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, u, 0, &u_glyph) ||
64 !hb_font_get_glyph (font, s, 0, &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
81 #if defined(_AIX)
82 /* workaround AIX xlC 12 compilation issues caused by the 2 cmp in the IntType template */
83 hb_stable_sort (&glyphs[0], num_glyphs, (int(*)(const OT::GlyphID*, const OT::GlyphID *)) OT::GlyphID::cmp, &substitutes[0]);
84 #else
85 hb_stable_sort (&glyphs[0], num_glyphs, OT::GlyphID::cmp, &substitutes[0]);
86 #endif
87
88 OT::Supplier<OT::GlyphID> glyphs_supplier (glyphs, num_glyphs);
89 OT::Supplier<OT::GlyphID> substitutes_supplier (substitutes, num_glyphs);
90
91 /* Each glyph takes four bytes max, and there's some overhead. */
92 char buf[(SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1) * 4 + 128];
93 OT::hb_serialize_context_t c (buf, sizeof (buf));
94 OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> ();
95 bool ret = lookup->serialize_single (&c,
96 OT::LookupFlag::IgnoreMarks,
97 glyphs_supplier,
98 substitutes_supplier,
99 num_glyphs);
100 c.end_serialize ();
101 /* TODO sanitize the results? */
102
103 return ret ? c.copy<OT::SubstLookup> () : nullptr;
104 }
105
106 static OT::SubstLookup *
107 arabic_fallback_synthesize_lookup_ligature (const hb_ot_shape_plan_t *plan HB_UNUSED,
108 hb_font_t *font)
109 {
110 OT::GlyphID first_glyphs[ARRAY_LENGTH_CONST (ligature_table)];
111 unsigned int first_glyphs_indirection[ARRAY_LENGTH_CONST (ligature_table)];
112 unsigned int ligature_per_first_glyph_count_list[ARRAY_LENGTH_CONST (first_glyphs)];
113 unsigned int num_first_glyphs = 0;
114
115 /* We know that all our ligatures are 2-component */
116 OT::GlyphID ligature_list[ARRAY_LENGTH_CONST (first_glyphs) * ARRAY_LENGTH_CONST(ligature_table[0].ligatures)];
117 unsigned int component_count_list[ARRAY_LENGTH_CONST (ligature_list)];
118 OT::GlyphID component_list[ARRAY_LENGTH_CONST (ligature_list) * 1/* One extra component per ligature */];
119 unsigned int num_ligatures = 0;
120
121 /* Populate arrays */
122
123 /* Sort out the first-glyphs */
124 for (unsigned int first_glyph_idx = 0; first_glyph_idx < ARRAY_LENGTH (first_glyphs); first_glyph_idx++)
125 {
126 hb_codepoint_t first_u = ligature_table[first_glyph_idx].first;
127 hb_codepoint_t first_glyph;
128 if (!hb_font_get_glyph (font, first_u, 0, &first_glyph))
129 continue;
130 first_glyphs[num_first_glyphs].set (first_glyph);
131 ligature_per_first_glyph_count_list[num_first_glyphs] = 0;
132 first_glyphs_indirection[num_first_glyphs] = first_glyph_idx;
133 num_first_glyphs++;
134 }
135
136 #if defined(_AIX)
137 /* workaround AIX xlC 12 compilation issues caused by the 2 cmp in the IntType template */
138 hb_stable_sort (&first_glyphs[0], num_first_glyphs, (int(*)(const OT::GlyphID *, const OT::GlyphID *)) OT::GlyphID::cmp, &first_glyphs_indirection[0]);
139 #else
140 hb_stable_sort (&first_glyphs[0], num_first_glyphs, OT::GlyphID::cmp, &first_glyphs_indirection[0]);
141 #endif
142
143 /* Now that the first-glyphs are sorted, walk again, populate ligatures. */
144 for (unsigned int i = 0; i < num_first_glyphs; i++)
145 {
146 unsigned int first_glyph_idx = first_glyphs_indirection[i];
147
148 for (unsigned int second_glyph_idx = 0; second_glyph_idx < ARRAY_LENGTH (ligature_table[0].ligatures); second_glyph_idx++)
149 {
150 hb_codepoint_t second_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].second;
151 hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].ligature;
152 hb_codepoint_t second_glyph, ligature_glyph;
