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bidi_line_iterator.h
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bidi_line_iterator.h
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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_GFX_BIDI_LINE_ITERATOR_H_
#define UI_GFX_BIDI_LINE_ITERATOR_H_
#include <memory>
#include <string>
#include "base/i18n/rtl.h"
#include "third_party/icu/source/common/unicode/ubidi.h"
#include "third_party/icu/source/common/unicode/uchar.h"
#include "ui/gfx/gfx_export.h"
namespace ui {
namespace gfx {
class UBiDiDeleter {
public:
void operator()(UBiDi* ptr) { ubidi_close(ptr); }
};
// A simple wrapper class for the bidirectional iterator of ICU.
// This class uses the bidirectional iterator of ICU to split a line of
// bidirectional texts into visual runs in its display order.
class GFX_EXPORT BiDiLineIterator {
public:
BiDiLineIterator();
BiDiLineIterator(const BiDiLineIterator&) = delete;
BiDiLineIterator& operator=(const BiDiLineIterator&) = delete;
~BiDiLineIterator();
// Initializes the bidirectional iterator with the specified text. Returns
// whether initialization succeeded.
bool Open(const std::u16string& text, base::i18n::TextDirection direction);
// Returns the number of visual runs in the text, or zero on error.
int CountRuns() const;
// Gets the logical offset, length, and direction of the specified visual run.
UBiDiDirection GetVisualRun(int index, int* start, int* length) const;
// Given a start position, figure out where the run ends (and the BiDiLevel).
void GetLogicalRun(int start, int* end, UBiDiLevel* level) const;
private:
std::unique_ptr<UBiDi, UBiDiDeleter> bidi_;
};
} // namespace gfx
} // namespace ui
#endif // UI_GFX_BIDI_LINE_ITERATOR_H_