[GSUB/GPOS] Remove context_length

The spec doesn't say contextual matching should be done this way,
and AOTS doesn't do it either.  It was inherited from old HarfBuzz.
Remove it.

diff --git a/src/hb-ot-layout-common-private.hh b/src/hb-ot-layout-common-private.hh
index 2051000..6ea28bc 100644 (file)
--- a/src/hb-ot-layout-common-private.hh
+++ b/src/hb-ot-layout-common-private.hh
@@ -34,7 +34,6 @@
 #include "hb-set-private.hh"
 
 
-#define NO_CONTEXT             ((unsigned int) 0x110000)
 #define NOT_COVERED            ((unsigned int) 0x110000)
 #define MAX_NESTING_LEVEL      8
 

diff --git a/src/hb-ot-layout-gpos-table.hh b/src/hb-ot-layout-gpos-table.hh
index 44ec65f..ecd06c4 100644 (file)
--- a/src/hb-ot-layout-gpos-table.hh
+++ b/src/hb-ot-layout-gpos-table.hh
@@ -1532,9 +1532,6 @@ static inline bool position_lookup (hb_apply_context_t *c, unsigned int lookup_i
   if (unlikely (c->nesting_level_left == 0))
     return false;
 
-  if (unlikely (c->context_length < 1))
-    return false;
-
   hb_apply_context_t new_c (*c);
   new_c.nesting_level_left--;
   new_c.set_lookup (l);

diff --git a/src/hb-ot-layout-gsub-table.hh b/src/hb-ot-layout-gsub-table.hh
index bc2b0e1..8c57f60 100644 (file)
--- a/src/hb-ot-layout-gsub-table.hh
+++ b/src/hb-ot-layout-gsub-table.hh
@@ -804,7 +804,8 @@ struct ReverseChainSingleSubstFormat1
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
-    if (unlikely (c->context_length != NO_CONTEXT)) return TRACE_RETURN (false); /* No chaining to this type */
+    if (unlikely (c->nesting_level_left != MAX_NESTING_LEVEL))
+      return TRACE_RETURN (false); /* No chaining to this type */
 
     unsigned int index = (this+coverage) (c->buffer->info[c->buffer->idx].codepoint);
     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
@@ -1243,9 +1244,6 @@ static inline bool substitute_lookup (hb_apply_context_t *c, unsigned int lookup
   if (unlikely (c->nesting_level_left == 0))
     return false;
 
-  if (unlikely (c->context_length < 1))
-    return false;
-
   hb_apply_context_t new_c (*c);
   new_c.nesting_level_left--;
   new_c.set_lookup (l);

diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index a000c15..2e8b92a 100644 (file)
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -106,7 +106,6 @@ struct hb_apply_context_t
   hb_buffer_t *buffer;
   hb_direction_t direction;
   hb_mask_t lookup_mask;
-  unsigned int context_length;
   unsigned int nesting_level_left;
   unsigned int lookup_props;
   unsigned int property; /* propety of first glyph */
@@ -117,12 +116,10 @@ struct hb_apply_context_t
                      hb_face_t *face_,
                      hb_buffer_t *buffer_,
                      hb_mask_t lookup_mask_,
-                     unsigned int context_length_ = NO_CONTEXT,
                      unsigned int nesting_level_left_ = MAX_NESTING_LEVEL) :
                        font (font_), face (face_), buffer (buffer_),
                        direction (buffer_->props.direction),
                        lookup_mask (lookup_mask_),
-                       context_length (context_length_),
                        nesting_level_left (nesting_level_left_),
                        lookup_props (0), property (0), debug_depth (0) {}
 
@@ -142,7 +139,7 @@ struct hb_apply_context_t
       num_items = num_items_;
       mask = context_match ? -1 : c->lookup_mask;
       syllable = context_match ? 0 : c->buffer->info[c->buffer->idx].syllable ();
-      end = MIN (c->buffer->len, c->buffer->idx + c->context_length);
+      end = c->buffer->len;
     }
     inline bool has_no_chance (void) const
     {
@@ -320,7 +317,7 @@ static inline bool match_input (hb_apply_context_t *c,
                                const USHORT input[], /* Array of input values--start with second glyph */
                                match_func_t match_func,
                                const void *match_data,
-                               unsigned int *context_length_out)
+                               unsigned int *end_offset = NULL)
 {
   hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1);
   if (skippy_iter.has_no_chance ())
@@ -335,7 +332,8 @@ static inline bool match_input (hb_apply_context_t *c,
       return false;
   }
 
-  *context_length_out = skippy_iter.idx - c->buffer->idx + 1;
+  if (end_offset)
+    *end_offset = skippy_iter.idx - c->buffer->idx + 1;
 
   return true;
 }
@@ -418,7 +416,7 @@ static inline bool apply_lookup (hb_apply_context_t *c,
                                 const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */
                                 apply_lookup_func_t apply_func)
 {
-  unsigned int end = MIN (c->buffer->len, c->buffer->idx + c->context_length);
+  unsigned int end = c->buffer->len;
   if (unlikely (count == 0 || c->buffer->idx + count > end))
     return false;
 
@@ -509,12 +507,10 @@ static inline bool context_apply_lookup (hb_apply_context_t *c,
                                         const LookupRecord lookupRecord[],
                                         ContextApplyLookupContext &lookup_context)
 {
-  hb_apply_context_t new_context = *c;
   return match_input (c,
                      inputCount, input,
-                     lookup_context.funcs.match, lookup_context.match_data,
-                     &new_context.context_length)
-      && apply_lookup (&new_context,
+                     lookup_context.funcs.match, lookup_context.match_data)
+      && apply_lookup (c,
                       inputCount,
                       lookupCount, lookupRecord,
                       lookup_context.funcs.apply);
@@ -883,25 +879,19 @@ static inline bool chain_context_apply_lookup (hb_apply_context_t *c,
                                               const LookupRecord lookupRecord[],
                                               ChainContextApplyLookupContext &lookup_context)
 {
-  /* First guess */
-  if (unlikely (c->buffer->backtrack_len () < backtrackCount ||
-               c->buffer->idx + inputCount + lookaheadCount > c->buffer->len ||
-               inputCount + lookaheadCount > c->context_length))
-    return false;
-
-  hb_apply_context_t new_context = *c;
+  unsigned int lookahead_offset;
   return match_backtrack (c,
                          backtrackCount, backtrack,
                          lookup_context.funcs.match, lookup_context.match_data[0])
       && match_input (c,
                      inputCount, input,
                      lookup_context.funcs.match, lookup_context.match_data[1],
-                     &new_context.context_length)
+                     &lookahead_offset)
       && match_lookahead (c,
                          lookaheadCount, lookahead,
                          lookup_context.funcs.match, lookup_context.match_data[2],
-                         new_context.context_length)
-      && apply_lookup (&new_context,
+                         lookahead_offset)
+      && apply_lookup (c,
                       inputCount,
                       lookupCount, lookupRecord,
                       lookup_context.funcs.apply);