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 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;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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 "Glyph.h"
34#include <string.h>
35#include <unicode/utypes.h>
36#include <wtf/PassRefPtr.h>
37#include <wtf/RefCounted.h>
38#include <wtf/RefPtr.h>
39
40namespace WebCore {
41
42class SimpleFontData;
43class GlyphPageTreeNode;
44
45// Holds the glyph index and the corresponding SimpleFontData information for a given
46// character.
47struct GlyphData {
48    GlyphData(Glyph g = 0, const SimpleFontData* f = 0)
49        : glyph(g)
50        , fontData(f)
51    {
52    }
53    Glyph glyph;
54    const SimpleFontData* fontData;
55};
56
57#if COMPILER(MSVC)
58#pragma warning(push)
59#pragma warning(disable: 4200) // Disable "zero-sized array in struct/union" warning
60#endif
61
62// A GlyphPage contains a fixed-size set of GlyphData mappings for a contiguous
63// range of characters in the Unicode code space. GlyphPages are indexed
64// starting from 0 and incrementing for each 256 glyphs.
65//
66// One page may actually include glyphs from other fonts if the characters are
67// missing in the primary font. It is owned by exactly one GlyphPageTreeNode,
68// although multiple nodes may reference it as their "page" if they are supposed
69// to be overriding the parent's node, but provide no additional information.
70class GlyphPage : public RefCounted<GlyphPage> {
71public:
72    static PassRefPtr<GlyphPage> createForMixedFontData(GlyphPageTreeNode* owner)
73    {
74        void* slot = fastMalloc(sizeof(GlyphPage) + sizeof(SimpleFontData*) * GlyphPage::size);
75        return adoptRef(new (NotNull, slot) GlyphPage(owner));
76    }
77
78    static PassRefPtr<GlyphPage> createForSingleFontData(GlyphPageTreeNode* owner, const SimpleFontData* fontData)
79    {
80        ASSERT(fontData);
81        return adoptRef(new GlyphPage(owner, fontData));
82    }
83
84    PassRefPtr<GlyphPage> createCopiedSystemFallbackPage(GlyphPageTreeNode* owner) const
85    {
86        RefPtr<GlyphPage> page = GlyphPage::createForMixedFontData(owner);
87        memcpy(page->m_glyphs, m_glyphs, sizeof(m_glyphs));
88        if (hasPerGlyphFontData())
89            memcpy(page->m_perGlyphFontData, m_perGlyphFontData, sizeof(SimpleFontData*) * GlyphPage::size);
90        else {
91            for (size_t i = 0; i < GlyphPage::size; ++i) {
92                page->m_perGlyphFontData[i] = m_glyphs[i] ? m_fontDataForAllGlyphs : 0;
93            }
94        }
95        return page.release();
96    }
97
98    ~GlyphPage() { }
99
100    static const size_t size = 256; // Covers Latin-1 in a single page.
101    static unsigned indexForCharacter(UChar32 c) { return c % GlyphPage::size; }
102
103    ALWAYS_INLINE GlyphData glyphDataForCharacter(UChar32 c) const
104    {
105        return glyphDataForIndex(indexForCharacter(c));
106    }
107
108    ALWAYS_INLINE GlyphData glyphDataForIndex(unsigned index) const
109    {
110        ASSERT_WITH_SECURITY_IMPLICATION(index < size);
111        Glyph glyph = m_glyphs[index];
112        if (hasPerGlyphFontData())
113            return GlyphData(glyph, m_perGlyphFontData[index]);
114        return GlyphData(glyph, glyph ? m_fontDataForAllGlyphs : 0);
115    }
116
117    ALWAYS_INLINE Glyph glyphAt(unsigned index) const
118    {
119        ASSERT_WITH_SECURITY_IMPLICATION(index < size);
120        return m_glyphs[index];
121    }
122
123    ALWAYS_INLINE const SimpleFontData* fontDataForCharacter(UChar32 c) const
124    {
125        unsigned index = indexForCharacter(c);
126        if (hasPerGlyphFontData())
127            return m_perGlyphFontData[index];
128        return m_glyphs[index] ? m_fontDataForAllGlyphs : 0;
129    }
130
131    void setGlyphDataForCharacter(UChar32 c, Glyph g, const SimpleFontData* f)
132    {
133        setGlyphDataForIndex(indexForCharacter(c), g, f);
134    }
135
136    void setGlyphDataForIndex(unsigned index, Glyph glyph, const SimpleFontData* fontData)
137    {
138        ASSERT_WITH_SECURITY_IMPLICATION(index < size);
139        m_glyphs[index] = glyph;
140
141        // GlyphPage getters will always return a null SimpleFontData* for glyph #0 if there's no per-glyph font array.
142        if (hasPerGlyphFontData()) {
143            m_perGlyphFontData[index] = glyph ? fontData : 0;
144            return;
145        }
146
147        // A single-font GlyphPage already assigned m_fontDataForAllGlyphs in the constructor.
148        ASSERT(!glyph || fontData == m_fontDataForAllGlyphs);
149    }
150
151    void setGlyphDataForIndex(unsigned index, const GlyphData& glyphData)
152    {
153        setGlyphDataForIndex(index, glyphData.glyph, glyphData.fontData);
154    }
155
156    void removeFontDataFromSystemFallbackPage(const SimpleFontData* fontData)
157    {
158        // This method should only be called on the system fallback page, which is never single-font.
159        ASSERT(hasPerGlyphFontData());
160        for (size_t i = 0; i < size; ++i) {
161            if (m_perGlyphFontData[i] == fontData) {
162                m_glyphs[i] = 0;
163                m_perGlyphFontData[i] = 0;
164            }
165        }
166    }
167
168    GlyphPageTreeNode* owner() const { return m_owner; }
169
170    // Implemented by the platform.
171    bool fill(unsigned offset, unsigned length, UChar* characterBuffer, unsigned bufferLength, const SimpleFontData*);
172#if PLATFORM(COCOA)
173    static bool mayUseMixedFontDataWhenFilling(const UChar* characterBuffer, unsigned bufferLength, const SimpleFontData*);
174#else
175    static bool mayUseMixedFontDataWhenFilling(const UChar*, unsigned, const SimpleFontData*) { return false; }
176#endif
177
178private:
179    explicit GlyphPage(GlyphPageTreeNode* owner, const SimpleFontData* fontDataForAllGlyphs = 0)
180        : m_fontDataForAllGlyphs(fontDataForAllGlyphs)
181        , m_owner(owner)
182    {
183        memset(m_glyphs, 0, sizeof(m_glyphs));
184        if (hasPerGlyphFontData())
185            memset(m_perGlyphFontData, 0, sizeof(SimpleFontData*) * GlyphPage::size);
186    }
187
188    bool hasPerGlyphFontData() const { return !m_fontDataForAllGlyphs; }
189
190    const SimpleFontData* m_fontDataForAllGlyphs;
191    GlyphPageTreeNode* m_owner;
192    Glyph m_glyphs[size];
193
194    // NOTE: This array has (GlyphPage::size) elements if m_fontDataForAllGlyphs is null.
195    const SimpleFontData* m_perGlyphFontData[0];
196};
197
198#if COMPILER(MSVC)
199#pragma warning(pop)
200#endif
201
202} // namespace WebCore
203
204#endif // GlyphPage_h
205