| // Copyright 2014 PDFium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com |
| |
| #ifndef CORE_FXCRT_FX_BIDI_H_ |
| #define CORE_FXCRT_FX_BIDI_H_ |
| |
| #include <memory> |
| #include <vector> |
| |
| #include "core/fxcrt/fx_string.h" |
| #include "core/fxcrt/fx_system.h" |
| |
| // Processes characters and group them into segments based on text direction. |
| class CFX_BidiChar { |
| public: |
| enum Direction { NEUTRAL, LEFT, RIGHT }; |
| struct Segment { |
| int32_t start; // Start position. |
| int32_t count; // Character count. |
| Direction direction; // Segment direction. |
| }; |
| |
| CFX_BidiChar(); |
| |
| // Append a character and classify it as left, right, or neutral. |
| // Returns true if the character has a different direction than the |
| // existing direction to indicate there is a segment to process. |
| bool AppendChar(wchar_t wch); |
| |
| // Call this after the last character has been appended. AppendChar() |
| // must not be called after this. |
| // Returns true if there is still a segment to process. |
| bool EndChar(); |
| |
| // Call after a change in direction is indicated by the above to get |
| // information about the segment to process. |
| Segment GetSegmentInfo() const { return m_LastSegment; } |
| |
| private: |
| void StartNewSegment(CFX_BidiChar::Direction direction); |
| |
| Segment m_CurrentSegment; |
| Segment m_LastSegment; |
| }; |
| |
| class CFX_BidiString { |
| public: |
| using const_iterator = std::vector<CFX_BidiChar::Segment>::const_iterator; |
| |
| explicit CFX_BidiString(const CFX_WideString& str); |
| ~CFX_BidiString(); |
| |
| // Overall direction is always LEFT or RIGHT, never NEUTRAL. |
| CFX_BidiChar::Direction OverallDirection() const { |
| return m_eOverallDirection; |
| } |
| |
| // Force the overall direction to be R2L regardless of what was detected. |
| void SetOverallDirectionRight(); |
| |
| wchar_t CharAt(size_t x) const { return m_Str[x]; } |
| const_iterator begin() const { return m_Order.begin(); } |
| const_iterator end() const { return m_Order.end(); } |
| |
| private: |
| const CFX_WideString m_Str; |
| std::unique_ptr<CFX_BidiChar> m_pBidiChar; |
| std::vector<CFX_BidiChar::Segment> m_Order; |
| CFX_BidiChar::Direction m_eOverallDirection; |
| }; |
| |
| #endif // CORE_FXCRT_FX_BIDI_H_ |