153 if (!second_u ||
154 !hb_font_get_glyph (font, second_u, 0, &second_glyph) ||
155 !hb_font_get_glyph (font, ligature_u, 0, &ligature_glyph))
156 continue;
157
158 ligature_per_first_glyph_count_list[i]++;
159
160 ligature_list[num_ligatures].set (ligature_glyph);
161 component_count_list[num_ligatures] = 2;
162 component_list[num_ligatures].set (second_glyph);
163 num_ligatures++;
164 }
165 }
166
167 if (!num_ligatures)
168 return nullptr;
169
170 OT::Supplier<OT::GlyphID> first_glyphs_supplier (first_glyphs, num_first_glyphs);
171 OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier (ligature_per_first_glyph_count_list, num_first_glyphs);
172 OT::Supplier<OT::GlyphID> ligatures_supplier (ligature_list, num_ligatures);
173 OT::Supplier<unsigned int > component_count_supplier (component_count_list, num_ligatures);
174 OT::Supplier<OT::GlyphID> component_supplier (component_list, num_ligatures);
175
176 /* 16 bytes per ligature ought to be enough... */
177 char buf[ARRAY_LENGTH_CONST (ligature_list) * 16 + 128];
178 OT::hb_serialize_context_t c (buf, sizeof (buf));
179 OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> ();
180 bool ret = lookup->serialize_ligature (&c,
181 OT::LookupFlag::IgnoreMarks,
182 first_glyphs_supplier,
183 ligature_per_first_glyph_count_supplier,
184 num_first_glyphs,
185 ligatures_supplier,
186 component_count_supplier,
187 component_supplier);
188
189 c.end_serialize ();
190 /* TODO sanitize the results? */
191
192 return ret ? c.copy<OT::SubstLookup> () : nullptr;
193 }
194
195 static OT::SubstLookup *
196 arabic_fallback_synthesize_lookup (const hb_ot_shape_plan_t *plan,
197 hb_font_t *font,
198 unsigned int feature_index)
199 {
200 if (feature_index < 4)
201 return arabic_fallback_synthesize_lookup_single (plan, font, feature_index);
202 else
203 return arabic_fallback_synthesize_lookup_ligature (plan, font);
204 }
205
206 #define ARABIC_FALLBACK_MAX_LOOKUPS 5
207
208 struct arabic_fallback_plan_t
209 {
210 ASSERT_POD ();
211
212 unsigned int num_lookups;
213 bool free_lookups;
214
215 hb_mask_t mask_array[ARABIC_FALLBACK_MAX_LOOKUPS];
216 OT::SubstLookup *lookup_array[ARABIC_FALLBACK_MAX_LOOKUPS];
217 hb_ot_layout_lookup_accelerator_t accel_array[ARABIC_FALLBACK_MAX_LOOKUPS];
218 };
219
220 static const arabic_fallback_plan_t arabic_fallback_plan_nil = {};
221
222 #if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(HB_NO_WIN1256)
223 #define HB_WITH_WIN1256
224 #endif
225
226 #ifdef HB_WITH_WIN1256
227 #include "hb-ot-shape-complex-arabic-win1256.hh"
228 #endif
229
230 struct ManifestLookup {
231 OT::Tag tag;
232 OT::OffsetTo<OT::SubstLookup> lookupOffset;
233 };
234 typedef OT::ArrayOf<ManifestLookup> Manifest;
235
236 static bool
237 arabic_fallback_plan_init_win1256 (arabic_fallback_plan_t *fallback_plan,
238 const hb_ot_shape_plan_t *plan,
239 hb_font_t *font)
240 {
241 #ifdef HB_WITH_WIN1256
242 /* Does this font look like it's Windows-1256-encoded? */
243 hb_codepoint_t g;
244 if (!(hb_font_get_glyph (font, 0x0627u, 0, &g) && g == 199 /* ALEF */ &&
245 hb_font_get_glyph (font, 0x0644u, 0, &g) && g == 225 /* LAM */ &&
246 hb_font_get_glyph (font, 0x0649u, 0, &g) && g == 236 /* ALEF MAKSURA */ &&
247 hb_font_get_glyph (font, 0x064Au, 0, &g) && g == 237 /* YEH */ &&
248 hb_font_get_glyph (font, 0x0652u, 0, &g) && g == 250 /* SUKUN */))
249 return false;
250
251 const Manifest &manifest = reinterpret_cast<const Manifest&> (arabic_win1256_gsub_lookups.manifest);
252 static_assert (sizeof (arabic_win1256_gsub_lookups.manifestData) / sizeof (ManifestLookup)
