// 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_