1 files changed, 115 insertions, 0 deletions
diff --git a/Source/WebKit2/WebProcess/WebPage/CoordinatedGraphics/AreaAllocator.h b/Source/WebKit2/WebProcess/WebPage/CoordinatedGraphics/AreaAllocator.h
new file mode 100644
index 000000000..20cadd613
--- /dev/null
+++ b/Source/WebKit2/WebProcess/WebPage/CoordinatedGraphics/AreaAllocator.h
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef AreaAllocator_h
+#define AreaAllocator_h
+
+#if USE(COORDINATED_GRAPHICS)
+
+#include <WebCore/IntPoint.h>
+#include <WebCore/IntRect.h>
+#include <WebCore/IntSize.h>
+
+namespace WebKit {
+
+inline int nextPowerOfTwo(int number)
+{
+    // This is a fast trick to get nextPowerOfTwo for an integer.
+    --number;
+    number |= number >> 1;
+    number |= number >> 2;
+    number |= number >> 4;
+    number |= number >> 8;
+    number |= number >> 16;
+    number++;
+    return number;
+}
+
+inline WebCore::IntSize nextPowerOfTwo(const WebCore::IntSize& size)
+{
+    return WebCore::IntSize(nextPowerOfTwo(size.width()), nextPowerOfTwo(size.height()));
+}
+
+class AreaAllocator {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    explicit AreaAllocator(const WebCore::IntSize&);
+    virtual ~AreaAllocator();
+
+    WebCore::IntSize size() const { return m_size; }
+
+    WebCore::IntSize minimumAllocation() const { return m_minAlloc; }
+    void setMinimumAllocation(const WebCore::IntSize& size) { m_minAlloc = size; }
+
+    WebCore::IntSize margin() const { return m_margin; }
+    void setMargin(const WebCore::IntSize &margin) { m_margin = margin; }
+
+    virtual void expand(const WebCore::IntSize&);
+    void expandBy(const WebCore::IntSize&);
+
+    virtual WebCore::IntRect allocate(const WebCore::IntSize&) = 0;
+    virtual void release(const WebCore::IntRect&);
+
+    virtual int overhead() const;
+
+protected:
+    WebCore::IntSize m_size;
+    WebCore::IntSize m_minAlloc;
+    WebCore::IntSize m_margin;
+
+    WebCore::IntSize roundAllocation(const WebCore::IntSize&) const;
+};
+
+class GeneralAreaAllocator final : public AreaAllocator {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    explicit GeneralAreaAllocator(const WebCore::IntSize&);
+    virtual ~GeneralAreaAllocator();
+
+    void expand(const WebCore::IntSize&) override;
+    WebCore::IntRect allocate(const WebCore::IntSize&) override;
+    void release(const WebCore::IntRect&) override;
+    int overhead() const override;
+
+private:
+    enum Split { SplitOnX, SplitOnY };
+
+    struct Node {
+        WTF_MAKE_FAST_ALLOCATED;
+    public:
+        WebCore::IntRect rect;
+        WebCore::IntSize largestFree;
+        Node* parent { nullptr };
+        Node* left { nullptr };
+        Node* right { nullptr };
+    };
+
+    Node* m_root;
+    int m_nodeCount;
+
+    static void freeNode(Node*);
+    WebCore::IntPoint allocateFromNode(const WebCore::IntSize&, Node*);
+    Node* splitNode(Node*, Split);
+    static void updateLargestFree(Node*);
+};
+
+} // namespace WebKit
+
+#endif // USE(COORDINATED_GRAPHICS)
+#endif // AreaAllocator_h