[lookup] Add skippy_iter.reset()

Towards reducing the cost of initializing skippy_iter()

src/hb-ot-layout-gpos-table.hh

@@ -684,7 +684,8 @@ struct PairPosFormat1
     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
 
-    hb_apply_context_t::skipping_iterator_t skippy_iter (c, buffer->idx, 1);
+    hb_apply_context_t::skipping_iterator_t skippy_iter (c);
+    skippy_iter.reset (buffer->idx, 1);
     if (!skippy_iter.next ()) return TRACE_RETURN (false);
 
     return TRACE_RETURN ((this+pairSet[index]).apply (c, &valueFormat1, skippy_iter.idx));
@@ -753,7 +754,8 @@ struct PairPosFormat2
     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
 
-    hb_apply_context_t::skipping_iterator_t skippy_iter (c, buffer->idx, 1);
+    hb_apply_context_t::skipping_iterator_t skippy_iter (c);
+    skippy_iter.reset (buffer->idx, 1);
     if (!skippy_iter.next ()) return TRACE_RETURN (false);
 
     unsigned int len1 = valueFormat1.get_len ();
@@ -902,7 +904,8 @@ struct CursivePosFormat1
     const EntryExitRecord &this_record = entryExitRecord[(this+coverage).get_coverage  (buffer->cur().codepoint)];
     if (!this_record.exitAnchor) return TRACE_RETURN (false);
 
-    hb_apply_context_t::skipping_iterator_t skippy_iter (c, buffer->idx, 1);
+    hb_apply_context_t::skipping_iterator_t skippy_iter (c);
+    skippy_iter.reset (buffer->idx, 1);
     if (!skippy_iter.next ()) return TRACE_RETURN (false);
 
     const EntryExitRecord &next_record = entryExitRecord[(this+coverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint)];
@@ -1045,7 +1048,8 @@ struct MarkBasePosFormat1
     if (likely (mark_index == NOT_COVERED)) return TRACE_RETURN (false);
 
     /* now we search backwards for a non-mark glyph */
-    hb_apply_context_t::skipping_iterator_t skippy_iter (c, buffer->idx, 1);
+    hb_apply_context_t::skipping_iterator_t skippy_iter (c);
+    skippy_iter.reset (buffer->idx, 1);
     skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
     do {
       if (!skippy_iter.prev ()) return TRACE_RETURN (false);
@@ -1149,7 +1153,8 @@ struct MarkLigPosFormat1
     if (likely (mark_index == NOT_COVERED)) return TRACE_RETURN (false);
 
     /* now we search backwards for a non-mark glyph */
-    hb_apply_context_t::skipping_iterator_t skippy_iter (c, buffer->idx, 1);
+    hb_apply_context_t::skipping_iterator_t skippy_iter (c);
+    skippy_iter.reset (buffer->idx, 1);
     skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
     if (!skippy_iter.prev ()) return TRACE_RETURN (false);
 
@@ -1265,7 +1270,8 @@ struct MarkMarkPosFormat1
     if (likely (mark1_index == NOT_COVERED)) return TRACE_RETURN (false);
 
     /* now we search backwards for a suitable mark glyph until a non-mark glyph */
-    hb_apply_context_t::skipping_iterator_t skippy_iter (c, buffer->idx, 1);
+    hb_apply_context_t::skipping_iterator_t skippy_iter (c);
+    skippy_iter.reset (buffer->idx, 1);
     skippy_iter.set_lookup_props (c->lookup_props & ~LookupFlag::IgnoreFlags);
     if (!skippy_iter.prev ()) return TRACE_RETURN (false);
 

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

@@ -338,14 +338,12 @@ struct hb_apply_context_t
   struct skipping_iterator_t
   {
     inline skipping_iterator_t (hb_apply_context_t *c_,
-				unsigned int start_index_,
-				unsigned int num_items_,
 				bool context_match = false) :
-				 idx (start_index_),
+				 idx (0),
 				 c (c_),
 				 match_glyph_data (NULL),
-				 num_items (num_items_),
-				 end (c->buffer->len)
+				 num_items (0),
+				 end (0)
     {
       matcher.set_lookup_props (c->lookup_props);
       /* Ignore ZWNJ if we are matching GSUB context, or matching GPOS. */
@@ -354,7 +352,6 @@ struct hb_apply_context_t
       matcher.set_ignore_zwj (context_match || c->table_index == 1 || c->auto_zwj);
       if (!context_match)
 	matcher.set_mask (c->lookup_mask);
-      matcher.set_syllable (start_index_ == c->buffer->idx ? c->buffer->cur().syllable () : 0);
     }
     inline void set_lookup_props (unsigned int lookup_props) { matcher.set_lookup_props (lookup_props); }
     inline void set_match_func (matcher_t::match_func_t match_func,
@@ -365,6 +362,15 @@ struct hb_apply_context_t
       match_glyph_data = glyph_data;
     }
 
+    inline void reset (unsigned int start_index_,
+		       unsigned int num_items_)
+    {
+      idx = start_index_;
+      num_items = num_items_;
+      end = c->buffer->len;
+      matcher.set_syllable (start_index_ == c->buffer->idx ? c->buffer->cur().syllable () : 0);
+    }
+
     inline void reject (void) { num_items++; match_glyph_data--; }
 
     inline bool next (void)
@@ -699,7 +705,8 @@ static inline bool match_input (hb_apply_context_t *c,
 
   hb_buffer_t *buffer = c->buffer;
 
-  hb_apply_context_t::skipping_iterator_t skippy_iter (c, buffer->idx, count - 1);
+  hb_apply_context_t::skipping_iterator_t skippy_iter (c);
+  skippy_iter.reset (buffer->idx, count - 1);
   skippy_iter.set_match_func (match_func, match_data, input);
 
   /*
@@ -867,7 +874,8 @@ static inline bool match_backtrack (hb_apply_context_t *c,
 {
   TRACE_APPLY (NULL);
 
-  hb_apply_context_t::skipping_iterator_t skippy_iter (c, c->buffer->backtrack_len (), count, true);
+  hb_apply_context_t::skipping_iterator_t skippy_iter (c, true);
+  skippy_iter.reset (c->buffer->backtrack_len (), count);
   skippy_iter.set_match_func (match_func, match_data, backtrack);
 
   for (unsigned int i = 0; i < count; i++)
@@ -886,7 +894,8 @@ static inline bool match_lookahead (hb_apply_context_t *c,
 {
   TRACE_APPLY (NULL);
 
-  hb_apply_context_t::skipping_iterator_t skippy_iter (c, c->buffer->idx + offset - 1, count, true);
+  hb_apply_context_t::skipping_iterator_t skippy_iter (c, true);
+  skippy_iter.reset (c->buffer->idx + offset - 1, count);
   skippy_iter.set_match_func (match_func, match_data, lookahead);
 
   for (unsigned int i = 0; i < count; i++)

src/hb-ot-shape-fallback.cc

@@ -441,13 +441,14 @@ _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
   OT::hb_apply_context_t c (1, font, buffer);
   c.set_lookup_mask (plan->kern_mask);
   c.set_lookup_props (OT::LookupFlag::IgnoreMarks);
+  OT::hb_apply_context_t::skipping_iterator_t skippy_iter (&c);
 
   unsigned int count = buffer->len;
   hb_glyph_info_t *info = buffer->info;
   hb_glyph_position_t *pos = buffer->pos;
   for (unsigned int idx = 0; idx < count;)
   {
-    OT::hb_apply_context_t::skipping_iterator_t skippy_iter (&c, idx, 1);
+    skippy_iter.reset (idx, 1);
     if (!skippy_iter.next ())
     {
       idx++;