ClickHouse/base/poco/Foundation/include/Poco/TextBufferIterator.h

//
// TextBufferIterator.h
//
// Library: Foundation
// Package: Text
// Module:  TextBufferIterator
//
// Definition of the TextBufferIterator class.
//
// Copyright (c) 2010, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_TextBufferIterator_INCLUDED
#define Foundation_TextBufferIterator_INCLUDED


#include <cstdlib>
#include "Poco/Foundation.h"


namespace Poco
{


class TextEncoding;


class Foundation_API TextBufferIterator
/// An unidirectional iterator for iterating over characters in a buffer.
/// The TextBufferIterator 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 buffer.
///
///     UTF8Encoding utf8Encoding;
///     char buffer[] = "...";
///     TextBufferIterator it(buffer, utf8Encoding);
///     TextBufferIterator end(it.end());
///     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 the characters in a std::string, see the
/// TextIterator class.
{
public:
    TextBufferIterator();
    /// Creates an uninitialized TextBufferIterator.

    TextBufferIterator(const char * begin, const TextEncoding & encoding);
    /// Creates a TextBufferIterator for the given buffer, which must be 0-terminated.
    /// The encoding object must not be deleted as long as the iterator
    /// is in use.

    TextBufferIterator(const char * begin, std::size_t size, const TextEncoding & encoding);
    /// Creates a TextBufferIterator for the given buffer with the given size.
    /// The encoding object must not be deleted as long as the iterator
    /// is in use.

    TextBufferIterator(const char * begin, const char * end, const TextEncoding & encoding);
    /// Creates a TextBufferIterator for the given range.
    /// The encoding object must not be deleted as long as the iterator
    /// is in use.

    TextBufferIterator(const char * end);
    /// Creates an end TextBufferIterator for the given buffer.

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

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

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

    void swap(TextBufferIterator & it);
    /// 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.

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

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

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

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

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

private:
    const TextEncoding * _pEncoding;
    const char * _it;
    const char * _end;
};


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


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


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


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


} // namespace Poco


#endif // Foundation_TextBufferIterator_INCLUDED