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

//
// DigestStream.h
//
// Library: Foundation
// Package: Crypt
// Module:  DigestStream
//
// Definition of classes DigestInputStream and DigestOutputStream.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_DigestStream_INCLUDED
#define Foundation_DigestStream_INCLUDED


#include <istream>
#include <ostream>
#include "Poco/BufferedStreamBuf.h"
#include "Poco/DigestEngine.h"
#include "Poco/Foundation.h"


namespace Poco
{


class Foundation_API DigestBuf : public BufferedStreamBuf
/// This streambuf computes a digest of all data going
/// through it.
{
public:
    DigestBuf(DigestEngine & eng);
    DigestBuf(DigestEngine & eng, std::istream & istr);
    DigestBuf(DigestEngine & eng, std::ostream & ostr);
    ~DigestBuf();
    int readFromDevice(char * buffer, std::streamsize length);
    int writeToDevice(const char * buffer, std::streamsize length);
    void close();

private:
    DigestEngine & _eng;
    std::istream * _pIstr;
    std::ostream * _pOstr;
    static const int BUFFER_SIZE;
};


class Foundation_API DigestIOS : public virtual std::ios
/// The base class for DigestInputStream and DigestOutputStream.
///
/// This class is needed to ensure the correct initialization
/// order of the stream buffer and base classes.
{
public:
    DigestIOS(DigestEngine & eng);
    DigestIOS(DigestEngine & eng, std::istream & istr);
    DigestIOS(DigestEngine & eng, std::ostream & ostr);
    ~DigestIOS();
    DigestBuf * rdbuf();

protected:
    DigestBuf _buf;
};


class Foundation_API DigestInputStream : public DigestIOS, public std::istream
/// This istream computes a digest of
/// all the data passing through it,
/// using a DigestEngine.
{
public:
    DigestInputStream(DigestEngine & eng, std::istream & istr);
    ~DigestInputStream();
};


class Foundation_API DigestOutputStream : public DigestIOS, public std::ostream
/// This ostream computes a digest of
/// all the data passing through it,
/// using a DigestEngine.
/// To ensure that all data has been incorporated
/// into the digest, call close() or flush() before
/// you obtain the digest from the digest engine.
{
public:
    DigestOutputStream(DigestEngine & eng);
    DigestOutputStream(DigestEngine & eng, std::ostream & ostr);
    ~DigestOutputStream();
    void close();
};


} // namespace Poco


#endif // Foundation_DigestStream_INCLUDED