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