summaryrefslogtreecommitdiff
path: root/thirdparty/harfbuzz/src/OT/Layout/GSUB/Ligature.hh
blob: 22ed65f858ad30a744827d320aeaf4656b65639b (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
#ifndef OT_LAYOUT_GSUB_LIGATURE_HH
#define OT_LAYOUT_GSUB_LIGATURE_HH

#include "Common.hh"

namespace OT {
namespace Layout {
namespace GSUB_impl {

template <typename Types>
struct Ligature
{
  protected:
  typename Types::HBGlyphID
		ligGlyph;               /* GlyphID of ligature to substitute */
  HeadlessArrayOf<typename Types::HBGlyphID>
		component;              /* Array of component GlyphIDs--start
                                         * with the second  component--ordered
                                         * in writing direction */
  public:
  DEFINE_SIZE_ARRAY (Types::size + 2, component);

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (ligGlyph.sanitize (c) && component.sanitize (c));
  }

  bool intersects (const hb_set_t *glyphs) const
  { return hb_all (component, glyphs); }

  void closure (hb_closure_context_t *c) const
  {
    if (!intersects (c->glyphs)) return;
    c->output->add (ligGlyph);
  }

  void collect_glyphs (hb_collect_glyphs_context_t *c) const
  {
    c->input->add_array (component.arrayZ, component.get_length ());
    c->output->add (ligGlyph);
  }

  bool would_apply (hb_would_apply_context_t *c) const
  {
    if (c->len != component.lenP1)
      return false;

    for (unsigned int i = 1; i < c->len; i++)
      if (likely (c->glyphs[i] != component[i]))
        return false;

    return true;
  }

  bool apply (hb_ot_apply_context_t *c) const
  {
    TRACE_APPLY (this);
    unsigned int count = component.lenP1;

    if (unlikely (!count)) return_trace (false);

    /* Special-case to make it in-place and not consider this
     * as a "ligated" substitution. */
    if (unlikely (count == 1))
    {
      c->replace_glyph (ligGlyph);
      return_trace (true);
    }

    unsigned int total_component_count = 0;

    unsigned int match_end = 0;
    unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];

    if (likely (!match_input (c, count,
                              &component[1],
                              match_glyph,
                              nullptr,
                              &match_end,
                              match_positions,
                              &total_component_count)))
    {
      c->buffer->unsafe_to_concat (c->buffer->idx, match_end);
      return_trace (false);
    }

    ligate_input (c,
                  count,
                  match_positions,
                  match_end,
                  ligGlyph,
                  total_component_count);

    return_trace (true);
  }

  template <typename Iterator,
            hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
  bool serialize (hb_serialize_context_t *c,
                  hb_codepoint_t ligature,
                  Iterator components /* Starting from second */)
  {
    TRACE_SERIALIZE (this);
    if (unlikely (!c->extend_min (this))) return_trace (false);
    ligGlyph = ligature;
    if (unlikely (!component.serialize (c, components))) return_trace (false);
    return_trace (true);
  }

  bool subset (hb_subset_context_t *c, unsigned coverage_idx) const
  {
    TRACE_SUBSET (this);
    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
    const hb_map_t &glyph_map = *c->plan->glyph_map;

    if (!intersects (&glyphset) || !glyphset.has (ligGlyph)) return_trace (false);
    // Ensure Coverage table is always packed after this.
    c->serializer->add_virtual_link (coverage_idx);

    auto it =
      + hb_iter (component)
      | hb_map (glyph_map)
      ;

    auto *out = c->serializer->start_embed (*this);
    return_trace (out->serialize (c->serializer,
                                  glyph_map[ligGlyph],
                                  it));  }
};


}
}
}

#endif  /* OT_LAYOUT_GSUB_LIGATURE_HH */