CFileStream.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#pragma once
 
#include <mrpt/io/CStream.h>
#include <fstream>
 
namespace mrpt
{
namespace io
{
/** File open modes are used in CFileStream
  *  Posible values are:
        - fomRead
        - fomWrite (creates the file if it didn't exist, otherwise truncates it).
        - fomAppend (creates the file if it didn't exist)
  */
using TFileOpenModes = int;
enum
{
        fomRead = 1,
        fomWrite = 2,
        fomAppend = 4
};
 
/** This CStream derived class allow using a file as a read/write binary stream,
 * creating it if the file didn't exist.
 *   The default behavior can be change to open as read, write, read and
 * write,... in the constructor.
 * \sa CStream, CFileInputStream, CFileOutputStrea, CFileGZInputStream
 * \ingroup mrpt_io_grp
 */
class CFileStream : public CStream
{
   private:
        /** The actual input file stream. */
        std::fstream m_f;
 
   public:
        /** Constructor and open a file
         * \param fileName The file to be open in this stream
         * \param mode The open mode: can be an or'd conbination of different
         * values.
         * \exception std::exception On error creating or accessing the file.
         *  By default the file is opened for open and write and created if not
         * found.
         */
        CFileStream(
                const std::string& fileName, TFileOpenModes mode = fomRead | fomWrite);
        /** Constructor */
        CFileStream();
 
        CFileStream(const CFileStream&) = delete;
        CFileStream& operator=(const CFileStream&) = delete;
 
        /** Destructor */
        virtual ~CFileStream();
 
        size_t Read(void* Buffer, size_t Count) override;
        size_t Write(const void* Buffer, size_t Count) override;
 
        /** Opens the file, returning true on success.
         * \param fileName The file to be open in this stream
         * \param mode The open mode: can be an or'd conbination of different
         * values.
         *  By default the file is opened for open and write and created if not
         * found.
         */
        bool open(
                const std::string& fileName, TFileOpenModes mode = fomRead | fomWrite);
        /** Closes the file */
        void close();
        /** Returns true if the file was open without errors. */
        bool fileOpenCorrectly() const;
        /** Returns true if the file was open without errors. */
        bool is_open() { return fileOpenCorrectly(); }
        /** Will be true if EOF has been already reached. */
        bool checkEOF();
        /** Resets stream error status bits (e.g. after an EOF) */
        void clearError();
 
        uint64_t Seek(
                int64_t off, CStream::TSeekOrigin org = sFromBeginning) override;
        uint64_t getTotalBytesCount() const override;
        // See docs in base class
        uint64_t getPosition() const override;
        /** The current Input cursor position, where 0 is the first byte */
        uint64_t getPositionI();
        /** The current Input cursor position, where 0 is the first byte */
        uint64_t getPositionO();
 
        /** Reads one string line from the file (until a new-line character)
         * \return true if a line has been read, false on EOF or error */
        bool readLine(std::string& str);
 
};  // End of class def.
}  // namespace io
}  // namespace mrpt