third_party/harfbuzz-ng/src/hb-ot-map-private.hh

   1 /*
   2  * Copyright © 2009,2010  Red Hat, Inc.
   3  * Copyright © 2010,2011,2012  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 #include "hb-ot-layout-private.hh"
  35
  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     hb_bool_t needs_fallback;
  53
  54     static int cmp (const feature_map_t *a, const feature_map_t *b)
  55     { return a->tag < b->tag ? -1 : a->tag > b->tag ? 1 : 0; }
  56   };
  57
  58   struct lookup_map_t {
  59     unsigned int index;
  60     hb_mask_t mask;
  61
  62     static int cmp (const lookup_map_t *a, const lookup_map_t *b)
  63     { return a->index < b->index ? -1 : a->index > b->index ? 1 : 0; }
  64   };
  65
  66   typedef void (*pause_func_t) (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer);
  67
  68   struct pause_map_t {
  69     unsigned int num_lookups; /* Cumulative */
  70     pause_func_t callback;
  71   };
  72
  73
  74   hb_ot_map_t (void) { memset (this, 0, sizeof (*this)); }
  75
  76   inline hb_mask_t get_global_mask (void) const { return global_mask; }
  77
  78   inline hb_mask_t get_mask (hb_tag_t feature_tag, unsigned int *shift = NULL) const {
  79     const feature_map_t *map = features.bsearch (&feature_tag);
  80     if (shift) *shift = map ? map->shift : 0;
  81     return map ? map->mask : 0;
  82   }
  83
  84   inline bool needs_fallback (hb_tag_t feature_tag) const {
  85     const feature_map_t *map = features.bsearch (&feature_tag);
  86     return map ? map->needs_fallback : false;
  87   }
  88
  89   inline hb_mask_t get_1_mask (hb_tag_t feature_tag) const {
  90     const feature_map_t *map = features.bsearch (&feature_tag);
  91     return map ? map->_1_mask : 0;
  92   }
  93
  94   inline unsigned int get_feature_index (unsigned int table_index, hb_tag_t feature_tag) const {
  95     const feature_map_t *map = features.bsearch (&feature_tag);
  96     return map ? map->index[table_index] : HB_OT_LAYOUT_NO_FEATURE_INDEX;
  97   }
  98
  99   inline unsigned int get_feature_stage (unsigned int table_index, hb_tag_t feature_tag) const {
 100     const feature_map_t *map = features.bsearch (&feature_tag);
 101     return map ? map->stage[table_index] : (unsigned int) -1;
 102   }
 103
 104   inline void get_stage_lookups (unsigned int table_index, unsigned int stage,
 105                                  const struct lookup_map_t **plookups, unsigned int *lookup_count) const {
 106     if (unlikely (stage == (unsigned int) -1)) {
 107       *plookups = NULL;
 108       *lookup_count = 0;
 109       return;
 110     }
 111     assert (stage <= pauses[table_index].len);
 112     unsigned int start = stage ? pauses[table_index][stage - 1].num_lookups : 0;
 113     unsigned int end   = stage < pauses[table_index].len ? pauses[table_index][stage].num_lookups : lookups[table_index].len;
 114     *plookups = &lookups[table_index][start];
 115     *lookup_count = end - start;
 116   }
 117
 118   inline hb_tag_t get_chosen_script (unsigned int table_index) const
 119   { return chosen_script[table_index]; }
 120
 121   HB_INTERNAL void substitute_closure (const struct hb_ot_shape_plan_t *plan, hb_face_t *face, hb_set_t *glyphs) const;
 122   HB_INTERNAL void substitute (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
 123   HB_INTERNAL void position (const struct hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const;
 124
 125   inline void finish (void) {
 126     features.finish ();
 127     lookups[0].finish ();
 128     lookups[1].finish ();
 129     pauses[0].finish ();
 130     pauses[1].finish ();
 131   }
 132
 133
 134   private:
 135
 136   HB_INTERNAL void add_lookups (hb_face_t    *face,
 137                                 unsigned int  table_index,
 138                                 unsigned int  feature_index,
 139                                 hb_mask_t     mask);
 140
 141   hb_mask_t global_mask;
 142
 143   hb_tag_t chosen_script[2];
 144   hb_prealloced_array_t<feature_map_t, 8> features;
 145   hb_prealloced_array_t<lookup_map_t, 32> lookups[2]; /* GSUB/GPOS */
 146   hb_prealloced_array_t<pause_map_t, 1> pauses[2]; /* GSUB/GPOS */
 147 };
 148
 149
 150 struct hb_ot_map_builder_t
 151 {
 152   public:
 153
 154   hb_ot_map_builder_t (void) { memset (this, 0, sizeof (*this)); }
 155
 156   HB_INTERNAL void add_feature (hb_tag_t tag, unsigned int value, bool global, bool has_fallback = false);
 157
 158   inline void add_bool_feature (hb_tag_t tag, bool global = true, bool has_fallback = false)
 159   { add_feature (tag, 1, global, has_fallback); }
 160
 161   inline void add_gsub_pause (hb_ot_map_t::pause_func_t pause_func)
 162   { add_pause (0, pause_func); }
 163   inline void add_gpos_pause (hb_ot_map_t::pause_func_t pause_func)
 164   { add_pause (1, pause_func); }
 165
 166   HB_INTERNAL void compile (hb_face_t *face,
 167                             const hb_segment_properties_t *props,
 168                             struct hb_ot_map_t &m);
 169
 170   inline void finish (void) {
 171     feature_infos.finish ();
 172     pauses[0].finish ();
 173     pauses[1].finish ();
 174   }
 175
 176   private:
 177
 178   struct feature_info_t {
 179     hb_tag_t tag;
 180     unsigned int seq; /* sequence#, used for stable sorting only */
 181     unsigned int max_value;
 182     bool global; /* whether the feature applies value to every glyph in the buffer */
 183     bool has_fallback; /* whether to allocate bits even if feature not found */
 184     unsigned int default_value; /* for non-global features, what should the unset glyphs take */
 185     unsigned int stage[2]; /* GSUB/GPOS */
 186
 187     static int cmp (const feature_info_t *a, const feature_info_t *b)
 188     { return (a->tag != b->tag) ?  (a->tag < b->tag ? -1 : 1) : (a->seq < b->seq ? -1 : 1); }
 189   };
 190
 191   struct pause_info_t {
 192     unsigned int stage;
 193     hb_ot_map_t::pause_func_t callback;
 194   };
 195
 196   HB_INTERNAL void add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func);
 197
 198   unsigned int current_stage[2]; /* GSUB/GPOS */
 199   hb_prealloced_array_t<feature_info_t,16> feature_infos;
 200   hb_prealloced_array_t<pause_info_t, 1> pauses[2]; /* GSUB/GPOS */
 201 };
 202
 203
 204
 205 #endif /* HB_OT_MAP_PRIVATE_HH */