2 * Copyright © 2010,2012 Google, Inc.
4 * This is part of HarfBuzz, a text shaping library.
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.
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
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.
24 * Google Author(s): Behdad Esfahbod
29 #ifndef HB_NO_OT_SHAPE
31 #include "hb-ot-shape-complex-arabic.hh"
32 #include "hb-ot-shape.hh"
35 /* buffer var allocations */
36 #define arabic_shaping_action() complex_var_u8_0() /* arabic shaping action */
38 #define HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH HB_BUFFER_SCRATCH_FLAG_COMPLEX0
41 * https://github.com/harfbuzz/harfbuzz/commit/6e6f82b6f3dde0fc6c3c7d991d9ec6cfff57823d#commitcomment-14248516 */
42 #define HB_ARABIC_GENERAL_CATEGORY_IS_WORD(gen_cat) \
43 (FLAG_UNSAFE (gen_cat) & \
44 (FLAG (HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED) | \
45 FLAG (HB_UNICODE_GENERAL_CATEGORY_PRIVATE_USE) | \
46 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) |*/ \
47 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) | \
48 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) | \
49 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) |*/ \
50 /*FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) |*/ \
51 FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) | \
52 FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | \
53 FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | \
54 FLAG (HB_UNICODE_GENERAL_CATEGORY_DECIMAL_NUMBER) | \
55 FLAG (HB_UNICODE_GENERAL_CATEGORY_LETTER_NUMBER) | \
56 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_NUMBER) | \
57 FLAG (HB_UNICODE_GENERAL_CATEGORY_CURRENCY_SYMBOL) | \
58 FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_SYMBOL) | \
59 FLAG (HB_UNICODE_GENERAL_CATEGORY_MATH_SYMBOL) | \
60 FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_SYMBOL)))
68 * Bits used in the joining tables
70 enum hb_arabic_joining_type_t {
75 JOINING_TYPE_C = JOINING_TYPE_D,
76 JOINING_GROUP_ALAPH = 4,
77 JOINING_GROUP_DALATH_RISH = 5,
78 NUM_STATE_MACHINE_COLS = 6,
81 JOINING_TYPE_X = 8 /* means: use general-category to choose between U or T. */
84 #include "hb-ot-shape-complex-arabic-table.hh"
86 static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat)
88 unsigned int j_type = joining_type(u);
89 if (likely (j_type != JOINING_TYPE_X))
92 return (FLAG_UNSAFE(gen_cat) &
93 (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) |
94 FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
95 FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT))
96 ) ? JOINING_TYPE_T : JOINING_TYPE_U;
99 #define FEATURE_IS_SYRIAC(tag) hb_in_range<unsigned char> ((unsigned char) (tag), '2', '3')
101 static const hb_tag_t arabic_features[] =
103 HB_TAG('i','s','o','l'),
104 HB_TAG('f','i','n','a'),
105 HB_TAG('f','i','n','2'),
106 HB_TAG('f','i','n','3'),
107 HB_TAG('m','e','d','i'),
108 HB_TAG('m','e','d','2'),
109 HB_TAG('i','n','i','t'),
114 /* Same order as the feature array */
115 enum arabic_action_t {
126 ARABIC_NUM_FEATURES = NONE,
128 /* We abuse the same byte for other things... */
133 static const struct arabic_state_table_entry {
137 } arabic_state_table[][NUM_STATE_MACHINE_COLS] =
139 /* jt_U, jt_L, jt_R, jt_D, jg_ALAPH, jg_DALATH_RISH */
141 /* State 0: prev was U, not willing to join. */
142 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,6}, },
144 /* State 1: prev was R or ISOL/ALAPH, not willing to join. */
145 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN2,5}, {NONE,ISOL,6}, },
147 /* State 2: prev was D/L in ISOL form, willing to join. */
148 { {NONE,NONE,0}, {NONE,ISOL,2}, {INIT,FINA,1}, {INIT,FINA,3}, {INIT,FINA,4}, {INIT,FINA,6}, },
150 /* State 3: prev was D in FINA form, willing to join. */
151 { {NONE,NONE,0}, {NONE,ISOL,2}, {MEDI,FINA,1}, {MEDI,FINA,3}, {MEDI,FINA,4}, {MEDI,FINA,6}, },
153 /* State 4: prev was FINA ALAPH, not willing to join. */
154 { {NONE,NONE,0}, {NONE,ISOL,2}, {MED2,ISOL,1}, {MED2,ISOL,2}, {MED2,FIN2,5}, {MED2,ISOL,6}, },
156 /* State 5: prev was FIN2/FIN3 ALAPH, not willing to join. */
157 { {NONE,NONE,0}, {NONE,ISOL,2}, {ISOL,ISOL,1}, {ISOL,ISOL,2}, {ISOL,FIN2,5}, {ISOL,ISOL,6}, },
159 /* State 6: prev was DALATH/RISH, not willing to join. */
160 { {NONE,NONE,0}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN3,5}, {NONE,ISOL,6}, }
165 arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
167 hb_buffer_t *buffer);
170 record_stch (const hb_ot_shape_plan_t *plan,
172 hb_buffer_t *buffer);
175 collect_features_arabic (hb_ot_shape_planner_t *plan)
177 hb_ot_map_builder_t *map = &plan->map;
179 /* We apply features according to the Arabic spec, with pauses
182 * The pause between init/medi/... and rlig is required. See eg:
183 * https://bugzilla.mozilla.org/show_bug.cgi?id=644184
185 * The pauses between init/medi/... themselves are not necessarily
186 * needed as only one of those features is applied to any character.
