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-private.hh"
28#include "hb-ot-layout-private.hh"
29
30/* buffer var allocations */
31#define indic_category() complex_var_u8_0() /* indic_category_t */
32#define indic_position() complex_var_u8_1() /* indic_position_t */
33
34
35/*
36 * Indic shaper.
37 */
38
39
40#define IN_HALF_BLOCK(u, Base) (((u) & ~0x7Fu) == (Base))
41
42#define IS_DEVA(u) (IN_HALF_BLOCK (u, 0x0900u))
43#define IS_BENG(u) (IN_HALF_BLOCK (u, 0x0980u))
44#define IS_GURU(u) (IN_HALF_BLOCK (u, 0x0A00u))
45#define IS_GUJR(u) (IN_HALF_BLOCK (u, 0x0A80u))
46#define IS_ORYA(u) (IN_HALF_BLOCK (u, 0x0B00u))
47#define IS_TAML(u) (IN_HALF_BLOCK (u, 0x0B80u))
48#define IS_TELU(u) (IN_HALF_BLOCK (u, 0x0C00u))
49#define IS_KNDA(u) (IN_HALF_BLOCK (u, 0x0C80u))
50#define IS_MLYM(u) (IN_HALF_BLOCK (u, 0x0D00u))
51#define IS_SINH(u) (IN_HALF_BLOCK (u, 0x0D80u))
52#define IS_KHMR(u) (IN_HALF_BLOCK (u, 0x1780u))
53
54
55#define MATRA_POS_LEFT(u) POS_PRE_M
56#define MATRA_POS_RIGHT(u) ( \
57 IS_DEVA(u) ? POS_AFTER_SUB : \
58 IS_BENG(u) ? POS_AFTER_POST : \
59 IS_GURU(u) ? POS_AFTER_POST : \
60 IS_GUJR(u) ? POS_AFTER_POST : \
61 IS_ORYA(u) ? POS_AFTER_POST : \
62 IS_TAML(u) ? POS_AFTER_POST : \
63 IS_TELU(u) ? (u <= 0x0C42u ? POS_BEFORE_SUB : POS_AFTER_SUB) : \
64 IS_KNDA(u) ? (u < 0x0CC3u || u > 0xCD6u ? POS_BEFORE_SUB : POS_AFTER_SUB) : \
65 IS_MLYM(u) ? POS_AFTER_POST : \
66 IS_SINH(u) ? POS_AFTER_SUB : \
67 IS_KHMR(u) ? POS_AFTER_POST : \
68 /*default*/ POS_AFTER_SUB \
69 )
70#define MATRA_POS_TOP(u) ( /* BENG and MLYM don't have top matras. */ \
71 IS_DEVA(u) ? POS_AFTER_SUB : \
72 IS_GURU(u) ? POS_AFTER_POST : /* Deviate from spec */ \
73 IS_GUJR(u) ? POS_AFTER_SUB : \
74 IS_ORYA(u) ? POS_AFTER_MAIN : \
75 IS_TAML(u) ? POS_AFTER_SUB : \
76 IS_TELU(u) ? POS_BEFORE_SUB : \
77 IS_KNDA(u) ? POS_BEFORE_SUB : \
78 IS_SINH(u) ? POS_AFTER_SUB : \
79 IS_KHMR(u) ? POS_AFTER_POST : \
80 /*default*/ POS_AFTER_SUB \
81 )
82#define MATRA_POS_BOTTOM(u) ( \
83 IS_DEVA(u) ? POS_AFTER_SUB : \
84 IS_BENG(u) ? POS_AFTER_SUB : \
85 IS_GURU(u) ? POS_AFTER_POST : \
86 IS_GUJR(u) ? POS_AFTER_POST : \
87 IS_ORYA(u) ? POS_AFTER_SUB : \
88 IS_TAML(u) ? POS_AFTER_POST : \
89 IS_TELU(u) ? POS_BEFORE_SUB : \
90 IS_KNDA(u) ? POS_BEFORE_SUB : \
91 IS_MLYM(u) ? POS_AFTER_POST : \
92 IS_SINH(u) ? POS_AFTER_SUB : \
93 IS_KHMR(u) ? POS_AFTER_POST : \
94 /*default*/ POS_AFTER_SUB \
95 )
96
97static inline indic_position_t
98matra_position (hb_codepoint_t u, indic_position_t side)
99{
100 switch ((int) side)
101 {
102 case POS_PRE_C: return MATRA_POS_LEFT (u);
103 case POS_POST_C: return MATRA_POS_RIGHT (u);
104 case POS_ABOVE_C: return MATRA_POS_TOP (u);
105 case POS_BELOW_C: return MATRA_POS_BOTTOM (u);
106 };
107 return side;
108}
109
110/* XXX
111 * This is a hack for now. We should move this data into the main Indic table.
112 * Or completely remove it and just check in the tables.
113 */
114static const hb_codepoint_t ra_chars[] = {
115 0x0930u, /* Devanagari */
116 0x09B0u, /* Bengali */
117 0x09F0u, /* Bengali */
118 0x0A30u, /* Gurmukhi */ /* No Reph */
119 0x0AB0u, /* Gujarati */
120 0x0B30u, /* Oriya */
121 0x0BB0u, /* Tamil */ /* No Reph */
122 0x0C30u, /* Telugu */ /* Reph formed only with ZWJ */
123 0x0CB0u, /* Kannada */
124 0x0D30u, /* Malayalam */ /* No Reph, Logical Repha */
125
126 0x0DBBu, /* Sinhala */ /* Reph formed only with ZWJ */
127
128 0x179Au, /* Khmer */ /* No Reph, Visual Repha */
129};
130
131static inline bool
132is_ra (hb_codepoint_t u)
133{
134 for (unsigned int i = 0; i < ARRAY_LENGTH (ra_chars); i++)
135 if (u == ra_chars[i])
136 return true;
137 return false;
138}
139
140static inline bool
141is_one_of (const hb_glyph_info_t &info, unsigned int flags)
142{
143 /* If it ligated, all bets are off. */
144 if (_hb_glyph_info_ligated (info: &info)) return false;
145 return !!(FLAG_UNSAFE (info.indic_category()) & flags);
146}
147
148static inline bool
149is_joiner (const hb_glyph_info_t &info)
150{
151 return is_one_of (info, JOINER_FLAGS);
152}
153
154static inline bool
155is_consonant (const hb_glyph_info_t &info)
156{
157 return is_one_of (info, CONSONANT_FLAGS);
158}
159
160static inline bool
161is_halant_or_coeng (const hb_glyph_info_t &info)
162{
163 return is_one_of (info, HALANT_OR_COENG_FLAGS);
164}
165
166static inline void
167set_indic_properties (hb_glyph_info_t &info)
168{
169 hb_codepoint_t u = info.codepoint;
170 unsigned int type = hb_indic_get_categories (u);
171 indic_category_t cat = (indic_category_t) (type & 0x7Fu);
172 indic_position_t pos = (indic_position_t) (type >> 8);
173
174
175 /*
176 * Re-assign category
177 */
178
179 /* The following act more like the Bindus. */
180 if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x0953u, 0x0954u)))
181 cat = OT_SM;
182 /* The following act like consonants. */
183 else if (unlikely (hb_in_ranges<hb_codepoint_t> (u, 0x0A72u, 0x0A73u,
184 0x1CF5u, 0x1CF6u)))
185 cat = OT_C;
186 /* TODO: The following should only be allowed after a Visarga.
187 * For now, just treat them like regular tone marks. */
188 else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1CE2u, 0x1CE8u)))
189 cat = OT_A;
190 /* TODO: The following should only be allowed after some of
191 * the nasalization marks, maybe only for U+1CE9..U+1CF1.
192 * For now, just treat them like tone marks. */
193 else if (unlikely (u == 0x1CEDu))
194 cat = OT_A;
195 /* The following take marks in standalone clusters, similar to Avagraha. */
196 else if (unlikely (hb_in_ranges<hb_codepoint_t> (u, 0xA8F2u, 0xA8F7u,
197 0x1CE9u, 0x1CECu,
198 0x1CEEu, 0x1CF1u)))
199 {
200 cat = OT_Symbol;
201 static_assert (((int) INDIC_SYLLABIC_CATEGORY_AVAGRAHA == OT_Symbol), "");
202 }
203 else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x17CDu, 0x17D1u) ||
204 u == 0x17CBu || u == 0x17D3u || u == 0x17DDu)) /* Khmer Various signs */
205 {
206 /* These can occur mid-syllable (eg. before matras), even though Unicode marks them as Syllable_Modifier.
