base/i18n/bidi_line_iterator.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_I18N_BIDI_LINE_ITERATOR_H_
   6 #define BASE_I18N_BIDI_LINE_ITERATOR_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/i18n/base_i18n_export.h"
  10 #include "base/string16.h"
  11 #include "third_party/icu/public/common/unicode/ubidi.h"
  12
  13 namespace base {
  14 namespace i18n {
  15
  16 // A simple wrapper class for the bidirectional iterator of ICU.
  17 // This class uses the bidirectional iterator of ICU to split a line of
  18 // bidirectional texts into visual runs in its display order.
  19 class BASE_I18N_EXPORT BiDiLineIterator {
  20  public:
  21   BiDiLineIterator();
  22   ~BiDiLineIterator();
  23
  24   // Initializes the bidirectional iterator with the specified text.  Returns
  25   // whether initialization succeeded.
  26   bool Open(const string16& text, bool right_to_left, bool url);
  27
  28   // Returns the number of visual runs in the text, or zero on error.
  29   int CountRuns();
  30
  31   // Gets the logical offset, length, and direction of the specified visual run.
  32   UBiDiDirection GetVisualRun(int index, int* start, int* length);
  33
  34   // Given a start position, figure out where the run ends (and the BiDiLevel).
  35   void GetLogicalRun(int start, int* end, UBiDiLevel* level);
  36
  37  private:
  38   UBiDi* bidi_;
  39
  40   DISALLOW_COPY_AND_ASSIGN(BiDiLineIterator);
  41 };
  42
  43 }  // namespace i18n
  44 }  // namespace base
  45
  46 #endif  // BASE_I18N_BIDI_LINE_ITERATOR_H_