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
97 static inline indic_position_t
98 matra_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 */
114 static 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
131 static inline bool
132 is_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
140 static inline bool
141 is_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)) return false;
145 return !!(FLAG_SAFE (info.indic_category()) & flags);
146 }
147
148 static inline bool
149 is_joiner (const hb_glyph_info_t &info)
150 {
151 return is_one_of (info, JOINER_FLAGS);
152 }
153
154 static inline bool
155 is_consonant (const hb_glyph_info_t &info)
156 {
157 return is_one_of (info, CONSONANT_FLAGS);
158 }
159
160 static inline bool
161 is_halant_or_coeng (const hb_glyph_info_t &info)
162 {
163 return is_one_of (info, HALANT_OR_COENG_FLAGS);
164 }
165
166 static inline void
167 set_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
180 /* The spec says U+0952 is OT_A. However, testing shows that Uniscribe
181 * treats a whole bunch of characters similarly.
182 * TESTS: For example, for U+0951:
183 * U+092E,U+0947,U+0952
184 * U+092E,U+0952,U+0947
185 * U+092E,U+0947,U+0951
186 * U+092E,U+0951,U+0947
187 * U+092E,U+0951,U+0952
188 * U+092E,U+0952,U+0951
189 */
190 if (unlikely (hb_in_ranges (u, 0x0951u, 0x0952u,
191 0x1CD0u, 0x1CD2u,
192 0x1CD4u, 0x1CE1u) ||
193 u == 0x1CF4u))
194 cat = OT_A;
195 /* The following act more like the Bindus. */
196 else if (unlikely (hb_in_range (u, 0x0953u, 0x0954u)))
197 cat = OT_SM;
198 /* The following act like consonants. */
199 else if (unlikely (hb_in_ranges (u, 0x0A72u, 0x0A73u,
200 0x1CF5u, 0x1CF6u)))
201 cat = OT_C;
202 /* TODO: The following should only be allowed after a Visarga.
203 * For now, just treat them like regular tone marks. */
204 else if (unlikely (hb_in_range (u, 0x1CE2u, 0x1CE8u)))
205 cat = OT_A;
206 /* TODO: The following should only be allowed after some of
207 * the nasalization marks, maybe only for U+1CE9..U+1CF1.
208 * For now, just treat them like tone marks. */
209 else if (unlikely (u == 0x1CEDu))
210 cat = OT_A;
211 /* The following take marks in standalone clusters, similar to Avagraha. */
212 else if (unlikely (hb_in_ranges (u, 0xA8F2u, 0xA8F7u,
213 0x1CE9u, 0x1CECu,
214 0x1CEEu, 0x1CF1u)))
215 {
216 cat = OT_Symbol;
217 ASSERT_STATIC ((int) INDIC_SYLLABIC_CATEGORY_AVAGRAHA == OT_Symbol);
218 }
219 else if (unlikely (hb_in_range (u, 0x17CDu, 0x17D1u) ||
220 u == 0x17CBu || u == 0x17D3u || u == 0x17DDu)) /* Khmer Various signs */
221 {
222 /* These are like Top Matras. */
223 cat = OT_M;
224 pos = POS_ABOVE_C;
225 }
226 else if (unlikely (u == 0x17C6u)) cat = OT_N; /* Khmer Bindu doesn't like to be repositioned. */
227 else if (unlikely (u == 0x17D2u)) cat = OT_Coeng; /* Khmer coeng */
228 else if (unlikely (hb_in_range (u, 0x2010u, 0x2011u)))
229 cat = OT_PLACEHOLDER;
230 else if (unlikely (u == 0x25CCu)) cat = OT_DOTTEDCIRCLE;
231 else if (unlikely (u == 0xA982u)) cat = OT_SM; /* Javanese repha. */
232 else if (unlikely (u == 0xA9BEu)) cat = OT_CM2; /* Javanese medial ya. */
233 else if (unlikely (u == 0xA9BDu)) { cat = OT_M; pos = POS_POST_C; } /* Javanese vocalic r. */
234
235
236 /*
237 * Re-assign position.
238 */
239
240 if ((FLAG_SAFE (cat) & CONSONANT_FLAGS))
241 {
242 pos = POS_BASE_C;
243 if (is_ra (u))
244 cat = OT_Ra;
245 }
246 else if (cat == OT_M)
247 {
248 pos = matra_position (u, pos);
249 }
250 else if ((FLAG_SAFE (cat) & (FLAG (OT_SM) | FLAG (OT_VD) | FLAG (OT_A) | FLAG (OT_Symbol))))
251 {
252 pos = POS_SMVD;
253 }
254
255 if (unlikely (u == 0x0B01u)) pos = POS_BEFORE_SUB; /* Oriya Bindu is BeforeSub in the spec. */
256
257
258
259 info.indic_category() = cat;
260 info.indic_position() = pos;
261 }
262
263 /*
264 * Things above this line should ideally be moved to the Indic table itself.
265 */
266
267
268 /*
269 * Indic configurations. Note that we do not want to keep every single script-specific
270 * behavior in these tables necessarily. This should mainly be used for per-script
271 * properties that are cheaper keeping here, than in the code. Ie. if, say, one and
272 * only one script has an exception, that one script can be if'ed directly in the code,
273 * instead of adding a new flag in these structs.
274 */
275
276 enum base_position_t {
277 BASE_POS_FIRST,
278 BASE_POS_LAST_SINHALA,
279 BASE_POS_LAST
280 };
281 enum reph_position_t {
282 REPH_POS_AFTER_MAIN = POS_AFTER_MAIN,
283 REPH_POS_BEFORE_SUB = POS_BEFORE_SUB,
284 REPH_POS_AFTER_SUB = POS_AFTER_SUB,
285 REPH_POS_BEFORE_POST = POS_BEFORE_POST,
286 REPH_POS_AFTER_POST = POS_AFTER_POST,
287 REPH_POS_DONT_CARE = POS_RA_TO_BECOME_REPH
288 };
289 enum reph_mode_t {
290 REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */
291 REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */
292 REPH_MODE_VIS_REPHA, /* Encoded Repha character, no reordering needed. */
293 REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */
294 };
295 enum blwf_mode_t {
296 BLWF_MODE_PRE_AND_POST, /* Below-forms feature applied to pre-base and post-base. */
297 BLWF_MODE_POST_ONLY /* Below-forms feature applied to post-base only. */
298 };
299 enum pref_len_t {
300 PREF_LEN_1 = 1,
301 PREF_LEN_2 = 2,
302 PREF_LEN_DONT_CARE = PREF_LEN_2
303 };
304 struct indic_config_t
305 {
306 hb_script_t script;
307 bool has_old_spec;
308 hb_codepoint_t virama;
309 base_position_t base_pos;
310 reph_position_t reph_pos;
311 reph_mode_t reph_mode;
312 blwf_mode_t blwf_mode;
313 pref_len_t pref_len;
314 };
315
316 static const indic_config_t indic_configs[] =
317 {
318 /* Default. Should be first. */
319 {HB_SCRIPT_INVALID, false, 0,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_1},
320 {HB_SCRIPT_DEVANAGARI,true, 0x094Du,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_DONT_CARE},
321 {HB_SCRIPT_BENGALI, true, 0x09CDu,BASE_POS_LAST, REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_DONT_CARE},
322 {HB_SCRIPT_GURMUKHI, true, 0x0A4Du,BASE_POS_LAST, REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_DONT_CARE},
323 {HB_SCRIPT_GUJARATI, true, 0x0ACDu,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_DONT_CARE},
324 {HB_SCRIPT_ORIYA, true, 0x0B4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_DONT_CARE},
325 {HB_SCRIPT_TAMIL, true, 0x0BCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_2},
326 {HB_SCRIPT_TELUGU, true, 0x0C4Du,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_POST_ONLY, PREF_LEN_2},
327 {HB_SCRIPT_KANNADA, true, 0x0CCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_POST_ONLY, PREF_LEN_2},
328 {HB_SCRIPT_MALAYALAM, true, 0x0D4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA,BLWF_MODE_PRE_AND_POST, PREF_LEN_2},
329 {HB_SCRIPT_SINHALA, false,0x0DCAu,BASE_POS_LAST_SINHALA,
330 REPH_POS_AFTER_MAIN, REPH_MODE_EXPLICIT, BLWF_MODE_PRE_AND_POST, PREF_LEN_DONT_CARE},
331 {HB_SCRIPT_KHMER, false,0x17D2u,BASE_POS_FIRST,REPH_POS_DONT_CARE, REPH_MODE_VIS_REPHA,BLWF_MODE_PRE_AND_POST, PREF_LEN_2},
332 {HB_SCRIPT_JAVANESE, false,0xA9C0u,BASE_POS_FIRST,REPH_POS_DONT_CARE, REPH_MODE_VIS_REPHA,BLWF_MODE_PRE_AND_POST, PREF_LEN_1},
333 };
334
335
336
337 /*
338 * Indic shaper.
