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 hb_stable_sort (&glyphs[0], num_glyphs, (int(*)(const OT::GlyphID*, const OT::GlyphID *)) OT::GlyphID::cmp, &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, 90 OT::LookupFlag::IgnoreMarks, 91 glyphs_supplier, 92 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, first_u, 0, &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 (&first_glyphs[0], num_first_glyphs, (int(*)(const OT::GlyphID*, const OT::GlyphID *)) OT::GlyphID::cmp, &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, second_u, 0, &second_glyph) || 143 !hb_font_get_glyph (font, ligature_u, 0, &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, 169 OT::LookupFlag::IgnoreMarks, 170 first_glyphs_supplier, 171 ligature_per_first_glyph_count_supplier, 172 num_first_glyphs, 173 ligatures_supplier, 174 component_count_supplier, 175 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 (arabic_fallback_features[i]); 279 if (fallback_plan->mask_array[j]) 280 { 281 fallback_plan->lookup_array[j] = arabic_fallback_synthesize_lookup (plan, font, i); 282 if (fallback_plan->lookup_array[j]) 283 { 284 fallback_plan->accel_array[j].init (*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 (1, 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 (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 (fallback_plan->lookup_array[i]); 333 } 334 335 free (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, 348 *fallback_plan->lookup_array[i], 349 fallback_plan->accel_array[i]); 350 } 351 } 352 353 354 #endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */ 355