207 * https://github.com/roozbehp/unicode-data/issues/5 */
208 cat = OT_M;
209 pos = POS_ABOVE_C;
210 }
211 else if (unlikely (u == 0x0A51u))
212 {
213 /* https://github.com/harfbuzz/harfbuzz/issues/524 */
214 cat = OT_M;
215 pos = POS_BELOW_C;
216 }
217
218 /* According to ScriptExtensions.txt, these Grantha marks may also be used in Tamil,
219 * so the Indic shaper needs to know their categories. */
220 else if (unlikely (u == 0x11301u || u == 0x11303u)) cat = OT_SM;
221 else if (unlikely (u == 0x1133cu)) cat = OT_N;
222
223 else if (unlikely (u == 0x0AFBu)) cat = OT_N; /* https://github.com/harfbuzz/harfbuzz/issues/552 */
224
225 else if (unlikely (u == 0x0980u)) cat = OT_PLACEHOLDER; /* https://github.com/harfbuzz/harfbuzz/issues/538 */
226 else if (unlikely (u == 0x0C80u)) cat = OT_PLACEHOLDER; /* https://github.com/harfbuzz/harfbuzz/pull/623 */
227 else if (unlikely (u == 0x17C6u)) cat = OT_N; /* Khmer Bindu doesn't like to be repositioned. */
228 else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x2010u, 0x2011u)))
229 cat = OT_PLACEHOLDER;
230 else if (unlikely (u == 0x25CCu)) cat = OT_DOTTEDCIRCLE;
231
232
233 /*
234 * Re-assign position.
235 */
236
237 if ((FLAG_UNSAFE (cat) & CONSONANT_FLAGS))
238 {
239 pos = POS_BASE_C;
240 if (is_ra (u))
241 cat = OT_Ra;
242 }
243 else if (cat == OT_M)
244 {
245 pos = matra_position (u, side: pos);
246 }
247 else if ((FLAG_UNSAFE (cat) & (FLAG (OT_SM) | FLAG (OT_VD) | FLAG (OT_A) | FLAG (OT_Symbol))))
248 {
249 pos = POS_SMVD;
250 }
251
252 if (unlikely (u == 0x0B01u)) pos = POS_BEFORE_SUB; /* Oriya Bindu is BeforeSub in the spec. */
253
254
255
256 info.indic_category() = cat;
257 info.indic_position() = pos;
258}
259
260/*
261 * Things above this line should ideally be moved to the Indic table itself.
262 */
263
264
265/*
266 * Indic configurations. Note that we do not want to keep every single script-specific
267 * behavior in these tables necessarily. This should mainly be used for per-script
268 * properties that are cheaper keeping here, than in the code. Ie. if, say, one and
269 * only one script has an exception, that one script can be if'ed directly in the code,
270 * instead of adding a new flag in these structs.
271 */
272
273enum base_position_t {
274 BASE_POS_FIRST,
275 BASE_POS_LAST_SINHALA,
276 BASE_POS_LAST
277};
278enum reph_position_t {
279 REPH_POS_AFTER_MAIN = POS_AFTER_MAIN,
280 REPH_POS_BEFORE_SUB = POS_BEFORE_SUB,
281 REPH_POS_AFTER_SUB = POS_AFTER_SUB,
282 REPH_POS_BEFORE_POST = POS_BEFORE_POST,
283 REPH_POS_AFTER_POST = POS_AFTER_POST,
284 REPH_POS_DONT_CARE = POS_RA_TO_BECOME_REPH
285};
286enum reph_mode_t {
287 REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */
288 REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */
289 REPH_MODE_VIS_REPHA, /* Encoded Repha character, no reordering needed. */
290 REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */
291};
292enum blwf_mode_t {
293 BLWF_MODE_PRE_AND_POST, /* Below-forms feature applied to pre-base and post-base. */
294 BLWF_MODE_POST_ONLY /* Below-forms feature applied to post-base only. */
295};
296struct indic_config_t
297{
298 hb_script_t script;
299 bool has_old_spec;
300 hb_codepoint_t virama;
301 base_position_t base_pos;
302 reph_position_t reph_pos;
303 reph_mode_t reph_mode;
304 blwf_mode_t blwf_mode;
305};
306
307static const indic_config_t indic_configs[] =
308{
309 /* Default. Should be first. */
310 {.script: HB_SCRIPT_INVALID, .has_old_spec: false, .virama: 0,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_BEFORE_POST,.reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
311 {.script: HB_SCRIPT_DEVANAGARI,.has_old_spec: true, .virama: 0x094Du,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_BEFORE_POST,.reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
312 {.script: HB_SCRIPT_BENGALI, .has_old_spec: true, .virama: 0x09CDu,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_AFTER_SUB, .reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
313 {.script: HB_SCRIPT_GURMUKHI, .has_old_spec: true, .virama: 0x0A4Du,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_BEFORE_SUB, .reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
314 {.script: HB_SCRIPT_GUJARATI, .has_old_spec: true, .virama: 0x0ACDu,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_BEFORE_POST,.reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
315 {.script: HB_SCRIPT_ORIYA, .has_old_spec: true, .virama: 0x0B4Du,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_AFTER_MAIN, .reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
316 {.script: HB_SCRIPT_TAMIL, .has_old_spec: true, .virama: 0x0BCDu,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_AFTER_POST, .reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
317 {.script: HB_SCRIPT_TELUGU, .has_old_spec: true, .virama: 0x0C4Du,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_AFTER_POST, .reph_mode: REPH_MODE_EXPLICIT, .blwf_mode: BLWF_MODE_POST_ONLY},
318 {.script: HB_SCRIPT_KANNADA, .has_old_spec: true, .virama: 0x0CCDu,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_AFTER_POST, .reph_mode: REPH_MODE_IMPLICIT, .blwf_mode: BLWF_MODE_POST_ONLY},
319 {.script: HB_SCRIPT_MALAYALAM, .has_old_spec: true, .virama: 0x0D4Du,.base_pos: BASE_POS_LAST, .reph_pos: REPH_POS_AFTER_MAIN, .reph_mode: REPH_MODE_LOG_REPHA,.blwf_mode: BLWF_MODE_PRE_AND_POST},
320 {.script: HB_SCRIPT_SINHALA, .has_old_spec: false,.virama: 0x0DCAu,.base_pos: BASE_POS_LAST_SINHALA,
321 .reph_pos: REPH_POS_AFTER_MAIN, .reph_mode: REPH_MODE_EXPLICIT, .blwf_mode: BLWF_MODE_PRE_AND_POST},
322 {.script: HB_SCRIPT_KHMER, .has_old_spec: false,.virama: 0x17D2u,.base_pos: BASE_POS_FIRST,.reph_pos: REPH_POS_DONT_CARE, .reph_mode: REPH_MODE_VIS_REPHA,.blwf_mode: BLWF_MODE_PRE_AND_POST},
323};
324
325
326
327/*
328 * Indic shaper.
329 */
330
331struct feature_list_t {
332 hb_tag_t tag;
333 hb_ot_map_feature_flags_t flags;
334};
335
336static const feature_list_t
337indic_features[] =
338{
339 /*
340 * Basic features.
341 * These features are applied in order, one at a time, after initial_reordering.
342 */
343 {HB_TAG('n','u','k','t'), .flags: F_GLOBAL},
344 {HB_TAG('a','k','h','n'), .flags: F_GLOBAL},
345 {HB_TAG('r','p','h','f'), .flags: F_NONE},
346 {HB_TAG('r','k','r','f'), .flags: F_GLOBAL},
347 {HB_TAG('p','r','e','f'), .flags: F_NONE},
348 {HB_TAG('b','l','w','f'), .flags: F_NONE},
349 {HB_TAG('a','b','v','f'), .flags: F_NONE},
350 {HB_TAG('h','a','l','f'), .flags: F_NONE},
351 {HB_TAG('p','s','t','f'), .flags: F_NONE},
352 {HB_TAG('v','a','t','u'), .flags: F_GLOBAL},
353 {HB_TAG('c','j','c','t'), .flags: F_GLOBAL},
354 {HB_TAG('c','f','a','r'), .flags: F_NONE},
355 /*
356 * Other features.
357 * These features are applied all at once, after final_reordering.
358 * Default Bengali font in Windows for example has intermixed
359 * lookups for init,pres,abvs,blws features.
360 */
361 {HB_TAG('i','n','i','t'), .flags: F_NONE},
362 {HB_TAG('p','r','e','s'), .flags: F_GLOBAL},
363 {HB_TAG('a','b','v','s'), .flags: F_GLOBAL},
364 {HB_TAG('b','l','w','s'), .flags: F_GLOBAL},
365 {HB_TAG('p','s','t','s'), .flags: F_GLOBAL},
366 {HB_TAG('h','a','l','n'), .flags: F_GLOBAL},
367 /* Positioning features, though we don't care about the types. */
368 {HB_TAG('d','i','s','t'), .flags: F_GLOBAL},
369 {HB_TAG('a','b','v','m'), .flags: F_GLOBAL},
370 {HB_TAG('b','l','w','m'), .flags: F_GLOBAL},
371};
372
373/*
374 * Must be in the same order as the indic_features array.
