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1 /*
2  * Copyright © 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 #ifndef HB_OT_SHAPE_COMPLEX_INDIC_HH
28 #define HB_OT_SHAPE_COMPLEX_INDIC_HH
29 
30 #include "hb.hh"
31 
32 #include "hb-ot-shape-complex.hh"
33 
34 
35 /* buffer var allocations */
36 #define indic_category() complex_var_u8_0() /* indic_category_t */
37 #define indic_position() complex_var_u8_1() /* indic_position_t */
38 
39 
40 #define INDIC_TABLE_ELEMENT_TYPE uint16_t
41 
42 /* Cateories used in the OpenType spec:
43  * https://docs.microsoft.com/en-us/typography/script-development/devanagari
44  */
45 /* Note: This enum is duplicated in the -machine.rl source file.
46  * Not sure how to avoid duplication. */
47 enum indic_category_t {
48   OT_X = 0,
49   OT_C = 1,
50   OT_V = 2,
51   OT_N = 3,
52   OT_H = 4,
53   OT_ZWNJ = 5,
54   OT_ZWJ = 6,
55   OT_M = 7,
56   OT_SM = 8,
57   /* OT_VD = 9, UNUSED; we use OT_A instead. */
58   OT_A = 10,
59   OT_PLACEHOLDER = 11,
60   OT_DOTTEDCIRCLE = 12,
61   OT_RS = 13, /* Register Shifter, used in Khmer OT spec. */
62   OT_Coeng = 14, /* Khmer-style Virama. */
63   OT_Repha = 15, /* Atomically-encoded logical or visual repha. */
64   OT_Ra = 16,
65   OT_CM = 17,  /* Consonant-Medial; Unused by Indic shaper. */
66   OT_Symbol = 18, /* Avagraha, etc that take marks (SM,A,VD). */
67   OT_CS = 19
68 };
69 
70 /* Note:
71  *
72  * We treat Vowels and placeholders as if they were consonants.  This is safe because Vowels
73  * cannot happen in a consonant syllable.  The plus side however is, we can call the
74  * consonant syllable logic from the vowel syllable function and get it all right! */
75 #define CONSONANT_FLAGS (FLAG (OT_C) | FLAG (OT_CS) | FLAG (OT_Ra) | FLAG (OT_V) | FLAG (OT_PLACEHOLDER) | FLAG (OT_DOTTEDCIRCLE))
76 #define JOINER_FLAGS (FLAG (OT_ZWJ) | FLAG (OT_ZWNJ))
77 
78 
79 /* Visual positions in a syllable from left to right. */
80 enum indic_position_t {
81   POS_START = 0,
82 
83   POS_RA_TO_BECOME_REPH = 1,
84   POS_PRE_M = 2,
85   POS_PRE_C = 3,
86 
87   POS_BASE_C = 4,
88   POS_AFTER_MAIN = 5,
89 
90   POS_ABOVE_C = 6,
91 
92   POS_BEFORE_SUB = 7,
93   POS_BELOW_C = 8,
94   POS_AFTER_SUB = 9,
95 
96   POS_BEFORE_POST = 10,
97   POS_POST_C = 11,
98   POS_AFTER_POST = 12,
99 
100   POS_FINAL_C = 13,
101   POS_SMVD = 14,
102 
103   POS_END = 15
104 };
105 
106 /* Categories used in IndicSyllabicCategory.txt from UCD. */
107 enum indic_syllabic_category_t {
108   INDIC_SYLLABIC_CATEGORY_OTHER				= OT_X,
109 
