Keep track of empty broadcaster segments, and delete them all in one go.

This massively speeds up the deletion of a large group of adjacent formula
cells. As an example, on machine, deletion of formula cells over B2:B109101
(109100 cells in total) got reduced from 4.7 seconds to 0.09 seconds).

Change-Id: Ib72da42a6644421601111907cf7c899d828c2996

1 files changed, 53 insertions, 0 deletions

diff --git a/sc/inc/columnspanset.hxx b/sc/inc/columnspanset.hxx
new file mode 100644
index 000000000000..afd17977add9
--- /dev/null
+++ b/sc/inc/columnspanset.hxx
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef SC_COLUMNSPANSET_HXX
+#define SC_COLUMNSPANSET_HXX
+
+#include "address.hxx"
+
+#include <vector>
+#include <mdds/flat_segment_tree.hpp>
+#include <boost/noncopyable.hpp>
+
+namespace sc {
+
+/**
+ * Structure that stores segments of boolean flags per column, and perform
+ * custom action on those segments.
+ */
+class ColumnSpanSet : boost::noncopyable
+{
+    typedef mdds::flat_segment_tree<SCROW, bool> ColumnSpansType;
+    typedef std::vector<ColumnSpansType*> TableType;
+    typedef std::vector<TableType*> DocType;
+
+    DocType maDoc;
+
+public:
+    class Action
+    {
+    public:
+        virtual ~Action() = 0;
+        virtual void execute(const ScAddress& rPos, SCROW nLength, bool bVal) = 0;
+    };
+
+    ~ColumnSpanSet();
+
+    void set(SCCOL nCol, SCROW nRow, SCTAB nTab, bool bVal);
+
+    void executeFromTop(Action& ac) const;
+    void executeFromBottom(Action& ac) const;
+};
+
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */