1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 // This file is available under and governed by the GNU General Public
26 // License version 2 only, as published by the Free Software Foundation.
27 // However, the following notice accompanied the original version of this
28 // file:
29 //
30 /*
31 * Copyright © 2012 Google, Inc.
32 *
33 * This is part of HarfBuzz, a text shaping library.
34 *
35 * Permission is hereby granted, without written agreement and without
36 * license or royalty fees, to use, copy, modify, and distribute this
37 * software and its documentation for any purpose, provided that the
38 * above copyright notice and the following two paragraphs appear in
39 * all copies of this software.
40 *
41 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
42 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
43 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
44 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
45 * DAMAGE.
46 *
47 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
48 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
49 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
50 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
51 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
52 *
53 * Google Author(s): Behdad Esfahbod
54 */
55
56 #ifndef HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH
57 #define HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH
58
59 #include "hb-private.hh"
60
61 #include "hb-ot-shape-private.hh"
62 #include "hb-ot-layout-gsub-table.hh"
63
64
65 /* Features ordered the same as the entries in shaping_table rows,
66 * followed by rlig. Don't change. */
67 static const hb_tag_t arabic_fallback_features[] =
68 {
69 HB_TAG('i','n','i','t'),
70 HB_TAG('m','e','d','i'),
71 HB_TAG('f','i','n','a'),
72 HB_TAG('i','s','o','l'),
73 HB_TAG('r','l','i','g'),
74 };
75
76 static OT::SubstLookup *
77 arabic_fallback_synthesize_lookup_single (const hb_ot_shape_plan_t *plan HB_UNUSED,
78 hb_font_t *font,
79 unsigned int feature_index)
80 {
81 OT::GlyphID glyphs[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1];
82 OT::GlyphID substitutes[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1];
83 unsigned int num_glyphs = 0;
84
85 /* Populate arrays */
86 for (hb_codepoint_t u = SHAPING_TABLE_FIRST; u < SHAPING_TABLE_LAST + 1; u++)
87 {
88 hb_codepoint_t s = shaping_table[u - SHAPING_TABLE_FIRST][feature_index];
89 hb_codepoint_t u_glyph, s_glyph;
90
91 if (!s ||
92 !hb_font_get_glyph (font, u, 0, &u_glyph) ||
93 !hb_font_get_glyph (font, s, 0, &s_glyph) ||
94 u_glyph == s_glyph ||
95 u_glyph > 0xFFFFu || s_glyph > 0xFFFFu)
96 continue;
97
98 glyphs[num_glyphs].set (u_glyph);
99 substitutes[num_glyphs].set (s_glyph);
100
101 num_glyphs++;
102 }
103
104 if (!num_glyphs)
105 return NULL;
106
107 /* Bubble-sort or something equally good!
108 * May not be good-enough for presidential candidate interviews, but good-enough for us... */
109 hb_stable_sort (&glyphs[0], num_glyphs, OT::GlyphID::cmp, &substitutes[0]);
110
111 OT::Supplier<OT::GlyphID> glyphs_supplier (glyphs, num_glyphs);
112 OT::Supplier<OT::GlyphID> substitutes_supplier (substitutes, num_glyphs);
113
114 /* Each glyph takes four bytes max, and there's some overhead. */
115 char buf[(SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1) * 4 + 128];
116 OT::hb_serialize_context_t c (buf, sizeof (buf));
117 OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> ();
118 bool ret = lookup->serialize_single (&c,
119 OT::LookupFlag::IgnoreMarks,
120 glyphs_supplier,
121 substitutes_supplier,
122 num_glyphs);
123 c.end_serialize ();
124 /* TODO sanitize the results? */
125
126 return ret ? c.copy<OT::SubstLookup> () : NULL;
127 }
128
129 static OT::SubstLookup *
130 arabic_fallback_synthesize_lookup_ligature (const hb_ot_shape_plan_t *plan HB_UNUSED,
131 hb_font_t *font)
132 {
133 OT::GlyphID first_glyphs[ARRAY_LENGTH_CONST (ligature_table)];
134 unsigned int first_glyphs_indirection[ARRAY_LENGTH_CONST (ligature_table)];
135 unsigned int ligature_per_first_glyph_count_list[ARRAY_LENGTH_CONST (first_glyphs)];
136 unsigned int num_first_glyphs = 0;
137
138 /* We know that all our ligatures are 2-component */
139 OT::GlyphID ligature_list[ARRAY_LENGTH_CONST (first_glyphs) * ARRAY_LENGTH_CONST(ligature_table[0].ligatures)];