187 * The only difference it makes is when fonts have contextual
188 * substitutions. We now follow the order of the spec, which makes
189 * for better experience if that's what Uniscribe is doing.
191 * At least for Arabic, looks like Uniscribe has a pause between
192 * rlig and calt. Otherwise the IranNastaliq's ALLAH ligature won't
193 * work. However, testing shows that rlig and calt are applied
194 * together for Mongolian in Uniscribe. As such, we only add a
195 * pause for Arabic, not other scripts.
197 * A pause after calt is required to make KFGQPC Uthmanic Script HAFS
198 * work correctly. See https://github.com/harfbuzz/harfbuzz/issues/505
202 map->enable_feature (HB_TAG('s','t','c','h'));
203 map->add_gsub_pause (record_stch);
205 map->enable_feature (HB_TAG('c','c','m','p'));
206 map->enable_feature (HB_TAG('l','o','c','l'));
208 map->add_gsub_pause (nullptr);
210 for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++)
212 bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]);
213 map->add_feature (arabic_features[i], has_fallback ? F_HAS_FALLBACK : F_NONE);
214 map->add_gsub_pause (nullptr);
217 /* Normally, Unicode says a ZWNJ means "don't ligate". In Arabic script
218 * however, it says a ZWJ should also mean "don't ligate". So we run
219 * the main ligating features as MANUAL_ZWJ. */
221 map->enable_feature (HB_TAG('r','l','i','g'), F_MANUAL_ZWJ | F_HAS_FALLBACK);
223 if (plan->props.script == HB_SCRIPT_ARABIC)
224 map->add_gsub_pause (arabic_fallback_shape);
226 /* No pause after rclt. See 98460779bae19e4d64d29461ff154b3527bf8420. */
227 map->enable_feature (HB_TAG('r','c','l','t'), F_MANUAL_ZWJ);
228 map->enable_feature (HB_TAG('c','a','l','t'), F_MANUAL_ZWJ);
229 map->add_gsub_pause (nullptr);
233 /* The spec includes 'cswh'. Earlier versions of Windows
234 * used to enable this by default, but testing suggests
235 * that Windows 8 and later do not enable it by default,
236 * and spec now says 'Off by default'.
237 * We disabled this in ae23c24c32.
238 * Note that IranNastaliq uses this feature extensively
239 * to fixup broken glyph sequences. Oh well...
