[HB] Add HeadlessArrayTo<>

src/hb-ot-layout-gsub-private.h

@@ -314,12 +314,10 @@ struct Ligature {
   friend struct LigatureSet;
 
   private:
-  DEFINE_ARRAY_TYPE (GlyphID, component, (compCount ? compCount - 1 : 0));
-
   inline bool substitute_ligature (LOOKUP_ARGS_DEF, bool is_mark) const {
 
     unsigned int i, j;
-    unsigned int count = compCount;
+    unsigned int count = component.len;
 
     if (HB_UNLIKELY (buffer->in_pos + count > buffer->in_length ||
 		     context_length < count))
@@ -336,7 +334,7 @@ struct Ligature {
 	    property &  LookupFlag::MarkAttachmentType))
 	is_mark = FALSE;
 
-      if (HB_LIKELY (IN_GLYPH(j) != (*this)[i - 1]))
+      if (HB_LIKELY (IN_GLYPH(j) != component[i]))
         return false;
     }
     if ( _hb_ot_layout_has_new_glyph_classes (layout) )
@@ -383,8 +381,8 @@ struct Ligature {
 
   private:
   GlyphID	ligGlyph;		/* GlyphID of ligature to substitute */
-  USHORT	compCount;		/* Number of components in the ligature */
-  GlyphID	component[];		/* Array of component GlyphIDs--start
+  HeadlessArrayOf<GlyphID>
+		component;		/* Array of component GlyphIDs--start
 					 * with the second  component--ordered
 					 * in writing direction */
 };

src/hb-ot-layout-gsubgpos-private.h

@@ -362,9 +362,8 @@ struct ChainRule {
 		backtrack;		/* Array of backtracking values
 					 * (to be matched before the input
 					 * sequence) */
-  USHORT	inputCountX;		/* Total number of values in the input
-					 * sequence (includes the first glyph) */
-  USHORT	inputX[];		/* Array of input values (start with
+  HeadlessArrayOf<USHORT>
+		inputX;			/* Array of input values (start with
 					 * second glyph) */
   ArrayOf<USHORT>
 		lookaheadX;		/* Array of lookahead values's (to be

src/hb-ot-layout-open-private.h

@@ -348,6 +348,25 @@ struct ArrayOf {
     if (HB_UNLIKELY (i >= len)) return Null(Type);
     return array[i];
   }
+  inline unsigned int get_size () const {
+    return sizeof (len) + len * sizeof (array[0]);
+  }
+
+  USHORT len;
+  Type array[];
+};
+
+/* An array with a USHORT number of elements,
+ * starting at second element. */
+template <typename Type>
+struct HeadlessArrayOf {
+  inline const Type& operator [] (unsigned int i) const {
+    if (HB_UNLIKELY (i >= len || !i)) return Null(Type);
+    return array[i-1];
+  }
+  inline unsigned int get_size () const {
+    return sizeof (len) + (len ? len - 1 : 0) * sizeof (array[0]);
+  }
 
   USHORT len;
   Type array[];