class mrpt::io::CFileGZInputStream

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

See also:

CFileInputStream

#include <mrpt/io/CFileGZInputStream.h>

class CFileGZInputStream: public mrpt::io::CStream
{
public:
    // structs

    struct Impl;

    // construction

    CFileGZInputStream();
    CFileGZInputStream(const std::string& fileName);
    CFileGZInputStream(const CFileGZInputStream&);

    //
methods

    CFileGZInputStream& operator = (const CFileGZInputStream&);
    virtual std::string getStreamDescription() const;
    bool open(const std::string& fileName, mrpt::optional_ref<std::string> error_msg = std::nullopt);
    void close();
    bool fileOpenCorrectly() const;
    bool is_open();
    bool checkEOF();
    std::string filePathAtUse() const;
    virtual uint64_t getTotalBytesCount() const;
    virtual uint64_t getPosition() const;
    virtual uint64_t Seek(int64_t, CStream::TSeekOrigin = sFromBeginning);
    virtual size_t Read(void* Buffer, size_t Count);
    virtual size_t Write(const void* Buffer, size_t Count);
};

Inherited Members

public:
    //
methods

    virtual size_t Read(void* Buffer, size_t Count) = 0;
    virtual size_t Write(const void* Buffer, size_t Count) = 0;
    virtual uint64_t getTotalBytesCount() const = 0;
    virtual uint64_t getPosition() const = 0;

Construction

CFileGZInputStream()

Constructor without open.

CFileGZInputStream(const std::string& fileName)

Constructor and open.

Parameters:

fileName	The file to be open in this stream
std::exception	If there’s an error opening the file.

Methods

virtual std::string getStreamDescription() const

Returns a human-friendly description of the stream, e.g.

a filename.

bool open(const std::string& fileName, mrpt::optional_ref<std::string> error_msg = std::nullopt)

Opens the file for read.

Parameters:

fileName

The file to be open in this stream

Returns:

false if there’s an error opening the file, true otherwise

void close()

Closes the file.

bool fileOpenCorrectly() const

Returns true if the file was open without errors.

bool is_open()

Returns true if the file was open without errors.

bool checkEOF()

Will be true if EOF has been already reached.

std::string filePathAtUse() const

Returns the path of the filename passed to open(), or empty if none.

virtual uint64_t getTotalBytesCount() const

Method for getting the total number of compressed bytes of in the file (the physical size of the compressed file).

virtual uint64_t getPosition() const

Method for getting the current cursor position in the compressed, where 0 is the first byte and TotalBytesCount-1 the last one.

virtual uint64_t Seek(int64_t, CStream::TSeekOrigin = sFromBeginning)

This method is not implemented in this class.

virtual size_t Read(void* Buffer, size_t Count)

Introduces a pure virtual method responsible for reading from the stream.

virtual size_t Write(const void* Buffer, size_t Count)

Introduces a pure virtual method responsible for writing to the stream.

Write attempts to write up to Count bytes to Buffer, and returns the number of bytes actually written.