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

//
// FileStream_POSIX.h
//
// Library: Foundation
// Package: Streams
// Module:  FileStream
//
// Definition of the FileStreamBuf, FileInputStream and FileOutputStream classes.
//
// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_FileStream_POSIX_INCLUDED
#define Foundation_FileStream_POSIX_INCLUDED


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


namespace Poco
{


class Foundation_API FileStreamBuf : public BufferedBidirectionalStreamBuf
/// This stream buffer handles Fileio
{
public:
    FileStreamBuf();
    /// Creates a FileStreamBuf.

    ~FileStreamBuf();
    /// Destroys the FileStream.

    void open(const std::string & path, std::ios::openmode mode);
    /// Opens the given file in the given mode.

    bool close();
    /// Closes the File stream buffer. Returns true if successful,
    /// false otherwise.

    std::streampos seekoff(std::streamoff off, std::ios::seekdir dir, std::ios::openmode mode = std::ios::in | std::ios::out);
    /// Change position by offset, according to way and mode.

    std::streampos seekpos(std::streampos pos, std::ios::openmode mode = std::ios::in | std::ios::out);
    /// Change to specified position, according to mode.

protected:
    enum
    {
        BUFFER_SIZE = 4096
    };

    int readFromDevice(char * buffer, std::streamsize length);
    int writeToDevice(const char * buffer, std::streamsize length);

private:
    std::string _path;
    int _fd;
    std::streamoff _pos;
};


} // namespace Poco


#endif // Foundation_FileStream_WIN32_INCLUDED