| /* |
| * 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_ |