CFileStream.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/io/CStream.h>
#include <fstream>

namespace mrpt::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 */
    ~CFileStream() override;

    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 mrpt::io