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_ARABIC_FALLBACK_HH |
28 | #define HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH |
29 | |
30 | #include "hb-private.hh" |
31 | |
32 | #include "hb-ot-shape-private.hh" |
33 | #include "hb-ot-layout-gsub-table.hh" |
34 | |
35 | |
36 | /* Features ordered the same as the entries in shaping_table rows, |
37 | * followed by rlig. Don't change. */ |
38 | static const hb_tag_t arabic_fallback_features[] = |
39 | { |
40 | HB_TAG('i','n','i','t'), |
41 | HB_TAG('m','e','d','i'), |
42 | HB_TAG('f','i','n','a'), |
43 | HB_TAG('i','s','o','l'), |
44 | HB_TAG('r','l','i','g'), |
45 | }; |
46 | |
47 | static OT::SubstLookup * |
48 | arabic_fallback_synthesize_lookup_single (const hb_ot_shape_plan_t *plan HB_UNUSED, |
49 | hb_font_t *font, |
50 | unsigned int feature_index) |
51 | { |
52 | OT::GlyphID glyphs[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1]; |
53 | OT::GlyphID substitutes[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1]; |
54 | unsigned int num_glyphs = 0; |
55 | |
56 | /* Populate arrays */ |
57 | for (hb_codepoint_t u = SHAPING_TABLE_FIRST; u < SHAPING_TABLE_LAST + 1; u++) |
58 | { |
59 | hb_codepoint_t s = shaping_table[u - SHAPING_TABLE_FIRST][feature_index]; |
60 | hb_codepoint_t u_glyph, s_glyph; |
61 | |
62 | if (!s || |
63 | !hb_font_get_glyph (font, unicode: u, variation_selector: 0, glyph: &u_glyph) || |
64 | !hb_font_get_glyph (font, unicode: s, variation_selector: 0, glyph: &s_glyph) || |
65 | u_glyph == s_glyph || |
66 | u_glyph > 0xFFFFu || s_glyph > 0xFFFFu) |
67 | continue; |
68 | |
69 | glyphs[num_glyphs].set (u_glyph); |
70 | substitutes[num_glyphs].set (s_glyph); |
71 | |
72 | num_glyphs++; |
73 | } |
74 | |
75 | if (!num_glyphs) |
76 | return nullptr; |
77 | |
78 | /* Bubble-sort or something equally good! |
79 | * May not be good-enough for presidential candidate interviews, but good-enough for us... */ |
80 | hb_stable_sort (array: &glyphs[0], len: num_glyphs, compar: (int(*)(const OT::GlyphID*, const OT::GlyphID *)) OT::GlyphID::cmp, array2: &substitutes[0]); |
81 | |
82 | OT::Supplier<OT::GlyphID> glyphs_supplier (glyphs, num_glyphs); |
83 | OT::Supplier<OT::GlyphID> substitutes_supplier (substitutes, num_glyphs); |
84 | |
85 | /* Each glyph takes four bytes max, and there's some overhead. */ |
86 | char buf[(SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1) * 4 + 128]; |
87 | OT::hb_serialize_context_t c (buf, sizeof (buf)); |
88 | OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> (); |
89 | bool ret = lookup->serialize_single (c: &c, |
90 | lookup_props: OT::LookupFlag::IgnoreMarks, |
91 | glyphs&: glyphs_supplier, |
92 | substitutes&: substitutes_supplier, |
93 | num_glyphs); |
94 | c.end_serialize (); |
95 | /* TODO sanitize the results? */ |
96 | |
97 | return ret ? c.copy<OT::SubstLookup> () : nullptr; |
98 | } |
99 | |
100 | static OT::SubstLookup * |
101 | arabic_fallback_synthesize_lookup_ligature (const hb_ot_shape_plan_t *plan HB_UNUSED, |
102 | hb_font_t *font) |
103 | { |
104 | OT::GlyphID first_glyphs[ARRAY_LENGTH_CONST (ligature_table)]; |
105 | unsigned int first_glyphs_indirection[ARRAY_LENGTH_CONST (ligature_table)]; |
106 | unsigned int ligature_per_first_glyph_count_list[ARRAY_LENGTH_CONST (first_glyphs)]; |
107 | unsigned int num_first_glyphs = 0; |
108 | |