253 <= ARABIC_FALLBACK_MAX_LOOKUPS, "");
254 /* TODO sanitize the table? */
255
256 unsigned j = 0;
257 unsigned int count = manifest.len;
258 for (unsigned int i = 0; i < count; i++)
259 {
260 fallback_plan->mask_array[j] = plan->map.get_1_mask (manifest[i].tag);
261 if (fallback_plan->mask_array[j])
262 {
263 fallback_plan->lookup_array[j] = const_cast<OT::SubstLookup*> (&(&manifest+manifest[i].lookupOffset));
264 if (fallback_plan->lookup_array[j])
265 {
266 fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]);
267 j++;
268 }
269 }
270 }
271
272 fallback_plan->num_lookups = j;
273 fallback_plan->free_lookups = false;
274
275 return j > 0;
276 #else
277 return false;
278 #endif
279 }
280
281 static bool
282 arabic_fallback_plan_init_unicode (arabic_fallback_plan_t *fallback_plan,
283 const hb_ot_shape_plan_t *plan,
284 hb_font_t *font)
285 {
286 static_assert ((ARRAY_LENGTH_CONST(arabic_fallback_features) <= ARABIC_FALLBACK_MAX_LOOKUPS), "");
287 unsigned int j = 0;
288 for (unsigned int i = 0; i < ARRAY_LENGTH(arabic_fallback_features) ; i++)
289 {
290 fallback_plan->mask_array[j] = plan->map.get_1_mask (arabic_fallback_features[i]);
291 if (fallback_plan->mask_array[j])
292 {
293 fallback_plan->lookup_array[j] = arabic_fallback_synthesize_lookup (plan, font, i);
294 if (fallback_plan->lookup_array[j])
295 {
296 fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]);
297 j++;
298 }
299 }
300 }
301
302 fallback_plan->num_lookups = j;
303 fallback_plan->free_lookups = true;
304
305 return j > 0;
306 }
307
308 static arabic_fallback_plan_t *
309 arabic_fallback_plan_create (const hb_ot_shape_plan_t *plan,
310 hb_font_t *font)
311 {
312 arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) calloc (1, sizeof (arabic_fallback_plan_t));
313 if (unlikely (!fallback_plan))
314 return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil);
315
316 fallback_plan->num_lookups = 0;
317 fallback_plan->free_lookups = false;
318
319 /* Try synthesizing GSUB table using Unicode Arabic Presentation Forms,
320 * in case the font has cmap entries for the presentation-forms characters. */
321 if (arabic_fallback_plan_init_unicode (fallback_plan, plan, font))
322 return fallback_plan;
323
324 /* See if this looks like a Windows-1256-encoded font. If it does, use a
325 * hand-coded GSUB table. */
326 if (arabic_fallback_plan_init_win1256 (fallback_plan, plan, font))
327 return fallback_plan;
328
329 free (fallback_plan);
330 return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil);
331 }
332
333 static void
334 arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan)
335 {
336 if (!fallback_plan || fallback_plan == &arabic_fallback_plan_nil)
337 return;
338
339 for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
340 if (fallback_plan->lookup_array[i])
341 {
342 fallback_plan->accel_array[i].fini ();
343 if (fallback_plan->free_lookups)
344 free (fallback_plan->lookup_array[i]);
345 }
346
347 free (fallback_plan);
348 }
349
350 static void
351 arabic_fallback_plan_shape (arabic_fallback_plan_t *fallback_plan,
352 hb_font_t *font,
353 hb_buffer_t *buffer)
354 {
355 OT::hb_apply_context_t c (0, font, buffer);
356 for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
357 if (fallback_plan->lookup_array[i]) {
358 c.set_lookup_mask (fallback_plan->mask_array[i]);
359 hb_ot_layout_substitute_lookup (&c,
360 *fallback_plan->lookup_array[i],
361 fallback_plan->accel_array[i]);
362 }
363 }
364
365
366 #endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */