1 /*
2 * Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #ifndef GlyphMetricsMap_h
30 #define GlyphMetricsMap_h
31
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"
39
40 namespace WebCore {
41
42 const float cGlyphSizeUnknown = -1;
43
44 template<class T> class GlyphMetricsMap {
45 WTF_MAKE_NONCOPYABLE(GlyphMetricsMap);
46 public:
GlyphMetricsMap()47 GlyphMetricsMap() : m_filledPrimaryPage(false) { }
metricsForGlyph(Glyph glyph)48 T metricsForGlyph(Glyph glyph)
49 {
50 return locatePage(glyph / GlyphMetricsPage::size)->metricsForGlyph(glyph);
51 }
52
setMetricsForGlyph(Glyph glyph,const T & metrics)53 void setMetricsForGlyph(Glyph glyph, const T& metrics)
54 {
55 locatePage(glyph / GlyphMetricsPage::size)->setMetricsForGlyph(glyph, metrics);
56 }
57
58 private:
59 class GlyphMetricsPage {
60 public:
61 static const size_t size = 256; // Usually covers Latin-1 in a single page.
62
metricsForGlyph(Glyph glyph)63 T metricsForGlyph(Glyph glyph) const { return m_metrics[glyph % size]; }
setMetricsForGlyph(Glyph glyph,const T & metrics)64 void setMetricsForGlyph(Glyph glyph, const T& metrics)
65 {
66 setMetricsForIndex(glyph % size, metrics);
67 }
setMetricsForIndex(unsigned index,const T & metrics)68 void setMetricsForIndex(unsigned index, const T& metrics)
69 {
70 ASSERT_WITH_SECURITY_IMPLICATION(index < size);
71 m_metrics[index] = metrics;
72 }
73
74 private:
75 T m_metrics[size];
76 };
77
locatePage(unsigned pageNumber)78 GlyphMetricsPage* locatePage(unsigned pageNumber)
79 {
80 if (!pageNumber && m_filledPrimaryPage)
81 return &m_primaryPage;
82 return locatePageSlowCase(pageNumber);
83 }
84
85 GlyphMetricsPage* locatePageSlowCase(unsigned pageNumber);
86
87 static T unknownMetrics();
88
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;
92 };
93
unknownMetrics()94 template<> inline float GlyphMetricsMap<float>::unknownMetrics()
95 {
96 return cGlyphSizeUnknown;
97 }
98
unknownMetrics()99 template<> inline FloatRect GlyphMetricsMap<FloatRect>::unknownMetrics()
100 {
101 return FloatRect(0, 0, cGlyphSizeUnknown, cGlyphSizeUnknown);
102 }
103
locatePageSlowCase(unsigned pageNumber)104 template<class T> typename GlyphMetricsMap<T>::GlyphMetricsPage* GlyphMetricsMap<T>::locatePageSlowCase(unsigned pageNumber)
105 {
106 GlyphMetricsPage* page;
107 if (!pageNumber) {
108 ASSERT(!m_filledPrimaryPage);
109 page = &m_primaryPage;
110 m_filledPrimaryPage = true;
111 } else {
112 if (m_pages) {
113 if ((page = m_pages->get(pageNumber)))
114 return page;
115 } else
116 m_pages = adoptPtr(new HashMap<int, OwnPtr<GlyphMetricsPage> >);
117 page = new GlyphMetricsPage;
118 m_pages->set(pageNumber, adoptPtr(page));
119 }
120
121 // Fill in the whole page with the unknown glyph information.
122 for (unsigned i = 0; i < GlyphMetricsPage::size; i++)
123 page->setMetricsForIndex(i, unknownMetrics());
124
125 return page;
126 }
127
128 } // namespace WebCore
129
130 #endif
131