summaryrefslogtreecommitdiffstats
path: root/gfx/harfbuzz/src/hb-ot-map.hh
blob: efc8cae96a4abd2b25f62d0b0c4a16a33c2d2bcb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
/*
 * Copyright © 2009,2010  Red Hat, Inc.
 * Copyright © 2010,2011,2012,2013  Google, Inc.
 *
 *  This is part of HarfBuzz, a text shaping library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Red Hat Author(s): Behdad Esfahbod
 * Google Author(s): Behdad Esfahbod
 */

#ifndef HB_OT_MAP_HH
#define HB_OT_MAP_HH

#include "hb-buffer.hh"


#define HB_OT_MAP_MAX_BITS 8u
#define HB_OT_MAP_MAX_VALUE ((1u << HB_OT_MAP_MAX_BITS) - 1u)

struct hb_ot_shape_plan_t;

static const hb_tag_t table_tags[2] = {HB_OT_TAG_GSUB, HB_OT_TAG_GPOS};

struct hb_ot_map_t
{
  friend struct hb_ot_map_builder_t;

  public:

  struct feature_map_t {
    hb_tag_t tag; /* should be first for our bsearch to work */
    unsigned int index[2]; /* GSUB/GPOS */
    unsigned int stage[2]; /* GSUB/GPOS */
    unsigned int shift;
    hb_mask_t mask;
    hb_mask_t _1_mask; /* mask for value=1, for quick access */
    unsigned int needs_fallback : 1;
    unsigned int auto_zwnj : 1;
    unsigned int auto_zwj : 1;
    unsigned int random : 1;
    unsigned int per_syllable : 1;

    int cmp (const hb_tag_t tag_) const
    { return tag_ < tag ? -1 : tag_ > tag ? 1 : 0; }
  };

  struct lookup_map_t {
    unsigned short index;
    unsigned short auto_zwnj : 1;
    unsigned short auto_zwj : 1;
    unsigned short random : 1;
    unsigned short per_syllable : 1;
    hb_mask_t mask;
    hb_tag_t feature_tag;

    HB_INTERNAL static int cmp (const void *pa, const void *pb)
    {
      const lookup_map_t *a = (const lookup_map_t *) pa;
      const lookup_map_t *b = (const lookup_map_t *) pb;
      return a->index < b->index ? -1 : a->index > b->index ? 1 : 0;
    }
  };

  /* Pause functions return true if new glyph indices might have been
   * added to the buffer.  This is used to update buffer digest. */
  typedef bool (*pause_func_t) (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer);

  struct stage_map_t {
    unsigned int last_lookup; /* Cumulative */
    pause_func_t pause_func;
  };

  void init ()
  {
    hb_memset (this, 0, sizeof (*this));

    features.init0 ();
    for (unsigned int table_index = 0; table_index < 2; table_index++)
    {
      lookups[table_index].init0 ();
      stages[table_index].init0 ();
    }
  }
  void fini ()
  {
    features.fini ();
    for (unsigned int table_index = 0; table_index < 2; table_index++)
    {
      lookups[table_index].fini ();
      stages[table_index].fini ();
    }
  }

  hb_mask_t get_global_mask () const { return global_mask; }

  hb_mask_t get_mask (hb_tag_t feature_tag, unsigned int *shift = nullptr) const
  {
    const feature_map_t *map = features.bsearch (feature_tag);
    if (shift) *shift = map ? map->shift : 0;
    return map ? map->mask : 0;
  }

  bool needs_fallback (hb_tag_t feature_tag) const
  {
    const feature_map_t *map = features.bsearch (feature_tag);
    return map ? map->needs_fallback : false;
  }

  hb_mask_t get_1_mask (hb_tag_t feature_tag) const
  {
    const feature_map_t *map = features.bsearch (feature_tag);
    return map ? map->_1_mask : 0;
  }

  unsigned int get_feature_index (unsigned int table_index, hb_tag_t feature_tag) const
  {
    const feature_map_t *map = features.bsearch (feature_tag);
    return map ? map->index[table_index] : HB_OT_LAYOUT_NO_FEATURE_INDEX;
  }

  unsigned int get_feature_stage (unsigned int table_index, hb_tag_t feature_tag) const
  {
    const feature_map_t *map = features.bsearch (feature_tag);
    return map ? map->stage[table_index] : UINT_MAX;
  }

  hb_array_t<const hb_ot_map_t::lookup_map_t>
  get_stage_lookups (unsigned int table_index, unsigned int stage) const
  {
    if (unlikely (stage > stages[table_index].length))
      return hb_array<const hb_ot_map_t::lookup_map_t> (nullptr, 0);

    unsigned int start = stage ? stages[table_index][stage - 1].last_lookup : 0;
    unsigned int end   = stage < stages[table_index].length ? stages[table_index][stage].last_lookup : lookups[table_index].length;
    return lookups[table_index].as_array ().sub_array (start, end - start);
  }

