//
// TextIterator.h
//
// Library: Foundation
// Package: Text
// Module:  TextIterator
//
// Definition of the TextIterator class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_TextIterator_INCLUDED
#define Foundation_TextIterator_INCLUDED


#include "Poco/Foundation.h"


namespace Poco {


class TextEncoding;


class Foundation_API TextIterator
	/// An unidirectional iterator for iterating over characters in a string.
	/// The TextIterator uses a TextEncoding object to
	/// work with multi-byte character encodings like UTF-8.
	/// Characters are reported in Unicode.
	///
	/// Example: Count the number of UTF-8 characters in a string.
	///
	///     UTF8Encoding utf8Encoding;
	///     std::string utf8String("....");
	///     TextIterator it(utf8String, utf8Encoding);
	///     TextIterator end(utf8String);
	///     int n = 0;
	///     while (it != end) { ++n; ++it; }
	///
	/// NOTE: When an UTF-16 encoding is used, surrogate pairs will be
	/// reported as two separate characters, due to restrictions of
	/// the TextEncoding class.
	///
	/// For iterating over char buffers, see the TextBufferIterator class.
{
public:
	TextIterator();
		/// Creates an uninitialized TextIterator.

	TextIterator(const std::string& str, const TextEncoding& encoding);
		/// Creates a TextIterator for the given string.
		/// The encoding object must not be deleted as long as the iterator
		/// is in use.

	TextIterator(const std::string::const_iterator& begin, const std::string::const_iterator& end, const TextEncoding& encoding);
		/// Creates a TextIterator for the given range.
		/// The encoding object must not be deleted as long as the iterator
		/// is in use.

	TextIterator(const std::string& str);
		/// Creates an end TextIterator for the given string.

	TextIterator(const std::string::const_iterator& end);
		/// Creates an end TextIterator.

	~TextIterator();
		/// Destroys the TextIterator.

	TextIterator(const TextIterator& it);
		/// Copy constructor.

	TextIterator& operator = (const TextIterator& it);
		/// Assignment operator.

	void swap(TextIterator& it) noexcept;
		/// Swaps the iterator with another one.

	int operator * () const;
		/// Returns the Unicode value of the current character.
		/// If there is no valid character at the current position,
		/// -1 is returned.

	TextIterator& operator ++ ();
		/// Prefix increment operator.

	TextIterator operator ++ (int);
		/// Postfix increment operator.

	bool operator == (const TextIterator& it) const;
		/// Compares two iterators for equality.

	bool operator != (const TextIterator& it) const;
		/// Compares two iterators for inequality.

	TextIterator end() const;
		/// Returns the end iterator for the range handled
		/// by the iterator.

private:
	const TextEncoding*         _pEncoding;
	std::string::const_iterator _it;
	std::string::const_iterator _end;
};


//
// inlines
//
inline bool TextIterator::operator == (const TextIterator& it) const
{
	return _it == it._it;
}


inline bool TextIterator::operator != (const TextIterator& it) const
{
	return _it != it._it;
}


inline void swap(TextIterator& it1, TextIterator& it2) noexcept
{
	it1.swap(it2);
}


inline TextIterator TextIterator::end() const
{
	return TextIterator(_end);
}


} // namespace Poco


#endif // Foundation_TextIterator_INCLUDED