375 */
376enum {
377 _NUKT,
378 _AKHN,
379 RPHF,
380 _RKRF,
381 PREF,
382 BLWF,
383 ABVF,
384 HALF,
385 PSTF,
386 _VATU,
387 _CJCT,
388 CFAR,
389
390 INIT,
391 _PRES,
392 _ABVS,
393 _BLWS,
394 _PSTS,
395 _HALN,
396 _DIST,
397 _ABVM,
398 _BLWM,
399
400 INDIC_NUM_FEATURES,
401 INDIC_BASIC_FEATURES = INIT /* Don't forget to update this! */
402};
403
404static void
405setup_syllables (const hb_ot_shape_plan_t *plan,
406 hb_font_t *font,
407 hb_buffer_t *buffer);
408static void
409initial_reordering (const hb_ot_shape_plan_t *plan,
410 hb_font_t *font,
411 hb_buffer_t *buffer);
412static void
413final_reordering (const hb_ot_shape_plan_t *plan,
414 hb_font_t *font,
415 hb_buffer_t *buffer);
416static void
417clear_syllables (const hb_ot_shape_plan_t *plan,
418 hb_font_t *font,
419 hb_buffer_t *buffer);
420
421static void
422collect_features_indic (hb_ot_shape_planner_t *plan)
423{
424 hb_ot_map_builder_t *map = &plan->map;
425
426 /* Do this before any lookups have been applied. */
427 map->add_gsub_pause (pause_func: setup_syllables);
428
429 map->add_global_bool_feature (HB_TAG('l','o','c','l'));
430 /* The Indic specs do not require ccmp, but we apply it here since if
431 * there is a use of it, it's typically at the beginning. */
432 map->add_global_bool_feature (HB_TAG('c','c','m','p'));
433
434
435 unsigned int i = 0;
436 map->add_gsub_pause (pause_func: initial_reordering);
437 for (; i < INDIC_BASIC_FEATURES; i++) {
438 map->add_feature (tag: indic_features[i].tag, value: 1, flags: indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
439 map->add_gsub_pause (pause_func: nullptr);
440 }
441 map->add_gsub_pause (pause_func: final_reordering);
442 for (; i < INDIC_NUM_FEATURES; i++) {
443 map->add_feature (tag: indic_features[i].tag, value: 1, flags: indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
444 }
445
446 map->add_global_bool_feature (HB_TAG('c','a','l','t'));
447 map->add_global_bool_feature (HB_TAG('c','l','i','g'));
448
449 map->add_gsub_pause (pause_func: clear_syllables);
450}
451
452static void
453override_features_indic (hb_ot_shape_planner_t *plan)
454{
455 /* Uniscribe does not apply 'kern' in Khmer. */
456 if (hb_options ().uniscribe_bug_compatible)
457 {
458 switch ((hb_tag_t) plan->props.script)
459 {
460 case HB_SCRIPT_KHMER:
461 plan->map.add_feature (HB_TAG('k','e','r','n'), value: 0, flags: F_GLOBAL);
462 break;
463 }
464 }
465
466 plan->map.add_feature (HB_TAG('l','i','g','a'), value: 0, flags: F_GLOBAL);
467}
468
469
470struct would_substitute_feature_t
471{
472 inline void init (const hb_ot_map_t *map, hb_tag_t feature_tag, bool zero_context_)
473 {
474 zero_context = zero_context_;
475 map->get_stage_lookups (table_index: 0/*GSUB*/,
476 stage: map->get_feature_stage (table_index: 0/*GSUB*/, feature_tag),
477 plookups: &lookups, lookup_count: &count);
478 }
479
480 inline bool would_substitute (const hb_codepoint_t *glyphs,
481 unsigned int glyphs_count,
482 hb_face_t *face) const
483 {
484 for (unsigned int i = 0; i < count; i++)
485 if (hb_ot_layout_lookup_would_substitute_fast (face, lookup_index: lookups[i].index, glyphs, glyphs_length: glyphs_count, zero_context))
486 return true;
487 return false;
488 }
489
490 private:
491 const hb_ot_map_t::lookup_map_t *lookups;
492 unsigned int count;
493 bool zero_context;
494};
495
496struct indic_shape_plan_t
497{
498 ASSERT_POD ();
499
500 inline bool get_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const
501 {
502 hb_codepoint_t glyph = virama_glyph;
503 if (unlikely (virama_glyph == (hb_codepoint_t) -1))
504 {
505 if (!config->virama || !font->get_nominal_glyph (unicode: config->virama, glyph: &glyph))
506 glyph = 0;
507 /* Technically speaking, the spec says we should apply 'locl' to virama too.
508 * Maybe one day... */
509
510 /* Our get_nominal_glyph() function needs a font, so we can't get the virama glyph
511 * during shape planning... Instead, overwrite it here. It's safe. Don't worry! */
512 virama_glyph = glyph;
513 }
514
515 *pglyph = glyph;
516 return glyph != 0;
517 }
518
519 const indic_config_t *config;
520
521 bool is_old_spec;
522 mutable hb_codepoint_t virama_glyph;
523
524 would_substitute_feature_t rphf;
525 would_substitute_feature_t pref;
526 would_substitute_feature_t blwf;
527 would_substitute_feature_t pstf;
528
529 hb_mask_t mask_array[INDIC_NUM_FEATURES];
530};
531
532static void *
533data_create_indic (const hb_ot_shape_plan_t *plan)
534{
535 indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (nmemb: 1, size: sizeof (indic_shape_plan_t));
536 if (unlikely (!indic_plan))
537 return nullptr;
538
539 indic_plan->config = &indic_configs[0];
540 for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++)
541 if (plan->props.script == indic_configs[i].script) {
542 indic_plan->config = &indic_configs[i];
543 break;
544 }
545
546 indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FFu) != '2');
547 indic_plan->virama_glyph = (hb_codepoint_t) -1;
548
549 /* Use zero-context would_substitute() matching for new-spec of the main
550 * Indic scripts, and scripts with one spec only, but not for old-specs.
551 * The new-spec for all dual-spec scripts says zero-context matching happens.
552 *
553 * However, testing with Malayalam shows that old and new spec both allow
554 * context. Testing with Bengali new-spec however shows that it doesn't.
555 * So, the heuristic here is the way it is. It should *only* be changed,
556 * as we discover more cases of what Windows does. DON'T TOUCH OTHERWISE.
557 */
558 bool zero_context = !indic_plan->is_old_spec && plan->props.script != HB_SCRIPT_MALAYALAM;
559 indic_plan->rphf.init (map: &plan->map, HB_TAG('r','p','h','f'), zero_context_: zero_context);
560 indic_plan->pref.init (map: &plan->map, HB_TAG('p','r','e','f'), zero_context_: zero_context);
561 indic_plan->blwf.init (map: &plan->map, HB_TAG('b','l','w','f'), zero_context_: zero_context);
562 indic_plan->pstf.init (map: &plan->map, HB_TAG('p','s','t','f'), zero_context_: zero_context);
563
564 for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++)
565 indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ?
566 0 : plan->map.get_1_mask (feature_tag: indic_features[i].tag);
567
568 return indic_plan;
569}
570
571static void
572data_destroy_indic (void *data)
573{
574 free (ptr: data);
575}
576
577static indic_position_t
578consonant_position_from_face (const indic_shape_plan_t *indic_plan,
579 const hb_codepoint_t consonant,
580 const hb_codepoint_t virama,
581 hb_face_t *face)
582{
583 /* For old-spec, the order of glyphs is Consonant,Virama,
584 * whereas for new-spec, it's Virama,Consonant. However,
585 * some broken fonts (like Free Sans) simply copied lookups
586 * from old-spec to new-spec without modification.
587 * And oddly enough, Uniscribe seems to respect those lookups.
