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_zwj : 1;
54 
cmphb_ot_map_t::feature_map_t55     static int cmp (const feature_map_t *a, const feature_map_t *b)
56     { return a->tag < b->tag ? -1 : a->tag > b->tag ? 1 : 0; }
57   };
58 
59   struct lookup_map_t {
60     unsigned short index;
61     unsigned short auto_zwj : 1;
62     hb_mask_t mask;
63 
cmphb_ot_map_t::lookup_map_t64     static int cmp (const lookup_map_t *a, const lookup_map_t *b)
65     { return a->index < b->index ? -1 : a->index > b->index ? 1 : 0; }
66   };
67 
68   typedef void (*pause_func_t) (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer);
69 
70   struct stage_map_t {
71     unsigned int last_lookup; /* Cumulative */
72     pause_func_t pause_func;
73   };
74 
75 
hb_ot_map_thb_ot_map_t76   hb_ot_map_t (void) { memset (this, 0, sizeof (*this)); }
77 
get_global_maskhb_ot_map_t78   inline hb_mask_t get_global_mask (void) const { return global_mask; }
79 
get_maskhb_ot_map_t80   inline hb_mask_t get_mask (hb_tag_t feature_tag, unsigned int *shift = NULL) const {
81     const feature_map_t *map = features.bsearch (&feature_tag);
82     if (shift) *shift = map ? map->shift : 0;
83     return map ? map->mask : 0;
84   }
85 
needs_fallbackhb_ot_map_t86   inline bool needs_fallback (hb_tag_t feature_tag) const {
87     const feature_map_t *map = features.bsearch (&feature_tag);
88     return map ? map->needs_fallback : false;
89   }
90 
get_1_maskhb_ot_map_t91   inline hb_mask_t get_1_mask (hb_tag_t feature_tag) const {
92     const feature_map_t *map = features.bsearch (&feature_tag);
93     return map ? map->_1_mask : 0;
94   }
95 
get_feature_indexhb_ot_map_t96   inline unsigned int get_feature_index (unsigned int table_index, hb_tag_t feature_tag) const {
97     const feature_map_t *map = features.bsearch (&feature_tag);
98     return map ? map->index[table_index] : HB_OT_LAYOUT_NO_FEATURE_INDEX;
99   }
100 
get_feature_stagehb_ot_map_t101   inline unsigned int get_feature_stage (unsigned int table_index, hb_tag_t feature_tag) const {
102     const feature_map_t *map = features.bsearch (&feature_tag);
103     return map ? map->stage[table_index] : (unsigned int) -1;
104   }
105 
get_stage_lookupshb_ot_map_t106   inline void get_stage_lookups (unsigned int table_index, unsigned int stage,
107 				 const struct lookup_map_t **plookups, unsigned int *lookup_count) const {
108     if (unlikely (stage == (unsigned int) -1)) {
109       *plookups = NULL;
110       *lookup_count = 0;
111       return;
112     }
113     assert (stage <= stages[table_index].len);
114     unsigned int start = stage ? stages[table_index][stage - 1].last_lookup : 0;
115     unsigned int end   = stage < stages[table_index].len ? stages[table_index][stage].last_lookup : lookups[table_index].len;
116     *plookups = &lookups[table_index][start];
117     *lookup_count = end - start;
118   }
119 
120   HB_INTERNAL void collect_lookups (unsigned int table_index, hb_set_t *lookups) const;
121   template <typename Proxy>
122   HB_INTERNAL inline void apply (const Proxy &proxy,
123 				 const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
124   HB_INTERNAL void substitute (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
125   HB_INTERNAL void position (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
126 
finishhb_ot_map_t127   inline void finish (void) {
128     features.finish ();
129     for (unsigned int table_index = 0; table_index < 2; table_index++)
130     {
131       lookups[table_index].finish ();
132       stages[table_index].finish ();
133     }
134   }
135 
136   public:
137   hb_tag_t chosen_script[2];
138   bool found_script[2];
139 
140   private:
141 
142   HB_INTERNAL void add_lookups (hb_face_t    *face,
143 				unsigned int  table_index,
144 				unsigned int  feature_index,
145 				hb_mask_t     mask,
146 				bool          auto_zwj);
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_ZWJ		= 0x0004u, /* Don't skip over ZWJ when matching. */
160   F_GLOBAL_SEARCH	= 0x0008u  /* If feature not found in LangSys, look for it in global feature list and pick one. */
161 };
162 HB_MARK_AS_FLAG_T (hb_ot_map_feature_flags_t);
163 /* Macro version for where const is desired. */
164 #define F_COMBINE(l,r) (hb_ot_map_feature_flags_t ((unsigned int) (l) | (unsigned int) (r)))
165 
166 
167 struct hb_ot_map_builder_t
168 {
169   public:
170 
171   HB_INTERNAL hb_ot_map_builder_t (hb_face_t *face_,
172 				   const hb_segment_properties_t *props_);
173 
174   HB_INTERNAL void add_feature (hb_tag_t tag, unsigned int value,
175 				hb_ot_map_feature_flags_t flags);
176 
add_global_bool_featurehb_ot_map_builder_t177   inline void add_global_bool_feature (hb_tag_t tag)
178   { add_feature (tag, 1, F_GLOBAL); }
179 
add_gsub_pausehb_ot_map_builder_t180   inline void add_gsub_pause (hb_ot_map_t::pause_func_t pause_func)
181   { add_pause (0, pause_func); }
add_gpos_pausehb_ot_map_builder_t182   inline void add_gpos_pause (hb_ot_map_t::pause_func_t pause_func)
183   { add_pause (1, pause_func); }
184 
185   HB_INTERNAL void compile (struct hb_ot_map_t &m);
186 
finishhb_ot_map_builder_t187   inline void finish (void) {
188     feature_infos.finish ();
189     for (unsigned int table_index = 0; table_index < 2; table_index++)
190     {
191       stages[table_index].finish ();
192     }
193   }
194 
195   private:
196 
197   struct feature_info_t {
198     hb_tag_t tag;
199     unsigned int seq; /* sequence#, used for stable sorting only */
200     unsigned int max_value;
201     hb_ot_map_feature_flags_t flags;
202     unsigned int default_value; /* for non-global features, what should the unset glyphs take */
203     unsigned int stage[2]; /* GSUB/GPOS */
204 
cmphb_ot_map_builder_t::feature_info_t205     static int cmp (const feature_info_t *a, const feature_info_t *b)
206     { return (a->tag != b->tag) ?  (a->tag < b->tag ? -1 : 1) :
207 	     (a->seq < b->seq ? -1 : a->seq > b->seq ? 1 : 0); }
208   };
209 
210   struct stage_info_t {
211     unsigned int index;
212     hb_ot_map_t::pause_func_t pause_func;
213   };
214 
215   HB_INTERNAL void add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func);
216 
217   public:
218 
219   hb_face_t *face;
220   hb_segment_properties_t props;
221 
222   hb_tag_t chosen_script[2];
223   bool found_script[2];
224   unsigned int script_index[2], language_index[2];
225 
226   private:
227 
228   unsigned int current_stage[2]; /* GSUB/GPOS */
229   hb_prealloced_array_t<feature_info_t, 32> feature_infos;
230   hb_prealloced_array_t<stage_info_t, 8> stages[2]; /* GSUB/GPOS */
231 };
232 
233 
234 
235 #endif /* HB_OT_MAP_PRIVATE_HH */
236