new_space] + 1; |
1214 | node.space = new_space; |
1215 | distance_invalid = true; |
1216 | positions_invalid = true; |
1217 | } |
1218 | } |
1219 | |
1220 | unsigned space_for (unsigned index, unsigned* root = nullptr) const |
1221 | { |
1222 | loop: |
1223 | assert (index < vertices_.length); |
1224 | const auto& node = vertices_[index]; |
1225 | if (node.space) |
1226 | { |
1227 | if (root != nullptr) |
1228 | *root = index; |
1229 | return node.space; |
1230 | } |
1231 | |
1232 | if (!node.incoming_edges ()) |
1233 | { |
1234 | if (root) |
1235 | *root = index; |
1236 | return 0; |
1237 | } |
1238 | |
1239 | index = *node.parents_iter (); |
1240 | goto loop; |
1241 | } |
1242 | |
1243 | void err_other_error () { this->successful = false; } |
1244 | |
1245 | size_t total_size_in_bytes () const { |
1246 | size_t total_size = 0; |
1247 | unsigned count = vertices_.length; |
1248 | for (unsigned i = 0; i < count; i++) { |
1249 | size_t size = vertices_.arrayZ[i].obj.tail - vertices_.arrayZ[i].obj.head; |
1250 | total_size += size; |
1251 | } |
1252 | return total_size; |
1253 | } |
1254 | |
1255 | |
1256 | private: |
1257 | |
1258 | /* |
1259 | * Returns the numbers of incoming edges that are 24 or 32 bits wide. |
1260 | */ |
1261 | unsigned wide_parents (unsigned node_idx, hb_set_t& parents) const |
1262 | { |
1263 | unsigned count = 0; |
1264 | for (unsigned p : vertices_[node_idx].parents_iter ()) |
1265 | { |
1266 | // Only real links can be wide |
1267 | for (const auto& l : vertices_[p].obj.real_links) |
1268 | { |
1269 | if (l.objidx == node_idx |
1270 | && (l.width == 3 || l.width == 4) |
1271 | && !l.is_signed) |
1272 | { |
1273 | count++; |
1274 | parents.add (p); |
1275 | } |
1276 | } |
1277 | } |
1278 | return count; |
1279 | } |
1280 | |
1281 | bool check_success (bool success) |
1282 | { return this->successful && (success || ((void) err_other_error (), false)); } |
1283 | |
1284 | public: |
1285 | /* |
1286 | * Creates a map from objid to # of incoming edges. |
1287 | */ |
1288 | void update_parents () |
1289 | { |
1290 | if (!parents_invalid) return; |
1291 | |
1292 | unsigned count = vertices_.length; |
1293 | |
1294 | for (unsigned i = 0; i < count; i++) |
1295 | vertices_.arrayZ[i].reset_parents (); |
1296 | |
1297 | for (unsigned p = 0; p < count; p++) |
1298 | { |
1299 | for (auto& l : vertices_.arrayZ[p].obj.all_links ()) |
1300 | vertices_[l.objidx].add_parent (p); |
1301 | } |
1302 | |
1303 | for (unsigned i = 0; i < count; i++) |
1304 | // parents arrays must be accurate or downstream operations like cycle detection |
1305 | // and sorting won't work correctly. |
1306 | check_success (!vertices_.arrayZ[i].in_error ()); |
1307 | |
1308 | parents_invalid = false; |
1309 | } |
1310 | |
1311 | /* |
1312 | * compute the serialized start and end positions for each vertex. |
1313 | */ |
1314 | void update_positions () |
1315 | { |
1316 | if (!positions_invalid) return; |
1317 | |
1318 | unsigned current_pos = 0; |
1319 | for (int i = root_idx (); i >= 0; i--) |
1320 | { |
1321 | auto& v = vertices_[i]; |
1322 | v.start = current_pos; |
1323 | current_pos += v.obj.tail - v.obj.head; |
1324 | v.end = current_pos; |
1325 | } |
1326 | |
1327 | positions_invalid = false; |
1328 | } |
1329 | |
1330 | /* |
1331 | * Finds the distance to each object in the graph |
1332 | * from the initial node. |
1333 | */ |
1334 | void update_distances () |
1335 | { |
1336 | if (!distance_invalid) return; |
1337 | |
1338 | // Uses Dijkstra's algorithm to find all of the shortest distances. |
1339 | // https://en.wikipedia.org/wiki/Dijkstra%27s_algorithm |
1340 | // |
1341 | // Implementation Note: |
1342 | // Since our priority queue doesn't support fast priority decreases |
1343 | // we instead just add new entries into the queue when a priority changes. |
1344 | // Redundant ones are filtered out later on by the visited set. |
1345 | // According to https://www3.cs.stonybrook.edu/~rezaul/papers/TR-07-54.pdf |
1346 | // for practical performance this is faster then using a more advanced queue |
1347 | // (such as a fibonacci queue) with a fast decrease priority. |
1348 | unsigned count = vertices_.length; |
1349 | for (unsigned i = 0; i < count; i++) |
1350 | vertices_.arrayZ[i].distance = hb_int_max (int64_t); |
1351 | vertices_.tail ().distance = 0; |
1352 | |
1353 | hb_priority_queue_t queue; |
1354 | queue.insert (0, vertices_.length - 1); |
1355 | |
1356 | hb_vector_t<bool> visited; |
1357 | visited.resize (vertices_.length); |
1358 | |
1359 | while (!queue.in_error () && !queue.is_empty ()) |
1360 | { |
1361 | unsigned next_idx = queue.pop_minimum ().second; |
1362 | if (visited[next_idx]) continue; |
1363 | const auto& next = vertices_[next_idx]; |