588 * Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds
589 * base at 0. The font however, only has lookups matching
590 * 930,94D in 'blwf', not the expected 94D,930 (with new-spec
591 * table). As such, we simply match both sequences. Seems
592 * to work. */
593 hb_codepoint_t glyphs[3] = {virama, consonant, virama};
594 if (indic_plan->blwf.would_substitute (glyphs , glyphs_count: 2, face) ||
595 indic_plan->blwf.would_substitute (glyphs: glyphs+1, glyphs_count: 2, face))
596 return POS_BELOW_C;
597 if (indic_plan->pstf.would_substitute (glyphs , glyphs_count: 2, face) ||
598 indic_plan->pstf.would_substitute (glyphs: glyphs+1, glyphs_count: 2, face))
599 return POS_POST_C;
600 if (indic_plan->pref.would_substitute (glyphs , glyphs_count: 2, face) ||
601 indic_plan->pref.would_substitute (glyphs: glyphs+1, glyphs_count: 2, face))
602 return POS_POST_C;
603 return POS_BASE_C;
604}
605
606
607enum syllable_type_t {
608 consonant_syllable,
609 vowel_syllable,
610 standalone_cluster,
611 symbol_cluster,
612 broken_cluster,
613 non_indic_cluster,
614};
615
616#include "hb-ot-shape-complex-indic-machine.hh"
617
618
619static void
620setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED,
621 hb_buffer_t *buffer,
622 hb_font_t *font HB_UNUSED)
623{
624 HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
625 HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
626
627 /* We cannot setup masks here. We save information about characters
628 * and setup masks later on in a pause-callback. */
629
630 unsigned int count = buffer->len;
631 hb_glyph_info_t *info = buffer->info;
632 for (unsigned int i = 0; i < count; i++)
633 set_indic_properties (info[i]);
634}
635
636static void
637setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
638 hb_font_t *font HB_UNUSED,
639 hb_buffer_t *buffer)
640{
641 find_syllables (buffer);
642 foreach_syllable (buffer, start, end)
643 buffer->unsafe_to_break (start, end);
644}
645
646static int
647compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
648{
649 int a = pa->indic_position();
650 int b = pb->indic_position();
651
652 return a < b ? -1 : a == b ? 0 : +1;
653}
654
655
656
657static void
658update_consonant_positions (const hb_ot_shape_plan_t *plan,
659 hb_font_t *font,
660 hb_buffer_t *buffer)
661{
662 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
663
664 if (indic_plan->config->base_pos != BASE_POS_LAST)
665 return;
666
667 hb_codepoint_t virama;
668 if (indic_plan->get_virama_glyph (font, pglyph: &virama))
669 {
670 hb_face_t *face = font->face;
671 unsigned int count = buffer->len;
672 hb_glyph_info_t *info = buffer->info;
673 for (unsigned int i = 0; i < count; i++)
674 if (info[i].indic_position() == POS_BASE_C)
675 {
676 hb_codepoint_t consonant = info[i].codepoint;
677 info[i].indic_position() = consonant_position_from_face (indic_plan, consonant, virama, face);
678 }
679 }
680}
681
682
683/* Rules from:
684 * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
685
686static void
687initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan,
688 hb_face_t *face,
689 hb_buffer_t *buffer,
690 unsigned int start, unsigned int end)
691{
692 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
693 hb_glyph_info_t *info = buffer->info;
694
695 /* https://github.com/harfbuzz/harfbuzz/issues/435#issuecomment-335560167
696 * // For compatibility with legacy usage in Kannada,
697 * // Ra+h+ZWJ must behave like Ra+ZWJ+h...
698 */
699 if (buffer->props.script == HB_SCRIPT_KANNADA &&
700 start + 3 <= end &&
701 is_one_of (info: info[start ], FLAG (OT_Ra)) &&
702 is_one_of (info: info[start+1], FLAG (OT_H)) &&
703 is_one_of (info: info[start+2], FLAG (OT_ZWJ)))
704 {
705 buffer->merge_clusters (start: start+1, end: start+3);
706 hb_glyph_info_t tmp = info[start+1];
707 info[start+1] = info[start+2];
708 info[start+2] = tmp;
709 }
710
711 /* 1. Find base consonant:
712 *
713 * The shaping engine finds the base consonant of the syllable, using the
714 * following algorithm: starting from the end of the syllable, move backwards
715 * until a consonant is found that does not have a below-base or post-base
716 * form (post-base forms have to follow below-base forms), or that is not a
717 * pre-base-reordering Ra, or arrive at the first consonant. The consonant
718 * stopped at will be the base.
719 *
720 * o If the syllable starts with Ra + Halant (in a script that has Reph)
721 * and has more than one consonant, Ra is excluded from candidates for
722 * base consonants.
723 */
724
725 unsigned int base = end;
726 bool has_reph = false;
727
728 {
729 /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
730 * and has more than one consonant, Ra is excluded from candidates for
731 * base consonants. */
732 unsigned int limit = start;
733 if (indic_plan->config->reph_pos != REPH_POS_DONT_CARE &&
734 indic_plan->mask_array[RPHF] &&
735 start + 3 <= end &&
736 (
737 (indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info: info[start + 2])) ||
738 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == OT_ZWJ)
739 ))
740 {
741 /* See if it matches the 'rphf' feature. */
742 hb_codepoint_t glyphs[3] = {info[start].codepoint,
743 info[start + 1].codepoint,
744 indic_plan->config->reph_mode == REPH_MODE_EXPLICIT ?
745 info[start + 2].codepoint : 0};
746 if (indic_plan->rphf.would_substitute (glyphs, glyphs_count: 2, face) ||
747 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT &&
748 indic_plan->rphf.would_substitute (glyphs, glyphs_count: 3, face)))
749 {
750 limit += 2;
751 while (limit < end && is_joiner (info: info[limit]))
752 limit++;
753 base = start;
754 has_reph = true;
755 }
756 } else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == OT_Repha)
757 {
758 limit += 1;
759 while (limit < end && is_joiner (info: info[limit]))
760 limit++;
761 base = start;
762 has_reph = true;
763 }
764
765 switch (indic_plan->config->base_pos)
766 {
767 case BASE_POS_LAST:
768 {
769 /* -> starting from the end of the syllable, move backwards */
770 unsigned int i = end;
771 bool seen_below = false;
772 do {
773 i--;
774 /* -> until a consonant is found */
775 if (is_consonant (info: info[i]))
776 {
777 /* -> that does not have a below-base or post-base form
778 * (post-base forms have to follow below-base forms), */
779 if (info[i].indic_position() != POS_BELOW_C &&
780 (info[i].indic_position() != POS_POST_C || seen_below))
781 {
782 base = i;
783 break;
784 }
785 if (info[i].indic_position() == POS_BELOW_C)
786 seen_below = true;
787
788 /* -> or that is not a pre-base-reordering Ra,
789 *
790 * IMPLEMENTATION NOTES:
791 *
792 * Our pre-base-reordering Ra's are marked POS_POST_C, so will be skipped
793 * by the logic above already.
794 */
795
796 /* -> or arrive at the first consonant. The consonant stopped at will
797 * be the base. */
798 base = i;
799 }
800 else
801 {
802 /* A ZWJ after a Halant stops the base search, and requests an explicit
803 * half form.
804 * A ZWJ before a Halant, requests a subjoined form instead, and hence
805 * search continues. This is particularly important for Bengali
806 * sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */
807 if (start < i &&
808 info[i].indic_category() == OT_ZWJ &&
809 info[i - 1].indic_category() == OT_H)
810 break;
811 }
812 } while (i > limit);
813 }
814 break;
815
816 case BASE_POS_LAST_SINHALA:
817 {
818 /* Sinhala base positioning is slightly different from main Indic, in that:
819 * 1. Its ZWJ behavior is different,
820 * 2. We don't need to look into the font for consonant positions.
821 */
822
823 if (!has_reph)
824 base = limit;
825
826 /* Find the last base consonant that is not blocked by ZWJ. If there is
827 * a ZWJ right before a base consonant, that would request a subjoined form. */
828 for (unsigned int i = limit; i < end; i++)
829 if (is_consonant (info: info[i]))
830 {
831 if (limit < i && info[i - 1].indic_category() == OT_ZWJ)
832 break;
833 else
834 base = i;
835 }
836
837 /* Mark all subsequent consonants as below. */
838 for (unsigned int i = base + 1; i < end; i++)
839 if (is_consonant (info: info[i]))
840 info[i].indic_position() = POS_BELOW_C;
841 }
842 break;
843
844 case BASE_POS_FIRST:
845 {
846 /* The first consonant is always the base. */
847
848 assert (indic_plan->config->reph_mode == REPH_MODE_VIS_REPHA);
849 assert (!has_reph);
850
851 base = start;
852
853 /* Mark all subsequent consonants as below. */
854 for (unsigned int i = base + 1; i < end; i++)
855 if (is_consonant (info: info[i]))
856 info[i].indic_position() = POS_BELOW_C;
857 }
858 break;
859 }
860
861 /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
862 * and has more than one consonant, Ra is excluded from candidates for
863 * base consonants.
864 *
865 * Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */
866 if (has_reph && base == start && limit - base <= 2) {
867 /* Have no other consonant, so Reph is not formed and Ra becomes base. */
868 has_reph = false;
869 }
870 }
871
872
873 /* 2. Decompose and reorder Matras:
874 *
875 * Each matra and any syllable modifier sign in the syllable are moved to the
876 * appropriate position relative to the consonant(s) in the syllable. The
877 * shaping engine decomposes two- or three-part matras into their constituent
878 * parts before any repositioning. Matra characters are classified by which
879 * consonant in a conjunct they have affinity for and are reordered to the
880 * following positions:
881 *
882 * o Before first half form in the syllable
883 * o After subjoined consonants
884 * o After post-form consonant
885 * o After main consonant (for above marks)
886 *
887 * IMPLEMENTATION NOTES:
888 *
889 * The normalize() routine has already decomposed matras for us, so we don't
890 * need to worry about that.
891 */
892
893
894 /* 3. Reorder marks to canonical order:
895 *
896 * Adjacent nukta and halant or nukta and vedic sign are always repositioned
897 * if necessary, so that the nukta is first.
898 *
899 * IMPLEMENTATION NOTES:
900 *
901 * We don't need to do this: the normalize() routine already did this for us.
