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1 /*
2  * Copyright © 2009,2010  Red Hat, Inc.
3  * Copyright © 2010,2011,2012,2013  Google, Inc.
4  *
5  *  This is part of HarfBuzz, a text shaping library.
6  *
7  * Permission is hereby granted, without written agreement and without
8  * license or royalty fees, to use, copy, modify, and distribute this
9  * software and its documentation for any purpose, provided that the
10  * above copyright notice and the following two paragraphs appear in
11  * all copies of this software.
12  *
13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17  * DAMAGE.
18  *
19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24  *
25  * Red Hat Author(s): Behdad Esfahbod
26  * Google Author(s): Behdad Esfahbod
27  */
28 
29 #ifndef HB_OT_MAP_PRIVATE_HH
30 #define HB_OT_MAP_PRIVATE_HH
31 
32 #include "hb-buffer-private.hh"
33 
34 
35 struct hb_ot_shape_plan_t;
36 
37 static const hb_tag_t table_tags[2] = {HB_OT_TAG_GSUB, HB_OT_TAG_GPOS};
38 
39 struct hb_ot_map_t
40 {
41   friend struct hb_ot_map_builder_t;
42 
43   public:
44 
45   struct feature_map_t {
46     hb_tag_t tag; /* should be first for our bsearch to work */
47     unsigned int index[2]; /* GSUB/GPOS */
48     unsigned int stage[2]; /* GSUB/GPOS */
49     unsigned int shift;
50     hb_mask_t mask;
51     hb_mask_t _1_mask; /* mask for value=1, for quick access */
52     unsigned int needs_fallback : 1;
53     unsigned int auto_zwnj : 1;
54     unsigned int auto_zwj : 1;
55 
cmphb_ot_map_t::feature_map_t56     inline int cmp (const hb_tag_t *tag_) const
57     { return *tag_ < tag ? -1 : *tag_ > tag ? 1 : 0; }
58   };
59 
60   struct lookup_map_t {
61     unsigned short index;
62     unsigned short auto_zwnj : 1;
63     unsigned short auto_zwj : 1;
64     hb_mask_t mask;
65 
cmphb_ot_map_t::lookup_map_t66     static int cmp (const void *pa, const void *pb)
67     {
68       const lookup_map_t *a = (const lookup_map_t *) pa;
69       const lookup_map_t *b = (const lookup_map_t *) pb;
70       return a->index < b->index ? -1 : a->index > b->index ? 1 : 0;
71     }
72   };
73 
74   typedef void (*pause_func_t) (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer);
75 
76   struct stage_map_t {
77     unsigned int last_lookup; /* Cumulative */
78     pause_func_t pause_func;
79   };
80 
81 
hb_ot_map_thb_ot_map_t82   hb_ot_map_t (void) { memset (this, 0, sizeof (*this)); }
83 
get_global_maskhb_ot_map_t84   inline hb_mask_t get_global_mask (void) const { return global_mask; }
85 
get_maskhb_ot_map_t86   inline hb_mask_t get_mask (hb_tag_t feature_tag, unsigned int *shift = nullptr) const {
87     const feature_map_t *map = features.bsearch (&feature_tag);
88     if (shift) *shift = map ? map->shift : 0;
89     return map ? map->mask : 0;
90   }
91 
needs_fallbackhb_ot_map_t92   inline bool needs_fallback (hb_tag_t feature_tag) const {
93     const feature_map_t *map = features.bsearch (&feature_tag);
94     return map ? map->needs_fallback : false;
95   }
96 
get_1_maskhb_ot_map_t97   inline hb_mask_t get_1_mask (hb_tag_t feature_tag) const {
98     const feature_map_t *map = features.bsearch (&feature_tag);
99     return map ? map->_1_mask : 0;
100   }
101 
get_feature_indexhb_ot_map_t102   inline unsigned int get_feature_index (unsigned int table_index, hb_tag_t feature_tag) const {
103     const feature_map_t *map = features.bsearch (&feature_tag);
104     return map ? map->index[table_index] : HB_OT_LAYOUT_NO_FEATURE_INDEX;
105   }
106 
get_feature_stagehb_ot_map_t107   inline unsigned int get_feature_stage (unsigned int table_index, hb_tag_t feature_tag) const {
108     const feature_map_t *map = features.bsearch (&feature_tag);
109     return map ? map->stage[table_index] : (unsigned int) -1;
110   }
111 
get_stage_lookupshb_ot_map_t112   inline void get_stage_lookups (unsigned int table_index, unsigned int stage,
113 				 const struct lookup_map_t **plookups, unsigned int *lookup_count) const {
114     if (unlikely (stage == (unsigned int) -1)) {
115       *plookups = nullptr;
116       *lookup_count = 0;
117       return;
118     }
119     assert (stage <= stages[table_index].len);
120     unsigned int start = stage ? stages[table_index][stage - 1].last_lookup : 0;
121     unsigned int end   = stage < stages[table_index].len ? stages[table_index][stage].last_lookup : lookups[table_index].len;
122     *plookups = end == start ? nullptr : &lookups[table_index][start];
123     *lookup_count = end - start;
124   }
125 
126   HB_INTERNAL void collect_lookups (unsigned int table_index, hb_set_t *lookups) const;
