kc3-lang/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat2.hh

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• Hash : 8775e9b4
  Author :
  Date : 2022-07-06T13:28:17
  

  [>64k:layout:SingleSubst] Implement format 3/4
  
  Implements https://github.com/be-fonts/boring-expansion-spec/issues/31
  

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• src/OT/Layout/GSUB/SingleSubstFormat2.hh

• #ifndef OT_LAYOUT_GSUB_SINGLESUBSTFORMAT2_HH
  #define OT_LAYOUT_GSUB_SINGLESUBSTFORMAT2_HH
  
  #include "Common.hh"
  
  namespace OT {
  namespace Layout {
  namespace GSUB_impl {
  
  template <typename Types>
  struct SingleSubstFormat2_4
  {
    protected:
    HBUINT16      format;                 /* Format identifier--format = 2 */
    typename Types::template OffsetTo<Coverage>
                  coverage;               /* Offset to Coverage table--from
                                           * beginning of Substitution table */
    Array16Of<typename Types::HBGlyphID>
                  substitute;             /* Array of substitute
                                           * GlyphIDs--ordered by Coverage Index */
  
    public:
    DEFINE_SIZE_ARRAY (4 + Types::size, substitute);
  
    bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (coverage.sanitize (c, this) && substitute.sanitize (c));
    }
  
    bool intersects (const hb_set_t *glyphs) const
    { return (this+coverage).intersects (glyphs); }
  
    bool may_have_non_1to1 () const
    { return false; }
  
    void closure (hb_closure_context_t *c) const
    {
      + hb_zip (this+coverage, substitute)
      | hb_filter (c->parent_active_glyphs (), hb_first)
      | hb_map (hb_second)
      | hb_sink (c->output)
      ;
  
    }
  
    void closure_lookups (hb_closure_lookups_context_t *c) const {}
  
    void collect_glyphs (hb_collect_glyphs_context_t *c) const
    {
      if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
      + hb_zip (this+coverage, substitute)
      | hb_map (hb_second)
      | hb_sink (c->output)
      ;
    }
  
    const Coverage &get_coverage () const { return this+coverage; }
  
    bool would_apply (hb_would_apply_context_t *c) const
    { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
  
    bool apply (hb_ot_apply_context_t *c) const
    {
      TRACE_APPLY (this);
      unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
      if (likely (index == NOT_COVERED)) return_trace (false);
  
      if (unlikely (index >= substitute.len)) return_trace (false);
  
      c->replace_glyph (substitute[index]);
  
      return_trace (true);
    }
  
    template<typename Iterator,
             hb_requires (hb_is_sorted_source_of (Iterator,
                                                  hb_codepoint_pair_t))>
    bool serialize (hb_serialize_context_t *c,
                    Iterator it)
    {
      TRACE_SERIALIZE (this);
      auto substitutes =
        + it
        | hb_map (hb_second)
        ;
      auto glyphs =
        + it
        | hb_map_retains_sorting (hb_first)
        ;
      if (unlikely (!c->extend_min (this))) return_trace (false);
      if (unlikely (!substitute.serialize (c, substitutes))) return_trace (false);
      if (unlikely (!coverage.serialize_serialize (c, glyphs))) return_trace (false);
      return_trace (true);
    }
  
    bool subset (hb_subset_context_t *c) const
    {
      TRACE_SUBSET (this);
      const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
      const hb_map_t &glyph_map = *c->plan->glyph_map;
  
      auto it =
      + hb_zip (this+coverage, substitute)
      | hb_filter (glyphset, hb_first)
      | hb_filter (glyphset, hb_second)
      | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const typename Types::HBGlyphID &> p) -> hb_codepoint_pair_t
                                { return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
      ;
  
      bool ret = bool (it);
      SingleSubst_serialize (c->serializer, it);
      return_trace (ret);
    }
  };
  
  }
  }
  }
  
  #endif /* OT_LAYOUT_GSUB_SINGLESUBSTFORMAT2_HH */
  

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