kc3-lang/harfbuzz/src/OT/Layout/GSUB/AlternateSubstFormat1.hh

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• Hash : 4a26e289
  Author :
  Date : 2025-09-30T15:31:04
  

  Add `hb_ot_layout_lookup_collect_glyph_alternates()` (#5367)
  
  * [map] Massage operator << overloads
  
  * [ot-layout] Add +hb_ot_layout_lookup_collect_glyph_alternates
  
  To collect all glyph mapping from SingleSubst or AlternateSubst
  lookups in one call.  Needed by FreeType autohinter for performance.
  
  New API:
  +hb_ot_layout_lookup_collect_glyph_alternates()
  
  * [layout] Change hb_ot_layout_lookup_collect_glyph_alternates() API
  
  https://github.com/harfbuzz/harfbuzz/pull/5367#discussion_r2149019638

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• src/OT/Layout/GSUB/AlternateSubstFormat1.hh

• #ifndef OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH
  #define OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH
  
  #include "AlternateSet.hh"
  #include "Common.hh"
  
  namespace OT {
  namespace Layout {
  namespace GSUB_impl {
  
  template <typename Types>
  struct AlternateSubstFormat1_2
  {
    protected:
    HBUINT16      format;                 /* Format identifier--format = 1 */
    typename Types::template OffsetTo<Coverage>
                  coverage;               /* Offset to Coverage table--from
                                           * beginning of Substitution table */
    Array16Of<typename Types::template OffsetTo<AlternateSet<Types>>>
                  alternateSet;           /* Array of AlternateSet tables
                                           * ordered by Coverage Index */
    public:
    DEFINE_SIZE_ARRAY (2 + 2 * Types::size, alternateSet);
  
    bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (coverage.sanitize (c, this) && alternateSet.sanitize (c, this));
    }
  
    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, alternateSet)
      | hb_filter (c->parent_active_glyphs (), hb_first)
      | hb_map (hb_second)
      | hb_map (hb_add (this))
      | hb_apply ([c] (const AlternateSet<Types> &_) { _.closure (c); })
      ;
    }
  
    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, alternateSet)
      | hb_map (hb_second)
      | hb_map (hb_add (this))
      | hb_apply ([c] (const AlternateSet<Types> &_) { _.collect_glyphs (c); })
      ;
    }
  
    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; }
  
    unsigned
    get_glyph_alternates (hb_codepoint_t  gid,
                          unsigned        start_offset,
                          unsigned       *alternate_count  /* IN/OUT.  May be NULL. */,
                          hb_codepoint_t *alternate_glyphs /* OUT.     May be NULL. */) const
    { return (this+alternateSet[(this+coverage).get_coverage (gid)])
             .get_alternates (start_offset, alternate_count, alternate_glyphs); }
  
    void
    collect_glyph_alternates (hb_map_t  *alternate_count /* IN/OUT */,
  			    hb_map_t  *alternate_glyphs /* IN/OUT */) const
    {
      + hb_iter (alternateSet)
      | hb_map (hb_add (this))
      | hb_zip (this+coverage)
      | hb_apply ([&] (const hb_pair_t<const AlternateSet<Types> &, hb_codepoint_t> _) {
  		  _.first.collect_alternates (_.second, alternate_count, alternate_glyphs);
  		})
      ;
    }
  
    bool apply (hb_ot_apply_context_t *c) const
    {
      TRACE_APPLY (this);
  
      unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
      if (index == NOT_COVERED) return_trace (false);
  
      return_trace ((this+alternateSet[index]).apply (c));
    }
  
    bool serialize (hb_serialize_context_t *c,
                    hb_sorted_array_t<const HBGlyphID16> glyphs,
                    hb_array_t<const unsigned int> alternate_len_list,
                    hb_array_t<const HBGlyphID16> alternate_glyphs_list)
    {
      TRACE_SERIALIZE (this);
      if (unlikely (!c->extend_min (this))) return_trace (false);
      if (unlikely (!alternateSet.serialize (c, glyphs.length))) return_trace (false);
      for (unsigned int i = 0; i < glyphs.length; i++)
      {
        unsigned int alternate_len = alternate_len_list[i];
        if (unlikely (!alternateSet[i]
                          .serialize_serialize (c, alternate_glyphs_list.sub_array (0, alternate_len))))
          return_trace (false);
        alternate_glyphs_list += alternate_len;
      }
      return_trace (coverage.serialize_serialize (c, glyphs));
    }
  
    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 *out = c->serializer->start_embed (*this);
      if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
      out->format = format;
  
      hb_sorted_vector_t<hb_codepoint_t> new_coverage;
      + hb_zip (this+coverage, alternateSet)
      | hb_filter (glyphset, hb_first)
      | hb_filter (subset_offset_array (c, out->alternateSet, this), hb_second)
      | hb_map (hb_first)
      | hb_map (glyph_map)
      | hb_sink (new_coverage)
      ;
      out->coverage.serialize_serialize (c->serializer, new_coverage.iter ());
      return_trace (bool (new_coverage));
    }
  };
  
  }
  }
  }
  
  #endif  /* OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH */
  

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