127   template <typename Proxy>
128   HB_INTERNAL inline void apply (const Proxy &proxy,
129 				 const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
130   HB_INTERNAL void substitute (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
131   HB_INTERNAL void position (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
132 
finishhb_ot_map_t133   inline void finish (void) {
134     features.finish ();
135     for (unsigned int table_index = 0; table_index < 2; table_index++)
136     {
137       lookups[table_index].finish ();
138       stages[table_index].finish ();
139     }
140   }
141 
142   public:
143   hb_tag_t chosen_script[2];
144   bool found_script[2];
145 
146   private:
147 
148   hb_mask_t global_mask;
149 
150   hb_prealloced_array_t<feature_map_t, 8> features;
151   hb_prealloced_array_t<lookup_map_t, 32> lookups[2]; /* GSUB/GPOS */
152   hb_prealloced_array_t<stage_map_t, 4> stages[2]; /* GSUB/GPOS */
153 };
154 
155 enum hb_ot_map_feature_flags_t {
156   F_NONE		= 0x0000u,
157   F_GLOBAL		= 0x0001u, /* Feature applies to all characters; results in no mask allocated for it. */
158   F_HAS_FALLBACK	= 0x0002u, /* Has fallback implementation, so include mask bit even if feature not found. */
159   F_MANUAL_ZWNJ		= 0x0004u, /* Don't skip over ZWNJ when matching **context**. */
160   F_MANUAL_ZWJ		= 0x0008u, /* Don't skip over ZWJ when matching **input**. */
161   F_GLOBAL_SEARCH	= 0x0010u  /* If feature not found in LangSys, look for it in global feature list and pick one. */
162 };
163 HB_MARK_AS_FLAG_T (hb_ot_map_feature_flags_t);
164 /* Macro version for where const is desired. */
165 #define F_COMBINE(l,r) (hb_ot_map_feature_flags_t ((unsigned int) (l) | (unsigned int) (r)))
166 
167 
168 struct hb_ot_map_builder_t
169 {
170   public:
171 
172   HB_INTERNAL hb_ot_map_builder_t (hb_face_t *face_,
173 				   const hb_segment_properties_t *props_);
174 
175   HB_INTERNAL void add_feature (hb_tag_t tag, unsigned int value,
176 				hb_ot_map_feature_flags_t flags);
177 
add_global_bool_featurehb_ot_map_builder_t178   inline void add_global_bool_feature (hb_tag_t tag)
179   { add_feature (tag, 1, F_GLOBAL); }
180 
add_gsub_pausehb_ot_map_builder_t181   inline void add_gsub_pause (hb_ot_map_t::pause_func_t pause_func)
182   { add_pause (0, pause_func); }
add_gpos_pausehb_ot_map_builder_t183   inline void add_gpos_pause (hb_ot_map_t::pause_func_t pause_func)
184   { add_pause (1, pause_func); }
185 
186   HB_INTERNAL void compile (hb_ot_map_t  &m,
187 			    const int    *coords,
188 			    unsigned int  num_coords);
189 
finishhb_ot_map_builder_t190   inline void finish (void) {
191     feature_infos.finish ();
192     for (unsigned int table_index = 0; table_index < 2; table_index++)
193     {
194       stages[table_index].finish ();
195     }
196   }
197 
198   private:
199 
200   HB_INTERNAL void add_lookups (hb_ot_map_t  &m,
201 				hb_face_t    *face,
202 				unsigned int  table_index,
203 				unsigned int  feature_index,
204 				unsigned int  variations_index,
205 				hb_mask_t     mask,
206 				bool          auto_zwnj = true,
207 				bool          auto_zwj = true);
208 
209   struct feature_info_t {
210     hb_tag_t tag;
211     unsigned int seq; /* sequence#, used for stable sorting only */
212     unsigned int max_value;
213     hb_ot_map_feature_flags_t flags;
214     unsigned int default_value; /* for non-global features, what should the unset glyphs take */
215     unsigned int stage[2]; /* GSUB/GPOS */
216 
cmphb_ot_map_builder_t::feature_info_t217     static int cmp (const void *pa, const void *pb)
218     {
219       const feature_info_t *a = (const feature_info_t *) pa;
220       const feature_info_t *b = (const feature_info_t *) pb;
221       return (a->tag != b->tag) ?  (a->tag < b->tag ? -1 : 1) :
222 	     (a->seq < b->seq ? -1 : a->seq > b->seq ? 1 : 0);
223     }
224   };
225 
226   struct stage_info_t {
227     unsigned int index;
228     hb_ot_map_t::pause_func_t pause_func;
229   };
230 
231   HB_INTERNAL void add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func);
232 
233   public:
234 
235   hb_face_t *face;
236   hb_segment_properties_t props;
237 
238   hb_tag_t chosen_script[2];
239   bool found_script[2];
240   unsigned int script_index[2], language_index[2];
241 
242   private:
243 
244   unsigned int current_stage[2]; /* GSUB/GPOS */
245   hb_prealloced_array_t<feature_info_t, 32> feature_infos;
246   hb_prealloced_array_t<stage_info_t, 8> stages[2]; /* GSUB/GPOS */
247 };
248 
249 
250 
251 #endif /* HB_OT_MAP_PRIVATE_HH */
252