Refactor WordIterator into base::BreakIterator....

base/i18n/word_iterator.h

-// Copyright (c) 2010 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 BASE_I18N_WORD_ITERATOR_H_
-#define BASE_I18N_WORD_ITERATOR_H_
-#pragma once
-
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/string16.h"
-
-// The WordIterator class iterates through the words and word breaks
-// in a UTF-16 string.
-//
-// It provides two modes, BREAK_WORD and BREAK_LINE, which modify how
-// trailing non-word characters are aggregated into the returned word.
-//
-// Under BREAK_WORD mode (more common), the non-word characters are
-// not included with a returned word (e.g. in the UTF-16 equivalent of
-// the string " foo bar! ", the word breaks are at the periods in
-// ". .foo. .bar.!. .").
-//
-// Under BREAK_LINE mode (less common), the non-word characters are
-// included in the word, breaking only when a space-equivalent character
-// is encountered (e.g. in the UTF16-equivalent of the string " foo bar! ",
-// the word breaks are at the periods in ". .foo .bar! .").
-//
-// To extract the words from a string, move a BREAK_WORD WordIterator
-// through the string and test whether IsWord() is true.  E.g.,
-//   WordIterator iter(&str, WordIterator::BREAK_WORD);
-//   if (!iter.Init()) return false;
-//   while (iter.Advance()) {
-//     if (iter.IsWord()) {
-//       // region [iter.prev(),iter.pos()) contains a word.
-//       VLOG(1) << "word: " << iter.GetWord();
-//     }
-//   }
-
-
-class WordIterator {
- public:
-  enum BreakType {
-    BREAK_WORD,
-    BREAK_LINE
-  };
-
-  // Requires |str| to live as long as the WordIterator does.
-  WordIterator(const string16* str, BreakType break_type);
-  ~WordIterator();
-
-  // Init() must be called before any of the iterators are valid.
-  // Returns false if ICU failed to initialize.
-  bool Init();
-
-  // Return the current break position within the string,
-  // or WordIterator::npos when done.
-  size_t pos() const { return pos_; }
-  // Return the value of pos() returned before Advance() was last called.
-  size_t prev() const { return prev_; }
-
-  // Advance to the next break.  Returns false if we've run past the end of
-  // the string.  (Note that the very last "word break" is after the final
-  // character in the string, and when we advance to that position it's the
-  // last time Advance() returns true.)
-  bool Advance();
-
-  // Returns true if the break we just hit is the end of a word.
-  // (Otherwise, the break iterator just skipped over e.g. whitespace
-  // or punctuation.)
-  bool IsWord() const;
-
-  // Return the word between prev() and pos().
-  // Advance() must have been called successfully at least once
-  // for pos() to have advanced to somewhere useful.
-  string16 GetWord() const;
-
- private:
-  // ICU iterator, avoiding ICU ubrk.h dependence.
-  // This is actually an ICU UBreakiterator* type, which turns out to be
-  // a typedef for a void* in the ICU headers. Using void* directly prevents
-  // callers from needing access to the ICU public headers directory.
-  void* iter_;
-
-  // The string we're iterating over.
-  const string16* string_;
-
-  // The breaking style (word/line).
-  BreakType break_type_;
-
-  // Previous and current iterator positions.
-  size_t prev_, pos_;
-
-  DISALLOW_COPY_AND_ASSIGN(WordIterator);
-};
-
-#endif  // BASE_I18N_WORD_ITERATOR_H__