// Copyright (c) 2011 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_CHAR_ITERATOR_H_ #define BASE_I18N_CHAR_ITERATOR_H_ #include #include "base/i18n/base_i18n_export.h" #include "base/strings/string_piece.h" // The CharIterator classes iterate through the characters in UTF8 and // UTF16 strings. Example usage: // // for (UTF8CharIterator iter(str); !iter.end(); iter.Advance()) { // VLOG(1) << iter.get(); // } namespace base { namespace i18n { class BASE_I18N_EXPORT UTF8CharIterator { public: // Requires |str| to live as long as the UTF8CharIterator does. explicit UTF8CharIterator(StringPiece str); UTF8CharIterator(const UTF8CharIterator&) = delete; UTF8CharIterator& operator=(const UTF8CharIterator&) = delete; ~UTF8CharIterator(); // Return the starting array index of the current character within the // string. size_t array_pos() const { return array_pos_; } // Return the logical index of the current character, independent of the // number of bytes each character takes. size_t char_pos() const { return char_pos_; } // Return the current char. int32_t get() const { return char_; } // Returns true if we're at the end of the string. bool end() const { return array_pos_ == str_.length(); } // Advance to the next actual character. Returns false if we're at the // end of the string. bool Advance(); private: // The string we're iterating over. StringPiece str_; // Array index. size_t array_pos_; // The next array index. size_t next_pos_; // Character index. size_t char_pos_; // The current character. int32_t char_; }; class BASE_I18N_EXPORT UTF16CharIterator { public: // Requires |str| to live as long as the UTF16CharIterator does. explicit UTF16CharIterator(StringPiece16 str); UTF16CharIterator(UTF16CharIterator&& to_move); UTF16CharIterator& operator=(UTF16CharIterator&& to_move); UTF16CharIterator(const UTF16CharIterator&) = delete; UTF16CharIterator operator=(const UTF16CharIterator&) = delete; ~UTF16CharIterator(); // Returns an iterator starting on the unicode character at offset // |array_index| into the string, or the previous array offset if // |array_index| is the second half of a surrogate pair. static UTF16CharIterator LowerBound(StringPiece16 str, size_t array_index); // Returns an iterator starting on the unicode character at offset // |array_index| into the string, or the next offset if |array_index| is the // second half of a surrogate pair. static UTF16CharIterator UpperBound(StringPiece16 str, size_t array_index); // Return the starting array index of the current character within the // string. size_t array_pos() const { return array_pos_; } // Returns the offset in code points from the initial iterator position, which // could be negative if Rewind() is called. The initial value is always zero, // regardless of how the iterator is constructed. int32_t char_offset() const { return char_offset_; } // Returns the code point at the current position. int32_t get() const { return char_; } // Returns the code point (i.e. the full Unicode character, not half of a // surrogate pair) following the current one. Should not be called if end() is // true. If the current code point is the last one in the string, returns // zero. int32_t NextCodePoint() const; // Returns the code point (i.e. the full Unicode character, not half of a // surrogate pair) preceding the current one. Should not be called if start() // is true. int32_t PreviousCodePoint() const; // Returns true if we're at the start of the string. bool start() const { return array_pos_ == 0; } // Returns true if we're at the end of the string. bool end() const { return array_pos_ == str_.length(); } // Advances to the next actual character. Returns false if we're at the // end of the string. bool Advance(); // Moves to the previous actual character. Returns false if we're at the start // of the string. bool Rewind(); private: UTF16CharIterator(base::StringPiece16 str, size_t initial_pos); // Fills in the current character we found and advances to the next // character, updating all flags as necessary. void ReadChar(); // The string we're iterating over. StringPiece16 str_; // Array index. size_t array_pos_; // The next array index. size_t next_pos_; // Character offset from the initial position of the iterator. int32_t char_offset_; // The current character. int32_t char_; }; } // namespace i18n } // namespace base #endif // BASE_I18N_CHAR_ITERATOR_H_