third_party/WebKit/Source/platform/fonts/GlyphPage.h

   1 /*
   2  * Copyright (C) 2006, 2007, 2008, 2013 Apple Inc. All rights reserved.
   3  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1.  Redistributions of source code must retain the above copyright
  10  *     notice, this list of conditions and the following disclaimer.
  11  * 2.  Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  15  *     its contributors may be used to endorse or promote products derived
  16  *     from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  22  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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  25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #ifndef GlyphPage_h
  31 #define GlyphPage_h
  32
  33 #include "platform/PlatformExport.h"
  34 #include "platform/fonts/CustomFontData.h"
  35 #include "platform/fonts/Glyph.h"
  36 #include "wtf/PassRefPtr.h"
  37 #include "wtf/RefCounted.h"
  38 #include "wtf/RefPtr.h"
  39 #include "wtf/text/Unicode.h"
  40 #include <string.h>
  41
  42 namespace blink {
  43
  44 class SimpleFontData;
  45 class GlyphPageTreeNodeBase;
  46
  47 // Holds the glyph index and the corresponding SimpleFontData information for a given
  48 // character.
  49 struct GlyphData {
  50     GlyphData(Glyph g = 0, const SimpleFontData* f = 0)
  51         : glyph(g)
  52         , fontData(f)
  53     {
  54     }
  55     Glyph glyph;
  56     const SimpleFontData* fontData;
  57 };
  58
  59 #if COMPILER(MSVC)
  60 #pragma warning(push)
  61 #pragma warning(disable: 4200) // Disable "zero-sized array in struct/union" warning
  62 #endif
  63
  64 // A GlyphPage contains a fixed-size set of GlyphData mappings for a contiguous
  65 // range of characters in the Unicode code space. GlyphPages are indexed
  66 // starting from 0 and incrementing for each 256 glyphs.
  67 //
  68 // One page may actually include glyphs from other fonts if the characters are
  69 // missing in the primary font. It is owned by exactly one GlyphPageTreeNode,
  70 // although multiple nodes may reference it as their "page" if they are supposed
  71 // to be overriding the parent's node, but provide no additional information.
  72 class PLATFORM_EXPORT GlyphPage : public RefCounted<GlyphPage> {
  73 public:
  74     static PassRefPtr<GlyphPage> createForMixedFontData(GlyphPageTreeNodeBase* owner)
  75     {
  76         void* slot = fastMalloc(sizeof(GlyphPage) + sizeof(SimpleFontData*) * GlyphPage::size);
  77         return adoptRef(new (slot) GlyphPage(owner));
  78     }
  79
  80     static PassRefPtr<GlyphPage> createForSingleFontData(GlyphPageTreeNodeBase* owner, const SimpleFontData* fontData)
  81     {
  82         ASSERT(fontData);
  83         return adoptRef(new GlyphPage(owner, fontData));
  84     }
  85
  86     PassRefPtr<GlyphPage> createCopiedSystemFallbackPage(GlyphPageTreeNodeBase* owner) const
  87     {
  88         RefPtr<GlyphPage> page = GlyphPage::createForMixedFontData(owner);
  89         memcpy(page->m_glyphs, m_glyphs, sizeof(m_glyphs));
  90         if (hasPerGlyphFontData())
  91             memcpy(page->m_perGlyphFontData, m_perGlyphFontData, sizeof(SimpleFontData*) * GlyphPage::size);
  92         else {
  93             for (size_t i = 0; i < GlyphPage::size; ++i) {
  94                 page->m_perGlyphFontData[i] = m_glyphs[i] ? m_fontDataForAllGlyphs : 0;
  95             }
  96         }
  97         page->m_customFontToLoad = m_customFontToLoad;
  98         return page.release();
  99     }
 100
 101     ~GlyphPage() { }
 102
 103     static const unsigned char sizeBits = 8;
 104     static const size_t size = (1 << GlyphPage::sizeBits); // Covers Latin-1 in a single page.
 105     static unsigned indexForCharacter(UChar32 c) { return c & 0xFF; }
 106
 107     ALWAYS_INLINE GlyphData glyphDataForCharacter(UChar32 c) const
 108     {
 109         unsigned index = indexForCharacter(c);
 110         if (const CustomFontData* customData = customFontToLoadAt(index))
 111             customData->beginLoadIfNeeded();
 112         return glyphDataForIndex(index);
 113     }
 114
 115     ALWAYS_INLINE GlyphData glyphDataForIndex(unsigned index) const
 116     {
 117         ASSERT_WITH_SECURITY_IMPLICATION(index < size);
 118         Glyph glyph = m_glyphs[index];
 119         if (hasPerGlyphFontData())
 120             return GlyphData(glyph, m_perGlyphFontData[index]);
 121         return GlyphData(glyph, glyph ? m_fontDataForAllGlyphs : 0);
 122     }
 123
 124     ALWAYS_INLINE Glyph glyphForCharacter(UChar32 c) const
 125     {
 126         return glyphAt(indexForCharacter(c));
 127     }
 128
 129     ALWAYS_INLINE Glyph glyphAt(unsigned index) const
 130     {
 131         ASSERT_WITH_SECURITY_IMPLICATION(index < size);
 132         return m_glyphs[index];
 133     }
 134
 135     void setGlyphDataForCharacter(UChar32 c, Glyph g, const SimpleFontData* f)
 136     {
 137         setGlyphDataForIndex(indexForCharacter(c), g, f);
 138     }
 139
 140     void setGlyphDataForIndex(unsigned index, Glyph glyph, const SimpleFontData* fontData)
 141     {
 142         ASSERT_WITH_SECURITY_IMPLICATION(index < size);
 143         m_glyphs[index] = glyph;
 144         setCustomFontToLoad(index, 0);
 145
 146         if (hasPerGlyphFontData()) {
 147             m_perGlyphFontData[index] = fontData;
 148         } else {
 149             // A single-font GlyphPage already assigned m_fontDataForAllGlyphs in the constructor.
 150             ASSERT(!glyph || fontData == m_fontDataForAllGlyphs);
 151         }
 152     }
 153
 154     void setGlyphDataForIndex(unsigned index, const GlyphData& glyphData)
 155     {
 156         setGlyphDataForIndex(index, glyphData.glyph, glyphData.fontData);
 157     }
 158
 159     const CustomFontData* customFontToLoadAt(unsigned index) const
 160     {
 161         ASSERT_WITH_SECURITY_IMPLICATION(index < size);
 162         return m_customFontToLoad ? m_customFontToLoad->at(index) : 0;
 163     }
 164
 165     void setCustomFontToLoad(unsigned index, const CustomFontData* customFontToLoad)
 166     {
 167         if (!m_customFontToLoad) {
 168             if (!customFontToLoad)
 169                 return;
 170             m_customFontToLoad = CustomDataPage::create();
 171         }
 172         ASSERT_WITH_SECURITY_IMPLICATION(index < size);
 173         m_customFontToLoad->set(index, customFontToLoad);
 174     }
 175
 176     void removePerGlyphFontData(const SimpleFontData* fontData)
 177     {
 178         // This method should only be called on the mixed page, which is never single-font.
 179         ASSERT(hasPerGlyphFontData());
 180         for (size_t i = 0; i < size; ++i) {
 181             if (m_perGlyphFontData[i] == fontData) {
 182                 m_glyphs[i] = 0;
 183                 m_perGlyphFontData[i] = 0;
 184             }
 185         }
 186     }
 187
 188     GlyphPageTreeNodeBase* owner() const { return m_owner; }
 189
 190     bool hasPerGlyphFontData() const { return !m_fontDataForAllGlyphs; }
 191
 192 private:
 193     explicit GlyphPage(GlyphPageTreeNodeBase* owner, const SimpleFontData* fontDataForAllGlyphs = 0)
 194         : m_fontDataForAllGlyphs(fontDataForAllGlyphs)
 195         , m_owner(owner)
 196     {
 197         memset(m_glyphs, 0, sizeof(m_glyphs));
 198         if (hasPerGlyphFontData())
 199             memset(m_perGlyphFontData, 0, sizeof(SimpleFontData*) * GlyphPage::size);
 200     }
 201
 202     class CustomDataPage : public RefCounted<CustomDataPage> {
 203     public:
 204         static RefPtr<CustomDataPage> create() { return adoptRef(new CustomDataPage()); }
 205         const CustomFontData* at(size_t index) const { return m_customData[index]; }
 206         void set(size_t index, const CustomFontData* data) { m_customData[index] = data; }
 207     private:
 208         CustomDataPage() { memset(m_customData, 0, sizeof(m_customData)); }
 209         const CustomFontData* m_customData[size];
 210     };
 211
 212     const SimpleFontData* m_fontDataForAllGlyphs;
 213     GlyphPageTreeNodeBase* m_owner;
 214     RefPtr<CustomDataPage> m_customFontToLoad;
 215     Glyph m_glyphs[size];
 216
 217     // NOTE: This array has (GlyphPage::size) elements if m_fontDataForAllGlyphs is null.
 218     const SimpleFontData* m_perGlyphFontData[0];
 219 };
 220
 221 #if COMPILER(MSVC)
 222 #pragma warning(pop)
 223 #endif
 224
 225 } // namespace blink
 226
 227 #endif // GlyphPage_h