Perf-sc: tdf#100709 avoid segment tree with ScMultiSelIter where possible

* create ScFlatBoolRowSegments in ScMultiSelIter only if necessary
* create ScMultiSelIter only for affected columns in
ScTable::MergeSelectionPattern() using ScMarkData::GetMarkedColSpans()
* obtaining a full ScRangeList in ScMarkData::GetMarkedColSpans() was
completely unnecessary, use existing selection containers instead and also
if possible avoid creating a segment tree that needs to be converted to
vector, directly use a vector instead

Improvement:
* under ScDocShell::Load()
previous: Ir:  26 454 571 612
now: Ir:  18 811 368 362

* thereof under ScTable::MergeSelectionPattern()
previous: Ir:   4 104 164 533
now: Ir:     664 738 808

Change-Id: I95895a3a000c1a0b7895fb0696b0889c6d6b4d49

2 files changed, 11 insertions, 2 deletions

diff --git a/sc/inc/markarr.hxx b/sc/inc/markarr.hxx
index 33a7b9031128..548d023db4d4 100644
--- a/sc/inc/markarr.hxx
+++ b/sc/inc/markarr.hxx
@@ -71,6 +71,7 @@ public:
                 ~ScMarkArrayIter();
 
     bool        Next( SCROW& rTop, SCROW& rBottom );
+    void        reset( const ScMarkArray* pNewArray );
 };
 
 #endif
diff --git a/sc/inc/markmulti.hxx b/sc/inc/markmulti.hxx
index 4999df5c5708..6ada78c243e6 100644
--- a/sc/inc/markmulti.hxx
+++ b/sc/inc/markmulti.hxx
@@ -63,20 +63,28 @@ public:
     void Clear();
     void MarkAllCols( SCROW nStartRow, SCROW nEndRow );
     bool HasAnyMarks() const;
+
+    // For faster access from within ScMarkData, instead of creating
+    // ScMultiSelIter with ScFlatBoolRowSegments bottleneck.
+    const ScMarkArray& GetRowSelArray() const;
+    const ScMarkArray* GetMultiSelArray( SCCOL nCol ) const;
 };
 
 class ScMultiSelIter
 {
 
 private:
-    ScFlatBoolRowSegments aRowSegs;
+    std::unique_ptr<ScFlatBoolRowSegments>  pRowSegs;
+    ScMarkArrayIter                         aMarkArrayIter;
     SCROW nNextSegmentStart;
 public:
     ScMultiSelIter( const ScMultiSel& rMultiSel, SCCOL nCol );
     ~ScMultiSelIter();
 
     bool Next( SCROW& rTop, SCROW& rBottom );
-    const ScFlatBoolRowSegments& GetRowSegments() const { return aRowSegs; }
+    /** Only to be used by ScMultiSel::IsAllMarked() or otherwise sure that a
+        segment tree is actually used. */
+    bool GetRangeData( SCROW nRow, ScFlatBoolRowSegments::RangeData& rRowRange ) const;
 };
 
 #endif