[GX] Revert "[GX] Add VariationAlternates, to allow conditional lookups in GSUB/GPOS"

This reverts commit 2859f1c7174d6f7ae5dcf0db5411bc0182b21594.
We are going in a different direction.

src/hb-open-type-private.hh

@@ -630,7 +630,6 @@ struct IntType
   inline operator Type(void) const { return v; }
   inline bool operator == (const IntType<Type,Size> &o) const { return (Type) v == (Type) o.v; }
   inline bool operator != (const IntType<Type,Size> &o) const { return !(*this == o); }
-  inline unsigned int get_size (void) const { return Size; }
   static inline int cmp (const IntType<Type,Size> *a, const IntType<Type,Size> *b) { return b->cmp (*a); }
   inline int cmp (Type a) const
   {

src/hb-ot-layout-common-private.hh

@@ -575,7 +575,6 @@ struct LookupFlag : USHORT
     IgnoreMarks		= 0x0008u,
     IgnoreFlags		= 0x000Eu,
     UseMarkFilteringSet	= 0x0010u,
-    UseVariationAlternates= 0x0020u,
     Reserved		= 0x00E0u,
     MarkAttachmentType	= 0xFF00u
   };
@@ -588,88 +587,6 @@ struct LookupFlag : USHORT
 HB_MARK_AS_FLAG_T (OT::LookupFlag::Flags);
 namespace OT {
 
-struct VariationGridAxis
-{
-  inline int locate (int *coords, unsigned int coord_len) const
-  {
-    int coord = axisIndex < coord_len ? coords[axisIndex] : 0;
-
-    unsigned int count = axisCoords.len;
-    unsigned int i = 0;
-    while (i + 1 < count && coord < axisCoords[i + 1])
-      i++;
-
-    return axisCoords[i] <= coord ? i : -1;
-  }
-
-  inline unsigned int get_len (void) const
-  {
-    return axisCoords.len - 1;
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (c->check_struct (this) && axisCoords.sanitize (c));
-  }
-
-  Index				axisIndex;
-  SortedArrayOf<F2DOT14>	axisCoords;
-  public:
-  DEFINE_SIZE_ARRAY (4, axisCoords);
-};
-
-struct VariationGrid
-{
-  inline int locate (int *coords, unsigned int coord_len) const
-  {
-    int location = 0;
-    unsigned int count = axes.len;
-    for (unsigned int i = 0; i < count; i++)
-    {
-      const VariationGridAxis &axis = (this+axes[i]);
-      int axisLoc = axis.locate (coords, coord_len);
-      if (axisLoc == -1)
-        return -1;
-      location = location * (axis.get_len () - 1) + axisLoc; /* XXX Check for overflow?. */
-    }
-    return location;
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (axes.sanitize (c, this));
-  }
-
-  OffsetArrayOf<VariationGridAxis>
-		axes;
-  public:
-  DEFINE_SIZE_ARRAY (2, axes);
-};
-
-struct VariationAlternates
-{
-  inline unsigned int get_lookup_index (int *coords, unsigned int coord_len) const
-  {
-    int location = (this+grid).locate (coords, coord_len);
-    if (location == -1)
-      return 0xFFFE; /* TODO: give it a name. */
-    return lookupIndex[location];
-  }
-
-  inline bool sanitize (hb_sanitize_context_t *c) const
-  {
-    TRACE_SANITIZE (this);
-    return_trace (grid.sanitize (c, this) && lookupIndex.sanitize (c));
-  }
-
-  OffsetTo<VariationGrid>	grid;
-  IndexArray			lookupIndex;
-  public:
-  DEFINE_SIZE_ARRAY (4, lookupIndex);
-};
-
 struct Lookup
 {
   inline unsigned int get_subtable_count (void) const { return subTable.len; }
@@ -738,17 +655,10 @@ struct Lookup
     TRACE_SANITIZE (this);
     /* Real sanitize of the subtables is done by GSUB/GPOS/... */
     if (!(c->check_struct (this) && subTable.sanitize (c))) return_trace (false);
-    const void *cursor = &StructAfter<char> (subTable);
     if (lookupFlag & LookupFlag::UseMarkFilteringSet)
     {
-      const USHORT &markFilteringSet = CastR<USHORT> (cursor);
+      const USHORT &markFilteringSet = StructAfter<USHORT> (subTable);
       if (!markFilteringSet.sanitize (c)) return_trace (false);
-      cursor = &StructAfter<char> (markFilteringSet);
-    }
-    if (lookupFlag & LookupFlag::UseVariationAlternates)
-    {
-      const OffsetTo<VariationAlternates,ULONG> &varAlts = CastR<const OffsetTo<VariationAlternates,ULONG> > (cursor);
-      if (!varAlts.sanitize (c, this)) return_trace (false);
     }
     return_trace (true);
   }
@@ -761,13 +671,8 @@ struct Lookup
   USHORT	markFilteringSetX[VAR];	/* Index (base 0) into GDEF mark glyph sets
 					 * structure. This field is only present if bit
 					 * UseMarkFilteringSet of lookup flags is set. */
-  OffsetTo<VariationAlternates,ULONG>
-		variationAlternatesZ[VAR];
-					/* Index (base 0) into GDEF mark glyph sets
-					 * structure. This field is only present if bit
-					 * UseMarkFilteringSet of lookup flags is set. */
   public:
-  DEFINE_SIZE_MIN (6);
+  DEFINE_SIZE_ARRAY2 (6, subTable, markFilteringSetX);
 };
 
 typedef OffsetListOf<Lookup> LookupList;