240 * Test case: U+0643,U+0640,U+0631. */
241 //map->enable_feature (HB_TAG('c','s','w','h'));
242 map->enable_feature (HB_TAG('m','s','e','t'));
245 #include "hb-ot-shape-complex-arabic-fallback.hh"
247 struct arabic_shape_plan_t
249 /* The "+ 1" in the next array is to accommodate for the "NONE" command,
250 * which is not an OpenType feature, but this simplifies the code by not
251 * having to do a "if (... < NONE) ..." and just rely on the fact that
252 * mask_array[NONE] == 0. */
253 hb_mask_t mask_array[ARABIC_NUM_FEATURES + 1];
255 hb_atomic_ptr_t<arabic_fallback_plan_t> fallback_plan;
257 unsigned int do_fallback : 1;
258 unsigned int has_stch : 1;
262 data_create_arabic (const hb_ot_shape_plan_t *plan)
264 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t));
265 if (unlikely (!arabic_plan))
268 arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC;
269 arabic_plan->has_stch = !!plan->map.get_1_mask (HB_TAG ('s','t','c','h'));
270 for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) {
271 arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]);
272 arabic_plan->do_fallback = arabic_plan->do_fallback &&
273 (FEATURE_IS_SYRIAC (arabic_features[i]) ||
274 plan->map.needs_fallback (arabic_features[i]));
281 data_destroy_arabic (void *data)
283 arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) data;
285 arabic_fallback_plan_destroy (arabic_plan->fallback_plan);
291 arabic_joining (hb_buffer_t *buffer)
293 unsigned int count = buffer->len;
294 hb_glyph_info_t *info = buffer->info;
295 unsigned int prev = UINT_MAX, state = 0;
297 /* Check pre-context */
298 for (unsigned int i = 0; i < buffer->context_len[0]; i++)
300 unsigned int this_type = get_joining_type (buffer->context[0][i], buffer->unicode->general_category (buffer->context[0][i]));
302 if (unlikely (this_type == JOINING_TYPE_T))
305 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
306 state = entry->next_state;
310 for (unsigned int i = 0; i < count; i++)
312 unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i]));
314 if (unlikely (this_type == JOINING_TYPE_T)) {
315 info[i].arabic_shaping_action() = NONE;
319 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
321 if (entry->prev_action != NONE && prev != UINT_MAX)
323 info[prev].arabic_shaping_action() = entry->prev_action;
324 buffer->unsafe_to_break (prev, i + 1);
327 info[i].arabic_shaping_action() = entry->curr_action;
330 state = entry->next_state;
333 for (unsigned int i = 0; i < buffer->context_len[1]; i++)
335 unsigned int this_type = get_joining_type (buffer->context[1][i], buffer->unicode->general_category (buffer->context[1][i]));
337 if (unlikely (this_type == JOINING_TYPE_T))
340 const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
341 if (entry->prev_action != NONE && prev != UINT_MAX)
342 info[prev].arabic_shaping_action() = entry->prev_action;
348 mongolian_variation_selectors (hb_buffer_t *buffer)
350 /* Copy arabic_shaping_action() from base to Mongolian variation selectors. */
351 unsigned int count = buffer->len;
352 hb_glyph_info_t *info = buffer->info;
353 for (unsigned int i = 1; i < count; i++)
354 if (unlikely (hb_in_range<hb_codepoint_t> (info[i].codepoint, 0x180Bu, 0x180Du)))
355 info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action();
359 setup_masks_arabic_plan (const arabic_shape_plan_t *arabic_plan,
363 HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
365 arabic_joining (buffer);
366 if (script == HB_SCRIPT_MONGOLIAN)
367 mongolian_variation_selectors (buffer);
369 unsigned int count = buffer->len;
370 hb_glyph_info_t *info = buffer->info;
371 for (unsigned int i = 0; i < count; i++)
372 info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()];
376 setup_masks_arabic (const hb_ot_shape_plan_t *plan,
378 hb_font_t *font HB_UNUSED)
380 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
381 setup_masks_arabic_plan (arabic_plan, buffer, plan->props.script);
385 arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
389 #ifdef HB_NO_OT_SHAPE_COMPLEX_ARABIC_FALLBACK
393 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
395 if (!arabic_plan->do_fallback)
399 arabic_fallback_plan_t *fallback_plan = arabic_plan->fallback_plan;
400 if (unlikely (!fallback_plan))
402 /* This sucks. We need a font to build the fallback plan... */
403 fallback_plan = arabic_fallback_plan_create (plan, font);
404 if (unlikely (!arabic_plan->fallback_plan.cmpexch (nullptr, fallback_plan)))
406 arabic_fallback_plan_destroy (fallback_plan);
411 arabic_fallback_plan_shape (fallback_plan, font, buffer);
415 * Stretch feature: "stch".
417 * https://docs.microsoft.com/en-us/typography/script-development/syriac
418 * We implement this in a generic way, such that the Arabic subtending
419 * marks can use it as well.
423 record_stch (const hb_ot_shape_plan_t *plan,
424 hb_font_t *font HB_UNUSED,
427 const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
428 if (!arabic_plan->has_stch)
431 /* 'stch' feature was just applied. Look for anything that multiplied,
432 * and record it for stch treatment later. Note that rtlm, frac, etc
433 * are applied before stch, but we assume that they didn't result in
434 * anything multiplying into 5 pieces, so it's safe-ish... */
436 unsigned int count = buffer->len;
437 hb_glyph_info_t *info = buffer->info;
438 for (unsigned int i = 0; i < count; i++)
439 if (unlikely (_hb_glyph_info_multiplied (&info[i])))
441 unsigned int comp = _hb_glyph_info_get_lig_comp (&info[i]);
442 info[i].arabic_shaping_action() = comp % 2 ? STCH_REPEATING : STCH_FIXED;
443 buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH;
448 apply_stch (const hb_ot_shape_plan_t *plan HB_UNUSED,
452 if (likely (!(buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_ARABIC_HAS_STCH)))
455 /* The Arabic shaper currently always processes in RTL mode, so we should
456 * stretch / position the stretched pieces to the left / preceding glyphs. */
458 /* We do a two pass implementation:
459 * First pass calculates the exact number of extra glyphs we need,
460 * We then enlarge buffer to have that much room,
461 * Second pass applies the stretch, copying things to the end of buffer.
464 int sign = font->x_scale < 0 ? -1 : +1;
465 unsigned int extra_glyphs_needed = 0; // Set during MEASURE, used during CUT
466 enum { MEASURE, CUT } /* step_t */;
468 for (unsigned int step = MEASURE; step <= CUT; step = step + 1)
470 unsigned int count = buffer->len;
471 hb_glyph_info_t *info = buffer->info;
472 hb_glyph_position_t *pos = buffer->pos;
473 unsigned int new_len = count + extra_glyphs_needed; // write head during CUT
474 unsigned int j = new_len;
475 for (unsigned int i = count; i; i--)
477 if (!hb_in_range<uint8_t> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING))
482 info[j] = info[i - 1];
488 /* Yay, justification! */
490 hb_position_t w_total = 0; // Total to be filled
491 hb_position_t w_fixed = 0; // Sum of fixed tiles
492 hb_position_t w_repeating = 0; // Sum of repeating tiles
496 unsigned int end = i;
498 hb_in_range<uint8_t> (info[i - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING))
501 hb_position_t width = font->get_glyph_h_advance (info[i].codepoint);
502 if (info[i].arabic_shaping_action() == STCH_FIXED)
509 w_repeating += width;
513 unsigned int start = i;
514 unsigned int context = i;
516 !hb_in_range<uint8_t> (info[context - 1].arabic_shaping_action(), STCH_FIXED, STCH_REPEATING) &&
517 (_hb_glyph_info_is_default_ignorable (&info[context - 1]) ||
518 HB_ARABIC_GENERAL_CATEGORY_IS_WORD (_hb_glyph_info_get_general_category (&info[context - 1]))))
521 w_total += pos[context].x_advance;
523 i++; // Don't touch i again.
525 DEBUG_MSG (ARABIC, nullptr, "%s stretch at (%d,%d,%d)",
526 step == MEASURE ? "measuring" : "cutting", context, start, end);
527 DEBUG_MSG (ARABIC, nullptr, "rest of word: count=%d width %d", start - context, w_total);
528 DEBUG_MSG (ARABIC, nullptr, "fixed tiles: count=%d width=%d", n_fixed, w_fixed);
529 DEBUG_MSG (ARABIC, nullptr, "repeating tiles: count=%d width=%d", n_repeating, w_repeating);
531 /* Number of additional times to repeat each repeating tile. */
534 hb_position_t w_remaining = w_total - w_fixed;
535 if (sign * w_remaining > sign * w_repeating && sign * w_repeating > 0)
536 n_copies = (sign * w_remaining) / (sign * w_repeating) - 1;
538 /* See if we can improve the fit by adding an extra repeat and squeezing them together a bit. */
539 hb_position_t extra_repeat_overlap = 0;
540 hb_position_t shortfall = sign * w_remaining - sign * w_repeating * (n_copies + 1);
541 if (shortfall > 0 && n_repeating > 0)
544 hb_position_t excess = (n_copies + 1) * sign * w_repeating - sign * w_remaining;
546 extra_repeat_overlap = excess / (n_copies * n_repeating);
551 extra_glyphs_needed += n_copies * n_repeating;
