1/*
2 * Copyright © 2011,2012 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#include "hb-ot-shape-complex-indic.hh"
28#include "hb-ot-layout.hh"
29
30
31/*
32 * Indic shaper.
33 */
34
35
36/*
37 * Indic configurations. Note that we do not want to keep every single script-specific
38 * behavior in these tables necessarily. This should mainly be used for per-script
39 * properties that are cheaper keeping here, than in the code. Ie. if, say, one and
40 * only one script has an exception, that one script can be if'ed directly in the code,
41 * instead of adding a new flag in these structs.
42 */
43
44enum base_position_t {
45 BASE_POS_LAST_SINHALA,
46 BASE_POS_LAST
47};
48enum reph_position_t {
49 REPH_POS_AFTER_MAIN = POS_AFTER_MAIN,
50 REPH_POS_BEFORE_SUB = POS_BEFORE_SUB,
51 REPH_POS_AFTER_SUB = POS_AFTER_SUB,
52 REPH_POS_BEFORE_POST = POS_BEFORE_POST,
53 REPH_POS_AFTER_POST = POS_AFTER_POST
54};
55enum reph_mode_t {
56 REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */
57 REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */
58 REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */
59};
60enum blwf_mode_t {
61 BLWF_MODE_PRE_AND_POST, /* Below-forms feature applied to pre-base and post-base. */
62 BLWF_MODE_POST_ONLY /* Below-forms feature applied to post-base only. */
63};
64struct indic_config_t
65{
66 hb_script_t script;
67 bool has_old_spec;
68 hb_codepoint_t virama;
69 base_position_t base_pos;
70 reph_position_t reph_pos;
71 reph_mode_t reph_mode;
72 blwf_mode_t blwf_mode;
73};
74
75static const indic_config_t indic_configs[] =
76{
77 /* Default. Should be first. */
78 {HB_SCRIPT_INVALID, false, 0,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
79 {HB_SCRIPT_DEVANAGARI,true, 0x094Du,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
80 {HB_SCRIPT_BENGALI, true, 0x09CDu,BASE_POS_LAST, REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
81 {HB_SCRIPT_GURMUKHI, true, 0x0A4Du,BASE_POS_LAST, REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
82 {HB_SCRIPT_GUJARATI, true, 0x0ACDu,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
83 {HB_SCRIPT_ORIYA, true, 0x0B4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
84 {HB_SCRIPT_TAMIL, true, 0x0BCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
85 {HB_SCRIPT_TELUGU, true, 0x0C4Du,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_POST_ONLY},
86 {HB_SCRIPT_KANNADA, true, 0x0CCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_POST_ONLY},
87 {HB_SCRIPT_MALAYALAM, true, 0x0D4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA,BLWF_MODE_PRE_AND_POST},
88 {HB_SCRIPT_SINHALA, false,0x0DCAu,BASE_POS_LAST_SINHALA,
89 REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_PRE_AND_POST},
90};
91
92
93
94/*
95 * Indic shaper.
96 */
97
98struct feature_list_t {
99 hb_tag_t tag;
100 hb_ot_map_feature_flags_t flags;
101};
102
103static const feature_list_t
104indic_features[] =
105{
106 /*
107 * Basic features.
108 * These features are applied in order, one at a time, after initial_reordering.
109 */
110 {HB_TAG('n','u','k','t'), F_GLOBAL},
111 {HB_TAG('a','k','h','n'), F_GLOBAL},
112 {HB_TAG('r','p','h','f'), F_NONE},
113 {HB_TAG('r','k','r','f'), F_GLOBAL},
114 {HB_TAG('p','r','e','f'), F_NONE},
115 {HB_TAG('b','l','w','f'), F_NONE},
116 {HB_TAG('a','b','v','f'), F_NONE},
117 {HB_TAG('h','a','l','f'), F_NONE},
118 {HB_TAG('p','s','t','f'), F_NONE},
119 {HB_TAG('v','a','t','u'), F_GLOBAL},
120 {HB_TAG('c','j','c','t'), F_GLOBAL},
121 /*
122 * Other features.
123 * These features are applied all at once, after final_reordering.
124 * Default Bengali font in Windows for example has intermixed
125 * lookups for init,pres,abvs,blws features.
126 */
127 {HB_TAG('i','n','i','t'), F_NONE},
128 {HB_TAG('p','r','e','s'), F_GLOBAL},
129 {HB_TAG('a','b','v','s'), F_GLOBAL},
130 {HB_TAG('b','l','w','s'), F_GLOBAL},
131 {HB_TAG('p','s','t','s'), F_GLOBAL},
132 {HB_TAG('h','a','l','n'), F_GLOBAL},
133 /* Positioning features, though we don't care about the types. */
134 {HB_TAG('d','i','s','t'), F_GLOBAL},
135 {HB_TAG('a','b','v','m'), F_GLOBAL},
136 {HB_TAG('b','l','w','m'), F_GLOBAL},
137};
138
139/*
140 * Must be in the same order as the indic_features array.
141 */
142enum {
143 _NUKT,
144 _AKHN,
145 RPHF,
146 _RKRF,
147 PREF,
148 BLWF,
149 ABVF,
150 HALF,
151 PSTF,
152 _VATU,
153 _CJCT,
154
155 INIT,
156 _PRES,
157 _ABVS,
158 _BLWS,
159 _PSTS,
160 _HALN,
161 _DIST,
162 _ABVM,
163 _BLWM,
164
165 INDIC_NUM_FEATURES,
166 INDIC_BASIC_FEATURES = INIT /* Don't forget to update this! */
167};
168
169static void
170setup_syllables (const hb_ot_shape_plan_t *plan,
171 hb_font_t *font,
172 hb_buffer_t *buffer);
173static void
174initial_reordering (const hb_ot_shape_plan_t *plan,
175 hb_font_t *font,
176 hb_buffer_t *buffer);
177static void
178final_reordering (const hb_ot_shape_plan_t *plan,
179 hb_font_t *font,
180 hb_buffer_t *buffer);
181static void
182clear_syllables (const hb_ot_shape_plan_t *plan,
183 hb_font_t *font,
184 hb_buffer_t *buffer);
185
186static void
187collect_features_indic (hb_ot_shape_planner_t *plan)
188{
189 hb_ot_map_builder_t *map = &plan->map;
190
191 /* Do this before any lookups have been applied. */
192 map->add_gsub_pause (setup_syllables);
193
194 map->add_global_bool_feature (HB_TAG('l','o','c','l'));
195 /* The Indic specs do not require ccmp, but we apply it here since if
196 * there is a use of it, it's typically at the beginning. */
197 map->add_global_bool_feature (HB_TAG('c','c','m','p'));
198
199
200 unsigned int i = 0;
201 map->add_gsub_pause (initial_reordering);
202 for (; i < INDIC_BASIC_FEATURES; i++) {
203 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
204 map->add_gsub_pause (nullptr);
205 }
206 map->add_gsub_pause (final_reordering);
207 for (; i < INDIC_NUM_FEATURES; i++) {
208 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
209 }
210
211 map->add_global_bool_feature (HB_TAG('c','a','l','t'));
212 map->add_global_bool_feature (HB_TAG('c','l','i','g'));
213
214 map->add_gsub_pause (clear_syllables);
215}
216
217static void
218override_features_indic (hb_ot_shape_planner_t *plan)
219{
220 plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL);
221}
222
223
224struct would_substitute_feature_t
225{
226 inline void init (const hb_ot_map_t *map, hb_tag_t feature_tag, bool zero_context_)
227 {
228 zero_context = zero_context_;
229 map->get_stage_lookups (0/*GSUB*/,
230 map->get_feature_stage (0/*GSUB*/, feature_tag),
231 &lookups, &count);
232 }
233
234 inline bool would_substitute (const hb_codepoint_t *glyphs,
235 unsigned int glyphs_count,
236 hb_face_t *face) const
237 {
238 for (unsigned int i = 0; i < count; i++)
239 if (hb_ot_layout_lookup_would_substitute_fast (face, lookups[i].index, glyphs, glyphs_count, zero_context))
240 return true;
241 return false;
242 }
243
244 private:
245 const hb_ot_map_t::lookup_map_t *lookups;
246 unsigned int count;
247 bool zero_context;
248};
249
250struct indic_shape_plan_t
251{
252 ASSERT_POD ();
253
254 inline bool load_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const
255 {
256 hb_codepoint_t glyph = virama_glyph.get_relaxed ();
257 if (unlikely (glyph == (hb_codepoint_t) -1))
258 {
259 if (!config->virama || !font->get_nominal_glyph (config->virama, &glyph))
260 glyph = 0;
261 /* Technically speaking, the spec says we should apply 'locl' to virama too.