  HB_INTERNAL void collect_lookups (unsigned int table_index, hb_set_t *lookups) const;
  template <typename Proxy>
  HB_INTERNAL void apply (const Proxy &proxy,
			  const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
  HB_INTERNAL void substitute (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
  HB_INTERNAL void position (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;

  public:
  hb_tag_t chosen_script[2];
  bool found_script[2];

  private:

  hb_mask_t global_mask = 0;

  hb_sorted_vector_t<feature_map_t> features;
  hb_vector_t<lookup_map_t> lookups[2]; /* GSUB/GPOS */
  hb_vector_t<stage_map_t> stages[2]; /* GSUB/GPOS */
};

enum hb_ot_map_feature_flags_t
{
  F_NONE		= 0x0000u,
  F_GLOBAL		= 0x0001u, /* Feature applies to all characters; results in no mask allocated for it. */
  F_HAS_FALLBACK	= 0x0002u, /* Has fallback implementation, so include mask bit even if feature not found. */
  F_MANUAL_ZWNJ		= 0x0004u, /* Don't skip over ZWNJ when matching **context**. */
  F_MANUAL_ZWJ		= 0x0008u, /* Don't skip over ZWJ when matching **input**. */
  F_MANUAL_JOINERS	= F_MANUAL_ZWNJ | F_MANUAL_ZWJ,
  F_GLOBAL_MANUAL_JOINERS= F_GLOBAL | F_MANUAL_JOINERS,
  F_GLOBAL_HAS_FALLBACK = F_GLOBAL | F_HAS_FALLBACK,
  F_GLOBAL_SEARCH	= 0x0010u, /* If feature not found in LangSys, look for it in global feature list and pick one. */
  F_RANDOM		= 0x0020u, /* Randomly select a glyph from an AlternateSubstFormat1 subtable. */
  F_PER_SYLLABLE	= 0x0040u  /* Contain lookup application to within syllable. */
};
HB_MARK_AS_FLAG_T (hb_ot_map_feature_flags_t);


struct hb_ot_map_feature_t
{
  hb_tag_t tag;
  hb_ot_map_feature_flags_t flags;
};

struct hb_ot_shape_plan_key_t;

struct hb_ot_map_builder_t
{
  public:

  HB_INTERNAL hb_ot_map_builder_t (hb_face_t *face_,
				   const hb_segment_properties_t &props_);

  HB_INTERNAL ~hb_ot_map_builder_t ();

  HB_INTERNAL void add_feature (hb_tag_t tag,
				hb_ot_map_feature_flags_t flags=F_NONE,
				unsigned int value=1);

  HB_INTERNAL bool has_feature (hb_tag_t tag);

  void add_feature (const hb_ot_map_feature_t &feat)
  { add_feature (feat.tag, feat.flags); }

  void enable_feature (hb_tag_t tag,
		       hb_ot_map_feature_flags_t flags=F_NONE,
		       unsigned int value=1)
  { add_feature (tag, F_GLOBAL | flags, value); }

  void disable_feature (hb_tag_t tag)
  { add_feature (tag, F_GLOBAL, 0); }

  void add_gsub_pause (hb_ot_map_t::pause_func_t pause_func)
  { add_pause (0, pause_func); }
  void add_gpos_pause (hb_ot_map_t::pause_func_t pause_func)
  { add_pause (1, pause_func); }

  HB_INTERNAL void compile (hb_ot_map_t                  &m,
			    const hb_ot_shape_plan_key_t &key);

  private:

  HB_INTERNAL void add_lookups (hb_ot_map_t  &m,
				unsigned int  table_index,
				unsigned int  feature_index,
				unsigned int  variations_index,
				hb_mask_t     mask,
				bool          auto_zwnj = true,
				bool          auto_zwj = true,
				bool          random = false,
				bool          per_syllable = false,
				hb_tag_t      feature_tag = HB_TAG(' ',' ',' ',' '));

  struct feature_info_t {
    hb_tag_t tag;
    unsigned int seq; /* sequence#, used for stable sorting only */
    unsigned int max_value;
    hb_ot_map_feature_flags_t flags;
    unsigned int default_value; /* for non-global features, what should the unset glyphs take */
    unsigned int stage[2]; /* GSUB/GPOS */

    HB_INTERNAL static int cmp (const void *pa, const void *pb)
    {
      const feature_info_t *a = (const feature_info_t *) pa;
      const feature_info_t *b = (const feature_info_t *) pb;
      return (a->tag != b->tag) ?  (a->tag < b->tag ? -1 : 1) :
	     (a->seq < b->seq ? -1 : a->seq > b->seq ? 1 : 0);
    }
  };

  struct stage_info_t {
    unsigned int index;
    hb_ot_map_t::pause_func_t pause_func;
  };

  HB_INTERNAL void add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func);

  public:

  hb_face_t *face;
  hb_segment_properties_t props;

  hb_tag_t chosen_script[2];
  bool found_script[2];
  unsigned int script_index[2], language_index[2];

  private:

  unsigned int current_stage[2]; /* GSUB/GPOS */
  hb_vector_t<feature_info_t> feature_infos;
  hb_vector_t<stage_info_t> stages[2]; /* GSUB/GPOS */
};



#endif /* HB_OT_MAP_HH */