kc3-lang/harfbuzz/src/OT/Layout/GSUB/SingleSubstFormat1.hh

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• Hash : 9aad3dba
  Author :
  Date : 2022-10-26T13:04:02
  

  [SingleSubst] Fix degenerate-lookup test
  
  Part of https://github.com/harfbuzz/harfbuzz/issues/3853
  

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• src/OT/Layout/GSUB/SingleSubstFormat1.hh

• #ifndef OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH
  #define OT_LAYOUT_GSUB_SINGLESUBSTFORMAT1_HH
  
  #include "Common.hh"
  
  namespace OT {
  namespace Layout {
  namespace GSUB_impl {
  
  template <typename Types>
  struct SingleSubstFormat1_3
  {
    protected:
    HBUINT16      format;                 /* Format identifier--format = 1 */
    typename Types::template OffsetTo<Coverage>
                  coverage;               /* Offset to Coverage table--from
                                           * beginning of Substitution table */
    typename Types::HBUINT
                  deltaGlyphID;           /* Add to original GlyphID to get
                                           * substitute GlyphID, modulo 0x10000 */
  
    public:
    DEFINE_SIZE_STATIC (2 + 2 * Types::size);
  
    bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (coverage.sanitize (c, this) && deltaGlyphID.sanitize (c));
    }
  
    hb_codepoint_t get_mask () const
    { return (1 << (8 * Types::size)) - 1; }
  
    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_codepoint_t d = deltaGlyphID;
      hb_codepoint_t mask = get_mask ();
  
      /* Help fuzzer avoid this function as much. */
      unsigned pop = (this+coverage).get_population ();
      if (pop >= mask)
        return;
  
      hb_set_t intersection;
      (this+coverage).intersect_set (c->parent_active_glyphs (), intersection);
  
      /* In degenerate fuzzer-found fonts, but not real fonts,
       * this table can keep adding new glyphs in each round of closure.
       * Refuse to close-over, if it maps glyph range to overlapping range. */
      hb_codepoint_t min_before = intersection.get_min ();
      hb_codepoint_t max_before = intersection.get_max ();
      hb_codepoint_t min_after = (min_before + d) & mask;
      hb_codepoint_t max_after = (max_before + d) & mask;
      if (intersection.get_population () == max_before - min_before + 1 &&
  	((min_before <= min_after && min_after <= max_before) ||
  	 (min_before <= max_after && max_after <= max_before)))
        return;
  
      + hb_iter (intersection)
      | hb_map ([d, mask] (hb_codepoint_t g) { return (g + d) & mask; })
      | 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_codepoint_t d = deltaGlyphID;
      hb_codepoint_t mask = get_mask ();
  
      + hb_iter (this+coverage)
      | hb_map ([d, mask] (hb_codepoint_t g) { return (g + d) & mask; })
      | 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);
      hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
      unsigned int index = (this+coverage).get_coverage (glyph_id);
      if (likely (index == NOT_COVERED)) return_trace (false);
  
      hb_codepoint_t d = deltaGlyphID;
      hb_codepoint_t mask = get_mask ();
  
      glyph_id = (glyph_id + d) & mask;
  
      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
      {
        c->buffer->sync_so_far ();
        c->buffer->message (c->font,
  			  "replacing glyph at %d (single substitution)",
  			  c->buffer->idx);
      }
  
      c->replace_glyph (glyph_id);
  
      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
      {
        c->buffer->message (c->font,
  			  "replaced glyph at %d (single substitution)",
  			  c->buffer->idx - 1);
      }
  
      return_trace (true);
    }
  
    template<typename Iterator,
             hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_t))>
    bool serialize (hb_serialize_context_t *c,
                    Iterator glyphs,
                    unsigned delta)
    {
      TRACE_SERIALIZE (this);
      if (unlikely (!c->extend_min (this))) return_trace (false);
      if (unlikely (!coverage.serialize_serialize (c, glyphs))) return_trace (false);
      c->check_assign (deltaGlyphID, delta, HB_SERIALIZE_ERROR_INT_OVERFLOW);
      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;
  
      hb_codepoint_t d = deltaGlyphID;
      hb_codepoint_t mask = get_mask ();
  
      hb_set_t intersection;
      (this+coverage).intersect_set (glyphset, intersection);
  
      auto it =
      + hb_iter (intersection)
      | hb_map_retains_sorting ([d, mask] (hb_codepoint_t g) {
                                  return hb_codepoint_pair_t (g,
                                                              (g + d) & mask); })
      | hb_filter (glyphset, hb_second)
      | hb_map_retains_sorting ([&] (hb_codepoint_pair_t 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_SINGLESUBSTFORMAT1_HH */
  

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