109 | /* We know that all our ligatures are 2-component */ |
110 | OT::GlyphID ligature_list[ARRAY_LENGTH_CONST (first_glyphs) * ARRAY_LENGTH_CONST(ligature_table[0].ligatures)]; |
111 | unsigned int component_count_list[ARRAY_LENGTH_CONST (ligature_list)]; |
112 | OT::GlyphID component_list[ARRAY_LENGTH_CONST (ligature_list) * 1/* One extra component per ligature */]; |
113 | unsigned int num_ligatures = 0; |
114 | |
115 | /* Populate arrays */ |
116 | |
117 | /* Sort out the first-glyphs */ |
118 | for (unsigned int first_glyph_idx = 0; first_glyph_idx < ARRAY_LENGTH (first_glyphs); first_glyph_idx++) |
119 | { |
120 | hb_codepoint_t first_u = ligature_table[first_glyph_idx].first; |
121 | hb_codepoint_t first_glyph; |
122 | if (!hb_font_get_glyph (font, unicode: first_u, variation_selector: 0, glyph: &first_glyph)) |
123 | continue; |
124 | first_glyphs[num_first_glyphs].set (first_glyph); |
125 | ligature_per_first_glyph_count_list[num_first_glyphs] = 0; |
126 | first_glyphs_indirection[num_first_glyphs] = first_glyph_idx; |
127 | num_first_glyphs++; |
128 | } |
129 | hb_stable_sort (array: &first_glyphs[0], len: num_first_glyphs, compar: (int(*)(const OT::GlyphID*, const OT::GlyphID *)) OT::GlyphID::cmp, array2: &first_glyphs_indirection[0]); |
130 | |
131 | /* Now that the first-glyphs are sorted, walk again, populate ligatures. */ |
132 | for (unsigned int i = 0; i < num_first_glyphs; i++) |
133 | { |
134 | unsigned int first_glyph_idx = first_glyphs_indirection[i]; |
135 | |
136 | for (unsigned int second_glyph_idx = 0; second_glyph_idx < ARRAY_LENGTH (ligature_table[0].ligatures); second_glyph_idx++) |
137 | { |
138 | hb_codepoint_t second_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].second; |
139 | hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].ligature; |
140 | hb_codepoint_t second_glyph, ligature_glyph; |
141 | if (!second_u || |
142 | !hb_font_get_glyph (font, unicode: second_u, variation_selector: 0, glyph: &second_glyph) || |
143 | !hb_font_get_glyph (font, unicode: ligature_u, variation_selector: 0, glyph: &ligature_glyph)) |
144 | continue; |
145 | |
146 | ligature_per_first_glyph_count_list[i]++; |
147 | |
148 | ligature_list[num_ligatures].set (ligature_glyph); |
149 | component_count_list[num_ligatures] = 2; |
150 | component_list[num_ligatures].set (second_glyph); |
151 | num_ligatures++; |
152 | } |
153 | } |
154 | |
155 | if (!num_ligatures) |
156 | return nullptr; |
157 | |
158 | OT::Supplier<OT::GlyphID> first_glyphs_supplier (first_glyphs, num_first_glyphs); |
159 | OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier (ligature_per_first_glyph_count_list, num_first_glyphs); |
160 | OT::Supplier<OT::GlyphID> ligatures_supplier (ligature_list, num_ligatures); |
161 | OT::Supplier<unsigned int > component_count_supplier (component_count_list, num_ligatures); |
162 | OT::Supplier<OT::GlyphID> component_supplier (component_list, num_ligatures); |
163 | |
164 | /* 16 bytes per ligature ought to be enough... */ |
165 | char buf[ARRAY_LENGTH_CONST (ligature_list) * 16 + 128]; |
166 | OT::hb_serialize_context_t c (buf, sizeof (buf)); |
167 | OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> (); |
168 | bool ret = lookup->serialize_ligature (c: &c, |
169 | lookup_props: OT::LookupFlag::IgnoreMarks, |
170 | first_glyphs&: first_glyphs_supplier, |
