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 <wtf/FixedArray.h>
33 #include <wtf/HashMap.h>
34 #include <wtf/OwnPtr.h>
35 #include <wtf/unicode/Unicode.h>
36
37 namespace WebCore {
38
39 typedef unsigned short Glyph;
40
41 const float cGlyphSizeUnknown = -1;
42
43 template<class T> class GlyphMetricsMap {
44 WTF_MAKE_NONCOPYABLE(GlyphMetricsMap);
45 public:
GlyphMetricsMap()46 GlyphMetricsMap() : m_filledPrimaryPage(false) { }
~GlyphMetricsMap()47 ~GlyphMetricsMap()
48 {
49 if (m_pages)
50 deleteAllValues(*m_pages);
51 }
52
metricsForGlyph(Glyph glyph)53 T metricsForGlyph(Glyph glyph)
54 {
55 return locatePage(glyph / GlyphMetricsPage::size)->metricsForGlyph(glyph);
56 }
57
setMetricsForGlyph(Glyph glyph,const T & metrics)58 void setMetricsForGlyph(Glyph glyph, const T& metrics)
59 {
60 locatePage(glyph / GlyphMetricsPage::size)->setMetricsForGlyph(glyph, metrics);
61 }
62
63 private:
64 struct GlyphMetricsPage {
65 static const size_t size = 256; // Usually covers Latin-1 in a single page.
66 FixedArray<T, size> m_metrics;
67
metricsForGlyphGlyphMetricsPage68 T metricsForGlyph(Glyph glyph) const { return m_metrics[glyph % size]; }
setMetricsForGlyphGlyphMetricsPage69 void setMetricsForGlyph(Glyph glyph, const T& metrics)
70 {
71 setMetricsForIndex(glyph % size, metrics);
72 }
setMetricsForIndexGlyphMetricsPage73 void setMetricsForIndex(unsigned index, const T& metrics)
74 {
75 m_metrics[index] = metrics;
76 }
77 };
78
locatePage(unsigned pageNumber)79 GlyphMetricsPage* locatePage(unsigned pageNumber)
80 {
81 if (!pageNumber && m_filledPrimaryPage)
82 return &m_primaryPage;
83 return locatePageSlowCase(pageNumber);
84 }
85
86 GlyphMetricsPage* locatePageSlowCase(unsigned pageNumber);
87
88 static T unknownMetrics();
89
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;
93 };
94
unknownMetrics()95 template<> inline float GlyphMetricsMap<float>::unknownMetrics()
96 {
97 return cGlyphSizeUnknown;
98 }
99
unknownMetrics()100 template<> inline FloatRect GlyphMetricsMap<FloatRect>::unknownMetrics()
101 {
102 return FloatRect(0, 0, cGlyphSizeUnknown, cGlyphSizeUnknown);
103 }
104
locatePageSlowCase(unsigned pageNumber)105 template<class T> typename GlyphMetricsMap<T>::GlyphMetricsPage* GlyphMetricsMap<T>::locatePageSlowCase(unsigned pageNumber)
106 {
107 GlyphMetricsPage* page;
108 if (!pageNumber) {
109 ASSERT(!m_filledPrimaryPage);
110 page = &m_primaryPage;
111 m_filledPrimaryPage = true;
112 } else {
113 if (m_pages) {
114 if ((page = m_pages->get(pageNumber)))
115 return page;
116 } else
117 m_pages = adoptPtr(new HashMap<int, GlyphMetricsPage*>);
118 page = new GlyphMetricsPage;
119 m_pages->set(pageNumber, page);
120 }
121
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());
125
126 return page;
127 }
128
129 } // namespace WebCore
130
131 #endif
132