262 * Maybe one day... */
263
264 /* Our get_nominal_glyph() function needs a font, so we can't get the virama glyph
265 * during shape planning... Instead, overwrite it here. */
266 virama_glyph.set_relaxed ((int) glyph);
267 }
268
269 *pglyph = glyph;
270 return glyph != 0;
271 }
272
273 const indic_config_t *config;
274
275 bool is_old_spec;
276 mutable hb_atomic_int_t virama_glyph;
277
278 would_substitute_feature_t rphf;
279 would_substitute_feature_t pref;
280 would_substitute_feature_t blwf;
281 would_substitute_feature_t pstf;
282
283 hb_mask_t mask_array[INDIC_NUM_FEATURES];
284};
285
286static void *
287data_create_indic (const hb_ot_shape_plan_t *plan)
288{
289 indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (1, sizeof (indic_shape_plan_t));
290 if (unlikely (!indic_plan))
291 return nullptr;
292
293 indic_plan->config = &indic_configs[0];
294 for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++)
295 if (plan->props.script == indic_configs[i].script) {
296 indic_plan->config = &indic_configs[i];
297 break;
298 }
299
300 indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FFu) != '2');
301 indic_plan->virama_glyph.set_relaxed (-1);
302
303 /* Use zero-context would_substitute() matching for new-spec of the main
304 * Indic scripts, and scripts with one spec only, but not for old-specs.
305 * The new-spec for all dual-spec scripts says zero-context matching happens.
306 *
307 * However, testing with Malayalam shows that old and new spec both allow
308 * context. Testing with Bengali new-spec however shows that it doesn't.
309 * So, the heuristic here is the way it is. It should *only* be changed,
310 * as we discover more cases of what Windows does. DON'T TOUCH OTHERWISE.
311 */
312 bool zero_context = !indic_plan->is_old_spec && plan->props.script != HB_SCRIPT_MALAYALAM;
313 indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'), zero_context);
314 indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), zero_context);
315 indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'), zero_context);
316 indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'), zero_context);
317
318 for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++)
319 indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ?
320 0 : plan->map.get_1_mask (indic_features[i].tag);
321
322 return indic_plan;
323}
324
325static void
326data_destroy_indic (void *data)
327{
328 free (data);
329}
330
331static indic_position_t
332consonant_position_from_face (const indic_shape_plan_t *indic_plan,
333 const hb_codepoint_t consonant,
334 const hb_codepoint_t virama,
335 hb_face_t *face)
336{
337 /* For old-spec, the order of glyphs is Consonant,Virama,
338 * whereas for new-spec, it's Virama,Consonant. However,
339 * some broken fonts (like Free Sans) simply copied lookups
340 * from old-spec to new-spec without modification.
341 * And oddly enough, Uniscribe seems to respect those lookups.
342 * Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds
343 * base at 0. The font however, only has lookups matching
344 * 930,94D in 'blwf', not the expected 94D,930 (with new-spec
345 * table). As such, we simply match both sequences. Seems
346 * to work. */
347 hb_codepoint_t glyphs[3] = {virama, consonant, virama};
348 if (indic_plan->blwf.would_substitute (glyphs , 2, face) ||
349 indic_plan->blwf.would_substitute (glyphs+1, 2, face))
350 return POS_BELOW_C;
351 if (indic_plan->pstf.would_substitute (glyphs , 2, face) ||
352 indic_plan->pstf.would_substitute (glyphs+1, 2, face))
353 return POS_POST_C;
354 if (indic_plan->pref.would_substitute (glyphs , 2, face) ||
355 indic_plan->pref.would_substitute (glyphs+1, 2, face))
356 return POS_POST_C;
357 return POS_BASE_C;
358}
359
360
361enum syllable_type_t {
362 consonant_syllable,
363 vowel_syllable,
364 standalone_cluster,
365 symbol_cluster,
366 broken_cluster,
367 non_indic_cluster,
368};
369
370#include "hb-ot-shape-complex-indic-machine.hh"
371
372
373static void
374setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED,
375 hb_buffer_t *buffer,
376 hb_font_t *font HB_UNUSED)
377{
378 HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
379 HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
380
381 /* We cannot setup masks here. We save information about characters
382 * and setup masks later on in a pause-callback. */
383
384 unsigned int count = buffer->len;
385 hb_glyph_info_t *info = buffer->info;
386 for (unsigned int i = 0; i < count; i++)
387 set_indic_properties (info[i]);
388}
389
390static void
391setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
392 hb_font_t *font HB_UNUSED,
393 hb_buffer_t *buffer)
394{
395 find_syllables (buffer);
396 foreach_syllable (buffer, start, end)
397 buffer->unsafe_to_break (start, end);
398}
399
400static int
401compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
402{
403 int a = pa->indic_position();
404 int b = pb->indic_position();
405
406 return a < b ? -1 : a == b ? 0 : +1;
407}
408
409
410
411static void
412update_consonant_positions (const hb_ot_shape_plan_t *plan,
413 hb_font_t *font,
414 hb_buffer_t *buffer)
415{
416 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
417
418 if (indic_plan->config->base_pos != BASE_POS_LAST)
419 return;
420
421 hb_codepoint_t virama;
422 if (indic_plan->load_virama_glyph (font, &virama))
423 {
424 hb_face_t *face = font->face;
425 unsigned int count = buffer->len;
426 hb_glyph_info_t *info = buffer->info;
427 for (unsigned int i = 0; i < count; i++)
428 if (info[i].indic_position() == POS_BASE_C)
429 {
430 hb_codepoint_t consonant = info[i].codepoint;
431 info[i].indic_position() = consonant_position_from_face (indic_plan, consonant, virama, face);
432 }
433 }
434}
435
436
437/* Rules from:
438 * https://docs.microsqoft.com/en-us/typography/script-development/devanagari */
439
440static void
441initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan,
442 hb_face_t *face,
443 hb_buffer_t *buffer,
444 unsigned int start, unsigned int end)
445{
446 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
447 hb_glyph_info_t *info = buffer->info;
448
449 /* https://github.com/harfbuzz/harfbuzz/issues/435#issuecomment-335560167
450 * // For compatibility with legacy usage in Kannada,
451 * // Ra+h+ZWJ must behave like Ra+ZWJ+h...
452 */
453 if (buffer->props.script == HB_SCRIPT_KANNADA &&
454 start + 3 <= end &&
455 is_one_of (info[start ], FLAG (OT_Ra)) &&
456 is_one_of (info[start+1], FLAG (OT_H)) &&
457 is_one_of (info[start+2], FLAG (OT_ZWJ)))
458 {
459 buffer->merge_clusters (start+1, start+3);
460 hb_glyph_info_t tmp = info[start+1];
461 info[start+1] = info[start+2];
462 info[start+2] = tmp;
463 }
464
465 /* 1. Find base consonant:
466 *
467 * The shaping engine finds the base consonant of the syllable, using the
468 * following algorithm: starting from the end of the syllable, move backwards
469 * until a consonant is found that does not have a below-base or post-base
470 * form (post-base forms have to follow below-base forms), or that is not a
471 * pre-base-reordering Ra, or arrive at the first consonant. The consonant
472 * stopped at will be the base.
473 *
474 * o If the syllable starts with Ra + Halant (in a script that has Reph)
475 * and has more than one consonant, Ra is excluded from candidates for
476 * base consonants.
477 */
478
479 unsigned int base = end;
480 bool has_reph = false;
481
482 {
483 /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
484 * and has more than one consonant, Ra is excluded from candidates for
485 * base consonants. */
486 unsigned int limit = start;
487 if (indic_plan->mask_array[RPHF] &&
488 start + 3 <= end &&
489 (
490 (indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info[start + 2])) ||
491 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == OT_ZWJ)
492 ))
493 {
494 /* See if it matches the 'rphf' feature. */
495 hb_codepoint_t glyphs[3] = {info[start].codepoint,
496 info[start + 1].codepoint,
497 indic_plan->config->reph_mode == REPH_MODE_EXPLICIT ?
498 info[start + 2].codepoint : 0};
499 if (indic_plan->rphf.would_substitute (glyphs, 2, face) ||
500 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT &&
501 indic_plan->rphf.would_substitute (glyphs, 3, face)))
502 {
503 limit += 2;
504 while (limit < end && is_joiner (info[limit]))
505 limit++;
506 base = start;
507 has_reph = true;
508 }
509 } else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == OT_Repha)
510 {
511 limit += 1;
512 while (limit < end && is_joiner (info[limit]))
513 limit++;
514 base = start;
515 has_reph = true;
516 }
517
518 switch (indic_plan->config->base_pos)
519 {
520 case BASE_POS_LAST:
521 {
522 /* -> starting from the end of the syllable, move backwards */
523 unsigned int i = end;
524 bool seen_below = false;
525 do {
526 i--;
527 /* -> until a consonant is found */
528 if (is_consonant (info[i]))
529 {
530 /* -> that does not have a below-base or post-base form
531 * (post-base forms have to follow below-base forms), */
532 if (info[i].indic_position() != POS_BELOW_C &&
533 (info[i].indic_position() != POS_POST_C || seen_below))
534 {
535 base = i;
536 break;
537 }
538 if (info[i].indic_position() == POS_BELOW_C)
539 seen_below = true;
540
541 /* -> or that is not a pre-base-reordering Ra,
542 *
543 * IMPLEMENTATION NOTES:
544 *
545 * Our pre-base-reordering Ra's are marked POS_POST_C, so will be skipped
546 * by the logic above already.
547 */
548
549 /* -> or arrive at the first consonant. The consonant stopped at will
550 * be the base. */
551 base = i;
552 }
553 else
554 {
555 /* A ZWJ after a Halant stops the base search, and requests an explicit
556 * half form.
557 * A ZWJ before a Halant, requests a subjoined form instead, and hence
558 * search continues. This is particularly important for Bengali
559 * sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */
560 if (start < i &&
561 info[i].indic_category() == OT_ZWJ &&
562 info[i - 1].indic_category() == OT_H)
563 break;
564 }
565 } while (i > limit);
566 }
567 break;
568
569 case BASE_POS_LAST_SINHALA:
570 {
571 /* Sinhala base positioning is slightly different from main Indic, in that:
572 * 1. Its ZWJ behavior is different,
573 * 2. We don't need to look into the font for consonant positions.
574 */
575
576 if (!has_reph)
577 base = limit;
578
579 /* Find the last base consonant that is not blocked by ZWJ. If there is
580 * a ZWJ right before a base consonant, that would request a subjoined form. */
581 for (unsigned int i = limit; i < end; i++)
582 if (is_consonant (info[i]))
583 {
584 if (limit < i && info[i - 1].indic_category() == OT_ZWJ)
585 break;
586 else
587 base = i;
588 }
589
590 /* Mark all subsequent consonants as below. */
591 for (unsigned int i = base + 1; i < end; i++)
592 if (is_consonant (info[i]))
593 info[i].indic_position() = POS_BELOW_C;
594 }
595 break;
596 }
597
598 /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
599 * and has more than one consonant, Ra is excluded from candidates for
600 * base consonants.
601 *
602 * Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */
603 if (has_reph && base == start && limit - base <= 2) {
604 /* Have no other consonant, so Reph is not formed and Ra becomes base. */
605 has_reph = false;
606 }
607 }
608
609
610 /* 2. Decompose and reorder Matras:
611 *
612 * Each matra and any syllable modifier sign in the syllable are moved to the
613 * appropriate position relative to the consonant(s) in the syllable. The
614 * shaping engine decomposes two- or three-part matras into their constituent
615 * parts before any repositioning. Matra characters are classified by which
616 * consonant in a conjunct they have affinity for and are reordered to the
617 * following positions:
618 *
619 * o Before first half form in the syllable
620 * o After subjoined consonants
621 * o After post-form consonant
622 * o After main consonant (for above marks)
623 *
624 * IMPLEMENTATION NOTES:
625 *
626 * The normalize() routine has already decomposed matras for us, so we don't
627 * need to worry about that.
628 */
629
630
631 /* 3. Reorder marks to canonical order:
632 *
633 * Adjacent nukta and halant or nukta and vedic sign are always repositioned
634 * if necessary, so that the nukta is first.