140 unsigned int component_count_list[ARRAY_LENGTH_CONST (ligature_list)];
141 OT::GlyphID component_list[ARRAY_LENGTH_CONST (ligature_list) * 1/* One extra component per ligature */];
142 unsigned int num_ligatures = 0;
143
144 /* Populate arrays */
145
146 /* Sort out the first-glyphs */
147 for (unsigned int first_glyph_idx = 0; first_glyph_idx < ARRAY_LENGTH (first_glyphs); first_glyph_idx++)
148 {
149 hb_codepoint_t first_u = ligature_table[first_glyph_idx].first;
150 hb_codepoint_t first_glyph;
151 if (!hb_font_get_glyph (font, first_u, 0, &first_glyph))
152 continue;
153 first_glyphs[num_first_glyphs].set (first_glyph);
154 ligature_per_first_glyph_count_list[num_first_glyphs] = 0;
155 first_glyphs_indirection[num_first_glyphs] = first_glyph_idx;
156 num_first_glyphs++;
157 }
158 hb_stable_sort (&first_glyphs[0], num_first_glyphs, OT::GlyphID::cmp, &first_glyphs_indirection[0]);
159
160 /* Now that the first-glyphs are sorted, walk again, populate ligatures. */
161 for (unsigned int i = 0; i < num_first_glyphs; i++)
162 {
163 unsigned int first_glyph_idx = first_glyphs_indirection[i];
164
165 for (unsigned int second_glyph_idx = 0; second_glyph_idx < ARRAY_LENGTH (ligature_table[0].ligatures); second_glyph_idx++)
166 {
167 hb_codepoint_t second_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].second;
168 hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].ligature;
169 hb_codepoint_t second_glyph, ligature_glyph;
170 if (!second_u ||
171 !hb_font_get_glyph (font, second_u, 0, &second_glyph) ||
172 !hb_font_get_glyph (font, ligature_u, 0, &ligature_glyph))
173 continue;
174
175 ligature_per_first_glyph_count_list[i]++;
176
177 ligature_list[num_ligatures].set (ligature_glyph);
178 component_count_list[num_ligatures] = 2;
179 component_list[num_ligatures].set (second_glyph);
180 num_ligatures++;
181 }
182 }
183
184 if (!num_ligatures)
185 return NULL;
186
187 OT::Supplier<OT::GlyphID> first_glyphs_supplier (first_glyphs, num_first_glyphs);
188 OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier (ligature_per_first_glyph_count_list, num_first_glyphs);
189 OT::Supplier<OT::GlyphID> ligatures_supplier (ligature_list, num_ligatures);
190 OT::Supplier<unsigned int > component_count_supplier (component_count_list, num_ligatures);
191 OT::Supplier<OT::GlyphID> component_supplier (component_list, num_ligatures);
192
193 /* 16 bytes per ligature ought to be enough... */
194 char buf[ARRAY_LENGTH_CONST (ligature_list) * 16 + 128];
195 OT::hb_serialize_context_t c (buf, sizeof (buf));
196 OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> ();
197 bool ret = lookup->serialize_ligature (&c,
198 OT::LookupFlag::IgnoreMarks,
199 first_glyphs_supplier,
200 ligature_per_first_glyph_count_supplier,
201 num_first_glyphs,
202 ligatures_supplier,
203 component_count_supplier,
204 component_supplier);
205
206 c.end_serialize ();
207 /* TODO sanitize the results? */
208
209 return ret ? c.copy<OT::SubstLookup> () : NULL;
210 }
211
212 static OT::SubstLookup *
213 arabic_fallback_synthesize_lookup (const hb_ot_shape_plan_t *plan,
214 hb_font_t *font,
215 unsigned int feature_index)
216 {
217 if (feature_index < 4)
218 return arabic_fallback_synthesize_lookup_single (plan, font, feature_index);
219 else
220 return arabic_fallback_synthesize_lookup_ligature (plan, font);
221 }
222
223 #define ARABIC_FALLBACK_MAX_LOOKUPS 5
224
225 struct arabic_fallback_plan_t
226 {
227 ASSERT_POD ();
228
229 unsigned int num_lookups;
230 bool free_lookups;
231
232 hb_mask_t mask_array[ARABIC_FALLBACK_MAX_LOOKUPS];
233 OT::SubstLookup *lookup_array[ARABIC_FALLBACK_MAX_LOOKUPS];
234 hb_ot_layout_lookup_accelerator_t accel_array[ARABIC_FALLBACK_MAX_LOOKUPS];
235 };
236
237 static const arabic_fallback_plan_t arabic_fallback_plan_nil = {};
238
239 #if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(HB_NO_WIN1256)
240 #define HB_WITH_WIN1256
241 #endif
242
243 #ifdef HB_WITH_WIN1256
244 #include "hb-ot-shape-complex-arabic-win1256.hh"
245 #endif
246
247 struct ManifestLookup {
248 OT::Tag tag;
249 OT::OffsetTo<OT::SubstLookup> lookupOffset;
250 };
251 typedef OT::ArrayOf<ManifestLookup> Manifest;
252
253 static bool
254 arabic_fallback_plan_init_win1256 (arabic_fallback_plan_t *fallback_plan,