1364 | int64_t next_distance = vertices_[next_idx].distance; |
1365 | visited[next_idx] = true; |
1366 | |
1367 | for (const auto& link : next.obj.all_links ()) |
1368 | { |
1369 | if (visited[link.objidx]) continue; |
1370 | |
1371 | const auto& child = vertices_.arrayZ[link.objidx].obj; |
1372 | unsigned link_width = link.width ? link.width : 4; // treat virtual offsets as 32 bits wide |
1373 | int64_t child_weight = (child.tail - child.head) + |
1374 | ((int64_t) 1 << (link_width * 8)) * (vertices_.arrayZ[link.objidx].space + 1); |
1375 | int64_t child_distance = next_distance + child_weight; |
1376 | |
1377 | if (child_distance < vertices_.arrayZ[link.objidx].distance) |
1378 | { |
1379 | vertices_.arrayZ[link.objidx].distance = child_distance; |
1380 | queue.insert (child_distance, link.objidx); |
1381 | } |
1382 | } |
1383 | } |
1384 | |
1385 | check_success (!queue.in_error ()); |
1386 | if (!check_success (queue.is_empty ())) |
1387 | { |
1388 | print_orphaned_nodes (); |
1389 | return; |
1390 | } |
1391 | |
1392 | distance_invalid = false; |
1393 | } |
1394 | |
1395 | private: |
1396 | /* |
1397 | * Updates a link in the graph to point to a different object. Corrects the |
1398 | * parents vector on the previous and new child nodes. |
1399 | */ |
1400 | void reassign_link (hb_serialize_context_t::object_t::link_t& link, |
1401 | unsigned parent_idx, |
1402 | unsigned new_idx) |
1403 | { |
1404 | unsigned old_idx = link.objidx; |
1405 | link.objidx = new_idx; |
1406 | vertices_[old_idx].remove_parent (parent_idx); |
1407 | vertices_[new_idx].add_parent (parent_idx); |
1408 | } |
1409 | |
1410 | /* |
1411 | * Updates all objidx's in all links using the provided mapping. Corrects incoming edge counts. |
1412 | */ |
1413 | template<typename Iterator, hb_requires (hb_is_iterator (Iterator))> |
1414 | void remap_obj_indices (const hb_map_t& id_map, |
1415 | Iterator subgraph, |
1416 | bool only_wide = false) |
1417 | { |
1418 | if (!id_map) return; |
1419 | for (unsigned i : subgraph) |
1420 | { |
1421 | for (auto& link : vertices_[i].obj.all_links_writer ()) |
1422 | { |
1423 | const uint32_t *v; |
1424 | if (!id_map.has (link.objidx, &v)) continue; |
1425 | if (only_wide && !(link.width == 4 && !link.is_signed)) continue; |
1426 | |
1427 | reassign_link (link, i, *v); |
1428 | } |
1429 | } |
1430 | } |
1431 | |
1432 | /* |
1433 | * Updates all objidx's in all links using the provided mapping. |
1434 | */ |
1435 | bool remap_all_obj_indices (const hb_vector_t<unsigned>& id_map, |
1436 | hb_vector_t<vertex_t>* sorted_graph) const |
1437 | { |
1438 | unsigned count = sorted_graph->length; |
1439 | for (unsigned i = 0; i < count; i++) |
1440 | { |
1441 | if (!(*sorted_graph)[i].remap_parents (id_map)) |
1442 | return false; |
1443 | for (auto& link : sorted_graph->arrayZ[i].obj.all_links_writer ()) |
1444 | { |
1445 | link.objidx = id_map[link.objidx]; |
1446 | } |
1447 | } |
1448 | return true; |
1449 | } |
1450 | |
1451 | /* |
1452 | * Finds all nodes in targets that are reachable from start_idx, nodes in visited will be skipped. |
1453 | * For this search the graph is treated as being undirected. |
1454 | * |
1455 | * Connected targets will be added to connected and removed from targets. All visited nodes |
1456 | * will be added to visited. |
1457 | */ |
1458 | void find_connected_nodes (unsigned start_idx, |
1459 | hb_set_t& targets, |
1460 | hb_set_t& visited, |
1461 | hb_set_t& connected) |
1462 | { |
1463 | if (unlikely (!check_success (!visited.in_error ()))) return; |
1464 | if (visited.has (start_idx)) return; |
1465 | visited.add (start_idx); |
1466 | |
1467 | if (targets.has (start_idx)) |
1468 | { |
1469 | targets.del (start_idx); |
1470 | connected.add (start_idx); |
1471 | } |
1472 | |
1473 | const auto& v = vertices_[start_idx]; |
1474 | |
1475 | // Graph is treated as undirected so search children and parents of start_idx |
1476 | for (const auto& l : v.obj.all_links ()) |
1477 | find_connected_nodes (l.objidx, targets, visited, connected); |
1478 | |
1479 | for (unsigned p : v.parents_iter ()) |
1480 | find_connected_nodes (p, targets, visited, connected); |
1481 | } |
1482 | |
1483 | public: |
1484 | // TODO(garretrieger): make private, will need to move most of offset overflow code into graph. |
1485 | hb_vector_t<vertex_t> vertices_; |
1486 | hb_vector_t<vertex_t> vertices_scratch_; |
1487 | private: |
1488 | bool parents_invalid; |
1489 | bool distance_invalid; |
1490 | bool positions_invalid; |
1491 | bool successful; |
1492 | hb_vector_t<unsigned> num_roots_for_space_; |
1493 | hb_vector_t<char*> buffers; |
1494 | }; |
1495 | |
1496 | } |
1497 | |
1498 | #endif // GRAPH_GRAPH_HH |
1499 | |