902 */
903
904
905 /* Reorder characters */
906
907 for (unsigned int i = start; i < base; i++)
908 info[i].indic_position() = MIN (a: POS_PRE_C, b: (indic_position_t) info[i].indic_position());
909
910 if (base < end)
911 info[base].indic_position() = POS_BASE_C;
912
913 /* Mark final consonants. A final consonant is one appearing after a matra,
914 * like in Khmer. */
915 for (unsigned int i = base + 1; i < end; i++)
916 if (info[i].indic_category() == OT_M) {
917 for (unsigned int j = i + 1; j < end; j++)
918 if (is_consonant (info: info[j])) {
919 info[j].indic_position() = POS_FINAL_C;
920 break;
921 }
922 break;
923 }
924
925 /* Handle beginning Ra */
926 if (has_reph)
927 info[start].indic_position() = POS_RA_TO_BECOME_REPH;
928
929 /* For old-style Indic script tags, move the first post-base Halant after
930 * last consonant.
931 *
932 * Reports suggest that in some scripts Uniscribe does this only if there
933 * is *not* a Halant after last consonant already (eg. Kannada), while it
934 * does it unconditionally in other scripts (eg. Malayalam). We don't
935 * currently know about other scripts, so we single out Malayalam for now.
936 *
937 * Kannada test case:
938 * U+0C9A,U+0CCD,U+0C9A,U+0CCD
939 * With some versions of Lohit Kannada.
940 * https://bugs.freedesktop.org/show_bug.cgi?id=59118
941 *
942 * Malayalam test case:
943 * U+0D38,U+0D4D,U+0D31,U+0D4D,U+0D31,U+0D4D
944 * With lohit-ttf-20121122/Lohit-Malayalam.ttf
945 */
946 if (indic_plan->is_old_spec)
947 {
948 bool disallow_double_halants = buffer->props.script != HB_SCRIPT_MALAYALAM;
949 for (unsigned int i = base + 1; i < end; i++)
950 if (info[i].indic_category() == OT_H)
951 {
952 unsigned int j;
953 for (j = end - 1; j > i; j--)
954 if (is_consonant (info: info[j]) ||
955 (disallow_double_halants && info[j].indic_category() == OT_H))
956 break;
957 if (info[j].indic_category() != OT_H && j > i) {
958 /* Move Halant to after last consonant. */
959 hb_glyph_info_t t = info[i];
960 memmove (dest: &info[i], src: &info[i + 1], n: (j - i) * sizeof (info[0]));
961 info[j] = t;
962 }
963 break;
964 }
965 }
966
967 /* Attach misc marks to previous char to move with them. */
968 {
969 indic_position_t last_pos = POS_START;
970 for (unsigned int i = start; i < end; i++)
971 {
972 if ((FLAG_UNSAFE (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | MEDIAL_FLAGS | HALANT_OR_COENG_FLAGS)))
973 {
974 info[i].indic_position() = last_pos;
975 if (unlikely (info[i].indic_category() == OT_H &&
976 info[i].indic_position() == POS_PRE_M))
977 {
978 /*
979 * Uniscribe doesn't move the Halant with Left Matra.
980 * TEST: U+092B,U+093F,U+094DE
981 * We follow. This is important for the Sinhala
982 * U+0DDA split matra since it decomposes to U+0DD9,U+0DCA
983 * where U+0DD9 is a left matra and U+0DCA is the virama.
984 * We don't want to move the virama with the left matra.
985 * TEST: U+0D9A,U+0DDA
986 */
987 for (unsigned int j = i; j > start; j--)
988 if (info[j - 1].indic_position() != POS_PRE_M) {
989 info[i].indic_position() = info[j - 1].indic_position();
990 break;
991 }
992 }
993 } else if (info[i].indic_position() != POS_SMVD) {
994 last_pos = (indic_position_t) info[i].indic_position();
995 }
996 }
997 }
998 /* For post-base consonants let them own anything before them
999 * since the last consonant or matra. */
1000 {
1001 unsigned int last = base;
1002 for (unsigned int i = base + 1; i < end; i++)
1003 if (is_consonant (info: info[i]))
1004 {
1005 for (unsigned int j = last + 1; j < i; j++)
1006 if (info[j].indic_position() < POS_SMVD)
1007 info[j].indic_position() = info[i].indic_position();
1008 last = i;
1009 } else if (info[i].indic_category() == OT_M)
1010 last = i;
1011 }
1012
1013
1014 {
1015 /* Use syllable() for sort accounting temporarily. */
1016 unsigned int syllable = info[start].syllable();
1017 for (unsigned int i = start; i < end; i++)
1018 info[i].syllable() = i - start;
1019
1020 /* Sit tight, rock 'n roll! */
1021 hb_stable_sort (array: info + start, len: end - start, compar: compare_indic_order);
1022 /* Find base again */
1023 base = end;
1024 for (unsigned int i = start; i < end; i++)
1025 if (info[i].indic_position() == POS_BASE_C)
1026 {
1027 base = i;
1028 break;
1029 }
1030 /* Things are out-of-control for post base positions, they may shuffle
1031 * around like crazy. In old-spec mode, we move halants around, so in
1032 * that case merge all clusters after base. Otherwise, check the sort
1033 * order and merge as needed.
1034 * For pre-base stuff, we handle cluster issues in final reordering.
1035 *
1036 * We could use buffer->sort() for this, if there was no special
1037 * reordering of pre-base stuff happening later...
1038 */
1039 if (indic_plan->is_old_spec || end - base > 127)
1040 buffer->merge_clusters (start: base, end);
1041 else
1042 {
1043 /* Note! syllable() is a one-byte field. */
1044 for (unsigned int i = base; i < end; i++)
1045 if (info[i].syllable() != 255)
1046 {
1047 unsigned int max = i;
1048 unsigned int j = start + info[i].syllable();
1049 while (j != i)
1050 {
1051 max = MAX (a: max, b: j);
1052 unsigned int next = start + info[j].syllable();
1053 info[j].syllable() = 255; /* So we don't process j later again. */
1054 j = next;
1055 }
1056 if (i != max)
1057 buffer->merge_clusters (start: i, end: max + 1);
1058 }
1059 }
1060
1061 /* Put syllable back in. */
1062 for (unsigned int i = start; i < end; i++)
1063 info[i].syllable() = syllable;
1064 }
1065
1066 /* Setup masks now */
1067
1068 {
1069 hb_mask_t mask;
1070
1071 /* Reph */
1072 for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++)
1073 info[i].mask |= indic_plan->mask_array[RPHF];
1074
1075 /* Pre-base */
1076 mask = indic_plan->mask_array[HALF];
1077 if (!indic_plan->is_old_spec &&
1078 indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST)
1079 mask |= indic_plan->mask_array[BLWF];
1080 for (unsigned int i = start; i < base; i++)
1081 info[i].mask |= mask;
1082 /* Base */
1083 mask = 0;
1084 if (base < end)
1085 info[base].mask |= mask;
1086 /* Post-base */
1087 mask = indic_plan->mask_array[BLWF] | indic_plan->mask_array[ABVF] | indic_plan->mask_array[PSTF];
1088 for (unsigned int i = base + 1; i < end; i++)
1089 info[i].mask |= mask;
1090 }
1091
1092 if (indic_plan->is_old_spec &&
1093 buffer->props.script == HB_SCRIPT_DEVANAGARI)
1094 {
1095 /* Old-spec eye-lash Ra needs special handling. From the
1096 * spec:
1097 *
1098 * "The feature 'below-base form' is applied to consonants
1099 * having below-base forms and following the base consonant.
1100 * The exception is vattu, which may appear below half forms
1101 * as well as below the base glyph. The feature 'below-base
1102 * form' will be applied to all such occurrences of Ra as well."
1103 *
1104 * Test case: U+0924,U+094D,U+0930,U+094d,U+0915
1105 * with Sanskrit 2003 font.
1106 *
1107 * However, note that Ra,Halant,ZWJ is the correct way to
1108 * request eyelash form of Ra, so we wouldbn't inhibit it
1109 * in that sequence.
1110 *
1111 * Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915
1112 */
1113 for (unsigned int i = start; i + 1 < base; i++)
1114 if (info[i ].indic_category() == OT_Ra &&
1115 info[i+1].indic_category() == OT_H &&
1116 (i + 2 == base ||
1117 info[i+2].indic_category() != OT_ZWJ))
1118 {
1119 info[i ].mask |= indic_plan->mask_array[BLWF];
1120 info[i+1].mask |= indic_plan->mask_array[BLWF];
1121 }
1122 }
1123
1124 unsigned int pref_len = 2;
1125 if (indic_plan->mask_array[PREF] && base + pref_len < end)
1126 {
1127 /* Find a Halant,Ra sequence and mark it for pre-base-reordering processing. */
1128 for (unsigned int i = base + 1; i + pref_len - 1 < end; i++) {
1129 hb_codepoint_t glyphs[2];
1130 for (unsigned int j = 0; j < pref_len; j++)
1131 glyphs[j] = info[i + j].codepoint;
1132 if (indic_plan->pref.would_substitute (glyphs, glyphs_count: pref_len, face))
1133 {
1134 for (unsigned int j = 0; j < pref_len; j++)
1135 info[i++].mask |= indic_plan->mask_array[PREF];
1136
1137 /* Mark the subsequent stuff with 'cfar'. Used in Khmer.
1138 * Read the feature spec.