110   INDIC_SYLLABIC_CATEGORY_AVAGRAHA			= OT_Symbol,
111   INDIC_SYLLABIC_CATEGORY_BINDU				= OT_SM,
112   INDIC_SYLLABIC_CATEGORY_BRAHMI_JOINING_NUMBER		= OT_PLACEHOLDER, /* Don't care. */
113   INDIC_SYLLABIC_CATEGORY_CANTILLATION_MARK		= OT_A,
114   INDIC_SYLLABIC_CATEGORY_CONSONANT			= OT_C,
115   INDIC_SYLLABIC_CATEGORY_CONSONANT_DEAD		= OT_C,
116   INDIC_SYLLABIC_CATEGORY_CONSONANT_FINAL		= OT_CM,
117   INDIC_SYLLABIC_CATEGORY_CONSONANT_HEAD_LETTER		= OT_C,
118   INDIC_SYLLABIC_CATEGORY_CONSONANT_KILLER		= OT_M, /* U+17CD only. */
119   INDIC_SYLLABIC_CATEGORY_CONSONANT_MEDIAL		= OT_CM,
120   INDIC_SYLLABIC_CATEGORY_CONSONANT_PLACEHOLDER		= OT_PLACEHOLDER,
121   INDIC_SYLLABIC_CATEGORY_CONSONANT_PRECEDING_REPHA	= OT_Repha,
122   INDIC_SYLLABIC_CATEGORY_CONSONANT_PREFIXED		= OT_X, /* Don't care. */
123   INDIC_SYLLABIC_CATEGORY_CONSONANT_SUBJOINED		= OT_CM,
124   INDIC_SYLLABIC_CATEGORY_CONSONANT_SUCCEEDING_REPHA	= OT_CM,
125   INDIC_SYLLABIC_CATEGORY_CONSONANT_WITH_STACKER	= OT_CS,
126   INDIC_SYLLABIC_CATEGORY_GEMINATION_MARK		= OT_SM, /* https://github.com/harfbuzz/harfbuzz/issues/552 */
127   INDIC_SYLLABIC_CATEGORY_INVISIBLE_STACKER		= OT_Coeng,
128   INDIC_SYLLABIC_CATEGORY_JOINER			= OT_ZWJ,
129   INDIC_SYLLABIC_CATEGORY_MODIFYING_LETTER		= OT_X,
130   INDIC_SYLLABIC_CATEGORY_NON_JOINER			= OT_ZWNJ,
131   INDIC_SYLLABIC_CATEGORY_NUKTA				= OT_N,
132   INDIC_SYLLABIC_CATEGORY_NUMBER			= OT_PLACEHOLDER,
133   INDIC_SYLLABIC_CATEGORY_NUMBER_JOINER			= OT_PLACEHOLDER, /* Don't care. */
134   INDIC_SYLLABIC_CATEGORY_PURE_KILLER			= OT_M, /* Is like a vowel matra. */
135   INDIC_SYLLABIC_CATEGORY_REGISTER_SHIFTER		= OT_RS,
136   INDIC_SYLLABIC_CATEGORY_SYLLABLE_MODIFIER		= OT_SM,
137   INDIC_SYLLABIC_CATEGORY_TONE_LETTER			= OT_X,
138   INDIC_SYLLABIC_CATEGORY_TONE_MARK			= OT_N,
139   INDIC_SYLLABIC_CATEGORY_VIRAMA			= OT_H,
140   INDIC_SYLLABIC_CATEGORY_VISARGA			= OT_SM,
141   INDIC_SYLLABIC_CATEGORY_VOWEL				= OT_V,
142   INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT		= OT_M,
143   INDIC_SYLLABIC_CATEGORY_VOWEL_INDEPENDENT		= OT_V
144 };
145 
146 /* Categories used in IndicSMatraCategory.txt from UCD */
147 enum indic_matra_category_t {
148   INDIC_MATRA_CATEGORY_NOT_APPLICABLE			= POS_END,
149 
150   INDIC_MATRA_CATEGORY_LEFT				= POS_PRE_C,
151   INDIC_MATRA_CATEGORY_TOP				= POS_ABOVE_C,
152   INDIC_MATRA_CATEGORY_BOTTOM				= POS_BELOW_C,
153   INDIC_MATRA_CATEGORY_RIGHT				= POS_POST_C,
154 
155   /* These should resolve to the position of the last part of the split sequence. */
156   INDIC_MATRA_CATEGORY_BOTTOM_AND_RIGHT			= INDIC_MATRA_CATEGORY_RIGHT,
157   INDIC_MATRA_CATEGORY_LEFT_AND_RIGHT			= INDIC_MATRA_CATEGORY_RIGHT,
158   INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM			= INDIC_MATRA_CATEGORY_BOTTOM,
159   INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM_AND_RIGHT		= INDIC_MATRA_CATEGORY_RIGHT,
160   INDIC_MATRA_CATEGORY_TOP_AND_LEFT			= INDIC_MATRA_CATEGORY_TOP,
161   INDIC_MATRA_CATEGORY_TOP_AND_LEFT_AND_RIGHT		= INDIC_MATRA_CATEGORY_RIGHT,
162   INDIC_MATRA_CATEGORY_TOP_AND_RIGHT			= INDIC_MATRA_CATEGORY_RIGHT,
163 
164   INDIC_MATRA_CATEGORY_OVERSTRUCK			= POS_AFTER_MAIN,
165   INDIC_MATRA_CATEGORY_VISUAL_ORDER_LEFT		= POS_PRE_M
166 };
167 
168 #define INDIC_COMBINE_CATEGORIES(S,M) \
169   ( \
170     ASSERT_STATIC_EXPR_ZERO (S < 255 && M < 255) + \
171     ( S | \
172      ( \
173       ( \
174        S == INDIC_SYLLABIC_CATEGORY_CONSONANT_MEDIAL || \
175        S == INDIC_SYLLABIC_CATEGORY_GEMINATION_MARK || \
176        S == INDIC_SYLLABIC_CATEGORY_REGISTER_SHIFTER || \
177        S == INDIC_SYLLABIC_CATEGORY_CONSONANT_SUCCEEDING_REPHA || \
178        S == INDIC_SYLLABIC_CATEGORY_VIRAMA || \
179        S == INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT || \
180        false \
181        ? M : INDIC_MATRA_CATEGORY_NOT_APPLICABLE \
182       ) << 8 \
183      ) \
184     ) \
185    )
186 
187 HB_INTERNAL INDIC_TABLE_ELEMENT_TYPE
188 hb_indic_get_categories (hb_codepoint_t u);
189 
190 
191 static inline bool
is_one_of(const hb_glyph_info_t & info,unsigned int flags)192 is_one_of (const hb_glyph_info_t &info, unsigned int flags)
193 {
194   /* If it ligated, all bets are off. */
195   if (_hb_glyph_info_ligated (&info)) return false;
196   return !!(FLAG_UNSAFE (info.indic_category()) & flags);
197 }
198 
199 static inline bool
is_joiner(const hb_glyph_info_t & info)200 is_joiner (const hb_glyph_info_t &info)
201 {
202   return is_one_of (info, JOINER_FLAGS);
203 }
204 
205 static inline bool
is_consonant(const hb_glyph_info_t & info)206 is_consonant (const hb_glyph_info_t &info)
207 {
208   return is_one_of (info, CONSONANT_FLAGS);
209 }
210 
211 static inline bool
is_halant(const hb_glyph_info_t & info)212 is_halant (const hb_glyph_info_t &info)
213 {
214   return is_one_of (info, FLAG (OT_H));
215 }
216 
217 #define IN_HALF_BLOCK(u, Base) (((u) & ~0x7Fu) == (Base))
218 
219 #define IS_DEVA(u) (IN_HALF_BLOCK (u, 0x0900u))
220 #define IS_BENG(u) (IN_HALF_BLOCK (u, 0x0980u))
221 #define IS_GURU(u) (IN_HALF_BLOCK (u, 0x0A00u))
222 #define IS_GUJR(u) (IN_HALF_BLOCK (u, 0x0A80u))
223 #define IS_ORYA(u) (IN_HALF_BLOCK (u, 0x0B00u))
224 #define IS_TAML(u) (IN_HALF_BLOCK (u, 0x0B80u))
225 #define IS_TELU(u) (IN_HALF_BLOCK (u, 0x0C00u))
226 #define IS_KNDA(u) (IN_HALF_BLOCK (u, 0x0C80u))
227 #define IS_MLYM(u) (IN_HALF_BLOCK (u, 0x0D00u))
228 #define IS_SINH(u) (IN_HALF_BLOCK (u, 0x0D80u))
229 
230 
231 #define MATRA_POS_LEFT(u)	POS_PRE_M
232 #define MATRA_POS_RIGHT(u)	( \
233 				  IS_DEVA(u) ? POS_AFTER_SUB  : \
234 				  IS_BENG(u) ? POS_AFTER_POST : \
235 				  IS_GURU(u) ? POS_AFTER_POST : \
236 				  IS_GUJR(u) ? POS_AFTER_POST : \
237 				  IS_ORYA(u) ? POS_AFTER_POST : \
238 				  IS_TAML(u) ? POS_AFTER_POST : \
239 				  IS_TELU(u) ? (u <= 0x0C42u ? POS_BEFORE_SUB : POS_AFTER_SUB) : \
240 				  IS_KNDA(u) ? (u < 0x0CC3u || u > 0xCD6u ? POS_BEFORE_SUB : POS_AFTER_SUB) : \
241 				  IS_MLYM(u) ? POS_AFTER_POST : \
242 				  IS_SINH(u) ? POS_AFTER_SUB  : \
243 				  /*default*/  POS_AFTER_SUB    \
244 				)
245 #define MATRA_POS_TOP(u)	( /* BENG and MLYM don't have top matras. */ \
246 				  IS_DEVA(u) ? POS_AFTER_SUB  : \
247 				  IS_GURU(u) ? POS_AFTER_POST : /* Deviate from spec */ \
248 				  IS_GUJR(u) ? POS_AFTER_SUB  : \
249 				  IS_ORYA(u) ? POS_AFTER_MAIN : \
250 				  IS_TAML(u) ? POS_AFTER_SUB  : \
251 				  IS_TELU(u) ? POS_BEFORE_SUB : \
252 				  IS_KNDA(u) ? POS_BEFORE_SUB : \
253 				  IS_SINH(u) ? POS_AFTER_SUB  : \
254 				  /*default*/  POS_AFTER_SUB    \
255 				)
256 #define MATRA_POS_BOTTOM(u)	( \
257 				  IS_DEVA(u) ? POS_AFTER_SUB  : \
258 				  IS_BENG(u) ? POS_AFTER_SUB  : \
259 				  IS_GURU(u) ? POS_AFTER_POST : \
260 				  IS_GUJR(u) ? POS_AFTER_POST : \
261 				  IS_ORYA(u) ? POS_AFTER_SUB  : \
262 				  IS_TAML(u) ? POS_AFTER_POST : \
263 				  IS_TELU(u) ? POS_BEFORE_SUB : \
264 				  IS_KNDA(u) ? POS_BEFORE_SUB : \
265 				  IS_MLYM(u) ? POS_AFTER_POST : \
266 				  IS_SINH(u) ? POS_AFTER_SUB  : \
267 				  /*default*/  POS_AFTER_SUB    \
268 				)
269 
270 static inline indic_position_t
matra_position_indic(hb_codepoint_t u,indic_position_t side)271 matra_position_indic (hb_codepoint_t u, indic_position_t side)
272 {
273   switch ((int) side)
274   {
275     case POS_PRE_C:	return MATRA_POS_LEFT (u);
276     case POS_POST_C:	return MATRA_POS_RIGHT (u);
277     case POS_ABOVE_C:	return MATRA_POS_TOP (u);
278     case POS_BELOW_C:	return MATRA_POS_BOTTOM (u);
279   };
280   return side;
281 }
282 
283 /* XXX
284  * This is a hack for now.  We should move this data into the main Indic table.
285  * Or completely remove it and just check in the tables.
286  */
287 static const hb_codepoint_t ra_chars[] = {
288   0x0930u, /* Devanagari */
289   0x09B0u, /* Bengali */
290   0x09F0u, /* Bengali */
291   0x0A30u, /* Gurmukhi */	/* No Reph */
292   0x0AB0u, /* Gujarati */
293   0x0B30u, /* Oriya */
294   0x0BB0u, /* Tamil */		/* No Reph */
295   0x0C30u, /* Telugu */		/* Reph formed only with ZWJ */
296   0x0CB0u, /* Kannada */
297   0x0D30u, /* Malayalam */	/* No Reph, Logical Repha */
298 
299   0x0DBBu, /* Sinhala */	/* Reph formed only with ZWJ */
300 
301   0x179Au, /* Khmer */
302 };
303 
304 static inline bool
is_ra(hb_codepoint_t u)305 is_ra (hb_codepoint_t u)
306 {
307   for (unsigned int i = 0; i < ARRAY_LENGTH (ra_chars); i++)
308     if (u == ra_chars[i])
309       return true;
310   return false;
311 }
312 
313 static inline void
set_indic_properties(hb_glyph_info_t & info)314 set_indic_properties (hb_glyph_info_t &info)
315 {
316   hb_codepoint_t u = info.codepoint;
317   unsigned int type = hb_indic_get_categories (u);
318   indic_category_t cat = (indic_category_t) (type & 0x7Fu);
319   indic_position_t pos = (indic_position_t) (type >> 8);
320 
321 
322   /*
323    * Re-assign category
324    */
325 
326   /* The following act more like the Bindus. */
327   if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x0953u, 0x0954u)))
328     cat = OT_SM;
329   /* The following act like consonants. */
330   else if (unlikely (hb_in_ranges<hb_codepoint_t> (u, 0x0A72u, 0x0A73u,
331 				      0x1CF5u, 0x1CF6u)))
332     cat = OT_C;
333   /* TODO: The following should only be allowed after a Visarga.
334    * For now, just treat them like regular tone marks. */
335   else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1CE2u, 0x1CE8u)))
336     cat = OT_A;
337   /* TODO: The following should only be allowed after some of
338    * the nasalization marks, maybe only for U+1CE9..U+1CF1.
339    * For now, just treat them like tone marks. */
340   else if (unlikely (u == 0x1CEDu))
341     cat = OT_A;
342   /* The following take marks in standalone clusters, similar to Avagraha. */
343   else if (unlikely (hb_in_ranges<hb_codepoint_t> (u, 0xA8F2u, 0xA8F7u,
344 				      0x1CE9u, 0x1CECu,
345 				      0x1CEEu, 0x1CF1u)))
346   {
347     cat = OT_Symbol;
348     static_assert (((int) INDIC_SYLLABIC_CATEGORY_AVAGRAHA == OT_Symbol), "");
349   }
350   else if (unlikely (u == 0x0A51u))
351   {
352     /* https://github.com/harfbuzz/harfbuzz/issues/524 */
353     cat = OT_M;
354     pos = POS_BELOW_C;
355   }
356 
357   /* According to ScriptExtensions.txt, these Grantha marks may also be used in Tamil,
358    * so the Indic shaper needs to know their categories. */
359   else if (unlikely (u == 0x11301u || u == 0x11303u)) cat = OT_SM;
360   else if (unlikely (u == 0x1133cu)) cat = OT_N;
361 
362   else if (unlikely (u == 0x0AFBu)) cat = OT_N; /* https://github.com/harfbuzz/harfbuzz/issues/552 */
363 
364   else if (unlikely (u == 0x0980u)) cat = OT_PLACEHOLDER; /* https://github.com/harfbuzz/harfbuzz/issues/538 */
365   else if (unlikely (u == 0x0C80u)) cat = OT_PLACEHOLDER; /* https://github.com/harfbuzz/harfbuzz/pull/623 */
366   else if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x2010u, 0x2011u)))
367 				    cat = OT_PLACEHOLDER;
368   else if (unlikely (u == 0x25CCu)) cat = OT_DOTTEDCIRCLE;
369 
370 
371   /*
372    * Re-assign position.
373    */
374 
375   if ((FLAG_UNSAFE (cat) & CONSONANT_FLAGS))
376   {
377     pos = POS_BASE_C;
378     if (is_ra (u))
379       cat = OT_Ra;
380   }
381   else if (cat == OT_M)
382   {
383     pos = matra_position_indic (u, pos);
384   }
385   else if ((FLAG_UNSAFE (cat) & (FLAG (OT_SM) /* | FLAG (OT_VD) */ | FLAG (OT_A) | FLAG (OT_Symbol))))
386   {
387     pos = POS_SMVD;
388   }
389 
390   if (unlikely (u == 0x0B01u)) pos = POS_BEFORE_SUB; /* Oriya Bindu is BeforeSub in the spec. */
391 
392 
393 
394   info.indic_category() = cat;
395   info.indic_position() = pos;
396 }
397 
398 
399 #endif /* HB_OT_SHAPE_COMPLEX_INDIC_HH */
400