635 *
636 * IMPLEMENTATION NOTES:
637 *
638 * We don't need to do this: the normalize() routine already did this for us.
639 */
640
641
642 /* Reorder characters */
643
644 for (unsigned int i = start; i < base; i++)
645 info[i].indic_position() = MIN (POS_PRE_C, (indic_position_t) info[i].indic_position());
646
647 if (base < end)
648 info[base].indic_position() = POS_BASE_C;
649
650 /* Mark final consonants. A final consonant is one appearing after a matra.
651 * Happens in Sinhala. */
652 for (unsigned int i = base + 1; i < end; i++)
653 if (info[i].indic_category() == OT_M) {
654 for (unsigned int j = i + 1; j < end; j++)
655 if (is_consonant (info[j])) {
656 info[j].indic_position() = POS_FINAL_C;
657 break;
658 }
659 break;
660 }
661
662 /* Handle beginning Ra */
663 if (has_reph)
664 info[start].indic_position() = POS_RA_TO_BECOME_REPH;
665
666 /* For old-style Indic script tags, move the first post-base Halant after
667 * last consonant.
668 *
669 * Reports suggest that in some scripts Uniscribe does this only if there
670 * is *not* a Halant after last consonant already. We know that is the
671 * case for Kannada, while it reorders unconditionally in other scripts,
672 * eg. Malayalam, Bengali, and Devanagari. We don't currently know about
673 * other scripts, so we blacklist Kannada.
674 *
675 * Kannada test case:
676 * U+0C9A,U+0CCD,U+0C9A,U+0CCD
677 * With some versions of Lohit Kannada.
678 * https://bugs.freedesktop.org/show_bug.cgi?id=59118
679 *
680 * Malayalam test case:
681 * U+0D38,U+0D4D,U+0D31,U+0D4D,U+0D31,U+0D4D
682 * With lohit-ttf-20121122/Lohit-Malayalam.ttf
683 *
684 * Bengali test case:
685 * U+0998,U+09CD,U+09AF,U+09CD
686 * With Windows XP vrinda.ttf
687 * https://github.com/harfbuzz/harfbuzz/issues/1073
688 *
689 * Devanagari test case:
690 * U+091F,U+094D,U+0930,U+094D
691 * With chandas.ttf
692 * https://github.com/harfbuzz/harfbuzz/issues/1071
693 */
694 if (indic_plan->is_old_spec)
695 {
696 bool disallow_double_halants = buffer->props.script == HB_SCRIPT_KANNADA;
697 for (unsigned int i = base + 1; i < end; i++)
698 if (info[i].indic_category() == OT_H)
699 {
700 unsigned int j;
701 for (j = end - 1; j > i; j--)
702 if (is_consonant (info[j]) ||
703 (disallow_double_halants && info[j].indic_category() == OT_H))
704 break;
705 if (info[j].indic_category() != OT_H && j > i) {
706 /* Move Halant to after last consonant. */
707 hb_glyph_info_t t = info[i];
708 memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0]));
709 info[j] = t;
710 }
711 break;
712 }
713 }
714
715 /* Attach misc marks to previous char to move with them. */
716 {
717 indic_position_t last_pos = POS_START;
718 for (unsigned int i = start; i < end; i++)
719 {
720 if ((FLAG_UNSAFE (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | MEDIAL_FLAGS | FLAG (OT_H))))
721 {
722 info[i].indic_position() = last_pos;
723 if (unlikely (info[i].indic_category() == OT_H &&
724 info[i].indic_position() == POS_PRE_M))
725 {
726 /*
727 * Uniscribe doesn't move the Halant with Left Matra.
728 * TEST: U+092B,U+093F,U+094DE
729 * We follow. This is important for the Sinhala
730 * U+0DDA split matra since it decomposes to U+0DD9,U+0DCA
731 * where U+0DD9 is a left matra and U+0DCA is the virama.
732 * We don't want to move the virama with the left matra.
733 * TEST: U+0D9A,U+0DDA
734 */
735 for (unsigned int j = i; j > start; j--)
736 if (info[j - 1].indic_position() != POS_PRE_M) {
737 info[i].indic_position() = info[j - 1].indic_position();
738 break;
739 }
740 }
741 } else if (info[i].indic_position() != POS_SMVD) {
742 last_pos = (indic_position_t) info[i].indic_position();
743 }
744 }
745 }
746 /* For post-base consonants let them own anything before them
747 * since the last consonant or matra. */
748 {
749 unsigned int last = base;
750 for (unsigned int i = base + 1; i < end; i++)
751 if (is_consonant (info[i]))
752 {
753 for (unsigned int j = last + 1; j < i; j++)
754 if (info[j].indic_position() < POS_SMVD)
755 info[j].indic_position() = info[i].indic_position();
756 last = i;
757 } else if (info[i].indic_category() == OT_M)
758 last = i;
759 }
760
761
762 {
763 /* Use syllable() for sort accounting temporarily. */
764 unsigned int syllable = info[start].syllable();
765 for (unsigned int i = start; i < end; i++)
766 info[i].syllable() = i - start;
767
768 /* Sit tight, rock 'n roll! */
769 hb_stable_sort (info + start, end - start, compare_indic_order);
770 /* Find base again */
771 base = end;
772 for (unsigned int i = start; i < end; i++)
773 if (info[i].indic_position() == POS_BASE_C)
774 {
775 base = i;
776 break;
777 }
778 /* Things are out-of-control for post base positions, they may shuffle
779 * around like crazy. In old-spec mode, we move halants around, so in
780 * that case merge all clusters after base. Otherwise, check the sort
781 * order and merge as needed.
782 * For pre-base stuff, we handle cluster issues in final reordering.
783 *
784 * We could use buffer->sort() for this, if there was no special
785 * reordering of pre-base stuff happening later...
786 */
787 if (indic_plan->is_old_spec || end - base > 127)
788 buffer->merge_clusters (base, end);
789 else
790 {
791 /* Note! syllable() is a one-byte field. */
792 for (unsigned int i = base; i < end; i++)
793 if (info[i].syllable() != 255)
794 {
795 unsigned int max = i;
796 unsigned int j = start + info[i].syllable();
797 while (j != i)
798 {
799 max = MAX (max, j);
800 unsigned int next = start + info[j].syllable();
801 info[j].syllable() = 255; /* So we don't process j later again. */
802 j = next;
803 }
804 if (i != max)
805 buffer->merge_clusters (i, max + 1);
806 }
807 }
808
809 /* Put syllable back in. */
810 for (unsigned int i = start; i < end; i++)
811 info[i].syllable() = syllable;
812 }
813
814 /* Setup masks now */
815
816 {
817 hb_mask_t mask;
818
819 /* Reph */
820 for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++)
821 info[i].mask |= indic_plan->mask_array[RPHF];
822
823 /* Pre-base */
824 mask = indic_plan->mask_array[HALF];
825 if (!indic_plan->is_old_spec &&
826 indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST)
827 mask |= indic_plan->mask_array[BLWF];
828 for (unsigned int i = start; i < base; i++)
829 info[i].mask |= mask;
830 /* Base */
831 mask = 0;
832 if (base < end)
833 info[base].mask |= mask;
834 /* Post-base */
835 mask = indic_plan->mask_array[BLWF] | indic_plan->mask_array[ABVF] | indic_plan->mask_array[PSTF];
836 for (unsigned int i = base + 1; i < end; i++)
837 info[i].mask |= mask;
838 }
839
840 if (indic_plan->is_old_spec &&
841 buffer->props.script == HB_SCRIPT_DEVANAGARI)
842 {
843 /* Old-spec eye-lash Ra needs special handling. From the
844 * spec:
845 *
846 * "The feature 'below-base form' is applied to consonants
847 * having below-base forms and following the base consonant.
848 * The exception is vattu, which may appear below half forms
849 * as well as below the base glyph. The feature 'below-base
850 * form' will be applied to all such occurrences of Ra as well."
851 *
852 * Test case: U+0924,U+094D,U+0930,U+094d,U+0915
853 * with Sanskrit 2003 font.
854 *
855 * However, note that Ra,Halant,ZWJ is the correct way to
856 * request eyelash form of Ra, so we wouldbn't inhibit it
857 * in that sequence.
858 *
859 * Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915
860 */
861 for (unsigned int i = start; i + 1 < base; i++)
862 if (info[i ].indic_category() == OT_Ra &&
863 info[i+1].indic_category() == OT_H &&
864 (i + 2 == base ||
865 info[i+2].indic_category() != OT_ZWJ))
866 {
867 info[i ].mask |= indic_plan->mask_array[BLWF];
868 info[i+1].mask |= indic_plan->mask_array[BLWF];
869 }
870 }
871
872 unsigned int pref_len = 2;
873 if (indic_plan->mask_array[PREF] && base + pref_len < end)
874 {
875 /* Find a Halant,Ra sequence and mark it for pre-base-reordering processing. */
876 for (unsigned int i = base + 1; i + pref_len - 1 < end; i++) {
877 hb_codepoint_t glyphs[2];
878 for (unsigned int j = 0; j < pref_len; j++)
879 glyphs[j] = info[i + j].codepoint;
880 if (indic_plan->pref.would_substitute (glyphs, pref_len, face))
881 {
882 for (unsigned int j = 0; j < pref_len; j++)
883 info[i++].mask |= indic_plan->mask_array[PREF];
884 break;
885 }
886 }
887 }
888
889 /* Apply ZWJ/ZWNJ effects */
890 for (unsigned int i = start + 1; i < end; i++)
891 if (is_joiner (info[i])) {
892 bool non_joiner = info[i].indic_category() == OT_ZWNJ;
893 unsigned int j = i;
894
895 do {
896 j--;
897
898 /* ZWJ/ZWNJ should disable CJCT. They do that by simply
899 * being there, since we don't skip them for the CJCT
900 * feature (ie. F_MANUAL_ZWJ) */
901
902 /* A ZWNJ disables HALF. */
903 if (non_joiner)
904 info[j].mask &= ~indic_plan->mask_array[HALF];
905
906 } while (j > start && !is_consonant (info[j]));
907 }
908}
909
910static void
911initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan,
912 hb_face_t *face,
913 hb_buffer_t *buffer,
914 unsigned int start, unsigned int end)
915{
916 /* We treat placeholder/dotted-circle as if they are consonants, so we
917 * should just chain. Only if not in compatibility mode that is... */
918
919 if (hb_options ().uniscribe_bug_compatible)
920 {
921 /* For dotted-circle, this is what Uniscribe does:
922 * If dotted-circle is the last glyph, it just does nothing.
923 * Ie. It doesn't form Reph. */
924 if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE)
925 return;
926 }
927
928 initial_reordering_consonant_syllable (plan, face, buffer, start, end);
929}
930
931static void
932initial_reordering_syllable (const hb_ot_shape_plan_t *plan,
933 hb_face_t *face,
934 hb_buffer_t *buffer,
935 unsigned int start, unsigned int end)
936{
937 syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
938 switch (syllable_type)
939 {
940 case vowel_syllable: /* We made the vowels look like consonants. So let's call the consonant logic! */
941 case consonant_syllable:
942 initial_reordering_consonant_syllable (plan, face, buffer, start, end);
943 break;
944
945 case broken_cluster: /* We already inserted dotted-circles, so just call the standalone_cluster. */
946 case standalone_cluster:
947 initial_reordering_standalone_cluster (plan, face, buffer, start, end);
948 break;
949
950 case symbol_cluster:
951 case non_indic_cluster:
952 break;
953 }
954}
955
956static inline void
957insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
958 hb_font_t *font,
959 hb_buffer_t *buffer)
960{
961 /* Note: This loop is extra overhead, but should not be measurable. */
962 bool has_broken_syllables = false;
963 unsigned int count = buffer->len;
964 hb_glyph_info_t *info = buffer->info;
965 for (unsigned int i = 0; i < count; i++)
966 if ((info[i].syllable() & 0x0F) == broken_cluster)
967 {
968 has_broken_syllables = true;
969 break;
970 }
971 if (likely (!has_broken_syllables))
972 return;
973
974
975 hb_codepoint_t dottedcircle_glyph;
976 if (!font->get_nominal_glyph (0x25CCu, &dottedcircle_glyph))
977 return;
978
979 hb_glyph_info_t dottedcircle = {0};
980 dottedcircle.codepoint = 0x25CCu;
981 set_indic_properties (dottedcircle);
982 dottedcircle.codepoint = dottedcircle_glyph;
983
984 buffer->clear_output ();
985
986 buffer->idx = 0;
987 unsigned int last_syllable = 0;
988 while (buffer->idx < buffer->len && buffer->successful)
989 {
990 unsigned int syllable = buffer->cur().syllable();
991 syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
992 if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
993 {
994 last_syllable = syllable;
995
996 hb_glyph_info_t ginfo = dottedcircle;
997 ginfo.cluster = buffer->cur().cluster;
998 ginfo.mask = buffer->cur().mask;
999 ginfo.syllable() = buffer->cur().syllable();
1000 /* TODO Set glyph_props? */
1001
1002 /* Insert dottedcircle after possible Repha. */
1003 while (buffer->idx < buffer->len && buffer->successful &&
1004 last_syllable == buffer->cur().syllable() &&
1005 buffer->cur().indic_category() == OT_Repha)
1006 buffer->next_glyph ();
1007
1008 buffer->output_info (ginfo);
1009 }
1010 else
1011 buffer->next_glyph ();
1012 }
1013
1014 buffer->swap_buffers ();
1015}
1016
1017static void
1018initial_reordering (const hb_ot_shape_plan_t *plan,
1019 hb_font_t *font,
1020 hb_buffer_t *buffer)
1021{
1022 update_consonant_positions (plan, font, buffer);
1023 insert_dotted_circles (plan, font, buffer);
1024
1025 foreach_syllable (buffer, start, end)
1026 initial_reordering_syllable (plan, font->face, buffer, start, end);
1027}
1028
1029static void
1030final_reordering_syllable (const hb_ot_shape_plan_t *plan,
1031 hb_buffer_t *buffer,
1032 unsigned int start, unsigned int end)
1033{
1034 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
1035 hb_glyph_info_t *info = buffer->info;
1036
1037
1038 /* This function relies heavily on halant glyphs. Lots of ligation
1039 * and possibly multiple substitutions happened prior to this
1040 * phase, and that might have messed up our properties. Recover
1041 * from a particular case of that where we're fairly sure that a
1042 * class of OT_H is desired but has been lost. */
1043 /* We don't call load_virama_glyph(), since we know it's already
1044 * loaded. */
1045 hb_codepoint_t virama_glyph = indic_plan->virama_glyph.get_relaxed ();
1046 if (virama_glyph)
1047 {
1048 for (unsigned int i = start; i < end; i++)
1049 if (info[i].codepoint == virama_glyph &&
1050 _hb_glyph_info_ligated (&info[i]) &&
1051 _hb_glyph_info_multiplied (&info[i]))
1052 {
1053 /* This will make sure that this glyph passes is_halant() test. */
1054 info[i].indic_category() = OT_H;
1055 _hb_glyph_info_clear_ligated_and_multiplied (&info[i]);
1056 }
1057 }
1058
1059
1060 /* 4. Final reordering:
1061 *
1062 * After the localized forms and basic shaping forms GSUB features have been
1063 * applied (see below), the shaping engine performs some final glyph
1064 * reordering before applying all the remaining font features to the entire
1065 * syllable.
1066 */
1067
1068 bool try_pref = !!indic_plan->mask_array[PREF];
1069
1070 /* Find base again */
1071 unsigned int base;
1072 for (base = start; base < end; base++)
1073 if (info[base].indic_position() >= POS_BASE_C)
1074 {
1075 if (try_pref && base + 1 < end)
1076 {
1077 for (unsigned int i = base + 1; i < end; i++)
1078 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0)
1079 {
1080 if (!(_hb_glyph_info_substituted (&info[i]) &&
1081 _hb_glyph_info_ligated_and_didnt_multiply (&info[i])))
1082 {
1083 /* Ok, this was a 'pref' candidate but didn't form any.
1084 * Base is around here... */
1085 base = i;
1086 while (base < end && is_halant (info[base]))
1087 base++;
1088 info[base].indic_position() = POS_BASE_C;
1089
1090 try_pref = false;
1091 }
1092 break;
1093 }
1094 }
1095 /* For Malayalam, skip over unformed below- (but NOT post-) forms. */
1096 if (buffer->props.script == HB_SCRIPT_MALAYALAM)
1097 {
1098 for (unsigned int i = base + 1; i < end; i++)
1099 {
1100 while (i < end && is_joiner (info[i]))
1101 i++;
1102 if (i == end || !is_halant (info[i]))
1103 break;
1104 i++; /* Skip halant. */
1105 while (i < end && is_joiner (info[i]))
1106 i++;
1107 if (i < end && is_consonant (info[i]) && info[i].indic_position() == POS_BELOW_C)
1108 {
1109 base = i;
1110 info[base].indic_position() = POS_BASE_C;
1111 }
1112 }
1113 }
1114
1115 if (start < base && info[base].indic_position() > POS_BASE_C)
1116 base--;
1117 break;
1118 }
1119 if (base == end && start < base &&
1120 is_one_of (info[base - 1], FLAG (OT_ZWJ)))
1121 base--;
1122 if (base < end)
1123 while (start < base &&
1124 is_one_of (info[base], (FLAG (OT_N) | FLAG (OT_H))))
1125 base--;
1126
1127
1128 /* o Reorder matras:
1129 *
1130 * If a pre-base matra character had been reordered before applying basic
1131 * features, the glyph can be moved closer to the main consonant based on
1132 * whether half-forms had been formed. Actual position for the matra is
1133 * defined as “after last standalone halant glyph, after initial matra
1134 * position and before the main consonant”. If ZWJ or ZWNJ follow this
1135 * halant, position is moved after it.
1136 *
1137 * IMPLEMENTATION NOTES:
1138 *
1139 * It looks like the last sentence is wrong. Testing, with Windows 7 Uniscribe
1140 * and Devanagari shows that the behavior is best described as:
1141 *
1142 * "If ZWJ follows this halant, matra is NOT repositioned after this halant.
1143 * If ZWNJ follows this halant, position is moved after it."
1144 *
1145 * Test case, with Adobe Devanagari or Nirmala UI:
1146 *
1147 * U+091F,U+094D,U+200C,U+092F,U+093F
1148 * (Matra moves to the middle, after ZWNJ.)
1149 *
1150 * U+091F,U+094D,U+200D,U+092F,U+093F
1151 * (Matra does NOT move, stays to the left.)
1152 *
1153 * https://github.com/harfbuzz/harfbuzz/issues/1070
1154 */
1155
1156 if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */
1157 {
1158 /* If we lost track of base, alas, position before last thingy. */
1159 unsigned int new_pos = base == end ? base - 2 : base - 1;
1160
1161 /* Malayalam / Tamil do not have "half" forms or explicit virama forms.
1162 * The glyphs formed by 'half' are Chillus or ligated explicit viramas.
1163 * We want to position matra after them.
1164 */
1165 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
1166 {
1167 search:
1168 while (new_pos > start &&
1169 !(is_one_of (info[new_pos], (FLAG (OT_M) | FLAG (OT_H)))))
1170 new_pos--;
1171
1172 /* If we found no Halant we are done.
1173 * Otherwise only proceed if the Halant does
1174 * not belong to the Matra itself! */
1175 if (is_halant (info[new_pos]) &&
1176 info[new_pos].indic_position() != POS_PRE_M)
1177 {
1178#if 0 // See comment above
1179 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
1180 if (new_pos + 1 < end && is_joiner (info[new_pos + 1]))
1181 new_pos++;
1182#endif
1183 if (new_pos + 1 < end)
1184 {
1185 /* -> If ZWJ follows this halant, matra is NOT repositioned after this halant. */
1186 if (info[new_pos + 1].indic_category() == OT_ZWJ)
1187 {
1188 /* Keep searching. */
1189 if (new_pos > start)
1190 {
1191 new_pos--;
1192 goto search;
1193 }
1194 }
1195 /* -> If ZWNJ follows this halant, position is moved after it. */
1196 if (info[new_pos + 1].indic_category() == OT_ZWNJ)
1197 new_pos++;
1198 }
1199 }
1200 else
1201 new_pos = start; /* No move. */
1202 }
1203
1204 if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M)
1205 {
1206 /* Now go see if there's actually any matras... */
1207 for (unsigned int i = new_pos; i > start; i--)
1208 if (info[i - 1].indic_position () == POS_PRE_M)
1209 {
1210 unsigned int old_pos = i - 1;
1211 if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */
1212 base--;
1213
1214 hb_glyph_info_t tmp = info[old_pos];
1215 memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0]));
1216 info[new_pos] = tmp;
1217
1218 /* Note: this merge_clusters() is intentionally *after* the reordering.
