[GSUB] Simplify would-apply

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

@@ -55,11 +55,6 @@ struct SingleSubstFormat1
     return this+coverage;
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -112,11 +107,6 @@ struct SingleSubstFormat2
     return this+coverage;
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -174,15 +164,6 @@ struct SingleSubst
     }
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    switch (u.format) {
-    case 1: return u.format1.would_apply (c);
-    case 2: return u.format2.would_apply (c);
-    default:return false;
-    }
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -276,11 +257,6 @@ struct MultipleSubstFormat1
     return this+coverage;
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -331,14 +307,6 @@ struct MultipleSubst
     }
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    switch (u.format) {
-    case 1: return u.format1.would_apply (c);
-    default:return false;
-    }
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -393,11 +361,6 @@ struct AlternateSubstFormat1
     return this+coverage;
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -466,14 +429,6 @@ struct AlternateSubst
     }
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    switch (u.format) {
-    case 1: return u.format1.would_apply (c);
-    default:return false;
-    }
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -675,9 +630,7 @@ struct LigatureSubstFormat1
 
   inline bool would_apply (hb_would_apply_context_t *c) const
   {
-    unsigned int index;
+    return (this+ligatureSet[(this+coverage) (c->first)]).would_apply (c);
-    return (index = (this+coverage) (c->first)) != NOT_COVERED &&
-	   (this+ligatureSet[index]).would_apply (c);
   }
 
   inline bool apply (hb_apply_context_t *c) const
@@ -871,11 +824,6 @@ struct ReverseChainSingleSubstFormat1
     return this+coverage;
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -958,14 +906,6 @@ struct ReverseChainSingleSubst
     }
   }
 
-  inline bool would_apply (hb_would_apply_context_t *c) const
-  {
-    switch (u.format) {
-    case 1: return u.format1.would_apply (c);
-    default:return false;
-    }
-  }
-
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY ();
@@ -1048,15 +988,16 @@ struct SubstLookupSubTable
 			   unsigned int lookup_type) const
   {
     TRACE_WOULD_APPLY ();
+    if (get_coverage (lookup_type).get_coverage (c->first) == NOT_COVERED) return false;
+    if (c->len == 1) return true; /* Done! */
+
+    /* Only need to look further for lookups that support substitutions
+     * of input longer than 1. */
     switch (lookup_type) {
-    case Single:		return u.single.would_apply (c);
-    case Multiple:		return u.multiple.would_apply (c);
-    case Alternate:		return u.alternate.would_apply (c);
     case Ligature:		return u.ligature.would_apply (c);
     case Context:		return u.context.would_apply (c);
     case ChainContext:		return u.chainContext.would_apply (c);
     case Extension:		return u.extension.would_apply (c);
-    case ReverseChainSingle:	return u.reverseChainContextSingle.would_apply (c);
     default:			return false;
     }
   }

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

@@ -677,11 +677,8 @@ struct ContextFormat1
   inline bool would_apply (hb_would_apply_context_t *c) const
   {
     TRACE_WOULD_APPLY ();
-    unsigned int index = (this+coverage) (c->first);
-    if (likely (index == NOT_COVERED))
-      return TRACE_RETURN (false);
 
-    const RuleSet &rule_set = this+ruleSet[index];
+    const RuleSet &rule_set = this+ruleSet[(this+coverage) (c->first)];
     struct ContextApplyLookupContext lookup_context = {
       {match_glyph, NULL},
       NULL
@@ -752,11 +749,9 @@ struct ContextFormat2
   inline bool would_apply (hb_would_apply_context_t *c) const
   {
     TRACE_WOULD_APPLY ();
-    unsigned int index = (this+coverage) (c->first);
-    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
 
     const ClassDef &class_def = this+classDef;
-    index = class_def (c->first);
+    unsigned int index = class_def (c->first);
     const RuleSet &rule_set = this+ruleSet[index];
     struct ContextApplyLookupContext lookup_context = {
       {match_class, NULL},
@@ -828,8 +823,6 @@ struct ContextFormat3
   inline bool would_apply (hb_would_apply_context_t *c) const
   {
     TRACE_WOULD_APPLY ();
-    unsigned int index = (this+coverage[0]) (c->first);
-    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
 
     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (coverage, coverage[0].static_size * glyphCount);
     struct ContextApplyLookupContext lookup_context = {
@@ -1180,10 +1173,8 @@ struct ChainContextFormat1
   inline bool would_apply (hb_would_apply_context_t *c) const
   {
     TRACE_WOULD_APPLY ();
-    unsigned int index = (this+coverage) (c->first);
-    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
 
-    const ChainRuleSet &rule_set = this+ruleSet[index];
+    const ChainRuleSet &rule_set = this+ruleSet[(this+coverage) (c->first)];
     struct ChainContextApplyLookupContext lookup_context = {
       {match_glyph, NULL},
       {NULL, NULL, NULL}
@@ -1256,12 +1247,10 @@ struct ChainContextFormat2
   inline bool would_apply (hb_would_apply_context_t *c) const
   {
     TRACE_WOULD_APPLY ();
-    unsigned int index = (this+coverage) (c->first);
-    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
 
     const ClassDef &input_class_def = this+inputClassDef;
 
-    index = input_class_def (c->first);
+    unsigned int index = input_class_def (c->first);
     const ChainRuleSet &rule_set = this+ruleSet[index];
     struct ChainContextApplyLookupContext lookup_context = {
       {match_class, NULL},
@@ -1359,11 +1348,8 @@ struct ChainContextFormat3
   inline bool would_apply (hb_would_apply_context_t *c) const
   {
     TRACE_WOULD_APPLY ();
+
     const OffsetArrayOf<Coverage> &input = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
-
-    unsigned int index = (this+input[0]) (c->first);
-    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
-
     const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (input);
     const ArrayOf<LookupRecord> &lookup = StructAfter<ArrayOf<LookupRecord> > (lookahead);
     struct ChainContextApplyLookupContext lookup_context = {