1139 * This allows distinguishing the following cases with MS Khmer fonts:
1140 * U+1784,U+17D2,U+179A,U+17D2,U+1782
1141 * U+1784,U+17D2,U+1782,U+17D2,U+179A
1142 */
1143 if (indic_plan->mask_array[CFAR])
1144 for (; i < end; i++)
1145 info[i].mask |= indic_plan->mask_array[CFAR];
1146
1147 break;
1148 }
1149 }
1150 }
1151
1152 /* Apply ZWJ/ZWNJ effects */
1153 for (unsigned int i = start + 1; i < end; i++)
1154 if (is_joiner (info: info[i])) {
1155 bool non_joiner = info[i].indic_category() == OT_ZWNJ;
1156 unsigned int j = i;
1157
1158 do {
1159 j--;
1160
1161 /* ZWJ/ZWNJ should disable CJCT. They do that by simply
1162 * being there, since we don't skip them for the CJCT
1163 * feature (ie. F_MANUAL_ZWJ) */
1164
1165 /* A ZWNJ disables HALF. */
1166 if (non_joiner)
1167 info[j].mask &= ~indic_plan->mask_array[HALF];
1168
1169 } while (j > start && !is_consonant (info: info[j]));
1170 }
1171}
1172
1173static void
1174initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan,
1175 hb_face_t *face,
1176 hb_buffer_t *buffer,
1177 unsigned int start, unsigned int end)
1178{
1179 /* We treat placeholder/dotted-circle as if they are consonants, so we
1180 * should just chain. Only if not in compatibility mode that is... */
1181
1182 if (hb_options ().uniscribe_bug_compatible)
1183 {
1184 /* For dotted-circle, this is what Uniscribe does:
1185 * If dotted-circle is the last glyph, it just does nothing.
1186 * Ie. It doesn't form Reph. */
1187 if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE)
1188 return;
1189 }
1190
1191 initial_reordering_consonant_syllable (plan, face, buffer, start, end);
1192}
1193
1194static void
1195initial_reordering_syllable (const hb_ot_shape_plan_t *plan,
1196 hb_face_t *face,
1197 hb_buffer_t *buffer,
1198 unsigned int start, unsigned int end)
1199{
1200 syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
1201 switch (syllable_type)
1202 {
1203 case vowel_syllable: /* We made the vowels look like consonants. So let's call the consonant logic! */
1204 case consonant_syllable:
1205 initial_reordering_consonant_syllable (plan, face, buffer, start, end);
1206 break;
1207
1208 case broken_cluster: /* We already inserted dotted-circles, so just call the standalone_cluster. */
1209 case standalone_cluster:
1210 initial_reordering_standalone_cluster (plan, face, buffer, start, end);
1211 break;
1212
1213 case symbol_cluster:
1214 case non_indic_cluster:
1215 break;
1216 }
1217}
1218
1219static inline void
1220insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
1221 hb_font_t *font,
1222 hb_buffer_t *buffer)
1223{
1224 /* Note: This loop is extra overhead, but should not be measurable. */
1225 bool has_broken_syllables = false;
1226 unsigned int count = buffer->len;
1227 hb_glyph_info_t *info = buffer->info;
1228 for (unsigned int i = 0; i < count; i++)
1229 if ((info[i].syllable() & 0x0F) == broken_cluster)
1230 {
1231 has_broken_syllables = true;
1232 break;
1233 }
1234 if (likely (!has_broken_syllables))
1235 return;
1236
1237
1238 hb_codepoint_t dottedcircle_glyph;
1239 if (!font->get_nominal_glyph (unicode: 0x25CCu, glyph: &dottedcircle_glyph))
1240 return;
1241
1242 hb_glyph_info_t dottedcircle = {.codepoint: 0};
1243 dottedcircle.codepoint = 0x25CCu;
1244 set_indic_properties (dottedcircle);
1245 dottedcircle.codepoint = dottedcircle_glyph;
1246
1247 buffer->clear_output ();
1248
1249 buffer->idx = 0;
1250 unsigned int last_syllable = 0;
1251 while (buffer->idx < buffer->len && !buffer->in_error)
1252 {
1253 unsigned int syllable = buffer->cur().syllable();
1254 syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
1255 if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
1256 {
1257 last_syllable = syllable;
1258
1259 hb_glyph_info_t ginfo = dottedcircle;
1260 ginfo.cluster = buffer->cur().cluster;
1261 ginfo.mask = buffer->cur().mask;
1262 ginfo.syllable() = buffer->cur().syllable();
1263 /* TODO Set glyph_props? */
1264
1265 /* Insert dottedcircle after possible Repha. */
1266 while (buffer->idx < buffer->len && !buffer->in_error &&
1267 last_syllable == buffer->cur().syllable() &&
1268 buffer->cur().indic_category() == OT_Repha)
1269 buffer->next_glyph ();
1270
1271 buffer->output_info (glyph_info: ginfo);
1272 }
1273 else
1274 buffer->next_glyph ();
1275 }
1276
1277 buffer->swap_buffers ();
1278}
1279
1280static void
1281initial_reordering (const hb_ot_shape_plan_t *plan,
1282 hb_font_t *font,
1283 hb_buffer_t *buffer)
1284{
1285 update_consonant_positions (plan, font, buffer);
1286 insert_dotted_circles (plan, font, buffer);
1287
1288 foreach_syllable (buffer, start, end)
1289 initial_reordering_syllable (plan, face: font->face, buffer, start, end);
1290}
1291
1292static void
1293final_reordering_syllable (const hb_ot_shape_plan_t *plan,
1294 hb_buffer_t *buffer,
1295 unsigned int start, unsigned int end)
1296{
1297 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
1298 hb_glyph_info_t *info = buffer->info;
1299
1300
1301 /* This function relies heavily on halant glyphs. Lots of ligation
1302 * and possibly multiple substitutions happened prior to this
1303 * phase, and that might have messed up our properties. Recover
1304 * from a particular case of that where we're fairly sure that a
1305 * class of OT_H is desired but has been lost. */
1306 if (indic_plan->virama_glyph)
1307 {
1308 unsigned int virama_glyph = indic_plan->virama_glyph;
1309 for (unsigned int i = start; i < end; i++)
1310 if (info[i].codepoint == virama_glyph &&
1311 _hb_glyph_info_ligated (info: &info[i]) &&
1312 _hb_glyph_info_multiplied (info: &info[i]))
1313 {
1314 /* This will make sure that this glyph passes is_halant_or_coeng() test. */
1315 info[i].indic_category() = OT_H;
1316 _hb_glyph_info_clear_ligated_and_multiplied (info: &info[i]);
1317 }
1318 }
1319
1320
1321 /* 4. Final reordering:
1322 *
1323 * After the localized forms and basic shaping forms GSUB features have been
1324 * applied (see below), the shaping engine performs some final glyph
1325 * reordering before applying all the remaining font features to the entire
1326 * syllable.
1327 */
1328
1329 bool try_pref = !!indic_plan->mask_array[PREF];
1330
1331 /* Find base again */
1332 unsigned int base;
1333 for (base = start; base < end; base++)
1334 if (info[base].indic_position() >= POS_BASE_C)
1335 {
1336 if (try_pref && base + 1 < end)
1337 {
1338 for (unsigned int i = base + 1; i < end; i++)
1339 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0)
1340 {
1341 if (!(_hb_glyph_info_substituted (info: &info[i]) &&
1342 _hb_glyph_info_ligated_and_didnt_multiply (info: &info[i])))
1343 {
1344 /* Ok, this was a 'pref' candidate but didn't form any.
1345 * Base is around here... */
1346 base = i;
1347 while (base < end && is_halant_or_coeng (info: info[base]))
1348 base++;
1349 info[base].indic_position() = POS_BASE_C;
1350
1351 try_pref = false;
1352 }
1353 break;
1354 }
1355 }
1356 /* For Malayalam, skip over unformed below- (but NOT post-) forms. */
1357 if (buffer->props.script == HB_SCRIPT_MALAYALAM)
1358 {
1359 for (unsigned int i = base + 1; i < end; i++)
1360 {
1361 while (i < end && is_joiner (info: info[i]))
1362 i++;
1363 if (i == end || !is_halant_or_coeng (info: info[i]))
1364 break;
1365 i++; /* Skip halant. */
1366 while (i < end && is_joiner (info: info[i]))
1367 i++;
1368 if (i < end && is_consonant (info: info[i]) && info[i].indic_position() == POS_BELOW_C)
1369 {
1370 base = i;
1371 info[base].indic_position() = POS_BASE_C;
1372 }
1373 }
1374 }
1375
1376 if (start < base && info[base].indic_position() > POS_BASE_C)
1377 base--;
1378 break;
1379 }
1380 if (base == end && start < base &&
1381 is_one_of (info: info[base - 1], FLAG (OT_ZWJ)))
1382 base--;
1383 if (base < end)
1384 while (start < base &&
1385 is_one_of (info: info[base], flags: (FLAG (OT_N) | HALANT_OR_COENG_FLAGS)))
1386 base--;
1387
1388
1389 /* o Reorder matras:
1390 *
1391 * If a pre-base matra character had been reordered before applying basic
1392 * features, the glyph can be moved closer to the main consonant based on
1393 * whether half-forms had been formed. Actual position for the matra is
1394 * defined as “after last standalone halant glyph, after initial matra
1395 * position and before the main consonant”. If ZWJ or ZWNJ follow this
1396 * halant, position is moved after it.
