1 // Copyright 2014 The PDFium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
6
7 #include "core/fxcrt/fx_bidi.h"
8
9 #include <algorithm>
10
11 #include "core/fxcrt/fx_unicode.h"
12 #include "third_party/base/check_op.h"
13
CFX_BidiChar()14 CFX_BidiChar::CFX_BidiChar()
15 : m_CurrentSegment({0, 0, Direction::kNeutral}),
16 m_LastSegment({0, 0, Direction::kNeutral}) {}
17
AppendChar(wchar_t wch)18 bool CFX_BidiChar::AppendChar(wchar_t wch) {
19 Direction direction;
20 switch (pdfium::unicode::GetBidiClass(wch)) {
21 case FX_BIDICLASS::kL:
22 direction = Direction::kLeft;
23 break;
24 case FX_BIDICLASS::kAN:
25 case FX_BIDICLASS::kEN:
26 case FX_BIDICLASS::kNSM:
27 case FX_BIDICLASS::kCS:
28 case FX_BIDICLASS::kES:
29 case FX_BIDICLASS::kET:
30 case FX_BIDICLASS::kBN:
31 direction = Direction::kLeftWeak;
32 break;
33 case FX_BIDICLASS::kR:
34 case FX_BIDICLASS::kAL:
35 direction = Direction::kRight;
36 break;
37 default:
38 direction = Direction::kNeutral;
39 break;
40 }
41
42 bool bChangeDirection = (direction != m_CurrentSegment.direction);
43 if (bChangeDirection)
44 StartNewSegment(direction);
45
46 m_CurrentSegment.count++;
47 return bChangeDirection;
48 }
49
EndChar()50 bool CFX_BidiChar::EndChar() {
51 StartNewSegment(Direction::kNeutral);
52 return m_LastSegment.count > 0;
53 }
54
StartNewSegment(CFX_BidiChar::Direction direction)55 void CFX_BidiChar::StartNewSegment(CFX_BidiChar::Direction direction) {
56 m_LastSegment = m_CurrentSegment;
57 m_CurrentSegment.start += m_CurrentSegment.count;
58 m_CurrentSegment.count = 0;
59 m_CurrentSegment.direction = direction;
60 }
61
CFX_BidiString(const WideString & str)62 CFX_BidiString::CFX_BidiString(const WideString& str) : m_Str(str) {
63 CFX_BidiChar bidi;
64 for (wchar_t c : m_Str) {
65 if (bidi.AppendChar(c))
66 m_Order.push_back(bidi.GetSegmentInfo());
67 }
68 if (bidi.EndChar())
69 m_Order.push_back(bidi.GetSegmentInfo());
70
71 size_t nR2L = std::count_if(
72 m_Order.begin(), m_Order.end(), [](const CFX_BidiChar::Segment& seg) {
73 return seg.direction == CFX_BidiChar::Direction::kRight;
74 });
75
76 size_t nL2R = std::count_if(
77 m_Order.begin(), m_Order.end(), [](const CFX_BidiChar::Segment& seg) {
78 return seg.direction == CFX_BidiChar::Direction::kLeft;
79 });
80
81 if (nR2L > 0 && nR2L >= nL2R)
82 SetOverallDirectionRight();
83 }
84
85 CFX_BidiString::~CFX_BidiString() = default;
86
OverallDirection() const87 CFX_BidiChar::Direction CFX_BidiString::OverallDirection() const {
88 DCHECK_NE(m_eOverallDirection, CFX_BidiChar::Direction::kNeutral);
89 DCHECK_NE(m_eOverallDirection, CFX_BidiChar::Direction::kLeftWeak);
90 return m_eOverallDirection;
91 }
92
SetOverallDirectionRight()93 void CFX_BidiString::SetOverallDirectionRight() {
94 if (m_eOverallDirection != CFX_BidiChar::Direction::kRight) {
95 std::reverse(m_Order.begin(), m_Order.end());
96 m_eOverallDirection = CFX_BidiChar::Direction::kRight;
97 }
98 }
99