339 */
340
341 struct feature_list_t {
342 hb_tag_t tag;
343 hb_ot_map_feature_flags_t flags;
344 };
345
346 static const feature_list_t
347 indic_features[] =
348 {
349 /*
350 * Basic features.
351 * These features are applied in order, one at a time, after initial_reordering.
352 */
353 {HB_TAG('n','u','k','t'), F_GLOBAL},
354 {HB_TAG('a','k','h','n'), F_GLOBAL},
355 {HB_TAG('r','p','h','f'), F_NONE},
356 {HB_TAG('r','k','r','f'), F_GLOBAL},
357 {HB_TAG('p','r','e','f'), F_NONE},
358 {HB_TAG('b','l','w','f'), F_NONE},
359 {HB_TAG('a','b','v','f'), F_NONE},
360 {HB_TAG('h','a','l','f'), F_NONE},
361 {HB_TAG('p','s','t','f'), F_NONE},
362 {HB_TAG('v','a','t','u'), F_GLOBAL},
363 {HB_TAG('c','j','c','t'), F_GLOBAL},
364 {HB_TAG('c','f','a','r'), F_NONE},
365 /*
366 * Other features.
367 * These features are applied all at once, after final_reordering.
368 * Default Bengali font in Windows for example has intermixed
369 * lookups for init,pres,abvs,blws features.
370 */
371 {HB_TAG('i','n','i','t'), F_NONE},
372 {HB_TAG('p','r','e','s'), F_GLOBAL},
373 {HB_TAG('a','b','v','s'), F_GLOBAL},
374 {HB_TAG('b','l','w','s'), F_GLOBAL},
375 {HB_TAG('p','s','t','s'), F_GLOBAL},
376 {HB_TAG('h','a','l','n'), F_GLOBAL},
377 /* Positioning features, though we don't care about the types. */
378 {HB_TAG('d','i','s','t'), F_GLOBAL},
379 {HB_TAG('a','b','v','m'), F_GLOBAL},
380 {HB_TAG('b','l','w','m'), F_GLOBAL},
381 };
382
383 /*
384 * Must be in the same order as the indic_features array.
385 */
386 enum {
387 _NUKT,
388 _AKHN,
389 RPHF,
390 _RKRF,
391 PREF,
392 BLWF,
393 ABVF,
394 HALF,
395 PSTF,
396 _VATU,
397 _CJCT,
398 CFAR,
399
400 INIT,
401 _PRES,
402 _ABVS,
403 _BLWS,
404 _PSTS,
405 _HALN,
406 _DIST,
407 _ABVM,
408 _BLWM,
409
410 INDIC_NUM_FEATURES,
411 INDIC_BASIC_FEATURES = INIT /* Don't forget to update this! */
412 };
413
414 static void
415 setup_syllables (const hb_ot_shape_plan_t *plan,
416 hb_font_t *font,
417 hb_buffer_t *buffer);
418 static void
419 initial_reordering (const hb_ot_shape_plan_t *plan,
420 hb_font_t *font,
421 hb_buffer_t *buffer);
422 static void
423 final_reordering (const hb_ot_shape_plan_t *plan,
424 hb_font_t *font,
425 hb_buffer_t *buffer);
426 static void
427 clear_syllables (const hb_ot_shape_plan_t *plan,
428 hb_font_t *font,
429 hb_buffer_t *buffer);
430
431 static void
432 collect_features_indic (hb_ot_shape_planner_t *plan)
433 {
434 hb_ot_map_builder_t *map = &plan->map;
435
436 /* Do this before any lookups have been applied. */
437 map->add_gsub_pause (setup_syllables);
438
439 map->add_global_bool_feature (HB_TAG('l','o','c','l'));
440 /* The Indic specs do not require ccmp, but we apply it here since if
441 * there is a use of it, it's typically at the beginning. */
442 map->add_global_bool_feature (HB_TAG('c','c','m','p'));
443
444
445 unsigned int i = 0;
446 map->add_gsub_pause (initial_reordering);
447 for (; i < INDIC_BASIC_FEATURES; i++) {
448 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ);
449 map->add_gsub_pause (NULL);
450 }
451 map->add_gsub_pause (final_reordering);
452 for (; i < INDIC_NUM_FEATURES; i++) {
453 map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ);
454 }
455
456 map->add_global_bool_feature (HB_TAG('c','a','l','t'));
457 map->add_global_bool_feature (HB_TAG('c','l','i','g'));
458
459 map->add_gsub_pause (clear_syllables);
460 }
461
462 static void
463 override_features_indic (hb_ot_shape_planner_t *plan)
464 {
465 /* Uniscribe does not apply 'kern' in Khmer. */
466 if (hb_options ().uniscribe_bug_compatible)
467 {
468 switch ((hb_tag_t) plan->props.script)
469 {
470 case HB_SCRIPT_KHMER:
471 plan->map.add_feature (HB_TAG('k','e','r','n'), 0, F_GLOBAL);
472 break;
473 }
474 }
475
476 plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL);
477 }
478
479
480 struct would_substitute_feature_t
481 {
482 inline void init (const hb_ot_map_t *map, hb_tag_t feature_tag, bool zero_context_)
483 {
484 zero_context = zero_context_;
485 map->get_stage_lookups (0/*GSUB*/,
486 map->get_feature_stage (0/*GSUB*/, feature_tag),
487 &lookups, &count);
488 }
489
490 inline bool would_substitute (const hb_codepoint_t *glyphs,
491 unsigned int glyphs_count,
492 hb_face_t *face) const
493 {
494 for (unsigned int i = 0; i < count; i++)
495 if (hb_ot_layout_lookup_would_substitute_fast (face, lookups[i].index, glyphs, glyphs_count, zero_context))
496 return true;
497 return false;
498 }
499
500 private:
501 const hb_ot_map_t::lookup_map_t *lookups;
502 unsigned int count;
503 bool zero_context;
504 };
505
506 struct indic_shape_plan_t
507 {
508 ASSERT_POD ();
509
510 inline bool get_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const
511 {
512 hb_codepoint_t glyph = virama_glyph;
513 if (unlikely (virama_glyph == (hb_codepoint_t) -1))
514 {
515 if (!config->virama || !font->get_glyph (config->virama, 0, &glyph))
516 glyph = 0;
517 /* Technically speaking, the spec says we should apply 'locl' to virama too.
