Line data Source code
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 0 : 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 0 : unsigned int num_glyphs = 0;
55 :
56 : /* Populate arrays */
57 0 : for (hb_codepoint_t u = SHAPING_TABLE_FIRST; u < SHAPING_TABLE_LAST + 1; u++)
58 : {
59 0 : hb_codepoint_t s = shaping_table[u - SHAPING_TABLE_FIRST][feature_index];
60 : hb_codepoint_t u_glyph, s_glyph;
61 :
62 0 : if (!s ||
63 0 : !hb_font_get_glyph (font, u, 0, &u_glyph) ||
64 0 : !hb_font_get_glyph (font, s, 0, &s_glyph) ||
65 0 : u_glyph == s_glyph ||
66 0 : u_glyph > 0xFFFFu || s_glyph > 0xFFFFu)
67 0 : continue;
68 :
69 0 : glyphs[num_glyphs].set (u_glyph);
70 0 : substitutes[num_glyphs].set (s_glyph);
71 :
72 0 : num_glyphs++;
73 : }
74 :
75 0 : if (!num_glyphs)
76 0 : return NULL;
77 :
78 : /* Bubble-sort or something equally good!
79 : * May not be good-enough for presidential candidate interviews, but good-enough for us... */
80 0 : hb_stable_sort (&glyphs[0], num_glyphs, OT::GlyphID::cmp, &substitutes[0]);
81 :
82 0 : OT::Supplier<OT::GlyphID> glyphs_supplier (glyphs, num_glyphs);
83 0 : 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 0 : OT::hb_serialize_context_t c (buf, sizeof (buf));
88 0 : 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 0 : num_glyphs);
94 0 : c.end_serialize ();
95 : /* TODO sanitize the results? */
96 :
97 0 : return ret ? c.copy<OT::SubstLookup> () : NULL;
98 : }
99 :
100 : static OT::SubstLookup *
101 0 : 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 0 : 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 0 : unsigned int num_ligatures = 0;
114 :
115 : /* Populate arrays */
116 :
117 : /* Sort out the first-glyphs */
118 0 : for (unsigned int first_glyph_idx = 0; first_glyph_idx < ARRAY_LENGTH (first_glyphs); first_glyph_idx++)
119 : {
120 0 : hb_codepoint_t first_u = ligature_table[first_glyph_idx].first;
121 : hb_codepoint_t first_glyph;
122 0 : if (!hb_font_get_glyph (font, first_u, 0, &first_glyph))
123 0 : continue;
124 0 : first_glyphs[num_first_glyphs].set (first_glyph);
125 0 : ligature_per_first_glyph_count_list[num_first_glyphs] = 0;
126 0 : first_glyphs_indirection[num_first_glyphs] = first_glyph_idx;
127 0 : num_first_glyphs++;
128 : }
129 0 : hb_stable_sort (&first_glyphs[0], num_first_glyphs, OT::GlyphID::cmp, &first_glyphs_indirection[0]);
130 :
131 : /* Now that the first-glyphs are sorted, walk again, populate ligatures. */
132 0 : for (unsigned int i = 0; i < num_first_glyphs; i++)
133 : {
134 0 : unsigned int first_glyph_idx = first_glyphs_indirection[i];
135 :
136 0 : for (unsigned int second_glyph_idx = 0; second_glyph_idx < ARRAY_LENGTH (ligature_table[0].ligatures); second_glyph_idx++)
137 : {
138 0 : hb_codepoint_t second_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].second;
139 0 : hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].ligature;
140 : hb_codepoint_t second_glyph, ligature_glyph;
141 0 : if (!second_u ||
142 0 : !hb_font_get_glyph (font, second_u, 0, &second_glyph) ||
143 0 : !hb_font_get_glyph (font, ligature_u, 0, &ligature_glyph))
144 0 : continue;
145 :
146 0 : ligature_per_first_glyph_count_list[i]++;
147 :
148 0 : ligature_list[num_ligatures].set (ligature_glyph);
149 0 : component_count_list[num_ligatures] = 2;
150 0 : component_list[num_ligatures].set (second_glyph);
151 0 : num_ligatures++;
152 : }
153 : }
154 :
155 0 : if (!num_ligatures)
156 0 : return NULL;
157 :
158 0 : OT::Supplier<OT::GlyphID> first_glyphs_supplier (first_glyphs, num_first_glyphs);
159 0 : OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier (ligature_per_first_glyph_count_list, num_first_glyphs);
160 0 : OT::Supplier<OT::GlyphID> ligatures_supplier (ligature_list, num_ligatures);
