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

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• Hash : dae2c8bb
  Author :
  Date : 2025-08-14T22:26:40
  

  [ligature] Add a set-digest on the second component (#5464)
  
  

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• src/OT/Layout/GSUB/LigatureSet.hh

• #ifndef OT_LAYOUT_GSUB_LIGATURESET_HH
  #define OT_LAYOUT_GSUB_LIGATURESET_HH
  
  #include "Common.hh"
  #include "Ligature.hh"
  
  namespace OT {
  namespace Layout {
  namespace GSUB_impl {
  
  template <typename Types>
  struct LigatureSet
  {
    public:
    Array16OfOffset16To<Ligature<Types>>
                  ligature;               /* Array LigatureSet tables
                                           * ordered by preference */
    
    DEFINE_SIZE_ARRAY (2, ligature);
  
    bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (ligature.sanitize (c, this));
    }
  
    bool intersects (const hb_set_t *glyphs) const
    {
      return
      + hb_iter (ligature)
      | hb_map (hb_add (this))
      | hb_map ([glyphs] (const Ligature<Types> &_) { return _.intersects (glyphs); })
      | hb_any
      ;
    }
  
    bool intersects_lig_glyph (const hb_set_t *glyphs) const
    {
      return
      + hb_iter (ligature)
      | hb_map (hb_add (this))
      | hb_map ([glyphs] (const Ligature<Types> &_) { 
        return _.intersects_lig_glyph (glyphs) && _.intersects (glyphs);
      })
      | hb_any
      ;
    }
  
    void closure (hb_closure_context_t *c) const
    {
      + hb_iter (ligature)
      | hb_map (hb_add (this))
      | hb_apply ([c] (const Ligature<Types> &_) { _.closure (c); })
      ;
    }
  
    void collect_glyphs (hb_collect_glyphs_context_t *c) const
    {
      + hb_iter (ligature)
      | hb_map (hb_add (this))
      | hb_apply ([c] (const Ligature<Types> &_) { _.collect_glyphs (c); })
      ;
    }
  
    template <typename set_t>
    void collect_seconds (set_t &s) const
    {
      + hb_iter (ligature)
      | hb_map (hb_add (this))
      | hb_apply ([&s] (const Ligature<Types> &_) { _.collect_second (s); })
      ;
    }
  
    bool would_apply (hb_would_apply_context_t *c) const
    {
      return
      + hb_iter (ligature)
      | hb_map (hb_add (this))
      | hb_map ([c] (const Ligature<Types> &_) { return _.would_apply (c); })
      | hb_any
      ;
    }
  
    bool apply (hb_ot_apply_context_t *c, const hb_set_digest_t *seconds = nullptr) const
    {
      TRACE_APPLY (this);
  
      unsigned int num_ligs = ligature.len;
  
  #ifndef HB_NO_OT_RULESETS_FAST_PATH
      if (HB_OPTIMIZE_SIZE_VAL || num_ligs <= 1)
  #endif
      {
      slow:
        for (unsigned int i = 0; i < num_ligs; i++)
        {
  	const auto &lig = this+ligature.arrayZ[i];
  	if (lig.apply (c)) return_trace (true);
        }
        return_trace (false);
      }
  
      /* This version is optimized for speed by matching the second component
       * of the ligature here, instead of calling into the ligation code.
       *
       * This is replicated in ChainRuleSet and RuleSet. */
  
      auto &skippy_iter = c->iter_input;
      skippy_iter.reset (c->buffer->idx);
      skippy_iter.set_match_func (match_always, nullptr);
      skippy_iter.set_glyph_data ((HBUINT16 *) nullptr);
      unsigned unsafe_to;
      hb_codepoint_t second = (unsigned) -1;
      bool matched = skippy_iter.next (&unsafe_to);
      if (likely (matched))
      {
        second = c->buffer->info[skippy_iter.idx].codepoint;
        unsafe_to = skippy_iter.idx + 1;
  
        if (skippy_iter.may_skip (c->buffer->info[skippy_iter.idx]))
        {
  	/* Can't use the fast path if eg. the next char is a default-ignorable
  	 * or other skippable. */
          goto slow;
        }
      }
      else
        goto slow;
  
      if (seconds && !seconds->may_have (second))
        return_trace (false);
      bool unsafe_to_concat = false;
      for (unsigned int i = 0; i < num_ligs; i++)
      {
        const auto &lig = this+ligature.arrayZ[i];
        if (unlikely (lig.component.lenP1 <= 1) ||
  	  lig.component.arrayZ[0] == second)
        {
  	if (lig.apply (c))
  	{
  	  if (unsafe_to_concat)
  	    c->buffer->unsafe_to_concat (c->buffer->idx, unsafe_to);
  	  return_trace (true);
  	}
        }
        else if (likely (lig.component.lenP1 > 1))
          unsafe_to_concat = true;
      }
      if (likely (unsafe_to_concat))
        c->buffer->unsafe_to_concat (c->buffer->idx, unsafe_to);
  
      return_trace (false);
    }
  
    bool serialize (hb_serialize_context_t *c,
                    hb_array_t<const HBGlyphID16> ligatures,
                    hb_array_t<const unsigned int> component_count_list,
                    hb_array_t<const HBGlyphID16> &component_list /* Starting from second for each ligature */)
    {
      TRACE_SERIALIZE (this);
      if (unlikely (!c->extend_min (this))) return_trace (false);
      if (unlikely (!ligature.serialize (c, ligatures.length))) return_trace (false);
      for (unsigned int i = 0; i < ligatures.length; i++)
      {
        unsigned int component_count = (unsigned) hb_max ((int) component_count_list[i] - 1, 0);
        if (unlikely (!ligature[i].serialize_serialize (c,
                                                        ligatures[i],
                                                        component_list.sub_array (0, component_count))))
          return_trace (false);
        component_list += component_count;
      }
      return_trace (true);
    }
  
    bool subset (hb_subset_context_t *c, unsigned coverage_idx) const
    {
      TRACE_SUBSET (this);
      auto *out = c->serializer->start_embed (*this);
      if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
  
      + hb_iter (ligature)
      | hb_filter (subset_offset_array (c, out->ligature, this, coverage_idx))
      | hb_drain
      ;
  
      if (bool (out->ligature))
        // Ensure Coverage table is always packed after this.
        c->serializer->add_virtual_link (coverage_idx);
  
      return_trace (bool (out->ligature));
    }
  };
  
  }
  }
  }
  
  #endif  /* OT_LAYOUT_GSUB_LIGATURESET_HH */
  

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