171 | ligature_per_first_glyph_count_list&: ligature_per_first_glyph_count_supplier, |
172 | num_first_glyphs, |
173 | ligatures_list&: ligatures_supplier, |
174 | component_count_list&: component_count_supplier, |
175 | component_list&: component_supplier); |
176 | |
177 | c.end_serialize (); |
178 | /* TODO sanitize the results? */ |
179 | |
180 | return ret ? c.copy<OT::SubstLookup> () : nullptr; |
181 | } |
182 | |
183 | static OT::SubstLookup * |
184 | arabic_fallback_synthesize_lookup (const hb_ot_shape_plan_t *plan, |
185 | hb_font_t *font, |
186 | unsigned int feature_index) |
187 | { |
188 | if (feature_index < 4) |
189 | return arabic_fallback_synthesize_lookup_single (plan, font, feature_index); |
190 | else |
191 | return arabic_fallback_synthesize_lookup_ligature (plan, font); |
192 | } |
193 | |
194 | #define ARABIC_FALLBACK_MAX_LOOKUPS 5 |
195 | |
196 | struct arabic_fallback_plan_t |
197 | { |
198 | ASSERT_POD (); |
199 | |
200 | unsigned int num_lookups; |
201 | bool free_lookups; |
202 | |
203 | hb_mask_t mask_array[ARABIC_FALLBACK_MAX_LOOKUPS]; |
204 | OT::SubstLookup *lookup_array[ARABIC_FALLBACK_MAX_LOOKUPS]; |
205 | hb_ot_layout_lookup_accelerator_t accel_array[ARABIC_FALLBACK_MAX_LOOKUPS]; |
206 | }; |
207 | |
208 | static const arabic_fallback_plan_t arabic_fallback_plan_nil = {}; |
209 | |
210 | #if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(HB_NO_WIN1256) |
211 | #define HB_WITH_WIN1256 |
212 | #endif |
213 | |
214 | #ifdef HB_WITH_WIN1256 |
215 | #include "hb-ot-shape-complex-arabic-win1256.hh" |
216 | #endif |
217 | |
218 | struct ManifestLookup { |
219 | OT::Tag tag; |
220 | OT::OffsetTo<OT::SubstLookup> lookupOffset; |
221 | }; |
222 | typedef OT::ArrayOf<ManifestLookup> Manifest; |
223 | |
224 | static bool |
225 | arabic_fallback_plan_init_win1256 (arabic_fallback_plan_t *fallback_plan, |
226 | const hb_ot_shape_plan_t *plan, |
227 | hb_font_t *font) |
228 | { |
229 | #ifdef HB_WITH_WIN1256 |
230 | /* Does this font look like it's Windows-1256-encoded? */ |
231 | hb_codepoint_t g; |
232 | if (!(hb_font_get_glyph (font, 0x0627u, 0, &g) && g == 199 /* ALEF */ && |
233 | hb_font_get_glyph (font, 0x0644u, 0, &g) && g == 225 /* LAM */ && |
234 | hb_font_get_glyph (font, 0x0649u, 0, &g) && g == 236 /* ALEF MAKSURA */ && |
235 | hb_font_get_glyph (font, 0x064Au, 0, &g) && g == 237 /* YEH */ && |
236 | hb_font_get_glyph (font, 0x0652u, 0, &g) && g == 250 /* SUKUN */)) |
237 | return false; |
238 | |
239 | const Manifest &manifest = reinterpret_cast<const Manifest&> (arabic_win1256_gsub_lookups.manifest); |
240 | static_assert (sizeof (arabic_win1256_gsub_lookups.manifestData) / sizeof (ManifestLookup) |
241 | <= ARABIC_FALLBACK_MAX_LOOKUPS, "" ); |
242 | /* TODO sanitize the table? */ |
243 | |
244 | unsigned j = 0; |
245 | unsigned int count = manifest.len; |
246 | for (unsigned int i = 0; i < count; i++) |
247 | { |
248 | fallback_plan->mask_array[j] = plan->map.get_1_mask (manifest[i].tag); |
249 | if (fallback_plan->mask_array[j]) |
250 | { |
251 | fallback_plan->lookup_array[j] = const_cast<OT::SubstLookup*> (&(&manifest+manifest[i].lookupOffset)); |
252 | if (fallback_plan->lookup_array[j]) |
253 | { |
254 | fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]); |
255 | j++; |
256 | } |
257 | } |
258 | } |
259 | |
260 | fallback_plan->num_lookups = j; |
261 | fallback_plan->free_lookups = false; |