161 0 : OT::Supplier<unsigned int > component_count_supplier (component_count_list, num_ligatures);
162 0 : 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 0 : OT::hb_serialize_context_t c (buf, sizeof (buf));
167 0 : 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 0 : component_supplier);
176 :
177 0 : c.end_serialize ();
178 : /* TODO sanitize the results? */
179 :
180 0 : return ret ? c.copy<OT::SubstLookup> () : NULL;
181 : }
182 :
183 : static OT::SubstLookup *
184 0 : arabic_fallback_synthesize_lookup (const hb_ot_shape_plan_t *plan,
185 : hb_font_t *font,
186 : unsigned int feature_index)
187 : {
188 0 : if (feature_index < 4)
189 0 : return arabic_fallback_synthesize_lookup_single (plan, font, feature_index);
190 : else
191 0 : 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 0 : 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 : ASSERT_STATIC (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 0 : return false;
266 : #endif
267 : }
268 :
269 : static bool
270 0 : 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 : ASSERT_STATIC (ARRAY_LENGTH_CONST(arabic_fallback_features) <= ARABIC_FALLBACK_MAX_LOOKUPS);
275 0 : unsigned int j = 0;
276 0 : for (unsigned int i = 0; i < ARRAY_LENGTH(arabic_fallback_features) ; i++)
277 : {
278 0 : fallback_plan->mask_array[j] = plan->map.get_1_mask (arabic_fallback_features[i]);
279 0 : if (fallback_plan->mask_array[j])
280 : {
281 0 : fallback_plan->lookup_array[j] = arabic_fallback_synthesize_lookup (plan, font, i);
282 0 : if (fallback_plan->lookup_array[j])
283 : {
284 0 : fallback_plan->accel_array[j].init (*fallback_plan->lookup_array[j]);
285 0 : j++;
286 : }
287 : }
288 : }
289 :
290 0 : fallback_plan->num_lookups = j;
291 0 : fallback_plan->free_lookups = true;
292 :
293 0 : return j > 0;
294 : }
295 :
296 : static arabic_fallback_plan_t *
297 0 : arabic_fallback_plan_create (const hb_ot_shape_plan_t *plan,
298 : hb_font_t *font)
299 : {
300 0 : arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) calloc (1, sizeof (arabic_fallback_plan_t));
301 0 : if (unlikely (!fallback_plan))
302 0 : return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil);
303 :
304 0 : fallback_plan->num_lookups = 0;
305 0 : 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 0 : if (arabic_fallback_plan_init_unicode (fallback_plan, plan, font))
310 0 : 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 0 : if (arabic_fallback_plan_init_win1256 (fallback_plan, plan, font))
315 0 : return fallback_plan;
316 :
317 0 : free (fallback_plan);
318 0 : return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil);
319 : }
320 :
321 : static void
322 0 : arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan)
323 : {
324 0 : if (!fallback_plan || fallback_plan == &arabic_fallback_plan_nil)
325 0 : return;
326 :
327 0 : for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
328 0 : if (fallback_plan->lookup_array[i])
329 : {
330 0 : fallback_plan->accel_array[i].fini ();
331 0 : if (fallback_plan->free_lookups)
332 0 : free (fallback_plan->lookup_array[i]);
333 : }
334 :
335 0 : free (fallback_plan);
336 : }
337 :
338 : static void
339 0 : arabic_fallback_plan_shape (arabic_fallback_plan_t *fallback_plan,
340 : hb_font_t *font,
341 : hb_buffer_t *buffer)
342 : {
343 0 : OT::hb_apply_context_t c (0, font, buffer);
344 0 : for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
345 0 : if (fallback_plan->lookup_array[i]) {
346 0 : c.set_lookup_mask (fallback_plan->mask_array[i]);
347 0 : hb_ot_layout_substitute_lookup (&c,
348 0 : *fallback_plan->lookup_array[i],
349 0 : fallback_plan->accel_array[i]);
350 : }
351 0 : }
352 :
353 :
354 : #endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */
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