support for fast O(U)String concatenation using operator+

Operator+ now, instead of requiring O(U)String operands and returning
another O(U)String object, keeps a track of the whole concatenation
operation using temporary O(U)StringConcat objects and performs
the whole operation only at the very end.

Change-Id: I94b3348300a137498514d26e96459c1698328520

1 files changed, 30 insertions, 0 deletions

diff --git a/sal/inc/rtl/strbuf.hxx b/sal/inc/rtl/strbuf.hxx
index 7bde9e79b152..945d1d2b179a 100644
--- a/sal/inc/rtl/strbuf.hxx
+++ b/sal/inc/rtl/strbuf.hxx
@@ -28,6 +28,10 @@
 #include <rtl/string.hxx>
 #include <rtl/stringutils.hxx>
 
+#ifdef RTL_FAST_STRING
+#include <rtl/stringconcat.hxx>
+#endif
+
 #ifdef __cplusplus
 
 // The unittest uses slightly different code to help check that the proper
@@ -218,6 +222,20 @@ public:
         rtl_stringbuffer_newFromStr_WithLength( &pData, value, length );
     }
 
+#ifdef RTL_FAST_STRING
+    template< typename T1, typename T2 >
+    OStringBuffer( const OStringConcat< T1, T2 >& c )
+    {
+        const int l = c.length();
+        rtl_String* buffer = NULL;
+        rtl_string_new_WithLength( &buffer, l );
+        char* end = c.addData( buffer->buffer );
+        buffer->length = end - buffer->buffer;
+        pData = buffer;
+        nCapacity = l + 16;
+    }
+#endif
+
     /** Assign to this a copy of value.
      */
     OStringBuffer& operator = ( const OStringBuffer& value )
@@ -830,6 +848,18 @@ private:
     sal_Int32       nCapacity;
 };
 
+#ifdef RTL_FAST_STRING
+template<>
+struct ToStringHelper< OStringBuffer >
+    {
+    static int length( const OStringBuffer& s ) { return s.getLength(); }
+    static char* addData( char* buffer, const OStringBuffer& s ) { return addDataHelper( buffer, s.getStr(), s.getLength()); }
+    static const bool allowOStringConcat = true;
+    static const bool allowOUStringConcat = false;
+    };
+#endif
+
+
 }
 
 #ifdef RTL_STRING_UNITTEST