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29 #ifndef GlyphMetricsMap_h
30 #define GlyphMetricsMap_h
32 #include <wtf/FixedArray.h>
33 #include <wtf/HashMap.h>
34 #include <wtf/OwnPtr.h>
35 #include <wtf/unicode/Unicode.h>
39 typedef unsigned short Glyph;
41 const float cGlyphSizeUnknown = -1;
43 template<class T> class GlyphMetricsMap {
44 WTF_MAKE_NONCOPYABLE(GlyphMetricsMap);
46 GlyphMetricsMap() : m_filledPrimaryPage(false) { }
50 deleteAllValues(*m_pages);
53 T metricsForGlyph(Glyph glyph)
55 return locatePage(glyph / GlyphMetricsPage::size)->metricsForGlyph(glyph);
58 void setMetricsForGlyph(Glyph glyph, const T& metrics)
60 locatePage(glyph / GlyphMetricsPage::size)->setMetricsForGlyph(glyph, metrics);
64 struct GlyphMetricsPage {
65 static const size_t size = 256; // Usually covers Latin-1 in a single page.
66 FixedArray<T, size> m_metrics;
68 T metricsForGlyph(Glyph glyph) const { return m_metrics[glyph % size]; }
69 void setMetricsForGlyph(Glyph glyph, const T& metrics)
71 setMetricsForIndex(glyph % size, metrics);
73 void setMetricsForIndex(unsigned index, const T& metrics)
75 m_metrics[index] = metrics;
79 GlyphMetricsPage* locatePage(unsigned pageNumber)
81 if (!pageNumber && m_filledPrimaryPage)
82 return &m_primaryPage;
83 return locatePageSlowCase(pageNumber);
86 GlyphMetricsPage* locatePageSlowCase(unsigned pageNumber);
88 static T unknownMetrics();
90 bool m_filledPrimaryPage;
91 GlyphMetricsPage m_primaryPage; // We optimize for the page that contains glyph indices 0-255.
92 OwnPtr<HashMap<int, GlyphMetricsPage*> > m_pages;
95 template<> inline float GlyphMetricsMap<float>::unknownMetrics()
97 return cGlyphSizeUnknown;
100 template<> inline FloatRect GlyphMetricsMap<FloatRect>::unknownMetrics()
102 return FloatRect(0, 0, cGlyphSizeUnknown, cGlyphSizeUnknown);
105 template<class T> typename GlyphMetricsMap<T>::GlyphMetricsPage* GlyphMetricsMap<T>::locatePageSlowCase(unsigned pageNumber)
107 GlyphMetricsPage* page;
109 ASSERT(!m_filledPrimaryPage);
110 page = &m_primaryPage;
111 m_filledPrimaryPage = true;
114 if ((page = m_pages->get(pageNumber)))
117 m_pages = adoptPtr(new HashMap<int, GlyphMetricsPage*>);
118 page = new GlyphMetricsPage;
119 m_pages->set(pageNumber, page);
122 // Fill in the whole page with the unknown glyph information.
123 for (unsigned i = 0; i < GlyphMetricsPage::size; i++)
124 page->setMetricsForIndex(i, unknownMetrics());
129 } // namespace WebCore