262 | |
263 | return j > 0; |
264 | #else |
265 | return false; |
266 | #endif |
267 | } |
268 | |
269 | static bool |
270 | arabic_fallback_plan_init_unicode (arabic_fallback_plan_t *fallback_plan, |
271 | const hb_ot_shape_plan_t *plan, |
272 | hb_font_t *font) |
273 | { |
274 | static_assert ((ARRAY_LENGTH_CONST(arabic_fallback_features) <= ARABIC_FALLBACK_MAX_LOOKUPS), "" ); |
275 | unsigned int j = 0; |
276 | for (unsigned int i = 0; i < ARRAY_LENGTH(arabic_fallback_features) ; i++) |
277 | { |
278 | fallback_plan->mask_array[j] = plan->map.get_1_mask (feature_tag: arabic_fallback_features[i]); |
279 | if (fallback_plan->mask_array[j]) |
280 | { |
281 | fallback_plan->lookup_array[j] = arabic_fallback_synthesize_lookup (plan, font, feature_index: i); |
282 | if (fallback_plan->lookup_array[j]) |
283 | { |
284 | fallback_plan->accel_array[j].init (lookup: *fallback_plan->lookup_array[j]); |
285 | j++; |
286 | } |
287 | } |
288 | } |
289 | |
290 | fallback_plan->num_lookups = j; |
291 | fallback_plan->free_lookups = true; |
292 | |
293 | return j > 0; |
294 | } |
295 | |
296 | static arabic_fallback_plan_t * |
297 | arabic_fallback_plan_create (const hb_ot_shape_plan_t *plan, |
298 | hb_font_t *font) |
299 | { |
300 | arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) calloc (nmemb: 1, size: sizeof (arabic_fallback_plan_t)); |
301 | if (unlikely (!fallback_plan)) |
302 | return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil); |
303 | |
304 | fallback_plan->num_lookups = 0; |
305 | fallback_plan->free_lookups = false; |
306 | |
307 | /* Try synthesizing GSUB table using Unicode Arabic Presentation Forms, |
308 | * in case the font has cmap entries for the presentation-forms characters. */ |
309 | if (arabic_fallback_plan_init_unicode (fallback_plan, plan, font)) |
310 | return fallback_plan; |
311 | |
312 | /* See if this looks like a Windows-1256-encoded font. If it does, use a |
313 | * hand-coded GSUB table. */ |
314 | if (arabic_fallback_plan_init_win1256 (fallback_plan, plan, font)) |
315 | return fallback_plan; |
316 | |
317 | free (ptr: fallback_plan); |
318 | return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil); |
319 | } |
320 | |
321 | static void |
322 | arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan) |
323 | { |
324 | if (!fallback_plan || fallback_plan == &arabic_fallback_plan_nil) |
325 | return; |
326 | |
327 | for (unsigned int i = 0; i < fallback_plan->num_lookups; i++) |
328 | if (fallback_plan->lookup_array[i]) |
329 | { |
330 | fallback_plan->accel_array[i].fini (); |
331 | if (fallback_plan->free_lookups) |
332 | free (ptr: fallback_plan->lookup_array[i]); |
333 | } |
334 | |
335 | free (ptr: fallback_plan); |
336 | } |
337 | |
338 | static void |
339 | arabic_fallback_plan_shape (arabic_fallback_plan_t *fallback_plan, |
340 | hb_font_t *font, |
341 | hb_buffer_t *buffer) |
342 | { |
343 | OT::hb_apply_context_t c (0, font, buffer); |
344 | for (unsigned int i = 0; i < fallback_plan->num_lookups; i++) |
345 | if (fallback_plan->lookup_array[i]) { |
346 | c.set_lookup_mask (fallback_plan->mask_array[i]); |
347 | hb_ot_layout_substitute_lookup (c: &c, |
348 | lookup: *fallback_plan->lookup_array[i], |
349 | accel: fallback_plan->accel_array[i]); |
350 | } |
351 | } |
352 | |
353 | |
354 | #endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */ |
355 | |