CFileGZInputStream.h

Go to the documentation of this file.

/* +---------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)               |
   |                          http://www.mrpt.org/                             |
   |                                                                           |
   | Copyright (c) 2005-2017, 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    |
   +---------------------------------------------------------------------------+ */
#ifndef  CFileGZInputStream_H
#define  CFileGZInputStream_H

#include <mrpt/utils/CStream.h>

namespace mrpt
{
        namespace utils
        {
                /** Transparently opens a compressed "gz" file and reads uncompressed data from it.
                 *   If the file is not a .gz file, it silently reads data from the file.
                 *  This class requires compiling MRPT with wxWidgets. If wxWidgets is not available then the class is actually mapped to the standard CFileInputStream
                 *
                 * \sa CFileInputStream
                 * \ingroup mrpt_base_grp
                 */
                class BASE_IMPEXP CFileGZInputStream : public CStream, public CUncopiable
                {
                protected:
                        size_t  Read(void *Buffer, size_t Count) MRPT_OVERRIDE;
                        size_t  Write(const void *Buffer, size_t Count) MRPT_OVERRIDE;
                private:
                        void            *m_f;
                        uint64_t        m_file_size;    //!< Compressed file size

                public:
                        CFileGZInputStream(); //!< Constructor without open

                         /** Constructor and open
                          * \param fileName The file to be open in this stream
                          * \exception std::exception If there's an error opening the file.
                          */
                        CFileGZInputStream(const std::string &fileName );

                        virtual ~CFileGZInputStream(); //!< Dtor

                         /** Opens the file for read.
                          * \param fileName The file to be open in this stream
                          * \return false if there's an error opening the file, true otherwise
                          */
                        bool open(const std::string &fileName );
                        void close(); //!< Closes the file
                        bool fileOpenCorrectly(); //!< Returns true if the file was open without errors.
                        bool is_open() { return fileOpenCorrectly(); } //!< Returns true if the file was open without errors.
                        bool checkEOF(); //!< Will be true if EOF has been already reached.

                        uint64_t getTotalBytesCount() MRPT_OVERRIDE; //!< Method for getting the total number of <b>compressed</b> bytes of in the file (the physical size of the compressed file).
                        uint64_t getPosition() MRPT_OVERRIDE; //!< Method for getting the current cursor position in the <b>compressed</b>, where 0 is the first byte and TotalBytesCount-1 the last one.

                        /** This method is not implemented in this class */
                        uint64_t Seek(int64_t Offset, CStream::TSeekOrigin Origin = sFromBeginning) MRPT_OVERRIDE
                        {
            MRPT_UNUSED_PARAM(Offset); MRPT_UNUSED_PARAM(Origin);
                                THROW_EXCEPTION("Seek is not implemented in this class");
                        }

                }; // End of class def.

        } // End of namespace
} // end of namespace
#endif