1219 * Indic matra reordering is special and tricky... */
1220 buffer->merge_clusters (new_pos, MIN (end, base + 1));
1221
1222 new_pos--;
1223 }
1224 } else {
1225 for (unsigned int i = start; i < base; i++)
1226 if (info[i].indic_position () == POS_PRE_M) {
1227 buffer->merge_clusters (i, MIN (end, base + 1));
1228 break;
1229 }
1230 }
1231 }
1232
1233
1234 /* o Reorder reph:
1235 *
1236 * Reph’s original position is always at the beginning of the syllable,
1237 * (i.e. it is not reordered at the character reordering stage). However,
1238 * it will be reordered according to the basic-forms shaping results.
1239 * Possible positions for reph, depending on the script, are; after main,
1240 * before post-base consonant forms, and after post-base consonant forms.
1241 */
1242
1243 /* Two cases:
1244 *
1245 * - If repha is encoded as a sequence of characters (Ra,H or Ra,H,ZWJ), then
1246 * we should only move it if the sequence ligated to the repha form.
1247 *
1248 * - If repha is encoded separately and in the logical position, we should only
1249 * move it if it did NOT ligate. If it ligated, it's probably the font trying
1250 * to make it work without the reordering.
1251 */
1252 if (start + 1 < end &&
1253 info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
1254 ((info[start].indic_category() == OT_Repha) ^
1255 _hb_glyph_info_ligated_and_didnt_multiply (&info[start])))
1256 {
1257 unsigned int new_reph_pos;
1258 reph_position_t reph_pos = indic_plan->config->reph_pos;
1259
1260 /* 1. If reph should be positioned after post-base consonant forms,
1261 * proceed to step 5.
1262 */
1263 if (reph_pos == REPH_POS_AFTER_POST)
1264 {
1265 goto reph_step_5;
1266 }
1267
1268 /* 2. If the reph repositioning class is not after post-base: target
1269 * position is after the first explicit halant glyph between the
1270 * first post-reph consonant and last main consonant. If ZWJ or ZWNJ
1271 * are following this halant, position is moved after it. If such
1272 * position is found, this is the target position. Otherwise,
1273 * proceed to the next step.
1274 *
1275 * Note: in old-implementation fonts, where classifications were
1276 * fixed in shaping engine, there was no case where reph position
1277 * will be found on this step.
1278 */
1279 {
1280 new_reph_pos = start + 1;
1281 while (new_reph_pos < base && !is_halant (info[new_reph_pos]))
1282 new_reph_pos++;
1283
1284 if (new_reph_pos < base && is_halant (info[new_reph_pos]))
1285 {
1286 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
1287 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
1288 new_reph_pos++;
1289 goto reph_move;
1290 }
1291 }
1292
1293 /* 3. If reph should be repositioned after the main consonant: find the
1294 * first consonant not ligated with main, or find the first
1295 * consonant that is not a potential pre-base-reordering Ra.
1296 */
1297 if (reph_pos == REPH_POS_AFTER_MAIN)
1298 {
1299 new_reph_pos = base;
1300 while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN)
1301 new_reph_pos++;
1302 if (new_reph_pos < end)
1303 goto reph_move;
1304 }
1305
1306 /* 4. If reph should be positioned before post-base consonant, find
1307 * first post-base classified consonant not ligated with main. If no
1308 * consonant is found, the target position should be before the
1309 * first matra, syllable modifier sign or vedic sign.
1310 */
1311 /* This is our take on what step 4 is trying to say (and failing, BADLY). */
1312 if (reph_pos == REPH_POS_AFTER_SUB)
1313 {
1314 new_reph_pos = base;
1315 while (new_reph_pos + 1 < end &&
1316 !( FLAG_UNSAFE (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD))))
1317 new_reph_pos++;
1318 if (new_reph_pos < end)
1319 goto reph_move;
1320 }
1321
1322 /* 5. If no consonant is found in steps 3 or 4, move reph to a position
1323 * immediately before the first post-base matra, syllable modifier
1324 * sign or vedic sign that has a reordering class after the intended
1325 * reph position. For example, if the reordering position for reph
1326 * is post-main, it will skip above-base matras that also have a
1327 * post-main position.
1328 */
1329 reph_step_5:
1330 {
1331 /* Copied from step 2. */
1332 new_reph_pos = start + 1;
1333 while (new_reph_pos < base && !is_halant (info[new_reph_pos]))
1334 new_reph_pos++;
1335
1336 if (new_reph_pos < base && is_halant (info[new_reph_pos]))
1337 {
1338 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
1339 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
1340 new_reph_pos++;
1341 goto reph_move;
1342 }
1343 }
1344
1345 /* 6. Otherwise, reorder reph to the end of the syllable.
1346 */
1347 {
1348 new_reph_pos = end - 1;
1349 while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
1350 new_reph_pos--;
1351
1352 /*
1353 * If the Reph is to be ending up after a Matra,Halant sequence,
1354 * position it before that Halant so it can interact with the Matra.
1355 * However, if it's a plain Consonant,Halant we shouldn't do that.
1356 * Uniscribe doesn't do this.
1357 * TEST: U+0930,U+094D,U+0915,U+094B,U+094D
1358 */
1359 if (!hb_options ().uniscribe_bug_compatible &&
1360 unlikely (is_halant (info[new_reph_pos]))) {
1361 for (unsigned int i = base + 1; i < new_reph_pos; i++)
1362 if (info[i].indic_category() == OT_M) {
1363 /* Ok, got it. */
1364 new_reph_pos--;
1365 }
1366 }
1367 goto reph_move;
1368 }
1369
1370 reph_move:
1371 {
1372 /* Move */
1373 buffer->merge_clusters (start, new_reph_pos + 1);
1374 hb_glyph_info_t reph = info[start];
1375 memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
1376 info[new_reph_pos] = reph;
1377
1378 if (start < base && base <= new_reph_pos)
1379 base--;
1380 }
1381 }
1382
1383
1384 /* o Reorder pre-base-reordering consonants:
1385 *
1386 * If a pre-base-reordering consonant is found, reorder it according to
1387 * the following rules:
1388 */
1389
1390 if (try_pref && base + 1 < end) /* Otherwise there can't be any pre-base-reordering Ra. */
1391 {
1392 for (unsigned int i = base + 1; i < end; i++)
1393 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0)
1394 {
1395 /* 1. Only reorder a glyph produced by substitution during application
1396 * of the <pref> feature. (Note that a font may shape a Ra consonant with
1397 * the feature generally but block it in certain contexts.)
1398 */
1399 /* Note: We just check that something got substituted. We don't check that
1400 * the <pref> feature actually did it...
1401 *
1402 * Reorder pref only if it ligated. */
1403 if (_hb_glyph_info_ligated_and_didnt_multiply (&info[i]))
1404 {
1405 /*
1406 * 2. Try to find a target position the same way as for pre-base matra.
1407 * If it is found, reorder pre-base consonant glyph.
1408 *
1409 * 3. If position is not found, reorder immediately before main
1410 * consonant.
