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

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


#ifndef Foundation_HexBinaryDecoder_INCLUDED
#define Foundation_HexBinaryDecoder_INCLUDED


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


namespace Poco
{


class Foundation_API HexBinaryDecoderBuf : public UnbufferedStreamBuf
/// This streambuf decodes all hexBinary-encoded data read
/// from the istream connected to it.
/// In hexBinary encoding, each binary octet is encoded as a character tuple,
/// consisting of two hexadecimal digits ([0-9a-fA-F]) representing the octet code.
/// See also: XML Schema Part 2: Datatypes (http://www.w3.org/TR/xmlschema-2/),
/// section 3.2.15.
///
/// Note: For performance reasons, the characters
/// are read directly from the given istream's
/// underlying streambuf, so the state
/// of the istream will not reflect that of
/// its streambuf.
{
public:
    HexBinaryDecoderBuf(std::istream & istr);
    ~HexBinaryDecoderBuf();

private:
    int readFromDevice();
    int readOne();

    std::streambuf & _buf;
};


class Foundation_API HexBinaryDecoderIOS : public virtual std::ios
/// The base class for HexBinaryDecoder.
///
/// This class is needed to ensure the correct initialization
/// order of the stream buffer and base classes.
{
public:
    HexBinaryDecoderIOS(std::istream & istr);
    ~HexBinaryDecoderIOS();
    HexBinaryDecoderBuf * rdbuf();

protected:
    HexBinaryDecoderBuf _buf;
};


class Foundation_API HexBinaryDecoder : public HexBinaryDecoderIOS, public std::istream
/// This istream decodes all hexBinary-encoded data read
/// from the istream connected to it.
/// In hexBinary encoding, each binary octet is encoded as a character tuple,
/// consisting of two hexadecimal digits ([0-9a-fA-F]) representing the octet code.
/// See also: XML Schema Part 2: Datatypes (http://www.w3.org/TR/xmlschema-2/),
/// section 3.2.15.
///
/// Note: For performance reasons, the characters
/// are read directly from the given istream's
/// underlying streambuf, so the state
/// of the istream will not reflect that of
/// its streambuf.
{
public:
    HexBinaryDecoder(std::istream & istr);
    ~HexBinaryDecoder();
};


} // namespace Poco


#endif // Foundation_HexBinaryDecoder_INCLUDED