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/i18n/rtl.h"
  11 #include "base/strings/string16.h"
  12 #include "third_party/icu/source/common/unicode/ubidi.h"
  13
  14 namespace base {
  15 namespace i18n {
  16
  17 // A simple wrapper class for the bidirectional iterator of ICU.
  18 // This class uses the bidirectional iterator of ICU to split a line of
  19 // bidirectional texts into visual runs in its display order.
  20 class BASE_I18N_EXPORT BiDiLineIterator {
  21  public:
  22   BiDiLineIterator();
  23   ~BiDiLineIterator();
  24
  25   // Initializes the bidirectional iterator with the specified text.  Returns
  26   // whether initialization succeeded.
  27   bool Open(const string16& text, TextDirection direction);
  28
  29   // Returns the number of visual runs in the text, or zero on error.
  30   int CountRuns();
  31
  32   // Gets the logical offset, length, and direction of the specified visual run.
  33   UBiDiDirection GetVisualRun(int index, int* start, int* length);
  34
  35   // Given a start position, figure out where the run ends (and the BiDiLevel).
  36   void GetLogicalRun(int start, int* end, UBiDiLevel* level);
  37
  38  private:
  39   UBiDi* bidi_;
  40
  41   DISALLOW_COPY_AND_ASSIGN(BiDiLineIterator);
  42 };
  43
  44 }  // namespace i18n
  45 }  // namespace base
  46
  47 #endif  // BASE_I18N_BIDI_LINE_ITERATOR_H_