1 /*
2 * Copyright © 2015 Mozilla Foundation.
3 * Copyright © 2015 Google, Inc.
4 *
5 * This is part of HarfBuzz, a text shaping library.
6 *
7 * Permission is hereby granted, without written agreement and without
8 * license or royalty fees, to use, copy, modify, and distribute this
9 * software and its documentation for any purpose, provided that the
10 * above copyright notice and the following two paragraphs appear in
11 * all copies of this software.
12 *
13 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17 * DAMAGE.
18 *
19 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
22 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24 *
25 * Mozilla Author(s): Jonathan Kew
26 * Google Author(s): Behdad Esfahbod
27 */
28
29 #include "hb-ot-shape-complex-use-private.hh"
30 #include "hb-ot-shape-complex-arabic-private.hh"
31
32 /* buffer var allocations */
33 #define use_category() complex_var_u8_0()
34
35
36 /*
37 * Universal Shaping Engine.
38 * https://www.microsoft.com/typography/OpenTypeDev/USE/intro.htm
39 */
40
41 static const hb_tag_t
42 basic_features[] =
43 {
44 /*
45 * Basic features.
46 * These features are applied all at once, before reordering.
47 */
48 HB_TAG('r','k','r','f'),
49 HB_TAG('a','b','v','f'),
50 HB_TAG('b','l','w','f'),
51 HB_TAG('h','a','l','f'),
52 HB_TAG('p','s','t','f'),
53 HB_TAG('v','a','t','u'),
54 HB_TAG('c','j','c','t'),
55 };
56 static const hb_tag_t
57 arabic_features[] =
58 {
59 HB_TAG('i','s','o','l'),
60 HB_TAG('i','n','i','t'),
61 HB_TAG('m','e','d','i'),
62 HB_TAG('f','i','n','a'),
63 /* The spec doesn't specify these but we apply anyway, since our Arabic shaper
64 * does. These are only used in Syriac spec. */
65 HB_TAG('m','e','d','2'),
66 HB_TAG('f','i','n','2'),
67 HB_TAG('f','i','n','3'),
68 };
69 /* Same order as arabic_features. Don't need Syriac stuff.*/
70 enum joining_form_t {
71 ISOL,
72 INIT,
73 MEDI,
74 FINA,
75 _NONE
76 };
77 static const hb_tag_t
78 other_features[] =
79 {
80 /*
81 * Other features.
82 * These features are applied all at once, after reordering.
83 */
84 HB_TAG('a','b','v','s'),
85 HB_TAG('b','l','w','s'),
86 HB_TAG('h','a','l','n'),
87 HB_TAG('p','r','e','s'),
88 HB_TAG('p','s','t','s'),
89 /* Positioning features, though we don't care about the types. */
90 HB_TAG('d','i','s','t'),
91 HB_TAG('a','b','v','m'),
92 HB_TAG('b','l','w','m'),
93 };
94
95 static void
96 setup_syllables (const hb_ot_shape_plan_t *plan,
97 hb_font_t *font,
98 hb_buffer_t *buffer);
99 static void
100 clear_substitution_flags (const hb_ot_shape_plan_t *plan,
101 hb_font_t *font,
102 hb_buffer_t *buffer);
103 static void
104 record_rphf (const hb_ot_shape_plan_t *plan,
105 hb_font_t *font,
106 hb_buffer_t *buffer);
107 static void
108 record_pref (const hb_ot_shape_plan_t *plan,
109 hb_font_t *font,
110 hb_buffer_t *buffer);
111 static void
112 reorder (const hb_ot_shape_plan_t *plan,
113 hb_font_t *font,
114 hb_buffer_t *buffer);
115
116 static void
117 collect_features_use (hb_ot_shape_planner_t *plan)
118 {
119 hb_ot_map_builder_t *map = &plan->map;
120
121 /* Do this before any lookups have been applied. */
122 map->add_gsub_pause (setup_syllables);
123
124 /* "Default glyph pre-processing group" */
125 map->add_global_bool_feature (HB_TAG('l','o','c','l'));
126 map->add_global_bool_feature (HB_TAG('c','c','m','p'));