518 * Maybe one day... */
519
520 /* Our get_glyph() function needs a font, so we can't get the virama glyph
521 * during shape planning... Instead, overwrite it here. It's safe. Don't worry! */
522 (const_cast<indic_shape_plan_t *> (this))->virama_glyph = glyph;
523 }
524
525 *pglyph = glyph;
526 return glyph != 0;
527 }
528
529 const indic_config_t *config;
530
531 bool is_old_spec;
532 hb_codepoint_t virama_glyph;
533
534 would_substitute_feature_t rphf;
535 would_substitute_feature_t pref;
536 would_substitute_feature_t blwf;
537 would_substitute_feature_t pstf;
538
539 hb_mask_t mask_array[INDIC_NUM_FEATURES];
540 };
541
542 static void *
543 data_create_indic (const hb_ot_shape_plan_t *plan)
544 {
545 indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (1, sizeof (indic_shape_plan_t));
546 if (unlikely (!indic_plan))
547 return NULL;
548
549 indic_plan->config = &indic_configs[0];
550 for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++)
551 if (plan->props.script == indic_configs[i].script) {
552 indic_plan->config = &indic_configs[i];
553 break;
554 }
555
556 indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FFu) != '2');
557 indic_plan->virama_glyph = (hb_codepoint_t) -1;
558
559 /* Use zero-context would_substitute() matching for new-spec of the main
560 * Indic scripts, and scripts with one spec only, but not for old-specs. */
561 bool zero_context = !indic_plan->is_old_spec;
562 indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'), zero_context);
563 indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), zero_context);
564 indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'), zero_context);
565 indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'), zero_context);
566
567 for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++)
568 indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ?
569 0 : plan->map.get_1_mask (indic_features[i].tag);
570
571 return indic_plan;
572 }
573
574 static void
575 data_destroy_indic (void *data)
576 {
577 free (data);
578 }
579
580 static indic_position_t
581 consonant_position_from_face (const indic_shape_plan_t *indic_plan,
582 const hb_codepoint_t consonant,
583 const hb_codepoint_t virama,
584 hb_face_t *face)
585 {
586 /* For old-spec, the order of glyphs is Consonant,Virama,
587 * whereas for new-spec, it's Virama,Consonant. However,
588 * some broken fonts (like Free Sans) simply copied lookups
589 * from old-spec to new-spec without modification.
590 * And oddly enough, Uniscribe seems to respect those lookups.
591 * Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds
592 * base at 0. The font however, only has lookups matching
593 * 930,94D in 'blwf', not the expected 94D,930 (with new-spec
594 * table). As such, we simply match both sequences. Seems
595 * to work. */
596 hb_codepoint_t glyphs[3] = {virama, consonant, virama};
597 if (indic_plan->blwf.would_substitute (glyphs , 2, face) ||
598 indic_plan->blwf.would_substitute (glyphs+1, 2, face))
599 return POS_BELOW_C;
600 if (indic_plan->pstf.would_substitute (glyphs , 2, face) ||
601 indic_plan->pstf.would_substitute (glyphs+1, 2, face))
602 return POS_POST_C;
603 unsigned int pref_len = indic_plan->config->pref_len;
604 if ((pref_len == PREF_LEN_2 &&
605 (indic_plan->pref.would_substitute (glyphs , 2, face) ||
606 indic_plan->pref.would_substitute (glyphs+1, 2, face)))
607 || (pref_len == PREF_LEN_1 &&
608 indic_plan->pref.would_substitute (glyphs+1, 1, face)))
609 return POS_POST_C;
610 return POS_BASE_C;
611 }
612
613
614 enum syllable_type_t {
615 consonant_syllable,
616 vowel_syllable,
617 standalone_cluster,
618 symbol_cluster,
619 broken_cluster,
620 non_indic_cluster,
621 };
622
623 #include "hb-ot-shape-complex-indic-machine.hh"
624
625
626 static void
627 setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED,
628 hb_buffer_t *buffer,
629 hb_font_t *font HB_UNUSED)
630 {
631 HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
632 HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
633
634 /* We cannot setup masks here. We save information about characters
635 * and setup masks later on in a pause-callback. */
636
637 unsigned int count = buffer->len;
638 hb_glyph_info_t *info = buffer->info;
639 for (unsigned int i = 0; i < count; i++)
640 set_indic_properties (info[i]);
641 }
642
643 static void
644 setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
645 hb_font_t *font HB_UNUSED,
646 hb_buffer_t *buffer)
647 {
648 find_syllables (buffer);
649 }
650
651 static int
652 compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
653 {
654 int a = pa->indic_position();
655 int b = pb->indic_position();
656
657 return a < b ? -1 : a == b ? 0 : +1;
658 }
659
660
661
662 static void
663 update_consonant_positions (const hb_ot_shape_plan_t *plan,
664 hb_font_t *font,
665 hb_buffer_t *buffer)
666 {
667 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
668
669 if (indic_plan->config->base_pos != BASE_POS_LAST)
670 return;
671
672 hb_codepoint_t virama;
673 if (indic_plan->get_virama_glyph (font, &virama))
674 {
675 hb_face_t *face = font->face;
676 unsigned int count = buffer->len;
677 hb_glyph_info_t *info = buffer->info;
678 for (unsigned int i = 0; i < count; i++)
679 if (info[i].indic_position() == POS_BASE_C)
680 {
681 hb_codepoint_t consonant = info[i].codepoint;
682 info[i].indic_position() = consonant_position_from_face (indic_plan, consonant, virama, face);
683 }
684 }
685 }
686
687
688 /* Rules from:
689 * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
690
691 static void
692 initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan,
693 hb_face_t *face,
694 hb_buffer_t *buffer,
695 unsigned int start, unsigned int end)
696 {
697 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
698 hb_glyph_info_t *info = buffer->info;
699
700
701 /* 1. Find base consonant:
702 *
703 * The shaping engine finds the base consonant of the syllable, using the
704 * following algorithm: starting from the end of the syllable, move backwards
705 * until a consonant is found that does not have a below-base or post-base
706 * form (post-base forms have to follow below-base forms), or that is not a
707 * pre-base reordering Ra, or arrive at the first consonant. The consonant
708 * stopped at will be the base.
709 *
710 * o If the syllable starts with Ra + Halant (in a script that has Reph)
711 * and has more than one consonant, Ra is excluded from candidates for
712 * base consonants.
713 */
714
715 unsigned int base = end;
716 bool has_reph = false;
717
718 {
719 /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
720 * and has more than one consonant, Ra is excluded from candidates for
721 * base consonants. */
722 unsigned int limit = start;
723 if (indic_plan->config->reph_pos != REPH_POS_DONT_CARE &&
724 indic_plan->mask_array[RPHF] &&
725 start + 3 <= end &&
726 (
727 (indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info[start + 2])) ||
728 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == OT_ZWJ)
729 ))
730 {
731 /* See if it matches the 'rphf' feature. */
732 hb_codepoint_t glyphs[3] = {info[start].codepoint,
733 info[start + 1].codepoint,
734 indic_plan->config->reph_mode == REPH_MODE_EXPLICIT ?
735 info[start + 2].codepoint : 0};
736 if (indic_plan->rphf.would_substitute (glyphs, 2, face) ||
737 (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT &&
738 indic_plan->rphf.would_substitute (glyphs, 3, face)))
739 {
740 limit += 2;
741 while (limit < end && is_joiner (info[limit]))
742 limit++;
743 base = start;
744 has_reph = true;
745 }
746 } else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == OT_Repha)
747 {
748 limit += 1;
749 while (limit < end && is_joiner (info[limit]))
750 limit++;
751 base = start;
752 has_reph = true;
753 }
754
755 switch (indic_plan->config->base_pos)
756 {
757 default:
758 assert (false);
759 /* fallthrough */
760
761 case BASE_POS_LAST:
762 {
763 /* -> starting from the end of the syllable, move backwards */
764 unsigned int i = end;
765 bool seen_below = false;
766 do {
767 i--;
768 /* -> until a consonant is found */
769 if (is_consonant (info[i]))
770 {
771 /* -> that does not have a below-base or post-base form
772 * (post-base forms have to follow below-base forms), */
773 if (info[i].indic_position() != POS_BELOW_C &&
774 (info[i].indic_position() != POS_POST_C || seen_below))
775 {
776 base = i;
777 break;
778 }
779 if (info[i].indic_position() == POS_BELOW_C)
780 seen_below = true;
781
782 /* -> or that is not a pre-base reordering Ra,
783 *
784 * IMPLEMENTATION NOTES:
785 *
786 * Our pre-base reordering Ra's are marked POS_POST_C, so will be skipped
787 * by the logic above already.
