avoid double-lookup in SharedStringPool::intern

An emplace_hint with the iterator pointing at end() doesn't really help,
so rather attempt an insert with a temporary value.

Also check if the upper-case string we got back is the same as the input
string, in which case, we can save memory by mapping the input string to
itself.

Change-Id: I40b9e2b65a831e44c4b88d51d835242a47d8a86d
Reviewed-on: https://gerrit.libreoffice.org/72516
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 12 insertions, 4 deletions

diff --git a/svl/source/misc/sharedstringpool.cxx b/svl/source/misc/sharedstringpool.cxx
index ad72b5a1addb..5c26c912bc42 100644
--- a/svl/source/misc/sharedstringpool.cxx
+++ b/svl/source/misc/sharedstringpool.cxx
@@ -49,13 +49,21 @@ SharedString SharedStringPool::intern( const OUString& rStr )
 {
     osl::MutexGuard aGuard(&mpImpl->maMutex);
 
-    auto mapIt = mpImpl->maStrMap.find(rStr);
-    if (mapIt == mpImpl->maStrMap.end())
+    auto [mapIt,bInserted] = mpImpl->maStrMap.emplace(rStr, rStr.pData);
+    if (bInserted)
     {
         // This is a new string insertion. Establish mapping to upper-case variant.
         OUString aUpper = mpImpl->mrCharClass.uppercase(rStr);
-        auto insertResult = mpImpl->maStrPoolUpper.insert(aUpper);
-        mapIt = mpImpl->maStrMap.emplace_hint(mapIt, rStr, insertResult.first->pData);
+        if (aUpper == rStr)
+        {
+            auto insertResult = mpImpl->maStrPoolUpper.insert(rStr);
+            mapIt->second = insertResult.first->pData;
+        }
+        else
+        {
+            auto insertResult = mpImpl->maStrPoolUpper.insert(aUpper);
+            mapIt->second = insertResult.first->pData;
+        }
     }
     return SharedString(mapIt->first.pData, mapIt->second);
 }