127 map->add_global_bool_feature (HB_TAG('n','u','k','t'));
128 map->add_global_bool_feature (HB_TAG('a','k','h','n'));
129
130 /* "Reordering group" */
131 map->add_gsub_pause (clear_substitution_flags);
132 map->add_feature (HB_TAG('r','p','h','f'), 1, F_MANUAL_ZWJ);
133 map->add_gsub_pause (record_rphf);
134 map->add_gsub_pause (clear_substitution_flags);
135 map->add_feature (HB_TAG('p','r','e','f'), 1, F_GLOBAL | F_MANUAL_ZWJ);
136 map->add_gsub_pause (record_pref);
137
138 /* "Orthographic unit shaping group" */
139 for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)
140 map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
141
142 map->add_gsub_pause (reorder);
143
144 /* "Topographical features" */
145 for (unsigned int i = 0; i < ARRAY_LENGTH (arabic_features); i++)
146 map->add_feature (arabic_features[i], 1, F_NONE);
147 map->add_gsub_pause (nullptr);
148
149 /* "Standard typographic presentation" and "Positional feature application" */
150 for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
151 map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
152 }
153
154 struct use_shape_plan_t
155 {
156 ASSERT_POD ();
157
158 hb_mask_t rphf_mask;
159
160 arabic_shape_plan_t *arabic_plan;
161 };
162
163 static bool
164 has_arabic_joining (hb_script_t script)
165 {
166 /* List of scripts that have data in arabic-table. */
167 switch ((int) script)
168 {
169 /* Unicode-1.1 additions */
170 case HB_SCRIPT_ARABIC:
171
172 /* Unicode-3.0 additions */
173 case HB_SCRIPT_MONGOLIAN:
174 case HB_SCRIPT_SYRIAC:
175
176 /* Unicode-5.0 additions */
177 case HB_SCRIPT_NKO:
178 case HB_SCRIPT_PHAGS_PA:
179
180 /* Unicode-6.0 additions */
181 case HB_SCRIPT_MANDAIC:
182
183 /* Unicode-7.0 additions */
184 case HB_SCRIPT_MANICHAEAN:
185 case HB_SCRIPT_PSALTER_PAHLAVI:
186
187 /* Unicode-9.0 additions */
188 case HB_SCRIPT_ADLAM:
189
190 return true;
191
192 default:
193 return false;
194 }
195 }
196
197 static void *
198 data_create_use (const hb_ot_shape_plan_t *plan)
199 {
200 use_shape_plan_t *use_plan = (use_shape_plan_t *) calloc (1, sizeof (use_shape_plan_t));
201 if (unlikely (!use_plan))
202 return nullptr;
203
204 use_plan->rphf_mask = plan->map.get_1_mask (HB_TAG('r','p','h','f'));
205
206 if (has_arabic_joining (plan->props.script))
207 {
208 use_plan->arabic_plan = (arabic_shape_plan_t *) data_create_arabic (plan);
209 if (unlikely (!use_plan->arabic_plan))
210 {
211 free (use_plan);
212 return nullptr;
213 }
214 }
215
216 return use_plan;
217 }
218
219 static void
220 data_destroy_use (void *data)
221 {
222 use_shape_plan_t *use_plan = (use_shape_plan_t *) data;
223
224 if (use_plan->arabic_plan)
225 data_destroy_arabic (use_plan->arabic_plan);
226
227 free (data);
228 }
229
230 enum syllable_type_t {
231 independent_cluster,
232 virama_terminated_cluster,
233 standard_cluster,
234 number_joiner_terminated_cluster,
235 numeral_cluster,
236 symbol_cluster,
237 broken_cluster,
238 non_cluster,
239 };
240
241 #include "hb-ot-shape-complex-use-machine.hh"
242
243
244 static void
245 setup_masks_use (const hb_ot_shape_plan_t *plan,
246 hb_buffer_t *buffer,
247 hb_font_t *font HB_UNUSED)
248 {
249 const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
250
251 /* Do this before allocating use_category(). */
252 if (use_plan->arabic_plan)
253 {
254 setup_masks_arabic_plan (use_plan->arabic_plan, buffer, plan->props.script);