788 */
789
790 /* -> or arrive at the first consonant. The consonant stopped at will
791 * be the base. */
792 base = i;
793 }
794 else
795 {
796 /* A ZWJ after a Halant stops the base search, and requests an explicit
797 * half form.
798 * A ZWJ before a Halant, requests a subjoined form instead, and hence
799 * search continues. This is particularly important for Bengali
800 * sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */
801 if (start < i &&
802 info[i].indic_category() == OT_ZWJ &&
803 info[i - 1].indic_category() == OT_H)
804 break;
805 }
806 } while (i > limit);
807 }
808 break;
809
810 case BASE_POS_LAST_SINHALA:
811 {
812 /* Sinhala base positioning is slightly different from main Indic, in that:
813 * 1. Its ZWJ behavior is different,
814 * 2. We don't need to look into the font for consonant positions.
815 */
816
817 if (!has_reph)
818 base = limit;
819
820 /* Find the last base consonant that is not blocked by ZWJ. If there is
821 * a ZWJ right before a base consonant, that would request a subjoined form. */
822 for (unsigned int i = limit; i < end; i++)
823 if (is_consonant (info[i]))
824 {
825 if (limit < i && info[i - 1].indic_category() == OT_ZWJ)
826 break;
827 else
828 base = i;
829 }
830
831 /* Mark all subsequent consonants as below. */
832 for (unsigned int i = base + 1; i < end; i++)
833 if (is_consonant (info[i]))
834 info[i].indic_position() = POS_BELOW_C;
835 }
836 break;
837
838 case BASE_POS_FIRST:
839 {
840 /* The first consonant is always the base. */
841
842 assert (indic_plan->config->reph_mode == REPH_MODE_VIS_REPHA);
843 assert (!has_reph);
844
845 base = start;
846
847 /* Mark all subsequent consonants as below. */
848 for (unsigned int i = base + 1; i < end; i++)
849 if (is_consonant (info[i]))
850 info[i].indic_position() = POS_BELOW_C;
851 }
852 break;
853 }
854
855 /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
856 * and has more than one consonant, Ra is excluded from candidates for
857 * base consonants.
858 *
859 * Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */
860 if (has_reph && base == start && limit - base <= 2) {
861 /* Have no other consonant, so Reph is not formed and Ra becomes base. */
862 has_reph = false;
863 }
864 }
865
866
867 /* 2. Decompose and reorder Matras:
868 *
869 * Each matra and any syllable modifier sign in the cluster are moved to the
870 * appropriate position relative to the consonant(s) in the cluster. The
871 * shaping engine decomposes two- or three-part matras into their constituent
872 * parts before any repositioning. Matra characters are classified by which
873 * consonant in a conjunct they have affinity for and are reordered to the
874 * following positions:
875 *
876 * o Before first half form in the syllable
877 * o After subjoined consonants
878 * o After post-form consonant
879 * o After main consonant (for above marks)
880 *
881 * IMPLEMENTATION NOTES:
882 *
883 * The normalize() routine has already decomposed matras for us, so we don't
884 * need to worry about that.
885 */
886
887
888 /* 3. Reorder marks to canonical order:
889 *
890 * Adjacent nukta and halant or nukta and vedic sign are always repositioned
891 * if necessary, so that the nukta is first.
892 *
893 * IMPLEMENTATION NOTES:
894 *
895 * We don't need to do this: the normalize() routine already did this for us.
896 */
897
898
899 /* Reorder characters */
900
901 for (unsigned int i = start; i < base; i++)
902 info[i].indic_position() = MIN (POS_PRE_C, (indic_position_t) info[i].indic_position());
903
904 if (base < end)
905 info[base].indic_position() = POS_BASE_C;
906
907 /* Mark final consonants. A final consonant is one appearing after a matra,
908 * like in Khmer. */
909 for (unsigned int i = base + 1; i < end; i++)
910 if (info[i].indic_category() == OT_M) {
911 for (unsigned int j = i + 1; j < end; j++)
912 if (is_consonant (info[j])) {
913 info[j].indic_position() = POS_FINAL_C;
914 break;
915 }
916 break;
917 }
918
919 /* Handle beginning Ra */
920 if (has_reph)
921 info[start].indic_position() = POS_RA_TO_BECOME_REPH;
922
923 /* For old-style Indic script tags, move the first post-base Halant after
924 * last consonant.
925 *
926 * Reports suggest that in some scripts Uniscribe does this only if there
927 * is *not* a Halant after last consonant already (eg. Kannada), while it
928 * does it unconditionally in other scripts (eg. Malayalam). We don't
929 * currently know about other scripts, so we single out Malayalam for now.
930 *
931 * Kannada test case:
932 * U+0C9A,U+0CCD,U+0C9A,U+0CCD
933 * With some versions of Lohit Kannada.
934 * https://bugs.freedesktop.org/show_bug.cgi?id=59118
935 *
936 * Malayalam test case:
937 * U+0D38,U+0D4D,U+0D31,U+0D4D,U+0D31,U+0D4D
938 * With lohit-ttf-20121122/Lohit-Malayalam.ttf
939 */
940 if (indic_plan->is_old_spec)
941 {
942 bool disallow_double_halants = buffer->props.script != HB_SCRIPT_MALAYALAM;
943 for (unsigned int i = base + 1; i < end; i++)
944 if (info[i].indic_category() == OT_H)
945 {
946 unsigned int j;
947 for (j = end - 1; j > i; j--)
948 if (is_consonant (info[j]) ||
949 (disallow_double_halants && info[j].indic_category() == OT_H))
950 break;
951 if (info[j].indic_category() != OT_H && j > i) {
952 /* Move Halant to after last consonant. */
953 hb_glyph_info_t t = info[i];
954 memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0]));
955 info[j] = t;
956 }
957 break;
958 }
959 }
960
961 /* Attach misc marks to previous char to move with them. */
962 {
963 indic_position_t last_pos = POS_START;
964 for (unsigned int i = start; i < end; i++)
965 {
966 if ((FLAG_SAFE (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | MEDIAL_FLAGS | HALANT_OR_COENG_FLAGS)))
967 {
968 info[i].indic_position() = last_pos;
969 if (unlikely (info[i].indic_category() == OT_H &&
970 info[i].indic_position() == POS_PRE_M))
971 {
972 /*
973 * Uniscribe doesn't move the Halant with Left Matra.
974 * TEST: U+092B,U+093F,U+094DE
975 * We follow. This is important for the Sinhala
976 * U+0DDA split matra since it decomposes to U+0DD9,U+0DCA
977 * where U+0DD9 is a left matra and U+0DCA is the virama.
978 * We don't want to move the virama with the left matra.
979 * TEST: U+0D9A,U+0DDA
980 */
981 for (unsigned int j = i; j > start; j--)
982 if (info[j - 1].indic_position() != POS_PRE_M) {
983 info[i].indic_position() = info[j - 1].indic_position();
984 break;
985 }
986 }
987 } else if (info[i].indic_position() != POS_SMVD) {
988 last_pos = (indic_position_t) info[i].indic_position();
989 }
990 }
991 }
992 /* For post-base consonants let them own anything before them
993 * since the last consonant or matra. */
994 {
995 unsigned int last = base;
996 for (unsigned int i = base + 1; i < end; i++)
997 if (is_consonant (info[i]))
998 {
999 for (unsigned int j = last + 1; j < i; j++)
1000 if (info[j].indic_position() < POS_SMVD)
1001 info[j].indic_position() = info[i].indic_position();
1002 last = i;
1003 } else if (info[i].indic_category() == OT_M)
1004 last = i;
1005 }
1006
1007
1008 {
1009 /* Use syllable() for sort accounting temporarily. */
1010 unsigned int syllable = info[start].syllable();
1011 for (unsigned int i = start; i < end; i++)
1012 info[i].syllable() = i - start;
1013
1014 /* Sit tight, rock 'n roll! */
1015 hb_stable_sort (info + start, end - start, compare_indic_order);
1016 /* Find base again */
1017 base = end;
1018 for (unsigned int i = start; i < end; i++)
1019 if (info[i].indic_position() == POS_BASE_C)
1020 {
1021 base = i;
1022 break;
1023 }
1024 /* Things are out-of-control for post base positions, they may shuffle
1025 * around like crazy. In old-spec mode, we move halants around, so in
1026 * that case merge all clusters after base. Otherwise, check the sort
1027 * order and merge as needed.
1028 * For pre-base stuff, we handle cluster issues in final reordering.
1029 *
1030 * We could use buffer->sort() for this, if there was no special
1031 * reordering of pre-base stuff happening later...
1032 */
1033 if (indic_plan->is_old_spec || end - base > 127)
1034 buffer->merge_clusters (base, end);
1035 else
1036 {
1037 /* Note! syllable() is a one-byte field. */
1038 for (unsigned int i = base; i < end; i++)
1039 if (info[i].syllable() != 255)
1040 {
1041 unsigned int max = i;
1042 unsigned int j = start + info[i].syllable();
1043 while (j != i)
1044 {
1045 max = MAX (max, j);
1046 unsigned int next = start + info[j].syllable();
1047 info[j].syllable() = 255; /* So we don't process j later again. */
1048 j = next;
1049 }
1050 if (i != max)
1051 buffer->merge_clusters (i, max + 1);
1052 }
1053 }
1054
1055 /* Put syllable back in. */
1056 for (unsigned int i = start; i < end; i++)
1057 info[i].syllable() = syllable;
1058 }
1059
1060 /* Setup masks now */
1061
1062 {
1063 hb_mask_t mask;
1064
1065 /* Reph */
1066 for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++)
1067 info[i].mask |= indic_plan->mask_array[RPHF];
1068
1069 /* Pre-base */
1070 mask = indic_plan->mask_array[HALF];
1071 if (!indic_plan->is_old_spec &&
1072 indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST)
1073 mask |= indic_plan->mask_array[BLWF];
1074 for (unsigned int i = start; i < base; i++)
1075 info[i].mask |= mask;
1076 /* Base */
1077 mask = 0;
1078 if (base < end)
1079 info[base].mask |= mask;
1080 /* Post-base */
1081 mask = indic_plan->mask_array[BLWF] | indic_plan->mask_array[ABVF] | indic_plan->mask_array[PSTF];
1082 for (unsigned int i = base + 1; i < end; i++)
1083 info[i].mask |= mask;
1084 }
1085
1086 if (indic_plan->is_old_spec &&
1087 buffer->props.script == HB_SCRIPT_DEVANAGARI)
1088 {
1089 /* Old-spec eye-lash Ra needs special handling. From the
1090 * spec:
1091 *
1092 * "The feature 'below-base form' is applied to consonants
1093 * having below-base forms and following the base consonant.
1094 * The exception is vattu, which may appear below half forms
1095 * as well as below the base glyph. The feature 'below-base
1096 * form' will be applied to all such occurrences of Ra as well."
1097 *
1098 * Test case: U+0924,U+094D,U+0930,U+094d,U+0915
1099 * with Sanskrit 2003 font.
1100 *
1101 * However, note that Ra,Halant,ZWJ is the correct way to
1102 * request eyelash form of Ra, so we wouldbn't inhibit it
1103 * in that sequence.
1104 *
1105 * Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915
1106 */
1107 for (unsigned int i = start; i + 1 < base; i++)
1108 if (info[i ].indic_category() == OT_Ra &&
1109 info[i+1].indic_category() == OT_H &&
1110 (i + 2 == base ||
1111 info[i+2].indic_category() != OT_ZWJ))
1112 {
1113 info[i ].mask |= indic_plan->mask_array[BLWF];
1114 info[i+1].mask |= indic_plan->mask_array[BLWF];
1115 }
1116 }
1117
1118 unsigned int pref_len = indic_plan->config->pref_len;
1119 if (indic_plan->mask_array[PREF] && base + pref_len < end)
1120 {
1121 assert (1 <= pref_len && pref_len <= 2);
1122 /* Find a Halant,Ra sequence and mark it for pre-base reordering processing. */
1123 for (unsigned int i = base + 1; i + pref_len - 1 < end; i++) {
1124 hb_codepoint_t glyphs[2];
1125 for (unsigned int j = 0; j < pref_len; j++)
1126 glyphs[j] = info[i + j].codepoint;
1127 if (indic_plan->pref.would_substitute (glyphs, pref_len, face))
1128 {
1129 for (unsigned int j = 0; j < pref_len; j++)
1130 info[i++].mask |= indic_plan->mask_array[PREF];
1131
1132 /* Mark the subsequent stuff with 'cfar'. Used in Khmer.
1133 * Read the feature spec.
1134 * This allows distinguishing the following cases with MS Khmer fonts:
1135 * U+1784,U+17D2,U+179A,U+17D2,U+1782
1136 * U+1784,U+17D2,U+1782,U+17D2,U+179A
1137 */
1138 if (indic_plan->mask_array[CFAR])
1139 for (; i < end; i++)
1140 info[i].mask |= indic_plan->mask_array[CFAR];
1141
1142 break;
1143 }
1144 }
1145 }
1146
1147 /* Apply ZWJ/ZWNJ effects */
1148 for (unsigned int i = start + 1; i < end; i++)
1149 if (is_joiner (info[i])) {
1150 bool non_joiner = info[i].indic_category() == OT_ZWNJ;
1151 unsigned int j = i;
1152
1153 do {
1154 j--;
1155
1156 /* ZWJ/ZWNJ should disable CJCT. They do that by simply
1157 * being there, since we don't skip them for the CJCT
1158 * feature (ie. F_MANUAL_ZWJ) */
1159
1160 /* A ZWNJ disables HALF. */
1161 if (non_joiner)
1162 info[j].mask &= ~indic_plan->mask_array[HALF];
1163
1164 } while (j > start && !is_consonant (info[j]));
1165 }
1166 }
1167
1168 static void
1169 initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan,
1170 hb_face_t *face,
1171 hb_buffer_t *buffer,
1172 unsigned int start, unsigned int end)
1173 {
1174 /* We treat placeholder/dotted-circle as if they are consonants, so we
1175 * should just chain. Only if not in compatibility mode that is... */
1176
1177 if (hb_options ().uniscribe_bug_compatible)
1178 {
1179 /* For dotted-circle, this is what Uniscribe does:
1180 * If dotted-circle is the last glyph, it just does nothing.
