Use shared string pool to share string instances among string item values.

This brings down the reload time from 22 seconds to 4.3 seconds with
my test document.  This is what I've been looking for!

1 files changed, 5 insertions, 0 deletions

diff --git a/sc/inc/dpcache.hxx b/sc/inc/dpcache.hxx
index 839f64b4bcf0..2591b3def302 100644
--- a/sc/inc/dpcache.hxx
+++ b/sc/inc/dpcache.hxx
@@ -36,6 +36,7 @@
 #include <boost/noncopyable.hpp>
 #include <boost/scoped_ptr.hpp>
 #include <boost/ptr_container/ptr_vector.hpp>
+#include <boost/unordered_set.hpp>
 #include <mdds/flat_segment_tree.hpp>
 
 #include <vector>
@@ -58,6 +59,8 @@ struct ScDPNumGroupInfo;
  */
 class SC_DLLPUBLIC ScDPCache : boost::noncopyable
 {
+    typedef boost::unordered_set<rtl::OUString, rtl::OUStringHash> StringSetType;
+
 public:
     typedef std::vector<ScDPItemData> ItemsType;
     typedef std::set<ScDPObject*> ObjectSetType;
@@ -112,6 +115,7 @@ private:
 
     FieldsType maFields;
     GroupFieldsType maGroupFields;
+    mutable StringSetType maStringPool;
 
     LabelsType maLabelNames;    // Stores dimension names.
     mdds::flat_segment_tree<SCROW, bool> maEmptyRows;
@@ -119,6 +123,7 @@ private:
     bool mbDisposing;
 
 public:
+    const rtl::OUString* InternString(const rtl::OUString& rStr) const;
     void AddReference(ScDPObject* pObj) const;
     void RemoveReference(ScDPObject* pObj) const;
     const ObjectSetType& GetAllReferences() const;