255 }
256
257 HB_BUFFER_ALLOCATE_VAR (buffer, use_category);
258
259 /* We cannot setup masks here. We save information about characters
260 * and setup masks later on in a pause-callback. */
261
262 unsigned int count = buffer->len;
263 hb_glyph_info_t *info = buffer->info;
264 for (unsigned int i = 0; i < count; i++)
265 info[i].use_category() = hb_use_get_categories (info[i].codepoint);
266 }
267
268 static void
269 setup_rphf_mask (const hb_ot_shape_plan_t *plan,
270 hb_buffer_t *buffer)
271 {
272 const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
273
274 hb_mask_t mask = use_plan->rphf_mask;
275 if (!mask) return;
276
277 hb_glyph_info_t *info = buffer->info;
278
279 foreach_syllable (buffer, start, end)
280 {
281 unsigned int limit = info[start].use_category() == USE_R ? 1 : MIN (3u, end - start);
282 for (unsigned int i = start; i < start + limit; i++)
283 info[i].mask |= mask;
284 }
285 }
286
287 static void
288 setup_topographical_masks (const hb_ot_shape_plan_t *plan,
289 hb_buffer_t *buffer)
290 {
291 const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
292 if (use_plan->arabic_plan)
293 return;
294
295 static_assert ((INIT < 4 && ISOL < 4 && MEDI < 4 && FINA < 4), "");
296 hb_mask_t masks[4], all_masks = 0;
297 for (unsigned int i = 0; i < 4; i++)
298 {
299 masks[i] = plan->map.get_1_mask (arabic_features[i]);
300 if (masks[i] == plan->map.get_global_mask ())
301 masks[i] = 0;
302 all_masks |= masks[i];
303 }
304 if (!all_masks)
305 return;
306 hb_mask_t other_masks = ~all_masks;
307
308 unsigned int last_start = 0;
309 joining_form_t last_form = _NONE;
310 hb_glyph_info_t *info = buffer->info;
311 foreach_syllable (buffer, start, end)
312 {
313 syllable_type_t syllable_type = (syllable_type_t) (info[start].syllable() & 0x0F);
314 switch (syllable_type)
315 {
316 case independent_cluster:
317 case symbol_cluster:
318 case non_cluster:
319 /* These don't join. Nothing to do. */
320 last_form = _NONE;
321 break;
322
323 case virama_terminated_cluster:
324 case standard_cluster:
325 case number_joiner_terminated_cluster:
326 case numeral_cluster:
327 case broken_cluster:
328
329 bool join = last_form == FINA || last_form == ISOL;
330
331 if (join)
332 {
333 /* Fixup previous syllable's form. */
334 last_form = last_form == FINA ? MEDI : INIT;
335 for (unsigned int i = last_start; i < start; i++)
336 info[i].mask = (info[i].mask & other_masks) | masks[last_form];
337 }
338
339 /* Form for this syllable. */
340 last_form = join ? FINA : ISOL;
341 for (unsigned int i = start; i < end; i++)
342 info[i].mask = (info[i].mask & other_masks) | masks[last_form];
343
344 break;
345 }
346
347 last_start = start;
348 }
349 }
350
351 static void
352 setup_syllables (const hb_ot_shape_plan_t *plan,
353 hb_font_t *font HB_UNUSED,
354 hb_buffer_t *buffer)
355 {
356 find_syllables (buffer);
357 foreach_syllable (buffer, start, end)
358 buffer->unsafe_to_break (start, end);
359 setup_rphf_mask (plan, buffer);
360 setup_topographical_masks (plan, buffer);
361 }
362
363 static void
364 clear_substitution_flags (const hb_ot_shape_plan_t *plan,
365 hb_font_t *font HB_UNUSED,
366 hb_buffer_t *buffer)
367 {
368 hb_glyph_info_t *info = buffer->info;
369 unsigned int count = buffer->len;
370 for (unsigned int i = 0; i < count; i++)
371 _hb_glyph_info_clear_substituted (&info[i]);
372 }
373
374 static void
375 record_rphf (const hb_ot_shape_plan_t *plan,
376 hb_font_t *font,
377 hb_buffer_t *buffer)
378 {
379 const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
380
381 hb_mask_t mask = use_plan->rphf_mask;
382 if (!mask) return;
383 hb_glyph_info_t *info = buffer->info;
384
385 foreach_syllable (buffer, start, end)
386 {
387 /* Mark a substituted repha as USE_R. */
388 for (unsigned int i = start; i < end && (info[i].mask & mask); i++)
389 if (_hb_glyph_info_substituted (&info[i]))
390 {
391 info[i].use_category() = USE_R;
392 break;
393 }
394 }
395 }
396
397 static void
398 record_pref (const hb_ot_shape_plan_t *plan,
399 hb_font_t *font,
400 hb_buffer_t *buffer)
401 {
402 hb_glyph_info_t *info = buffer->info;
403
404 foreach_syllable (buffer, start, end)
405 {
406 /* Mark a substituted pref as VPre, as they behave the same way. */
407 for (unsigned int i = start; i < end; i++)
408 if (_hb_glyph_info_substituted (&info[i]))
409 {
410 info[i].use_category() = USE_VPre;
411 break;
412 }
413 }
414 }
415
416 static inline bool
417 is_halant (const hb_glyph_info_t &info)
418 {
419 return info.use_category() == USE_H && !_hb_glyph_info_ligated (&info);
420 }
421
422 static void
423 reorder_syllable (hb_buffer_t *buffer, unsigned int start, unsigned int end)
424 {
425 syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
426 /* Only a few syllable types need reordering. */
427 if (unlikely (!(FLAG_UNSAFE (syllable_type) &
428 (FLAG (virama_terminated_cluster) |
429 FLAG (standard_cluster) |
430 FLAG (broken_cluster) |
431 0))))
432 return;
433
434 hb_glyph_info_t *info = buffer->info;
435
436 #define BASE_FLAGS (FLAG (USE_B) | FLAG (USE_GB))
437
438 /* Move things forward. */
439 if (info[start].use_category() == USE_R && end - start > 1)
440 {
441 /* Got a repha. Reorder it to after first base, before first halant. */
442 for (unsigned int i = start + 1; i < end; i++)
443 if ((FLAG_UNSAFE (info[i].use_category()) & (BASE_FLAGS)) || is_halant (info[i]))
444 {
445 /* If we hit a halant, move before it; otherwise it's a base: move to it's
446 * place, and shift things in between backward. */
447
448 if (is_halant (info[i]))
449 i--;
450
451 buffer->merge_clusters (start, i + 1);
452 hb_glyph_info_t t = info[start];
453 memmove (&info[start], &info[start + 1], (i - start) * sizeof (info[0]));
454 info[i] = t;
455
456 break;
457 }
458 }
459
460 /* Move things back. */
461 unsigned int j = end;
462 for (unsigned int i = start; i < end; i++)
463 {
464 uint32_t flag = FLAG_UNSAFE (info[i].use_category());
465 if ((flag & (BASE_FLAGS)) || is_halant (info[i]))
466 {
467 /* If we hit a halant, move after it; otherwise it's a base: move to it's
468 * place, and shift things in between backward. */
469 if (is_halant (info[i]))
470 j = i + 1;
471 else
472 j = i;
473 }
474 else if (((flag) & (FLAG (USE_VPre) | FLAG (USE_VMPre))) &&
475 /* Only move the first component of a MultipleSubst. */
476 0 == _hb_glyph_info_get_lig_comp (&info[i]) &&
477 j < i)
478 {
479 buffer->merge_clusters (j, i + 1);
480 hb_glyph_info_t t = info[i];
481 memmove (&info[j + 1], &info[j], (i - j) * sizeof (info[0]));
482 info[j] = t;
483 }
484 }
485 }
486
487 static inline void
488 insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
489 hb_font_t *font,
490 hb_buffer_t *buffer)
491 {
492 /* Note: This loop is extra overhead, but should not be measurable. */