1181 * Ie. It doesn't form Reph. */
1182 if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE)
1183 return;
1184 }
1185
1186 initial_reordering_consonant_syllable (plan, face, buffer, start, end);
1187 }
1188
1189 static void
1190 initial_reordering_syllable (const hb_ot_shape_plan_t *plan,
1191 hb_face_t *face,
1192 hb_buffer_t *buffer,
1193 unsigned int start, unsigned int end)
1194 {
1195 syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
1196 switch (syllable_type)
1197 {
1198 case vowel_syllable: /* We made the vowels look like consonants. So let's call the consonant logic! */
1199 case consonant_syllable:
1200 initial_reordering_consonant_syllable (plan, face, buffer, start, end);
1201 break;
1202
1203 case broken_cluster: /* We already inserted dotted-circles, so just call the standalone_cluster. */
1204 case standalone_cluster:
1205 initial_reordering_standalone_cluster (plan, face, buffer, start, end);
1206 break;
1207
1208 case symbol_cluster:
1209 case non_indic_cluster:
1210 break;
1211 }
1212 }
1213
1214 static inline void
1215 insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
1216 hb_font_t *font,
1217 hb_buffer_t *buffer)
1218 {
1219 /* Note: This loop is extra overhead, but should not be measurable. */
1220 bool has_broken_syllables = false;
1221 unsigned int count = buffer->len;
1222 hb_glyph_info_t *info = buffer->info;
1223 for (unsigned int i = 0; i < count; i++)
1224 if ((info[i].syllable() & 0x0F) == broken_cluster)
1225 {
1226 has_broken_syllables = true;
1227 break;
1228 }
1229 if (likely (!has_broken_syllables))
1230 return;
1231
1232
1233 hb_codepoint_t dottedcircle_glyph;
1234 if (!font->get_glyph (0x25CCu, 0, &dottedcircle_glyph))
1235 return;
1236
1237 hb_glyph_info_t dottedcircle = {0};
1238 dottedcircle.codepoint = 0x25CCu;
1239 set_indic_properties (dottedcircle);
1240 dottedcircle.codepoint = dottedcircle_glyph;
1241
1242 buffer->clear_output ();
1243
1244 buffer->idx = 0;
1245 unsigned int last_syllable = 0;
1246 while (buffer->idx < buffer->len)
1247 {
1248 unsigned int syllable = buffer->cur().syllable();
1249 syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
1250 if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
1251 {
1252 last_syllable = syllable;
1253
1254 hb_glyph_info_t info = dottedcircle;
1255 info.cluster = buffer->cur().cluster;
1256 info.mask = buffer->cur().mask;
1257 info.syllable() = buffer->cur().syllable();
1258 /* TODO Set glyph_props? */
1259
1260 /* Insert dottedcircle after possible Repha. */
1261 while (buffer->idx < buffer->len &&
1262 last_syllable == buffer->cur().syllable() &&
1263 buffer->cur().indic_category() == OT_Repha)
1264 buffer->next_glyph ();
1265
1266 buffer->output_info (info);
1267 }
1268 else
1269 buffer->next_glyph ();
1270 }
1271
1272 buffer->swap_buffers ();
1273 }
1274
1275 static void
1276 initial_reordering (const hb_ot_shape_plan_t *plan,
1277 hb_font_t *font,
1278 hb_buffer_t *buffer)
1279 {
1280 update_consonant_positions (plan, font, buffer);
1281 insert_dotted_circles (plan, font, buffer);
1282
1283 foreach_syllable (buffer, start, end)
1284 initial_reordering_syllable (plan, font->face, buffer, start, end);
1285 }
1286
1287 static void
1288 final_reordering_syllable (const hb_ot_shape_plan_t *plan,
1289 hb_buffer_t *buffer,
1290 unsigned int start, unsigned int end)
1291 {
1292 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
1293 hb_glyph_info_t *info = buffer->info;
1294
1295
1296 /* This function relies heavily on halant glyphs. Lots of ligation
1297 * and possibly multiplication substitutions happened prior to this
1298 * phase, and that might have messed up our properties. Recover
1299 * from a particular case of that where we're fairly sure that a
1300 * class of OT_H is desired but has been lost. */
1301 if (indic_plan->virama_glyph)
1302 {
1303 unsigned int virama_glyph = indic_plan->virama_glyph;
1304 for (unsigned int i = start; i < end; i++)
1305 if (info[i].codepoint == virama_glyph &&
1306 _hb_glyph_info_ligated (&info[i]) &&
1307 _hb_glyph_info_multiplied (&info[i]))
1308 {
1309 /* This will make sure that this glyph passes is_halant_or_coeng() test. */
1310 info[i].indic_category() = OT_H;
1311 _hb_glyph_info_clear_ligated_and_multiplied (&info[i]);
1312 }
1313 }
1314
1315
1316 /* 4. Final reordering:
1317 *
1318 * After the localized forms and basic shaping forms GSUB features have been
1319 * applied (see below), the shaping engine performs some final glyph
1320 * reordering before applying all the remaining font features to the entire
1321 * cluster.
1322 */
1323
1324 bool try_pref = !!indic_plan->mask_array[PREF];
1325
1326 /* Find base again */
1327 unsigned int base;
1328 for (base = start; base < end; base++)
1329 if (info[base].indic_position() >= POS_BASE_C)
1330 {
1331 if (try_pref && base + 1 < end && indic_plan->config->pref_len == 2)
1332 {
1333 for (unsigned int i = base + 1; i < end; i++)
1334 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0)
1335 {
1336 if (!(_hb_glyph_info_substituted (&info[i]) &&
1337 _hb_glyph_info_ligated_and_didnt_multiply (&info[i])))
1338 {
1339 /* Ok, this was a 'pref' candidate but didn't form any.
1340 * Base is around here... */
1341 base = i;
1342 while (base < end && is_halant_or_coeng (info[base]))
1343 base++;
1344 info[base].indic_position() = POS_BASE_C;
1345
1346 try_pref = false;
1347 }
1348 break;
1349 }
1350 }
1351
1352 if (start < base && info[base].indic_position() > POS_BASE_C)
1353 base--;
1354 break;
1355 }
1356 if (base == end && start < base &&
1357 is_one_of (info[base - 1], FLAG (OT_ZWJ)))
1358 base--;
1359 if (base < end)
1360 while (start < base &&
1361 is_one_of (info[base], (FLAG (OT_N) | HALANT_OR_COENG_FLAGS)))
1362 base--;
1363
1364
1365 /* o Reorder matras:
1366 *
1367 * If a pre-base matra character had been reordered before applying basic
1368 * features, the glyph can be moved closer to the main consonant based on
1369 * whether half-forms had been formed. Actual position for the matra is
1370 * defined as “after last standalone halant glyph, after initial matra
1371 * position and before the main consonant”. If ZWJ or ZWNJ follow this
1372 * halant, position is moved after it.
1373 */
1374
1375 if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */
1376 {
1377 /* If we lost track of base, alas, position before last thingy. */
1378 unsigned int new_pos = base == end ? base - 2 : base - 1;
1379
1380 /* Malayalam / Tamil do not have "half" forms or explicit virama forms.
1381 * The glyphs formed by 'half' are Chillus or ligated explicit viramas.
1382 * We want to position matra after them.
1383 */
1384 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
1385 {
1386 while (new_pos > start &&
1387 !(is_one_of (info[new_pos], (FLAG (OT_M) | HALANT_OR_COENG_FLAGS))))
1388 new_pos--;
1389
1390 /* If we found no Halant we are done.
1391 * Otherwise only proceed if the Halant does
1392 * not belong to the Matra itself! */
1393 if (is_halant_or_coeng (info[new_pos]) &&
1394 info[new_pos].indic_position() != POS_PRE_M)
1395 {
1396 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
1397 if (new_pos + 1 < end && is_joiner (info[new_pos + 1]))
1398 new_pos++;
1399 }
1400 else
1401 new_pos = start; /* No move. */
1402 }
1403
1404 if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M)
1405 {
1406 /* Now go see if there's actually any matras... */
1407 for (unsigned int i = new_pos; i > start; i--)
1408 if (info[i - 1].indic_position () == POS_PRE_M)
1409 {
1410 unsigned int old_pos = i - 1;
1411 if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */
1412 base--;
1413
1414 hb_glyph_info_t tmp = info[old_pos];
1415 memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0]));
1416 info[new_pos] = tmp;
1417
1418 /* Note: this merge_clusters() is intentionally *after* the reordering.