1397 */
1398
1399 if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */
1400 {
1401 /* If we lost track of base, alas, position before last thingy. */
1402 unsigned int new_pos = base == end ? base - 2 : base - 1;
1403
1404 /* Malayalam / Tamil do not have "half" forms or explicit virama forms.
1405 * The glyphs formed by 'half' are Chillus or ligated explicit viramas.
1406 * We want to position matra after them.
1407 */
1408 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
1409 {
1410 while (new_pos > start &&
1411 !(is_one_of (info: info[new_pos], flags: (FLAG (OT_M) | HALANT_OR_COENG_FLAGS))))
1412 new_pos--;
1413
1414 /* If we found no Halant we are done.
1415 * Otherwise only proceed if the Halant does
1416 * not belong to the Matra itself! */
1417 if (is_halant_or_coeng (info: info[new_pos]) &&
1418 info[new_pos].indic_position() != POS_PRE_M)
1419 {
1420 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
1421 if (new_pos + 1 < end && is_joiner (info: info[new_pos + 1]))
1422 new_pos++;
1423 }
1424 else
1425 new_pos = start; /* No move. */
1426 }
1427
1428 if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M)
1429 {
1430 /* Now go see if there's actually any matras... */
1431 for (unsigned int i = new_pos; i > start; i--)
1432 if (info[i - 1].indic_position () == POS_PRE_M)
1433 {
1434 unsigned int old_pos = i - 1;
1435 if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */
1436 base--;
1437
1438 hb_glyph_info_t tmp = info[old_pos];
1439 memmove (dest: &info[old_pos], src: &info[old_pos + 1], n: (new_pos - old_pos) * sizeof (info[0]));
1440 info[new_pos] = tmp;
1441
1442 /* Note: this merge_clusters() is intentionally *after* the reordering.
1443 * Indic matra reordering is special and tricky... */
1444 buffer->merge_clusters (start: new_pos, end: MIN (a: end, b: base + 1));
1445
1446 new_pos--;
1447 }
1448 } else {
1449 for (unsigned int i = start; i < base; i++)
1450 if (info[i].indic_position () == POS_PRE_M) {
1451 buffer->merge_clusters (start: i, end: MIN (a: end, b: base + 1));
1452 break;
1453 }
1454 }
1455 }
1456
1457
1458 /* o Reorder reph:
1459 *
1460 * Reph’s original position is always at the beginning of the syllable,
1461 * (i.e. it is not reordered at the character reordering stage). However,
1462 * it will be reordered according to the basic-forms shaping results.
1463 * Possible positions for reph, depending on the script, are; after main,
1464 * before post-base consonant forms, and after post-base consonant forms.
1465 */
1466
1467 /* Two cases:
1468 *
1469 * - If repha is encoded as a sequence of characters (Ra,H or Ra,H,ZWJ), then
1470 * we should only move it if the sequence ligated to the repha form.
1471 *
1472 * - If repha is encoded separately and in the logical position, we should only
1473 * move it if it did NOT ligate. If it ligated, it's probably the font trying
1474 * to make it work without the reordering.
1475 */
1476 if (start + 1 < end &&
1477 info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
1478 ((info[start].indic_category() == OT_Repha) ^
1479 _hb_glyph_info_ligated_and_didnt_multiply (info: &info[start])))
1480 {
1481 unsigned int new_reph_pos;
1482 reph_position_t reph_pos = indic_plan->config->reph_pos;
1483
1484 assert (reph_pos != REPH_POS_DONT_CARE);
1485
1486 /* 1. If reph should be positioned after post-base consonant forms,
1487 * proceed to step 5.
1488 */
1489 if (reph_pos == REPH_POS_AFTER_POST)
1490 {
1491 goto reph_step_5;
1492 }
1493
1494 /* 2. If the reph repositioning class is not after post-base: target
1495 * position is after the first explicit halant glyph between the
1496 * first post-reph consonant and last main consonant. If ZWJ or ZWNJ
1497 * are following this halant, position is moved after it. If such
1498 * position is found, this is the target position. Otherwise,
1499 * proceed to the next step.
1500 *
1501 * Note: in old-implementation fonts, where classifications were
1502 * fixed in shaping engine, there was no case where reph position
1503 * will be found on this step.
1504 */
1505 {
1506 new_reph_pos = start + 1;
1507 while (new_reph_pos < base && !is_halant_or_coeng (info: info[new_reph_pos]))
1508 new_reph_pos++;
1509
1510 if (new_reph_pos < base && is_halant_or_coeng (info: info[new_reph_pos]))
1511 {
1512 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
1513 if (new_reph_pos + 1 < base && is_joiner (info: info[new_reph_pos + 1]))
1514 new_reph_pos++;
1515 goto reph_move;
1516 }
1517 }
1518
1519 /* 3. If reph should be repositioned after the main consonant: find the
1520 * first consonant not ligated with main, or find the first
1521 * consonant that is not a potential pre-base-reordering Ra.
1522 */
1523 if (reph_pos == REPH_POS_AFTER_MAIN)
1524 {
1525 new_reph_pos = base;
1526 while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN)
1527 new_reph_pos++;
1528 if (new_reph_pos < end)
1529 goto reph_move;
1530 }
1531
1532 /* 4. If reph should be positioned before post-base consonant, find
1533 * first post-base classified consonant not ligated with main. If no
1534 * consonant is found, the target position should be before the
1535 * first matra, syllable modifier sign or vedic sign.
1536 */
1537 /* This is our take on what step 4 is trying to say (and failing, BADLY). */
1538 if (reph_pos == REPH_POS_AFTER_SUB)
1539 {
1540 new_reph_pos = base;
1541 while (new_reph_pos + 1 < end &&
1542 !( FLAG_UNSAFE (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD))))
1543 new_reph_pos++;
1544 if (new_reph_pos < end)
1545 goto reph_move;
1546 }
1547
1548 /* 5. If no consonant is found in steps 3 or 4, move reph to a position
1549 * immediately before the first post-base matra, syllable modifier
1550 * sign or vedic sign that has a reordering class after the intended
1551 * reph position. For example, if the reordering position for reph
1552 * is post-main, it will skip above-base matras that also have a
1553 * post-main position.
1554 */
1555 reph_step_5:
1556 {
1557 /* Copied from step 2. */
1558 new_reph_pos = start + 1;
1559 while (new_reph_pos < base && !is_halant_or_coeng (info: info[new_reph_pos]))
1560 new_reph_pos++;
1561
1562 if (new_reph_pos < base && is_halant_or_coeng (info: info[new_reph_pos]))
1563 {
1564 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
1565 if (new_reph_pos + 1 < base && is_joiner (info: info[new_reph_pos + 1]))
1566 new_reph_pos++;
1567 goto reph_move;
1568 }
1569 }
1570
1571 /* 6. Otherwise, reorder reph to the end of the syllable.
1572 */
1573 {
1574 new_reph_pos = end - 1;
1575 while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
1576 new_reph_pos--;
1577
1578 /*
1579 * If the Reph is to be ending up after a Matra,Halant sequence,
1580 * position it before that Halant so it can interact with the Matra.
1581 * However, if it's a plain Consonant,Halant we shouldn't do that.
1582 * Uniscribe doesn't do this.
1583 * TEST: U+0930,U+094D,U+0915,U+094B,U+094D
1584 */
1585 if (!hb_options ().uniscribe_bug_compatible &&
1586 unlikely (is_halant_or_coeng (info[new_reph_pos]))) {
1587 for (unsigned int i = base + 1; i < new_reph_pos; i++)
1588 if (info[i].indic_category() == OT_M) {
1589 /* Ok, got it. */
1590 new_reph_pos--;
1591 }
1592 }
1593 goto reph_move;
1594 }
1595
1596 reph_move:
1597 {
1598 /* Move */
1599 buffer->merge_clusters (start, end: new_reph_pos + 1);
1600 hb_glyph_info_t reph = info[start];
1601 memmove (dest: &info[start], src: &info[start + 1], n: (new_reph_pos - start) * sizeof (info[0]));
1602 info[new_reph_pos] = reph;
1603
1604 if (start < base && base <= new_reph_pos)
1605 base--;
1606 }
1607 }
1608
1609
1610 /* o Reorder pre-base-reordering consonants:
1611 *
1612 * If a pre-base-reordering consonant is found, reorder it according to
1613 * the following rules:
1614 */
1615
1616 if (try_pref && base + 1 < end) /* Otherwise there can't be any pre-base-reordering Ra. */
1617 {
1618 for (unsigned int i = base + 1; i < end; i++)
1619 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0)
1620 {
1621 /* 1. Only reorder a glyph produced by substitution during application
1622 * of the <pref> feature. (Note that a font may shape a Ra consonant with
1623 * the feature generally but block it in certain contexts.)
