1/*
2 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
3 * Copyright (C) 2003-2017 Apple Inc. All right reserved.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public License
16 * along with this library; see the file COPYING.LIB. If not, write to
17 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18 * Boston, MA 02110-1301, USA.
19 *
20 */
21
22#pragma once
23
24#include <unicode/uchar.h>
25#include <wtf/RefCounted.h>
26#include <wtf/RefPtr.h>
27
28namespace WebCore {
29
30enum BidiEmbeddingSource { FromStyleOrDOM, FromUnicode };
31
32// Used to keep track of explicit embeddings.
33class BidiContext : public RefCounted<BidiContext> {
34public:
35 WEBCORE_EXPORT static Ref<BidiContext> create(unsigned char level, UCharDirection, bool override = false, BidiEmbeddingSource = FromStyleOrDOM, BidiContext* parent = nullptr);
36
37 BidiContext* parent() const { return m_parent.get(); }
38 unsigned char level() const { return m_level; }
39 UCharDirection dir() const { return static_cast<UCharDirection>(m_direction); }
40 bool override() const { return m_override; }
41 BidiEmbeddingSource source() const { return static_cast<BidiEmbeddingSource>(m_source); }
42
43 WEBCORE_EXPORT Ref<BidiContext> copyStackRemovingUnicodeEmbeddingContexts();
44
45private:
46 BidiContext(unsigned char level, UCharDirection, bool override, BidiEmbeddingSource, BidiContext* parent);
47
48 static Ref<BidiContext> createUncached(unsigned char level, UCharDirection, bool override, BidiEmbeddingSource, BidiContext* parent);
49
50 unsigned m_level : 6; // The maximium bidi level is 62: http://unicode.org/reports/tr9/#Explicit_Levels_and_Directions
51 unsigned m_direction : 5; // Direction
52 unsigned m_override : 1;
53 unsigned m_source : 1; // BidiEmbeddingSource
54 RefPtr<BidiContext> m_parent;
55};
56
57inline unsigned char nextGreaterOddLevel(unsigned char level)
58{
59 return (level + 1) | 1;
60}
61
62inline unsigned char nextGreaterEvenLevel(unsigned char level)
63{
64 return (level + 2) & ~1;
65}
66
67bool operator==(const BidiContext&, const BidiContext&);
68
69} // namespace WebCore
70