71 lines
2.1 KiB
C++
71 lines
2.1 KiB
C++
// 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 <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(wchar_t 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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const 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 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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// Force the overall direction to be R2L regardless of what was detected.
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void SetOverallDirectionRight();
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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 WideString& m_Str;
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std::vector<CFX_BidiChar::Segment> m_Order;
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CFX_BidiChar::Direction m_eOverallDirection = CFX_BidiChar::LEFT;
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};
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#endif // CORE_FXCRT_FX_BIDI_H_
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