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92 lines
3.3 KiB
C++
92 lines
3.3 KiB
C++
/*
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* Copyright (C) 2000 Lars Knoll (knoll@kde.org)
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* Copyright (C) 2003, 2004, 2006, 2007, 2009, 2010 Apple Inc. All right reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public License
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* along with this library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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*/
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#ifndef SKY_ENGINE_PLATFORM_TEXT_BIDICONTEXT_H_
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#define SKY_ENGINE_PLATFORM_TEXT_BIDICONTEXT_H_
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#include "sky/engine/platform/PlatformExport.h"
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#include "sky/engine/wtf/Assertions.h"
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#include "sky/engine/wtf/PassRefPtr.h"
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#include "sky/engine/wtf/RefCounted.h"
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#include "sky/engine/wtf/RefPtr.h"
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#include "sky/engine/wtf/unicode/Unicode.h"
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namespace blink {
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enum BidiEmbeddingSource {
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FromStyleOrDOM,
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FromUnicode
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};
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// Used to keep track of explicit embeddings.
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class PLATFORM_EXPORT BidiContext : public RefCounted<BidiContext> {
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public:
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static PassRefPtr<BidiContext> create(unsigned char level, WTF::Unicode::Direction, bool override = false, BidiEmbeddingSource = FromStyleOrDOM, BidiContext* parent = 0);
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BidiContext* parent() const { return m_parent.get(); }
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unsigned char level() const { return m_level; }
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WTF::Unicode::Direction dir() const { return static_cast<WTF::Unicode::Direction>(m_direction); }
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bool override() const { return m_override; }
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BidiEmbeddingSource source() const { return static_cast<BidiEmbeddingSource>(m_source); }
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PassRefPtr<BidiContext> copyStackRemovingUnicodeEmbeddingContexts();
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// http://www.unicode.org/reports/tr9/#Modifications
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// 6.3 raised the limit from 61 to 125.
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// http://unicode.org/reports/tr9/#BD2
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static const unsigned char kMaxLevel = 125;
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private:
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BidiContext(unsigned char level, WTF::Unicode::Direction direction, bool override, BidiEmbeddingSource source, BidiContext* parent)
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: m_level(level)
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, m_direction(direction)
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, m_override(override)
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, m_source(source)
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, m_parent(parent)
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{
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ASSERT(level <= kMaxLevel);
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}
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static PassRefPtr<BidiContext> createUncached(unsigned char level, WTF::Unicode::Direction, bool override, BidiEmbeddingSource, BidiContext* parent);
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unsigned m_level : 7; // The maximium bidi level is 125: http://unicode.org/reports/tr9/#Explicit_Levels_and_Directions
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unsigned m_direction : 5; // Direction
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unsigned m_override : 1;
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unsigned m_source : 1; // BidiEmbeddingSource
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RefPtr<BidiContext> m_parent;
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};
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inline unsigned char nextGreaterOddLevel(unsigned char level)
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{
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return (level + 1) | 1;
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}
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inline unsigned char nextGreaterEvenLevel(unsigned char level)
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{
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return (level + 2) & ~1;
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}
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PLATFORM_EXPORT bool operator==(const BidiContext&, const BidiContext&);
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} // namespace blink
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#endif // SKY_ENGINE_PLATFORM_TEXT_BIDICONTEXT_H_
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