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diff --git a/Source/WebCore/platform/graphics/GlyphMetricsMap.h b/Source/WebCore/platform/graphics/GlyphMetricsMap.h
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+++ b/Source/WebCore/platform/graphics/GlyphMetricsMap.h
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+/*
+ * Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer. 
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution. 
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef GlyphMetricsMap_h
+#define GlyphMetricsMap_h
+
+#include <wtf/FixedArray.h>
+#include <wtf/HashMap.h>
+#include <wtf/OwnPtr.h>
+#include <wtf/unicode/Unicode.h>
+
+namespace WebCore {
+
+typedef unsigned short Glyph;
+
+const float cGlyphSizeUnknown = -1;
+
+template<class T> class GlyphMetricsMap : public Noncopyable {
+public:
+    GlyphMetricsMap() : m_filledPrimaryPage(false) { }
+    ~GlyphMetricsMap()
+    { 
+        if (m_pages)
+            deleteAllValues(*m_pages);
+    }
+
+    T metricsForGlyph(Glyph glyph)
+    {
+        return locatePage(glyph / GlyphMetricsPage::size)->metricsForGlyph(glyph);
+    }
+
+    void setMetricsForGlyph(Glyph glyph, const T& metrics)
+    {
+        locatePage(glyph / GlyphMetricsPage::size)->setMetricsForGlyph(glyph, metrics);
+    }
+
+private:
+    struct GlyphMetricsPage {
+        static const size_t size = 256; // Usually covers Latin-1 in a single page.
+        FixedArray<T, size> m_metrics;
+
+        T metricsForGlyph(Glyph glyph) const { return m_metrics[glyph % size]; }
+        void setMetricsForGlyph(Glyph glyph, const T& metrics)
+        {
+            setMetricsForIndex(glyph % size, metrics);
+        }
+        void setMetricsForIndex(unsigned index, const T& metrics)
+        {
+            m_metrics[index] = metrics;
+        }
+    };
+    
+    GlyphMetricsPage* locatePage(unsigned pageNumber)
+    {
+        if (!pageNumber && m_filledPrimaryPage)
+            return &m_primaryPage;
+        return locatePageSlowCase(pageNumber);
+    }
+
+    GlyphMetricsPage* locatePageSlowCase(unsigned pageNumber);
+    
+    static T unknownMetrics();
+
+    bool m_filledPrimaryPage;
+    GlyphMetricsPage m_primaryPage; // We optimize for the page that contains glyph indices 0-255.
+    OwnPtr<HashMap<int, GlyphMetricsPage*> > m_pages;
+};
+
+template<> inline float GlyphMetricsMap<float>::unknownMetrics()
+{
+    return cGlyphSizeUnknown;
+}
+
+template<> inline FloatRect GlyphMetricsMap<FloatRect>::unknownMetrics()
+{
+    return FloatRect(0, 0, cGlyphSizeUnknown, cGlyphSizeUnknown);
+}
+
+template<class T> typename GlyphMetricsMap<T>::GlyphMetricsPage* GlyphMetricsMap<T>::locatePageSlowCase(unsigned pageNumber)
+{
+    GlyphMetricsPage* page;
+    if (!pageNumber) {
+        ASSERT(!m_filledPrimaryPage);
+        page = &m_primaryPage;
+        m_filledPrimaryPage = true;
+    } else {
+        if (m_pages) {
+            if ((page = m_pages->get(pageNumber)))
+                return page;
+        } else
+            m_pages = adoptPtr(new HashMap<int, GlyphMetricsPage*>);
+        page = new GlyphMetricsPage;
+        m_pages->set(pageNumber, page);
+    }
+
+    // Fill in the whole page with the unknown glyph information.
+    for (unsigned i = 0; i < GlyphMetricsPage::size; i++)
+        page->setMetricsForIndex(i, unknownMetrics());
+
+    return page;
+}
+    
+} // namespace WebCore
+
+#endif