552 DEBUG_MSG (ARABIC, nullptr, "will add extra %d copies of repeating tiles", n_copies);
556 buffer->unsafe_to_break (context, end);
557 hb_position_t x_offset = 0;
558 for (unsigned int k = end; k > start; k--)
560 hb_position_t width = font->get_glyph_h_advance (info[k - 1].codepoint);
562 unsigned int repeat = 1;
563 if (info[k - 1].arabic_shaping_action() == STCH_REPEATING)
566 DEBUG_MSG (ARABIC, nullptr, "appending %d copies of glyph %d; j=%d",
567 repeat, info[k - 1].codepoint, j);
568 for (unsigned int n = 0; n < repeat; n++)
572 x_offset += extra_repeat_overlap;
573 pos[k - 1].x_offset = x_offset;
576 info[j] = info[k - 1];
585 if (unlikely (!buffer->ensure (count + extra_glyphs_needed)))
591 buffer->len = new_len;
598 postprocess_glyphs_arabic (const hb_ot_shape_plan_t *plan,
602 apply_stch (plan, buffer, font);
604 HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
607 /* https://www.unicode.org/reports/tr53/ */
609 static hb_codepoint_t
610 modifier_combining_marks[] =
612 0x0654u, /* ARABIC HAMZA ABOVE */
613 0x0655u, /* ARABIC HAMZA BELOW */
614 0x0658u, /* ARABIC MARK NOON GHUNNA */
615 0x06DCu, /* ARABIC SMALL HIGH SEEN */
616 0x06E3u, /* ARABIC SMALL LOW SEEN */
617 0x06E7u, /* ARABIC SMALL HIGH YEH */
618 0x06E8u, /* ARABIC SMALL HIGH NOON */
619 0x08D3u, /* ARABIC SMALL LOW WAW */
620 0x08F3u, /* ARABIC SMALL HIGH WAW */
624 info_is_mcm (const hb_glyph_info_t &info)
626 hb_codepoint_t u = info.codepoint;
627 for (unsigned int i = 0; i < ARRAY_LENGTH (modifier_combining_marks); i++)
628 if (u == modifier_combining_marks[i])
634 reorder_marks_arabic (const hb_ot_shape_plan_t *plan HB_UNUSED,
639 hb_glyph_info_t *info = buffer->info;
641 DEBUG_MSG (ARABIC, buffer, "Reordering marks from %d to %d", start, end);
643 unsigned int i = start;
644 for (unsigned int cc = 220; cc <= 230; cc += 10)
646 DEBUG_MSG (ARABIC, buffer, "Looking for %d's starting at %d", cc, i);
647 while (i < end && info_cc(info[i]) < cc)
649 DEBUG_MSG (ARABIC, buffer, "Looking for %d's stopped at %d", cc, i);
654 if (info_cc(info[i]) > cc)
658 while (j < end && info_cc(info[j]) == cc && info_is_mcm (info[j]))
664 DEBUG_MSG (ARABIC, buffer, "Found %d's from %d to %d", cc, i, j);
667 DEBUG_MSG (ARABIC, buffer, "Shifting %d's: %d %d", cc, i, j);
668 hb_glyph_info_t temp[HB_OT_SHAPE_COMPLEX_MAX_COMBINING_MARKS];
669 assert (j - i <= ARRAY_LENGTH (temp));
670 buffer->merge_clusters (start, j);
671 memmove (temp, &info[i], (j - i) * sizeof (hb_glyph_info_t));
672 memmove (&info[start + j - i], &info[start], (i - start) * sizeof (hb_glyph_info_t));
673 memmove (&info[start], temp, (j - i) * sizeof (hb_glyph_info_t));
675 /* Renumber CC such that the reordered sequence is still sorted.
676 * 22 and 26 are chosen because they are smaller than all Arabic categories,
677 * and are folded back to 220/230 respectively during fallback mark positioning.
679 * We do this because the CGJ-handling logic in the normalizer relies on
680 * mark sequences having an increasing order even after this reordering.
681 * https://github.com/harfbuzz/harfbuzz/issues/554
682 * This, however, does break some obscure sequences, where the normalizer
683 * might compose a sequence that it should not. For example, in the seequence
684 * ALEF, HAMZAH, MADDAH, we should NOT try to compose ALEF+MADDAH, but with this
685 * renumbering, we will.
687 unsigned int new_start = start + j - i;
688 unsigned int new_cc = cc == 220 ? HB_MODIFIED_COMBINING_CLASS_CCC22 : HB_MODIFIED_COMBINING_CLASS_CCC26;
689 while (start < new_start)
691 _hb_glyph_info_set_modified_combining_class (&info[start], new_cc);
699 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic =
701 collect_features_arabic,
702 nullptr, /* override_features */
705 nullptr, /* preprocess_text */
706 postprocess_glyphs_arabic,
707 HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
708 nullptr, /* decompose */
709 nullptr, /* compose */
711 HB_TAG_NONE, /* gpos_tag */
712 reorder_marks_arabic,
713 HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
714 true, /* fallback_position */