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      1 /*
      2  * Copyright  2011,2012,2013  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 
     29 /* buffer var allocations */
     30 #define myanmar_category() complex_var_u8_0() /* myanmar_category_t */
     31 #define myanmar_position() complex_var_u8_1() /* myanmar_position_t */
     32 
     33 
     34 /*
     35  * Myanmar shaper.
     36  */
     37 
     38 static const hb_tag_t
     39 basic_features[] =
     40 {
     41   /*
     42    * Basic features.
     43    * These features are applied in order, one at a time, after initial_reordering.
     44    */
     45   HB_TAG('r','p','h','f'),
     46   HB_TAG('p','r','e','f'),
     47   HB_TAG('b','l','w','f'),
     48   HB_TAG('p','s','t','f'),
     49 };
     50 static const hb_tag_t
     51 other_features[] =
     52 {
     53   /*
     54    * Other features.
     55    * These features are applied all at once, after final_reordering.
     56    */
     57   HB_TAG('p','r','e','s'),
     58   HB_TAG('a','b','v','s'),
     59   HB_TAG('b','l','w','s'),
     60   HB_TAG('p','s','t','s'),
     61   /* Positioning features, though we don't care about the types. */
     62   HB_TAG('d','i','s','t'),
     63   /* Pre-release version of Windows 8 Myanmar font had abvm,blwm
     64    * features.  The released Windows 8 version of the font (as well
     65    * as the released spec) used 'mark' instead.  The Windows 8
     66    * shaper however didn't apply 'mark' but did apply 'mkmk'.
     67    * Perhaps it applied abvm/blwm.  This was fixed in a Windows 8
     68    * update, so now it applies mark/mkmk.  We are guessing that
     69    * it still applies abvm/blwm too.
     70    */
     71   HB_TAG('a','b','v','m'),
     72   HB_TAG('b','l','w','m'),
     73 };
     74 
     75 static void
     76 setup_syllables (const hb_ot_shape_plan_t *plan,
     77 		 hb_font_t *font,
     78 		 hb_buffer_t *buffer);
     79 static void
     80 initial_reordering (const hb_ot_shape_plan_t *plan,
     81 		    hb_font_t *font,
     82 		    hb_buffer_t *buffer);
     83 static void
     84 final_reordering (const hb_ot_shape_plan_t *plan,
     85 		  hb_font_t *font,
     86 		  hb_buffer_t *buffer);
     87 
     88 static void
     89 collect_features_myanmar (hb_ot_shape_planner_t *plan)
     90 {
     91   hb_ot_map_builder_t *map = &plan->map;
     92 
     93   /* Do this before any lookups have been applied. */
     94   map->add_gsub_pause (setup_syllables);
     95 
     96   map->add_global_bool_feature (HB_TAG('l','o','c','l'));
     97   /* The Indic specs do not require ccmp, but we apply it here since if
     98    * there is a use of it, it's typically at the beginning. */
     99   map->add_global_bool_feature (HB_TAG('c','c','m','p'));
    100 
    101 
    102   map->add_gsub_pause (initial_reordering);
    103   for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)
    104   {
    105     map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
    106     map->add_gsub_pause (NULL);
    107   }
    108   map->add_gsub_pause (final_reordering);
    109   for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
    110     map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
    111 }
    112 
    113 static void
    114 override_features_myanmar (hb_ot_shape_planner_t *plan)
    115 {
    116   plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL);
    117 }
    118 
    119 
    120 enum syllable_type_t {
    121   consonant_syllable,
    122   punctuation_cluster,
    123   broken_cluster,
    124   non_myanmar_cluster,
    125 };
    126 
    127 #include "hb-ot-shape-complex-myanmar-machine.hh"
    128 
    129 
    130 /* Note: This enum is duplicated in the -machine.rl source file.
    131  * Not sure how to avoid duplication. */
    132 enum myanmar_category_t {
    133   OT_As  = 18, /* Asat */
    134   OT_D   = 19, /* Digits except zero */
    135   OT_D0  = 20, /* Digit zero */
    136   OT_DB  = OT_N, /* Dot below */
    137   OT_GB  = OT_PLACEHOLDER,
    138   OT_MH  = 21, /* Various consonant medial types */
    139   OT_MR  = 22, /* Various consonant medial types */
    140   OT_MW  = 23, /* Various consonant medial types */
    141   OT_MY  = 24, /* Various consonant medial types */
    142   OT_PT  = 25, /* Pwo and other tones */
    143   OT_VAbv = 26,
    144   OT_VBlw = 27,
    145   OT_VPre = 28,
    146   OT_VPst = 29,
    147   OT_VS   = 30, /* Variation selectors */
    148   OT_P    = 31  /* Punctuation */
    149 };
    150 
    151 
    152 static inline bool
    153 is_one_of (const hb_glyph_info_t &info, unsigned int flags)
    154 {
    155   /* If it ligated, all bets are off. */
    156   if (_hb_glyph_info_ligated (&info)) return false;
    157   return !!(FLAG_SAFE (info.myanmar_category()) & flags);
    158 }
    159 
    160 static inline bool
    161 is_consonant (const hb_glyph_info_t &info)
    162 {
    163   return is_one_of (info, CONSONANT_FLAGS);
    164 }
    165 
    166 
    167 static inline void
    168 set_myanmar_properties (hb_glyph_info_t &info)
    169 {
    170   hb_codepoint_t u = info.codepoint;
    171   unsigned int type = hb_indic_get_categories (u);
    172   indic_category_t cat = (indic_category_t) (type & 0x7Fu);
    173   indic_position_t pos = (indic_position_t) (type >> 8);
    174 
    175   /* Myanmar
    176    * http://www.microsoft.com/typography/OpenTypeDev/myanmar/intro.htm#analyze
    177    */
    178   if (unlikely (hb_in_range (u, 0xFE00u, 0xFE0Fu)))
    179     cat = (indic_category_t) OT_VS;
    180 
    181   switch (u)
    182   {
    183     case 0x104Eu:
    184       cat = (indic_category_t) OT_C; /* The spec says C, IndicSyllableCategory doesn't have. */
    185       break;
    186 
    187     case 0x002Du: case 0x00A0u: case 0x00D7u: case 0x2012u:
    188     case 0x2013u: case 0x2014u: case 0x2015u: case 0x2022u:
    189     case 0x25CCu: case 0x25FBu: case 0x25FCu: case 0x25FDu:
    190     case 0x25FEu:
    191       cat = (indic_category_t) OT_GB;
    192       break;
    193 
    194     case 0x1004u: case 0x101Bu: case 0x105Au:
    195       cat = (indic_category_t) OT_Ra;
    196       break;
    197 
    198     case 0x1032u: case 0x1036u:
    199       cat = (indic_category_t) OT_A;
    200       break;
    201 
    202     case 0x1039u:
    203       cat = (indic_category_t) OT_H;
    204       break;
    205 
    206     case 0x103Au:
    207       cat = (indic_category_t) OT_As;
    208       break;
    209 
    210     case 0x1041u: case 0x1042u: case 0x1043u: case 0x1044u:
    211     case 0x1045u: case 0x1046u: case 0x1047u: case 0x1048u:
    212     case 0x1049u: case 0x1090u: case 0x1091u: case 0x1092u:
    213     case 0x1093u: case 0x1094u: case 0x1095u: case 0x1096u:
    214     case 0x1097u: case 0x1098u: case 0x1099u:
    215       cat = (indic_category_t) OT_D;
    216       break;
    217 
    218     case 0x1040u:
    219       cat = (indic_category_t) OT_D; /* XXX The spec says D0, but Uniscribe doesn't seem to do. */
    220       break;
    221 
    222     case 0x103Eu: case 0x1060u:
    223       cat = (indic_category_t) OT_MH;
    224       break;
    225 
    226     case 0x103Cu:
    227       cat = (indic_category_t) OT_MR;
    228       break;
    229 
    230     case 0x103Du: case 0x1082u:
    231       cat = (indic_category_t) OT_MW;
    232       break;
    233 
    234     case 0x103Bu: case 0x105Eu: case 0x105Fu:
    235       cat = (indic_category_t) OT_MY;
    236       break;
    237 
    238     case 0x1063u: case 0x1064u: case 0x1069u: case 0x106Au:
    239     case 0x106Bu: case 0x106Cu: case 0x106Du: case 0xAA7Bu:
    240       cat = (indic_category_t) OT_PT;
    241       break;
    242 
    243     case 0x1038u: case 0x1087u: case 0x1088u: case 0x1089u:
    244     case 0x108Au: case 0x108Bu: case 0x108Cu: case 0x108Du:
    245     case 0x108Fu: case 0x109Au: case 0x109Bu: case 0x109Cu:
    246       cat = (indic_category_t) OT_SM;
    247       break;
    248 
    249     case 0x104Au: case 0x104Bu:
    250       cat = (indic_category_t) OT_P;
    251       break;
    252 
    253     case 0xAA74u: case 0xAA75u: case 0xAA76u:
    254       /* https://github.com/roozbehp/unicode-data/issues/3 */
    255       cat = (indic_category_t) OT_C;
    256       break;
    257   }
    258 
    259   if (cat == OT_M)
    260   {
    261     switch ((int) pos)
    262     {
    263       case POS_PRE_C:	cat = (indic_category_t) OT_VPre;
    264 			pos = POS_PRE_M;                  break;
    265       case POS_ABOVE_C:	cat = (indic_category_t) OT_VAbv; break;
    266       case POS_BELOW_C:	cat = (indic_category_t) OT_VBlw; break;
    267       case POS_POST_C:	cat = (indic_category_t) OT_VPst; break;
    268     }
    269   }
    270 
    271   info.myanmar_category() = (myanmar_category_t) cat;
    272   info.myanmar_position() = pos;
    273 }
    274 
    275 
    276 
    277 static void
    278 setup_masks_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED,
    279 		   hb_buffer_t              *buffer,
    280 		   hb_font_t                *font HB_UNUSED)
    281 {
    282   HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_category);
    283   HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_position);
    284 
    285   /* We cannot setup masks here.  We save information about characters
    286    * and setup masks later on in a pause-callback. */
    287 
    288   unsigned int count = buffer->len;
    289   hb_glyph_info_t *info = buffer->info;
    290   for (unsigned int i = 0; i < count; i++)
    291     set_myanmar_properties (info[i]);
    292 }
    293 
    294 static void
    295 setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
    296 		 hb_font_t *font HB_UNUSED,
    297 		 hb_buffer_t *buffer)
    298 {
    299   find_syllables (buffer);
    300 }
    301 
    302 static int
    303 compare_myanmar_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
    304 {
    305   int a = pa->myanmar_position();
    306   int b = pb->myanmar_position();
    307 
    308   return a < b ? -1 : a == b ? 0 : +1;
    309 }
    310 
    311 
    312 /* Rules from:
    313  * http://www.microsoft.com/typography/OpenTypeDev/myanmar/intro.htm */
    314 
    315 static void
    316 initial_reordering_consonant_syllable (hb_buffer_t *buffer,
    317 				       unsigned int start, unsigned int end)
    318 {
    319   hb_glyph_info_t *info = buffer->info;
    320 
    321   unsigned int base = end;
    322   bool has_reph = false;
    323 
    324   {
    325     unsigned int limit = start;
    326     if (start + 3 <= end &&
    327 	info[start  ].myanmar_category() == OT_Ra &&
    328 	info[start+1].myanmar_category() == OT_As &&
    329 	info[start+2].myanmar_category() == OT_H)
    330     {
    331       limit += 3;
    332       base = start;
    333       has_reph = true;
    334     }
    335 
    336     {
    337       if (!has_reph)
    338 	base = limit;
    339 
    340       for (unsigned int i = limit; i < end; i++)
    341 	if (is_consonant (info[i]))
    342 	{
    343 	  base = i;
    344 	  break;
    345 	}
    346     }
    347   }
    348 
    349   /* Reorder! */
    350   {
    351     unsigned int i = start;
    352     for (; i < start + (has_reph ? 3 : 0); i++)
    353       info[i].myanmar_position() = POS_AFTER_MAIN;
    354     for (; i < base; i++)
    355       info[i].myanmar_position() = POS_PRE_C;
    356     if (i < end)
    357     {
    358       info[i].myanmar_position() = POS_BASE_C;
    359       i++;
    360     }
    361     indic_position_t pos = POS_AFTER_MAIN;
    362     /* The following loop may be ugly, but it implements all of
    363      * Myanmar reordering! */
    364     for (; i < end; i++)
    365     {
    366       if (info[i].myanmar_category() == OT_MR) /* Pre-base reordering */
    367       {
    368 	info[i].myanmar_position() = POS_PRE_C;
    369 	continue;
    370       }
    371       if (info[i].myanmar_position() < POS_BASE_C) /* Left matra */
    372       {
    373 	continue;
    374       }
    375 
    376       if (pos == POS_AFTER_MAIN && info[i].myanmar_category() == OT_VBlw)
    377       {
    378 	pos = POS_BELOW_C;
    379 	info[i].myanmar_position() = pos;
    380 	continue;
    381       }
    382 
    383       if (pos == POS_BELOW_C && info[i].myanmar_category() == OT_A)
    384       {
    385 	info[i].myanmar_position() = POS_BEFORE_SUB;
    386 	continue;
    387       }
    388       if (pos == POS_BELOW_C && info[i].myanmar_category() == OT_VBlw)
    389       {
    390 	info[i].myanmar_position() = pos;
    391 	continue;
    392       }
    393       if (pos == POS_BELOW_C && info[i].myanmar_category() != OT_A)
    394       {
    395         pos = POS_AFTER_SUB;
    396 	info[i].myanmar_position() = pos;
    397 	continue;
    398       }
    399       info[i].myanmar_position() = pos;
    400     }
    401   }
    402 
    403   /* Sit tight, rock 'n roll! */
    404   buffer->sort (start, end, compare_myanmar_order);
    405 }
    406 
    407 static void
    408 initial_reordering_syllable (const hb_ot_shape_plan_t *plan,
    409 			     hb_face_t *face,
    410 			     hb_buffer_t *buffer,
    411 			     unsigned int start, unsigned int end)
    412 {
    413   syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
    414   switch (syllable_type) {
    415 
    416     case broken_cluster: /* We already inserted dotted-circles, so just call the consonant_syllable. */
    417     case consonant_syllable:
    418       initial_reordering_consonant_syllable  (buffer, start, end);
    419       break;
    420 
    421     case punctuation_cluster:
    422     case non_myanmar_cluster:
    423       break;
    424   }
    425 }
    426 
    427 static inline void
    428 insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
    429 		       hb_font_t *font,
    430 		       hb_buffer_t *buffer)
    431 {
    432   /* Note: This loop is extra overhead, but should not be measurable. */
    433   bool has_broken_syllables = false;
    434   unsigned int count = buffer->len;
    435   hb_glyph_info_t *info = buffer->info;
    436   for (unsigned int i = 0; i < count; i++)
    437     if ((info[i].syllable() & 0x0F) == broken_cluster)
    438     {
    439       has_broken_syllables = true;
    440       break;
    441     }
    442   if (likely (!has_broken_syllables))
    443     return;
    444 
    445 
    446   hb_codepoint_t dottedcircle_glyph;
    447   if (!font->get_nominal_glyph (0x25CCu, &dottedcircle_glyph))
    448     return;
    449 
    450   hb_glyph_info_t dottedcircle = {0};
    451   dottedcircle.codepoint = 0x25CCu;
    452   set_myanmar_properties (dottedcircle);
    453   dottedcircle.codepoint = dottedcircle_glyph;
    454 
    455   buffer->clear_output ();
    456 
    457   buffer->idx = 0;
    458   unsigned int last_syllable = 0;
    459   while (buffer->idx < buffer->len && !buffer->in_error)
    460   {
    461     unsigned int syllable = buffer->cur().syllable();
    462     syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
    463     if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
    464     {
    465       last_syllable = syllable;
    466 
    467       hb_glyph_info_t ginfo = dottedcircle;
    468       ginfo.cluster = buffer->cur().cluster;
    469       ginfo.mask = buffer->cur().mask;
    470       ginfo.syllable() = buffer->cur().syllable();
    471 
    472       buffer->output_info (ginfo);
    473     }
    474     else
    475       buffer->next_glyph ();
    476   }
    477 
    478   buffer->swap_buffers ();
    479 }
    480 
    481 static void
    482 initial_reordering (const hb_ot_shape_plan_t *plan,
    483 		    hb_font_t *font,
    484 		    hb_buffer_t *buffer)
    485 {
    486   insert_dotted_circles (plan, font, buffer);
    487 
    488   foreach_syllable (buffer, start, end)
    489     initial_reordering_syllable (plan, font->face, buffer, start, end);
    490 }
    491 
    492 static void
    493 final_reordering (const hb_ot_shape_plan_t *plan,
    494 		  hb_font_t *font HB_UNUSED,
    495 		  hb_buffer_t *buffer)
    496 {
    497   hb_glyph_info_t *info = buffer->info;
    498   unsigned int count = buffer->len;
    499 
    500   /* Zero syllables now... */
    501   for (unsigned int i = 0; i < count; i++)
    502     info[i].syllable() = 0;
    503 
    504   HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_category);
    505   HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_position);
    506 }
    507 
    508 
    509 /* Uniscribe seems to have a shaper for 'mymr' that is like the
    510  * generic shaper, except that it zeros mark advances GDEF_LATE. */
    511 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar_old =
    512 {
    513   "default",
    514   NULL, /* collect_features */
    515   NULL, /* override_features */
    516   NULL, /* data_create */
    517   NULL, /* data_destroy */
    518   NULL, /* preprocess_text */
    519   NULL, /* postprocess_glyphs */
    520   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
    521   NULL, /* decompose */
    522   NULL, /* compose */
    523   NULL, /* setup_masks */
    524   NULL, /* disable_otl */
    525   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
    526   true, /* fallback_position */
    527 };
    528 
    529 const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar =
    530 {
    531   "myanmar",
    532   collect_features_myanmar,
    533   override_features_myanmar,
    534   NULL, /* data_create */
    535   NULL, /* data_destroy */
    536   NULL, /* preprocess_text */
    537   NULL, /* postprocess_glyphs */
    538   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
    539   NULL, /* decompose */
    540   NULL, /* compose */
    541   setup_masks_myanmar,
    542   NULL, /* disable_otl */
    543   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
    544   false, /* fallback_position */
    545 };
    546