1 // Copyright (c) 2009 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_WORD_ITERATOR_H_ 6 #define BASE_I18N_WORD_ITERATOR_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "unicode/uchar.h" 12 13 #include "base/basictypes.h" 14 15 // The WordIterator class iterates through the words and word breaks 16 // in a string. (In the string " foo bar! ", the word breaks are at the 17 // periods in ". .foo. .bar.!. .".) 18 // 19 // To extract the words from a string, move a WordIterator through the 20 // string and test whether IsWord() is true. E.g., 21 // WordIterator iter(str, WordIterator::BREAK_WORD); 22 // if (!iter.Init()) return false; 23 // while (iter.Advance()) { 24 // if (iter.IsWord()) { 25 // // region [iter.prev(),iter.pos()) contains a word. 26 // LOG(INFO) << "word: " << iter.GetWord(); 27 // } 28 // } 29 30 31 class WordIterator { 32 public: 33 enum BreakType { 34 BREAK_WORD, 35 BREAK_LINE 36 }; 37 38 // Requires |str| to live as long as the WordIterator does. 39 WordIterator(const std::wstring& str, BreakType break_type); 40 ~WordIterator(); 41 42 // Init() must be called before any of the iterators are valid. 43 // Returns false if ICU failed to initialize. 44 bool Init(); 45 46 // Return the current break position within the string, 47 // or WordIterator::npos when done. pos()48 size_t pos() const { return pos_; } 49 // Return the value of pos() returned before Advance() was last called. prev()50 size_t prev() const { return prev_; } 51 52 // Advance to the next break. Returns false if we've run past the end of 53 // the string. (Note that the very last "word break" is after the final 54 // character in the string, and when we advance to that position it's the 55 // last time Advance() returns true.) 56 bool Advance(); 57 58 // Returns true if the break we just hit is the end of a word. 59 // (Otherwise, the break iterator just skipped over e.g. whitespace 60 // or punctuation.) 61 bool IsWord() const; 62 63 // Return the word between prev() and pos(). 64 // Advance() must have been called successfully at least once 65 // for pos() to have advanced to somewhere useful. 66 std::wstring GetWord() const; 67 68 private: 69 // ICU iterator. 70 void* iter_; 71 #if !defined(WCHAR_T_IS_UTF16) 72 std::vector<UChar> chars_; 73 #endif 74 75 // The string we're iterating over. 76 const std::wstring& string_; 77 78 // The breaking style (word/line). 79 BreakType break_type_; 80 81 // Previous and current iterator positions. 82 size_t prev_, pos_; 83 84 DISALLOW_COPY_AND_ASSIGN(WordIterator); 85 }; 86 87 #endif // BASE_I18N_WORD_ITERATOR_H__ 88