1624 */
1625 /* Note: We just check that something got substituted. We don't check that
1626 * the <pref> feature actually did it...
1627 *
1628 * Reorder pref only if it ligated. */
1629 if (_hb_glyph_info_ligated_and_didnt_multiply (info: &info[i]))
1630 {
1631 /*
1632 * 2. Try to find a target position the same way as for pre-base matra.
1633 * If it is found, reorder pre-base consonant glyph.
1634 *
1635 * 3. If position is not found, reorder immediately before main
1636 * consonant.
1637 */
1638
1639 unsigned int new_pos = base;
1640 /* Malayalam / Tamil do not have "half" forms or explicit virama forms.
1641 * The glyphs formed by 'half' are Chillus or ligated explicit viramas.
1642 * We want to position matra after them.
1643 */
1644 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
1645 {
1646 while (new_pos > start &&
1647 !(is_one_of (info: info[new_pos - 1], FLAG(OT_M) | HALANT_OR_COENG_FLAGS)))
1648 new_pos--;
1649
1650 /* In Khmer coeng model, a H,Ra can go *after* matras. If it goes after a
1651 * split matra, it should be reordered to *before* the left part of such matra. */
1652 if (new_pos > start && info[new_pos - 1].indic_category() == OT_M)
1653 {
1654 unsigned int old_pos = i;
1655 for (unsigned int j = base + 1; j < old_pos; j++)
1656 if (info[j].indic_category() == OT_M)
1657 {
1658 new_pos--;
1659 break;
1660 }
1661 }
1662 }
1663
1664 if (new_pos > start && is_halant_or_coeng (info: info[new_pos - 1]))
1665 {
1666 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
1667 if (new_pos < end && is_joiner (info: info[new_pos]))
1668 new_pos++;
1669 }
1670
1671 {
1672 unsigned int old_pos = i;
1673
1674 buffer->merge_clusters (start: new_pos, end: old_pos + 1);
1675 hb_glyph_info_t tmp = info[old_pos];
1676 memmove (dest: &info[new_pos + 1], src: &info[new_pos], n: (old_pos - new_pos) * sizeof (info[0]));
1677 info[new_pos] = tmp;
1678
1679 if (new_pos <= base && base < old_pos)
1680 base++;
1681 }
1682 }
1683
1684 break;
1685 }
1686 }
1687
1688
1689 /* Apply 'init' to the Left Matra if it's a word start. */
1690 if (info[start].indic_position () == POS_PRE_M)
1691 {
1692 if (!start ||
1693 !(FLAG_UNSAFE (_hb_glyph_info_get_general_category (&info[start - 1])) &
1694 FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))
1695 info[start].mask |= indic_plan->mask_array[INIT];
1696 else
1697 buffer->unsafe_to_break (start: start - 1, end: start + 1);
1698 }
1699
1700
1701 /*
1702 * Finish off the clusters and go home!
1703 */
1704 if (hb_options ().uniscribe_bug_compatible)
1705 {
1706 switch ((hb_tag_t) plan->props.script)
1707 {
1708 case HB_SCRIPT_TAMIL:
1709 case HB_SCRIPT_SINHALA:
1710 break;
1711
1712 default:
1713 /* Uniscribe merges the entire syllable into a single cluster... Except for Tamil & Sinhala.
1714 * This means, half forms are submerged into the main consonant's cluster.
1715 * This is unnecessary, and makes cursor positioning harder, but that's what
1716 * Uniscribe does. */
1717 buffer->merge_clusters (start, end);
1718 break;
1719 }
1720 }
1721}
1722
1723
1724static void
1725final_reordering (const hb_ot_shape_plan_t *plan,
1726 hb_font_t *font HB_UNUSED,
1727 hb_buffer_t *buffer)
1728{
1729 unsigned int count = buffer->len;
1730 if (unlikely (!count)) return;
1731
1732 foreach_syllable (buffer, start, end)
1733 final_reordering_syllable (plan, buffer, start, end);
1734
1735 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
1736 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
1737}
1738
1739
1740static void
1741clear_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
1742 hb_font_t *font HB_UNUSED,
1743 hb_buffer_t *buffer)
1744{
1745 hb_glyph_info_t *info = buffer->info;
1746 unsigned int count = buffer->len;
1747 for (unsigned int i = 0; i < count; i++)
1748 info[i].syllable() = 0;
1749}
1750
1751
1752static bool
1753decompose_indic (const hb_ot_shape_normalize_context_t *c,
1754 hb_codepoint_t ab,
1755 hb_codepoint_t *a,
1756 hb_codepoint_t *b)
1757{
1758 switch (ab)
1759 {
1760 /* Don't decompose these. */
1761 case 0x0931u : return false; /* DEVANAGARI LETTER RRA */
1762 case 0x0B94u : return false; /* TAMIL LETTER AU */
1763
1764
1765 /*
1766 * Decompose split matras that don't have Unicode decompositions.
1767 */
1768
1769 /* Khmer */
1770 case 0x17BEu : *a = 0x17C1u; *b= 0x17BEu; return true;
1771 case 0x17BFu : *a = 0x17C1u; *b= 0x17BFu; return true;
1772 case 0x17C0u : *a = 0x17C1u; *b= 0x17C0u; return true;
1773 case 0x17C4u : *a = 0x17C1u; *b= 0x17C4u; return true;
1774 case 0x17C5u : *a = 0x17C1u; *b= 0x17C5u; return true;
1775
1776#if 0
1777 /* Gujarati */
1778 /* This one has no decomposition in Unicode, but needs no decomposition either. */
1779 /* case 0x0AC9u : return false; */
1780
1781 /* Oriya */
1782 case 0x0B57u : *a = no decomp, -> RIGHT; return true;
1783#endif
1784 }
1785
1786 if ((ab == 0x0DDAu || hb_in_range<hb_codepoint_t> (u: ab, lo: 0x0DDCu, hi: 0x0DDEu)))
1787 {
1788 /*
1789 * Sinhala split matras... Let the fun begin.
1790 *
1791 * These four characters have Unicode decompositions. However, Uniscribe
1792 * decomposes them "Khmer-style", that is, it uses the character itself to
1793 * get the second half. The first half of all four decompositions is always
1794 * U+0DD9.
1795 *
1796 * Now, there are buggy fonts, namely, the widely used lklug.ttf, that are
1797 * broken with Uniscribe. But we need to support them. As such, we only
1798 * do the Uniscribe-style decomposition if the character is transformed into
1799 * its "sec.half" form by the 'pstf' feature. Otherwise, we fall back to
1800 * Unicode decomposition.
1801 *
1802 * Note that we can't unconditionally use Unicode decomposition. That would
1803 * break some other fonts, that are designed to work with Uniscribe, and
1804 * don't have positioning features for the Unicode-style decomposition.
1805 *
1806 * Argh...
1807 *
1808 * The Uniscribe behavior is now documented in the newly published Sinhala
1809 * spec in 2012:
1810 *
1811 * http://www.microsoft.com/typography/OpenTypeDev/sinhala/intro.htm#shaping
1812 */
1813
1814 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data;
1815
1816 hb_codepoint_t glyph;
1817
1818 if (hb_options ().uniscribe_bug_compatible ||
1819 (c->font->get_nominal_glyph (unicode: ab, glyph: &glyph) &&
1820 indic_plan->pstf.would_substitute (glyphs: &glyph, glyphs_count: 1, face: c->font->face)))
1821 {
1822 /* Ok, safe to use Uniscribe-style decomposition. */
1823 *a = 0x0DD9u;
1824 *b = ab;
1825 return true;
1826 }
1827 }
1828
1829 return (bool) c->unicode->decompose (ab, a, b);
1830}
1831
1832static bool
1833compose_indic (const hb_ot_shape_normalize_context_t *c,
1834 hb_codepoint_t a,
1835 hb_codepoint_t b,
1836 hb_codepoint_t *ab)
1837{
1838 /* Avoid recomposing split matras. */
1839 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
1840 return false;
1841
1842 /* Composition-exclusion exceptions that we want to recompose. */
1843 if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; }
1844
1845 return (bool) c->unicode->compose (a, b, ab);
1846}
1847
1848
1849const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
1850{
1851 .collect_features: collect_features_indic,
1852 .override_features: override_features_indic,
1853 .data_create: data_create_indic,
1854 .data_destroy: data_destroy_indic,
1855 .preprocess_text: nullptr, /* preprocess_text */
1856 .postprocess_glyphs: nullptr, /* postprocess_glyphs */
1857 .normalization_preference: HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
1858 .decompose: decompose_indic,
1859 .compose: compose_indic,
1860 .setup_masks: setup_masks_indic,
1861 .disable_otl: nullptr, /* disable_otl */
1862 .reorder_marks: nullptr, /* reorder_marks */
1863 .zero_width_marks: HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
1864 .fallback_position: false, /* fallback_position */
1865};
1866

source code of qtbase/src/3rdparty/harfbuzz-ng/src/hb-ot-shape-complex-indic.cc