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

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


#ifndef Foundation_StreamConverter_INCLUDED
#define Foundation_StreamConverter_INCLUDED


#include <istream>
#include <ostream>
#include "Poco/Foundation.h"
#include "Poco/TextEncoding.h"
#include "Poco/UnbufferedStreamBuf.h"


namespace Poco
{


class Foundation_API StreamConverterBuf : public UnbufferedStreamBuf
/// A StreamConverter converts streams from one encoding (inEncoding)
/// into another (outEncoding).
/// If a character cannot be represented in outEncoding, defaultChar
/// is used instead.
/// If a byte sequence is not valid in inEncoding, defaultChar is used
/// instead and the encoding error count is incremented.
{
public:
    StreamConverterBuf(std::istream & istr, const TextEncoding & inEncoding, const TextEncoding & outEncoding, int defaultChar = '?');
    /// Creates the StreamConverterBuf and connects it
    /// to the given input stream.

    StreamConverterBuf(std::ostream & ostr, const TextEncoding & inEncoding, const TextEncoding & outEncoding, int defaultChar = '?');
    /// Creates the StreamConverterBuf and connects it
    /// to the given output stream.

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

    int errors() const;
    /// Returns the number of encoding errors encountered.

protected:
    int readFromDevice();
    int writeToDevice(char c);

private:
    std::istream * _pIstr;
    std::ostream * _pOstr;
    const TextEncoding & _inEncoding;
    const TextEncoding & _outEncoding;
    int _defaultChar;
    unsigned char _buffer[TextEncoding::MAX_SEQUENCE_LENGTH];
    int _sequenceLength;
    int _pos;
    int _errors;
};


class Foundation_API StreamConverterIOS : public virtual std::ios
/// The base class for InputStreamConverter and OutputStreamConverter.
///
/// This class is needed to ensure the correct initialization
/// order of the stream buffer and base classes.
{
public:
    StreamConverterIOS(std::istream & istr, const TextEncoding & inEncoding, const TextEncoding & outEncoding, int defaultChar = '?');
    StreamConverterIOS(std::ostream & ostr, const TextEncoding & inEncoding, const TextEncoding & outEncoding, int defaultChar = '?');
    ~StreamConverterIOS();
    StreamConverterBuf * rdbuf();
    int errors() const;

protected:
    StreamConverterBuf _buf;
};


class Foundation_API InputStreamConverter : public StreamConverterIOS, public std::istream
/// This stream converts all characters read from the
/// underlying istream from one character encoding into another.
/// If a character cannot be represented in outEncoding, defaultChar
/// is used instead.
/// If a byte sequence read from the underlying stream is not valid in inEncoding,
/// defaultChar is used instead and the encoding error count is incremented.
{
public:
    InputStreamConverter(std::istream & istr, const TextEncoding & inEncoding, const TextEncoding & outEncoding, int defaultChar = '?');
    /// Creates the InputStreamConverter and connects it
    /// to the given input stream.

    ~InputStreamConverter();
    /// Destroys the stream.
};


class Foundation_API OutputStreamConverter : public StreamConverterIOS, public std::ostream
/// This stream converts all characters written to the
/// underlying ostream from one character encoding into another.
/// If a character cannot be represented in outEncoding, defaultChar
/// is used instead.
/// If a byte sequence written to the stream is not valid in inEncoding,
/// defaultChar is used instead and the encoding error count is incremented.
{
public:
    OutputStreamConverter(std::ostream & ostr, const TextEncoding & inEncoding, const TextEncoding & outEncoding, int defaultChar = '?');
    /// Creates the OutputStreamConverter and connects it
    /// to the given input stream.

    ~OutputStreamConverter();
    /// Destroys the CountingOutputStream.
};


} // namespace Poco


#endif // Foundation_StreamConverter_INCLUDED