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// Copyright (c) 2006-2008 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_WORD_ITERATOR_H__
#define BASE_WORD_ITERATOR_H__
#include <string>
#include <vector>
#include "unicode/uchar.h"
#include "base/basictypes.h"
// The WordIterator class iterates through the words and word breaks
// in a string. (In the string " foo bar! ", the word breaks are at the
// periods in ". .foo. .bar.!. .".)
//
// To extract the words from a string, move a 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.
// LOG(INFO) << "word: " << iter.GetWord();
// }
// }
class WordIterator {
public:
enum BreakType {
BREAK_WORD,
BREAK_LINE
};
// Requires |str| to live as long as the WordIterator does.
WordIterator(const std::wstring& 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.
std::wstring GetWord() const;
private:
// ICU iterator.
void* iter_;
#if !defined(WCHAR_T_IS_UTF16)
std::vector<UChar> chars_;
#endif
// The string we're iterating over.
const std::wstring& string_;
// The breaking style (word/line).
BreakType break_type_;
// Previous and current iterator positions.
size_t prev_, pos_;
DISALLOW_EVIL_CONSTRUCTORS(WordIterator);
};
#endif // BASE_WORD_ITERATOR_H__
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