xref: /aosp_15_r20/external/harfbuzz_ng/src/OT/Layout/GSUB/AlternateSubst.hh (revision 2d1272b857b1f7575e6e246373e1cb218663db8a)
1 #ifndef OT_LAYOUT_GSUB_ALTERNATESUBST_HH
2 #define OT_LAYOUT_GSUB_ALTERNATESUBST_HH
3 
4 #include "AlternateSubstFormat1.hh"
5 #include "Common.hh"
6 
7 namespace OT {
8 namespace Layout {
9 namespace GSUB_impl {
10 
11 struct AlternateSubst
12 {
13   protected:
14   union {
15   HBUINT16				format;         /* Format identifier */
16   AlternateSubstFormat1_2<SmallTypes>	format1;
17 #ifndef HB_NO_BEYOND_64K
18   AlternateSubstFormat1_2<MediumTypes>	format2;
19 #endif
20   } u;
21   public:
22 
23   template <typename context_t, typename ...Ts>
dispatchOT::Layout::GSUB_impl::AlternateSubst24   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
25   {
26     if (unlikely (!c->may_dispatch (this, &u.format))) return c->no_dispatch_return_value ();
27     TRACE_DISPATCH (this, u.format);
28     switch (u.format) {
29     case 1: return_trace (c->dispatch (u.format1, std::forward<Ts> (ds)...));
30 #ifndef HB_NO_BEYOND_64K
31     case 2: return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
32 #endif
33     default:return_trace (c->default_return_value ());
34     }
35   }
36 
37   /* TODO This function is unused and not updated to 24bit GIDs. Should be done by using
38    * iterators. While at it perhaps using iterator of arrays of hb_codepoint_t instead. */
serializeOT::Layout::GSUB_impl::AlternateSubst39   bool serialize (hb_serialize_context_t *c,
40                   hb_sorted_array_t<const HBGlyphID16> glyphs,
41                   hb_array_t<const unsigned int> alternate_len_list,
42                   hb_array_t<const HBGlyphID16> alternate_glyphs_list)
43   {
44     TRACE_SERIALIZE (this);
45     if (unlikely (!c->extend_min (u.format))) return_trace (false);
46     unsigned int format = 1;
47     u.format = format;
48     switch (u.format) {
49     case 1: return_trace (u.format1.serialize (c, glyphs, alternate_len_list, alternate_glyphs_list));
50     default:return_trace (false);
51     }
52   }
53 
54   /* TODO subset() should choose format. */
55 
56 };
57 
58 }
59 }
60 }
61 
62 #endif  /* OT_LAYOUT_GSUB_ALTERNATESUBST_HH */
63