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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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_BIDI_CONTEXT_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_BIDI_CONTEXT_H_
#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/wtf/assertions.h"
#include "third_party/blink/renderer/platform/wtf/text/unicode.h"
#include "third_party/blink/renderer/platform/wtf/thread_safe_ref_counted.h"
namespace blink {
enum BidiEmbeddingSource { kFromStyleOrDOM, kFromUnicode };
// Used to keep track of explicit embeddings.
class PLATFORM_EXPORT BidiContext : public ThreadSafeRefCounted<BidiContext> {
public:
static scoped_refptr<BidiContext> Create(
unsigned char level,
WTF::unicode::CharDirection,
bool override = false,
BidiEmbeddingSource = kFromStyleOrDOM,
BidiContext* parent = nullptr);
BidiContext* Parent() const { return parent_.get(); }
unsigned char Level() const { return level_; }
WTF::unicode::CharDirection Dir() const {
return static_cast<WTF::unicode::CharDirection>(direction_);
}
bool Override() const { return override_; }
BidiEmbeddingSource Source() const {
return static_cast<BidiEmbeddingSource>(source_);
}
scoped_refptr<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)
: level_(level),
direction_(direction),
override_(override),
source_(source),
parent_(parent) {
DCHECK(level <= kMaxLevel);
}
static scoped_refptr<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 level_ : 7;
unsigned direction_ : 5; // Direction
unsigned override_ : 1;
unsigned source_ : 1; // BidiEmbeddingSource
scoped_refptr<BidiContext> 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 // THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_BIDI_CONTEXT_H_
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