1419 * Indic matra reordering is special and tricky... */
1420 buffer->merge_clusters (new_pos, MIN (end, base + 1));
1421
1422 new_pos--;
1423 }
1424 } else {
1425 for (unsigned int i = start; i < base; i++)
1426 if (info[i].indic_position () == POS_PRE_M) {
1427 buffer->merge_clusters (i, MIN (end, base + 1));
1428 break;
1429 }
1430 }
1431 }
1432
1433
1434 /* o Reorder reph:
1435 *
1436 * Reph’s original position is always at the beginning of the syllable,
1437 * (i.e. it is not reordered at the character reordering stage). However,
1438 * it will be reordered according to the basic-forms shaping results.
1439 * Possible positions for reph, depending on the script, are; after main,
1440 * before post-base consonant forms, and after post-base consonant forms.
1441 */
1442
1443 /* Two cases:
1444 *
1445 * - If repha is encoded as a sequence of characters (Ra,H or Ra,H,ZWJ), then
1446 * we should only move it if the sequence ligated to the repha form.
1447 *
1448 * - If repha is encoded separately and in the logical position, we should only
1449 * move it if it did NOT ligate. If it ligated, it's probably the font trying
1450 * to make it work without the reordering.
1451 */
1452 if (start + 1 < end &&
1453 info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
1454 ((info[start].indic_category() == OT_Repha) ^
1455 _hb_glyph_info_ligated_and_didnt_multiply (&info[start])))
1456 {
1457 unsigned int new_reph_pos;
1458 reph_position_t reph_pos = indic_plan->config->reph_pos;
1459
1460 assert (reph_pos != REPH_POS_DONT_CARE);
1461
1462 /* 1. If reph should be positioned after post-base consonant forms,
1463 * proceed to step 5.
1464 */
1465 if (reph_pos == REPH_POS_AFTER_POST)
1466 {
1467 goto reph_step_5;
1468 }
1469
1470 /* 2. If the reph repositioning class is not after post-base: target
1471 * position is after the first explicit halant glyph between the
1472 * first post-reph consonant and last main consonant. If ZWJ or ZWNJ
1473 * are following this halant, position is moved after it. If such
1474 * position is found, this is the target position. Otherwise,
1475 * proceed to the next step.
1476 *
1477 * Note: in old-implementation fonts, where classifications were
1478 * fixed in shaping engine, there was no case where reph position
1479 * will be found on this step.
1480 */
1481 {
1482 new_reph_pos = start + 1;
1483 while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos]))
1484 new_reph_pos++;
1485
1486 if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos]))
1487 {
1488 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
1489 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
1490 new_reph_pos++;
1491 goto reph_move;
1492 }
1493 }
1494
1495 /* 3. If reph should be repositioned after the main consonant: find the
1496 * first consonant not ligated with main, or find the first
1497 * consonant that is not a potential pre-base reordering Ra.
1498 */
1499 if (reph_pos == REPH_POS_AFTER_MAIN)
1500 {
1501 new_reph_pos = base;
1502 while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN)
1503 new_reph_pos++;
1504 if (new_reph_pos < end)
1505 goto reph_move;
1506 }
1507
1508 /* 4. If reph should be positioned before post-base consonant, find
1509 * first post-base classified consonant not ligated with main. If no
1510 * consonant is found, the target position should be before the
1511 * first matra, syllable modifier sign or vedic sign.
1512 */
1513 /* This is our take on what step 4 is trying to say (and failing, BADLY). */
1514 if (reph_pos == REPH_POS_AFTER_SUB)
1515 {
1516 new_reph_pos = base;
1517 while (new_reph_pos < end &&
1518 !( FLAG_SAFE (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD))))
1519 new_reph_pos++;
1520 if (new_reph_pos < end)
1521 goto reph_move;
1522 }
1523
1524 /* 5. If no consonant is found in steps 3 or 4, move reph to a position
1525 * immediately before the first post-base matra, syllable modifier
1526 * sign or vedic sign that has a reordering class after the intended
1527 * reph position. For example, if the reordering position for reph
1528 * is post-main, it will skip above-base matras that also have a
1529 * post-main position.
1530 */
1531 reph_step_5:
1532 {
1533 /* Copied from step 2. */
1534 new_reph_pos = start + 1;
1535 while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos]))
1536 new_reph_pos++;
1537
1538 if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos]))
1539 {
1540 /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
1541 if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
1542 new_reph_pos++;
1543 goto reph_move;
1544 }
1545 }
1546
1547 /* 6. Otherwise, reorder reph to the end of the syllable.
1548 */
1549 {
1550 new_reph_pos = end - 1;
1551 while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
1552 new_reph_pos--;
1553
1554 /*
1555 * If the Reph is to be ending up after a Matra,Halant sequence,
1556 * position it before that Halant so it can interact with the Matra.
1557 * However, if it's a plain Consonant,Halant we shouldn't do that.
1558 * Uniscribe doesn't do this.
1559 * TEST: U+0930,U+094D,U+0915,U+094B,U+094D
1560 */
1561 if (!hb_options ().uniscribe_bug_compatible &&
1562 unlikely (is_halant_or_coeng (info[new_reph_pos]))) {
1563 for (unsigned int i = base + 1; i < new_reph_pos; i++)
1564 if (info[i].indic_category() == OT_M) {
1565 /* Ok, got it. */
1566 new_reph_pos--;
1567 }
1568 }
1569 goto reph_move;
1570 }
1571
1572 reph_move:
1573 {
1574 /* Move */
1575 buffer->merge_clusters (start, new_reph_pos + 1);
1576 hb_glyph_info_t reph = info[start];
1577 memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
1578 info[new_reph_pos] = reph;
1579
1580 if (start < base && base <= new_reph_pos)
1581 base--;
1582 }
1583 }
1584
1585
1586 /* o Reorder pre-base reordering consonants:
1587 *
1588 * If a pre-base reordering consonant is found, reorder it according to
1589 * the following rules:
1590 */
1591
1592 if (try_pref && base + 1 < end) /* Otherwise there can't be any pre-base reordering Ra. */
1593 {
1594 unsigned int pref_len = indic_plan->config->pref_len;
1595 for (unsigned int i = base + 1; i < end; i++)
1596 if ((info[i].mask & indic_plan->mask_array[PREF]) != 0)
1597 {
1598 /* 1. Only reorder a glyph produced by substitution during application
1599 * of the <pref> feature. (Note that a font may shape a Ra consonant with
1600 * the feature generally but block it in certain contexts.)
1601 */
1602 /* Note: We just check that something got substituted. We don't check that
1603 * the <pref> feature actually did it...
1604 *
1605 * If pref len is longer than one, then only reorder if it ligated. If
1606 * pref len is one, only reorder if it didn't ligate with other things. */
1607 if (_hb_glyph_info_substituted (&info[i]) &&
1608 ((pref_len == 1) ^ _hb_glyph_info_ligated_and_didnt_multiply (&info[i])))
1609 {
1610 /*
1611 * 2. Try to find a target position the same way as for pre-base matra.
1612 * If it is found, reorder pre-base consonant glyph.
1613 *
1614 * 3. If position is not found, reorder immediately before main
1615 * consonant.
1616 */
1617
1618 unsigned int new_pos = base;
1619 /* Malayalam / Tamil do not have "half" forms or explicit virama forms.
1620 * The glyphs formed by 'half' are Chillus or ligated explicit viramas.
1621 * We want to position matra after them.
1622 */
1623 if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
1624 {
1625 while (new_pos > start &&
1626 !(is_one_of (info[new_pos - 1], FLAG(OT_M) | HALANT_OR_COENG_FLAGS)))
1627 new_pos--;
1628
1629 /* In Khmer coeng model, a H,Ra can go *after* matras. If it goes after a
1630 * split matra, it should be reordered to *before* the left part of such matra. */
1631 if (new_pos > start && info[new_pos - 1].indic_category() == OT_M)
1632 {
1633 unsigned int old_pos = i;
1634 for (unsigned int i = base + 1; i < old_pos; i++)
1635 if (info[i].indic_category() == OT_M)
1636 {
1637 new_pos--;
1638 break;
1639 }
1640 }
1641 }
1642
1643 if (new_pos > start && is_halant_or_coeng (info[new_pos - 1]))
1644 {
1645 /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
1646 if (new_pos < end && is_joiner (info[new_pos]))
1647 new_pos++;
1648 }
1649
1650 {
1651 unsigned int old_pos = i;
1652
1653 buffer->merge_clusters (new_pos, old_pos + 1);
1654 hb_glyph_info_t tmp = info[old_pos];
1655 memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0]));
1656 info[new_pos] = tmp;
1657
1658 if (new_pos <= base && base < old_pos)
1659 base++;
1660 }
1661 }
1662
1663 break;
1664 }
1665 }
1666
1667
1668 /* Apply 'init' to the Left Matra if it's a word start. */
1669 if (info[start].indic_position () == POS_PRE_M &&
1670 (!start ||
1671 !(FLAG_SAFE (_hb_glyph_info_get_general_category (&info[start - 1])) &
1672 FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK))))
1673 info[start].mask |= indic_plan->mask_array[INIT];
1674
1675
1676 /*
1677 * Finish off the clusters and go home!
1678 */
1679 if (hb_options ().uniscribe_bug_compatible)
1680 {
1681 switch ((hb_tag_t) plan->props.script)
1682 {
1683 case HB_SCRIPT_TAMIL:
1684 case HB_SCRIPT_SINHALA:
1685 break;
1686
1687 default:
1688 /* Uniscribe merges the entire cluster... Except for Tamil & Sinhala.
1689 * This means, half forms are submerged into the main consonants cluster.
1690 * This is unnecessary, and makes cursor positioning harder, but that's what
1691 * Uniscribe does. */
1692 buffer->merge_clusters (start, end);
1693 break;
1694 }
1695 }
1696 }
1697
1698
1699 static void
1700 final_reordering (const hb_ot_shape_plan_t *plan,
1701 hb_font_t *font HB_UNUSED,
1702 hb_buffer_t *buffer)
1703 {
1704 unsigned int count = buffer->len;
1705 if (unlikely (!count)) return;
1706
1707 foreach_syllable (buffer, start, end)
1708 final_reordering_syllable (plan, buffer, start, end);
1709
1710 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
1711 HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
1712 }
1713
1714
1715 static void
1716 clear_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
1717 hb_font_t *font HB_UNUSED,
1718 hb_buffer_t *buffer)
1719 {
1720 hb_glyph_info_t *info = buffer->info;
1721 unsigned int count = buffer->len;
1722 for (unsigned int i = 0; i < count; i++)
1723 info[i].syllable() = 0;
1724 }
1725
1726
1727 static bool
1728 decompose_indic (const hb_ot_shape_normalize_context_t *c,
1729 hb_codepoint_t ab,
1730 hb_codepoint_t *a,
1731 hb_codepoint_t *b)
1732 {
1733 switch (ab)
1734 {
1735 /* Don't decompose these. */
1736 case 0x0931u : return false;
1737 case 0x0B94u : return false;
1738
1739
1740 /*
1741 * Decompose split matras that don't have Unicode decompositions.
1742 */
1743
1744 case 0x0F77u : *a = 0x0FB2u; *b= 0x0F81u; return true;
1745 case 0x0F79u : *a = 0x0FB3u; *b= 0x0F81u; return true;
1746 case 0x17BEu : *a = 0x17C1u; *b= 0x17BEu; return true;
1747 case 0x17BFu : *a = 0x17C1u; *b= 0x17BFu; return true;
1748 case 0x17C0u : *a = 0x17C1u; *b= 0x17C0u; return true;
1749 case 0x17C4u : *a = 0x17C1u; *b= 0x17C4u; return true;
1750 case 0x17C5u : *a = 0x17C1u; *b= 0x17C5u; return true;
1751 case 0x1925u : *a = 0x1920u; *b= 0x1923u; return true;
1752 case 0x1926u : *a = 0x1920u; *b= 0x1924u; return true;
1753 case 0x1B3Cu : *a = 0x1B42u; *b= 0x1B3Cu; return true;
1754 case 0x1112Eu : *a = 0x11127u; *b= 0x11131u; return true;
1755 case 0x1112Fu : *a = 0x11127u; *b= 0x11132u; return true;
1756 #if 0
1757 /* This one has no decomposition in Unicode, but needs no decomposition either. */
1758 /* case 0x0AC9u : return false; */
1759 case 0x0B57u : *a = no decomp, -> RIGHT; return true;
1760 case 0x1C29u : *a = no decomp, -> LEFT; return true;
1761 case 0xA9C0u : *a = no decomp, -> RIGHT; return true;
1762 case 0x111BuF : *a = no decomp, -> ABOVE; return true;
1763 #endif
1764 }
1765
1766 if ((ab == 0x0DDAu || hb_in_range (ab, 0x0DDCu, 0x0DDEu)))
1767 {
1768 /*
1769 * Sinhala split matras... Let the fun begin.
1770 *
1771 * These four characters have Unicode decompositions. However, Uniscribe
1772 * decomposes them "Khmer-style", that is, it uses the character itself to
1773 * get the second half. The first half of all four decompositions is always
1774 * U+0DD9.
1775 *
1776 * Now, there are buggy fonts, namely, the widely used lklug.ttf, that are
1777 * broken with Uniscribe. But we need to support them. As such, we only
1778 * do the Uniscribe-style decomposition if the character is transformed into
1779 * its "sec.half" form by the 'pstf' feature. Otherwise, we fall back to
1780 * Unicode decomposition.
1781 *
1782 * Note that we can't unconditionally use Unicode decomposition. That would
1783 * break some other fonts, that are designed to work with Uniscribe, and
1784 * don't have positioning features for the Unicode-style decomposition.
1785 *
1786 * Argh...
1787 *
1788 * The Uniscribe behavior is now documented in the newly published Sinhala
1789 * spec in 2012:
1790 *
1791 * http://www.microsoft.com/typography/OpenTypeDev/sinhala/intro.htm#shaping
1792 */
1793
1794 const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data;
1795
1796 hb_codepoint_t glyph;
1797
1798 if (hb_options ().uniscribe_bug_compatible ||
1799 (c->font->get_glyph (ab, 0, &glyph) &&
1800 indic_plan->pstf.would_substitute (&glyph, 1, c->font->face)))
1801 {
1802 /* Ok, safe to use Uniscribe-style decomposition. */
1803 *a = 0x0DD9u;
1804 *b = ab;
1805 return true;
1806 }
1807 }
1808
1809 return c->unicode->decompose (ab, a, b);
1810 }
1811
1812 static bool
1813 compose_indic (const hb_ot_shape_normalize_context_t *c,
1814 hb_codepoint_t a,
1815 hb_codepoint_t b,
1816 hb_codepoint_t *ab)
1817 {
1818 /* Avoid recomposing split matras. */
1819 if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
1820 return false;
1821
1822 /* Composition-exclusion exceptions that we want to recompose. */
1823 if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; }
1824
1825 return c->unicode->compose (a, b, ab);
1826 }
1827
1828
1829 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
1830 {
1831 "indic",
1832 collect_features_indic,
1833 override_features_indic,
1834 data_create_indic,
1835 data_destroy_indic,
1836 NULL, /* preprocess_text */
1837 HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
1838 decompose_indic,
1839 compose_indic,
1840 setup_masks_indic,
1841 HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
1842 false, /* fallback_position */
1843 };