255 const hb_ot_shape_plan_t *plan,
256 hb_font_t *font)
257 {
258 #ifdef HB_WITH_WIN1256
259 /* Does this font look like it's Windows-1256-encoded? */
260 hb_codepoint_t g;
261 if (!(hb_font_get_glyph (font, 0x0627u, 0, &g) && g == 199 /* ALEF */ &&
262 hb_font_get_glyph (font, 0x0644u, 0, &g) && g == 225 /* LAM */ &&
263 hb_font_get_glyph (font, 0x0649u, 0, &g) && g == 236 /* ALEF MAKSURA */ &&
264 hb_font_get_glyph (font, 0x064Au, 0, &g) && g == 237 /* YEH */ &&
265 hb_font_get_glyph (font, 0x0652u, 0, &g) && g == 250 /* SUKUN */))
266 return false;
267
268 const Manifest &manifest = reinterpret_cast<const Manifest&> (arabic_win1256_gsub_lookups.manifest);
269 ASSERT_STATIC (sizeof (arabic_win1256_gsub_lookups.manifestData) / sizeof (ManifestLookup)
270 <= ARABIC_FALLBACK_MAX_LOOKUPS);
271 /* TODO sanitize the table? */
272
273 unsigned j = 0;
274 unsigned int count = manifest.len;
275 for (unsigned int i = 0; i < count; i++)
276 {
277 fallback_plan->mask_array[j] = plan->map.get_1_mask (manifest[i].tag);
278 if (fallback_plan->mask_array[j])
279 {
280 fallback_plan->lookup_array[j] = const_cast<OT::SubstLookup*> (&(&manifest+manifest[i].lookupOffset));
281 if (fallback_plan->lookup_array[j])
282 {
283 fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]);
284 j++;
285 }
286 }
287 }
288
289 fallback_plan->num_lookups = j;
290 fallback_plan->free_lookups = false;
291
292 return j > 0;
293 #else
294 return false;
295 #endif
296 }
297
298 static bool
299 arabic_fallback_plan_init_unicode (arabic_fallback_plan_t *fallback_plan,
300 const hb_ot_shape_plan_t *plan,
301 hb_font_t *font)
302 {
303 ASSERT_STATIC (ARRAY_LENGTH_CONST(arabic_fallback_features) <= ARABIC_FALLBACK_MAX_LOOKUPS);
304 unsigned int j = 0;
305 for (unsigned int i = 0; i < ARRAY_LENGTH(arabic_fallback_features) ; i++)
306 {
307 fallback_plan->mask_array[j] = plan->map.get_1_mask (arabic_fallback_features[i]);
308 if (fallback_plan->mask_array[j])
309 {
310 fallback_plan->lookup_array[j] = arabic_fallback_synthesize_lookup (plan, font, i);
311 if (fallback_plan->lookup_array[j])
312 {
313 fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]);
314 j++;
315 }
316 }
317 }
318
319 fallback_plan->num_lookups = j;
320 fallback_plan->free_lookups = true;
321
322 return j > 0;
323 }
324
325 static arabic_fallback_plan_t *
326 arabic_fallback_plan_create (const hb_ot_shape_plan_t *plan,
327 hb_font_t *font)
328 {
329 arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) calloc (1, sizeof (arabic_fallback_plan_t));
330 if (unlikely (!fallback_plan))
331 return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil);
332
333 fallback_plan->num_lookups = 0;
334 fallback_plan->free_lookups = false;
335
336 /* Try synthesizing GSUB table using Unicode Arabic Presentation Forms,
337 * in case the font has cmap entries for the presentation-forms characters. */
338 if (arabic_fallback_plan_init_unicode (fallback_plan, plan, font))
339 return fallback_plan;
340
341 /* See if this looks like a Windows-1256-encoded font. If it does, use a
342 * hand-coded GSUB table. */
343 if (arabic_fallback_plan_init_win1256 (fallback_plan, plan, font))
344 return fallback_plan;
345
346 free (fallback_plan);
347 return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil);
348 }
349
350 static void
351 arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan)
352 {
353 if (!fallback_plan || fallback_plan == &arabic_fallback_plan_nil)
354 return;
355
356 for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
357 if (fallback_plan->lookup_array[i])
358 {
359 fallback_plan->accel_array[i].fini ();
360 if (fallback_plan->free_lookups)
361 free (fallback_plan->lookup_array[i]);
362 }
363
364 free (fallback_plan);
365 }
366
367 static void
368 arabic_fallback_plan_shape (arabic_fallback_plan_t *fallback_plan,
369 hb_font_t *font,
370 hb_buffer_t *buffer)
371 {
372 OT::hb_apply_context_t c (0, font, buffer);
373 for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
374 if (fallback_plan->lookup_array[i]) {
375 c.set_lookup_mask (fallback_plan->mask_array[i]);
376 hb_ot_layout_substitute_lookup (&c,
377 *fallback_plan->lookup_array[i],
378 fallback_plan->accel_array[i]);
379 }
380 }
381
382
383 #endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */