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