493 bool has_broken_syllables = false;
494 unsigned int count = buffer->len;
495 hb_glyph_info_t *info = buffer->info;
496 for (unsigned int i = 0; i < count; i++)
497 if ((info[i].syllable() & 0x0F) == broken_cluster)
498 {
499 has_broken_syllables = true;
500 break;
501 }
502 if (likely (!has_broken_syllables))
503 return;
504
505 hb_glyph_info_t dottedcircle = {0};
506 if (!font->get_nominal_glyph (0x25CCu, &dottedcircle.codepoint))
507 return;
508 dottedcircle.use_category() = hb_use_get_categories (0x25CC);
509
510 buffer->clear_output ();
511
512 buffer->idx = 0;
513 unsigned int last_syllable = 0;
514 while (buffer->idx < buffer->len && !buffer->in_error)
515 {
516 unsigned int syllable = buffer->cur().syllable();
517 syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
518 if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
519 {
520 last_syllable = syllable;
521
522 hb_glyph_info_t ginfo = dottedcircle;
523 ginfo.cluster = buffer->cur().cluster;
524 ginfo.mask = buffer->cur().mask;
525 ginfo.syllable() = buffer->cur().syllable();
526 /* TODO Set glyph_props? */
527
528 /* Insert dottedcircle after possible Repha. */
529 while (buffer->idx < buffer->len && !buffer->in_error &&
530 last_syllable == buffer->cur().syllable() &&
531 buffer->cur().use_category() == USE_R)
532 buffer->next_glyph ();
533
534 buffer->output_info (ginfo);
535 }
536 else
537 buffer->next_glyph ();
538 }
539
540 buffer->swap_buffers ();
541 }
542
543 static void
544 reorder (const hb_ot_shape_plan_t *plan,
545 hb_font_t *font,
546 hb_buffer_t *buffer)
547 {
548 insert_dotted_circles (plan, font, buffer);
549
550 hb_glyph_info_t *info = buffer->info;
551
552 foreach_syllable (buffer, start, end)
553 reorder_syllable (buffer, start, end);
554
555 /* Zero syllables now... */
556 unsigned int count = buffer->len;
557 for (unsigned int i = 0; i < count; i++)
558 info[i].syllable() = 0;
559
560 HB_BUFFER_DEALLOCATE_VAR (buffer, use_category);
561 }
562
563 static bool
564 decompose_use (const hb_ot_shape_normalize_context_t *c,
565 hb_codepoint_t ab,
566 hb_codepoint_t *a,
567 hb_codepoint_t *b)
568 {
569 switch (ab)
570 {
571 /* Chakma:
572 * Special case where the Unicode decomp gives matras in the wrong order
573 * for cluster validation.
574 */
575 case 0x1112Eu : *a = 0x11127u; *b= 0x11131u; return true;
576 case 0x1112Fu : *a = 0x11127u; *b= 0x11132u; return true;
577 }
578
579 return (bool) c->unicode->decompose (ab, a, b);
580 }
581
582 static bool
583 compose_use (const hb_ot_shape_normalize_context_t *c,
584 hb_codepoint_t a,
585 hb_codepoint_t b,
586 hb_codepoint_t *ab)
587 {
588 /* Avoid recomposing split matras. */
589 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
590 return false;
591
592 return (bool)c->unicode->compose (a, b, ab);
593 }
594
595
596 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_use =
597 {
598 collect_features_use,
599 nullptr, /* override_features */
600 data_create_use,
601 data_destroy_use,
602 nullptr, /* preprocess_text */
603 nullptr, /* postprocess_glyphs */
604 HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
605 decompose_use,
606 compose_use,
607 setup_masks_use,
608 nullptr, /* disable_otl */
609 nullptr, /* reorder_marks */
610 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
611 false, /* fallback_position */
612 };