[Libreoffice-commits] core.git: Branch 'feature/chart-opengl2' - sax/source

[Michael Meeks]

 sax/source/fastparser/fastparser.cxx |   22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

New commits:
commit 17e74f2989ad20b1149084205fbfcbedb06a2bd0
Author: Michael Meeks <michael.meeks at collabora.com>
Date:   Tue Dec 31 12:59:03 2013 +0000

    fastparser: avoid std::stack::top() - cache it's results.
    
    amazingly std::stack::top() takes 146 pseudo-cycles to do not much,
    so instead cache the result in a single pointer in lieu of burning
    that code.
    
    Change-Id: Ie326be47da6cbad0850e5f1026a1632bb840b6b8

diff --git a/sax/source/fastparser/fastparser.cxx b/sax/source/fastparser/fastparser.cxx
index a7ba27b..cc9ad2f 100644
--- a/sax/source/fastparser/fastparser.cxx
+++ b/sax/source/fastparser/fastparser.cxx
@@ -231,8 +231,8 @@ public:
 
     void pushEntity( const Entity& rEntity );
     void popEntity();
-    Entity& getEntity();
-    const Entity& getEntity() const;
+    Entity& getEntity()             { return *mpTop; }
+    const Entity& getEntity() const { return *mpTop; }
     void parse();
     void produce( CallbackType aType );
 
@@ -263,6 +263,8 @@ private:
     NamespaceMap                            maNamespaceMap;
 
     ParserData maData;                      /// Cached parser configuration for next call of parseStream().
+
+    Entity *mpTop;                          /// std::stack::top() is amazingly slow => cache this.
     ::std::stack< Entity > maEntities;      /// Entity stack for each call of parseStream().
     FastTokenLookup maTokenLookup;
 };
@@ -631,7 +633,9 @@ void Entity::saveException( const Exception &e )
 
 namespace sax_fastparser {
 
-FastSaxParserImpl::FastSaxParserImpl( FastSaxParser* pFront ) : mpFront(pFront)
+FastSaxParserImpl::FastSaxParserImpl( FastSaxParser* pFront ) :
+    mpFront(pFront),
+    mpTop(NULL)
 {
     mxDocumentLocator.set( new FastLocatorImpl( this ) );
 }
@@ -1078,21 +1082,13 @@ bool FastSaxParserImpl::consume(EventList *pEventList)
 void FastSaxParserImpl::pushEntity( const Entity& rEntity )
 {
     maEntities.push( rEntity );
+    mpTop = &maEntities.top();
 }
 
 void FastSaxParserImpl::popEntity()
 {
     maEntities.pop();
-}
-
-Entity& FastSaxParserImpl::getEntity()
-{
-    return maEntities.top();
-}
-
-const Entity& FastSaxParserImpl::getEntity() const
-{
-    return maEntities.top();
+    mpTop = &maEntities.top();
 }
 
 // starts parsing with actual parser !