1411 */
1412
1413 unsigned int new_pos = base;
1414 /* Malayalam / Tamil do not have "half" forms or explicit virama forms.
1415 * The glyphs formed by 'half' are Chillus or ligated explicit viramas.
1416 * We want to position matra after them.
1417 */
1418 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
1419 {
1420 while (new_pos > start &&
1421 !(is_one_of (info[new_pos - 1], FLAG(OT_M) | FLAG (OT_H))))
1422 new_pos--;
1423 }
1424
1425 if (new_pos > start && is_halant (info[new_pos - 1]))
1426 {
1427 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
1428 if (new_pos < end && is_joiner (info[new_pos]))
1429 new_pos++;
1430 }
1431
1432 {
1433 unsigned int old_pos = i;
1434
1435 buffer->merge_clusters (new_pos, old_pos + 1);
1436 hb_glyph_info_t tmp = info[old_pos];
1437 memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0]));
1438 info[new_pos] = tmp;
1439
1440 if (new_pos <= base && base < old_pos)
1441 base++;
1442 }
1443 }
1444
1445 break;
1446 }
1447 }
1448
1449
1450 /* Apply 'init' to the Left Matra if it's a word start. */
1451 if (info[start].indic_position () == POS_PRE_M)
1452 {
1453 if (!start ||
1454 !(FLAG_UNSAFE (_hb_glyph_info_get_general_category (&info[start - 1])) &
1455 FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))
1456 info[start].mask |= indic_plan->mask_array[INIT];
1457 else
1458 buffer->unsafe_to_break (start - 1, start + 1);
1459 }
1460
1461
1462 /*
1463 * Finish off the clusters and go home!
1464 */
1465 if (hb_options ().uniscribe_bug_compatible)
1466 {
1467 switch ((hb_tag_t) plan->props.script)
1468 {
1469 case HB_SCRIPT_TAMIL:
1470 case HB_SCRIPT_SINHALA:
1471 break;
1472
1473 default:
1474 /* Uniscribe merges the entire syllable into a single cluster... Except for Tamil & Sinhala.
1475 * This means, half forms are submerged into the main consonant's cluster.
1476 * This is unnecessary, and makes cursor positioning harder, but that's what
1477 * Uniscribe does. */
1478 buffer->merge_clusters (start, end);
1479 break;
1480 }
1481 }
1482}
1483
1484
1485static void
1486final_reordering (const hb_ot_shape_plan_t *plan,
1487 hb_font_t *font HB_UNUSED,
1488 hb_buffer_t *buffer)
1489{
1490 unsigned int count = buffer->len;
1491 if (unlikely (!count)) return;
1492
1493 foreach_syllable (buffer, start, end)
1494 final_reordering_syllable (plan, buffer, start, end);
1495
1496 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
1497 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
1498}
1499
1500
1501static void
1502clear_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
1503 hb_font_t *font HB_UNUSED,
1504 hb_buffer_t *buffer)
1505{
1506 hb_glyph_info_t *info = buffer->info;
1507 unsigned int count = buffer->len;
1508 for (unsigned int i = 0; i < count; i++)
1509 info[i].syllable() = 0;
1510}
1511
1512
1513static bool
1514decompose_indic (const hb_ot_shape_normalize_context_t *c,
1515 hb_codepoint_t ab,
1516 hb_codepoint_t *a,
1517 hb_codepoint_t *b)
1518{
1519 switch (ab)
1520 {
1521 /* Don't decompose these. */
1522 case 0x0931u : return false; /* DEVANAGARI LETTER RRA */
1523 // https://github.com/harfbuzz/harfbuzz/issues/779
1524 case 0x09DCu : return false; /* BENGALI LETTER RRA */
1525 case 0x09DDu : return false; /* BENGALI LETTER RHA */
1526 case 0x0B94u : return false; /* TAMIL LETTER AU */
1527
1528
1529 /*
1530 * Decompose split matras that don't have Unicode decompositions.
1531 */
1532
1533#if 0
1534 /* Gujarati */
1535 /* This one has no decomposition in Unicode, but needs no decomposition either. */
1536 /* case 0x0AC9u : return false; */
1537
1538 /* Oriya */
1539 case 0x0B57u : *a = no decomp, -> RIGHT; return true;
1540#endif
1541 }
1542
1543 if ((ab == 0x0DDAu || hb_in_range<hb_codepoint_t> (ab, 0x0DDCu, 0x0DDEu)))
1544 {
1545 /*
1546 * Sinhala split matras... Let the fun begin.
1547 *
1548 * These four characters have Unicode decompositions. However, Uniscribe
1549 * decomposes them "Khmer-style", that is, it uses the character itself to
1550 * get the second half. The first half of all four decompositions is always
1551 * U+0DD9.
1552 *
1553 * Now, there are buggy fonts, namely, the widely used lklug.ttf, that are
1554 * broken with Uniscribe. But we need to support them. As such, we only
1555 * do the Uniscribe-style decomposition if the character is transformed into
1556 * its "sec.half" form by the 'pstf' feature. Otherwise, we fall back to
1557 * Unicode decomposition.
1558 *
1559 * Note that we can't unconditionally use Unicode decomposition. That would
1560 * break some other fonts, that are designed to work with Uniscribe, and
1561 * don't have positioning features for the Unicode-style decomposition.
1562 *
1563 * Argh...
1564 *
1565 * The Uniscribe behavior is now documented in the newly published Sinhala
1566 * spec in 2012:
1567 *
1568 * https://docs.microsoft.com/en-us/typography/script-development/sinhala#shaping
1569 */
1570
1571 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data;
1572
1573 hb_codepoint_t glyph;
1574
1575 if (hb_options ().uniscribe_bug_compatible ||
1576 (c->font->get_nominal_glyph (ab, &glyph) &&
1577 indic_plan->pstf.would_substitute (&glyph, 1, c->font->face)))
1578 {
1579 /* Ok, safe to use Uniscribe-style decomposition. */
1580 *a = 0x0DD9u;
1581 *b = ab;
1582 return true;
1583 }
1584 }
1585
1586 return (bool) c->unicode->decompose (ab, a, b);
1587}
1588
1589static bool
1590compose_indic (const hb_ot_shape_normalize_context_t *c,
1591 hb_codepoint_t a,
1592 hb_codepoint_t b,
1593 hb_codepoint_t *ab)
1594{
1595 /* Avoid recomposing split matras. */
1596 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
1597 return false;
1598
1599 /* Composition-exclusion exceptions that we want to recompose. */
1600 if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; }
1601
1602 return (bool) c->unicode->compose (a, b, ab);
1603}
1604
1605
1606const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
1607{
1608 collect_features_indic,
1609 override_features_indic,
1610 data_create_indic,
1611 data_destroy_indic,
1612 nullptr, /* preprocess_text */
1613 nullptr, /* postprocess_glyphs */
1614 HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
1615 decompose_indic,
1616 compose_indic,
1617 setup_masks_indic,
1618 nullptr, /* disable_otl */
1619 nullptr, /* reorder_marks */
1620 HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
1621 false, /* fallback_position */
1622};
1623