[apparmor] [PATCH 01/11] Speed up DFA creation by including set size in comparison

[John Johansen]

Use set size as part of set comparison, short circuiting comparing sets
of pointers when it isn't necessary.  This results in a nice little
performance increase in dfa creation.
---
 parser/libapparmor_re/regexp.y |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/parser/libapparmor_re/regexp.y b/parser/libapparmor_re/regexp.y
index e1bbbfd..e19214d 100644
--- a/parser/libapparmor_re/regexp.y
+++ b/parser/libapparmor_re/regexp.y
@@ -1300,13 +1300,18 @@ void dump_syntax_tree(ostream& os, Node *node) {
 }
 
 /* Comparison operator for sets of <NodeSet *>.
- * Do compare pointer comparison on set of <Node *>, the pointer comparison
+ * Compare set sizes, and if the sets are the same size
+ * do compare pointer comparison on set of <Node *>, the pointer comparison
  * allows us to determine which Sets of <Node *> we have seen already from
  * new ones when constructing the DFA.
  */
 struct deref_less_than {
   bool operator()(NodeSet * const & lhs, NodeSet * const & rhs) const
-  { return *lhs < *rhs; }
+  { if (lhs->size() == rhs->size())
+      return *lhs < *rhs;
+    else
+      return lhs->size() < rhs->size();
+  }
 };
 
 class State;
-- 
1.7.1