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29 #ifndef GlyphMetricsMap_h
30 #define GlyphMetricsMap_h
32 #include "platform/fonts/Glyph.h"
33 #include "platform/geometry/FloatRect.h"
34 #include "wtf/Assertions.h"
35 #include "wtf/HashMap.h"
36 #include "wtf/OwnPtr.h"
37 #include "wtf/PassOwnPtr.h"
38 #include "wtf/unicode/Unicode.h"
42 const float cGlyphSizeUnknown = -1;
44 template<class T> class GlyphMetricsMap {
45 WTF_MAKE_NONCOPYABLE(GlyphMetricsMap);
47 GlyphMetricsMap() : m_filledPrimaryPage(false) { }
48 T metricsForGlyph(Glyph glyph)
50 return locatePage(glyph / GlyphMetricsPage::size)->metricsForGlyph(glyph);
53 void setMetricsForGlyph(Glyph glyph, const T& metrics)
55 locatePage(glyph / GlyphMetricsPage::size)->setMetricsForGlyph(glyph, metrics);
59 class GlyphMetricsPage {
61 static const size_t size = 256; // Usually covers Latin-1 in a single page.
63 T metricsForGlyph(Glyph glyph) const { return m_metrics[glyph % size]; }
64 void setMetricsForGlyph(Glyph glyph, const T& metrics)
66 setMetricsForIndex(glyph % size, metrics);
68 void setMetricsForIndex(unsigned index, const T& metrics)
70 ASSERT_WITH_SECURITY_IMPLICATION(index < size);
71 m_metrics[index] = metrics;
78 GlyphMetricsPage* locatePage(unsigned pageNumber)
80 if (!pageNumber && m_filledPrimaryPage)
81 return &m_primaryPage;
82 return locatePageSlowCase(pageNumber);
85 GlyphMetricsPage* locatePageSlowCase(unsigned pageNumber);
87 static T unknownMetrics();
89 bool m_filledPrimaryPage;
90 GlyphMetricsPage m_primaryPage; // We optimize for the page that contains glyph indices 0-255.
91 OwnPtr<HashMap<int, OwnPtr<GlyphMetricsPage> > > m_pages;
94 template<> inline float GlyphMetricsMap<float>::unknownMetrics()
96 return cGlyphSizeUnknown;
99 template<> inline FloatRect GlyphMetricsMap<FloatRect>::unknownMetrics()
101 return FloatRect(0, 0, cGlyphSizeUnknown, cGlyphSizeUnknown);
104 template<class T> typename GlyphMetricsMap<T>::GlyphMetricsPage* GlyphMetricsMap<T>::locatePageSlowCase(unsigned pageNumber)
106 GlyphMetricsPage* page;
108 ASSERT(!m_filledPrimaryPage);
109 page = &m_primaryPage;
110 m_filledPrimaryPage = true;
113 page = m_pages->get(pageNumber);
117 m_pages = adoptPtr(new HashMap<int, OwnPtr<GlyphMetricsPage> >);
118 page = new GlyphMetricsPage;
119 m_pages->set(pageNumber, adoptPtr(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());