CFileGZInputStream.cpp

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 |
   +------------------------------------------------------------------------+ */

#include "base-precomp.h"  // Precompiled headers

#ifdef _MSC_VER
#define _SCL_SECURE_NO_WARNINGS
#endif

#include <mrpt/utils/CFileGZInputStream.h>
#include <mrpt/system/os.h>
#include <mrpt/system/filesystem.h>

#include <zlib.h>

using namespace mrpt::utils;
using namespace std;

#define THE_GZFILE reinterpret_cast<gzFile>(m_f)

/*---------------------------------------------------------------
                                                        Constructor
 ---------------------------------------------------------------*/
CFileGZInputStream::CFileGZInputStream(const string& fileName) : m_f(nullptr)
{
        MRPT_START
        open(fileName);
        MRPT_END
}
/*---------------------------------------------------------------
                                                        Constructor
 ---------------------------------------------------------------*/
CFileGZInputStream::CFileGZInputStream() : m_f(nullptr) {}
/*---------------------------------------------------------------
                                                        open
 ---------------------------------------------------------------*/
bool CFileGZInputStream::open(const std::string& fileName)
{
        MRPT_START

        if (m_f) gzclose(THE_GZFILE);

        // Get compressed file size:
        m_file_size = mrpt::system::getFileSize(fileName);
        if (m_file_size == uint64_t(-1))
                THROW_EXCEPTION_FMT("Couldn't access the file '%s'", fileName.c_str());

        // Open gz stream:
        m_f = gzopen(fileName.c_str(), "rb");
        return m_f != nullptr;

        MRPT_END
}

/*---------------------------------------------------------------
                                                        close
 ---------------------------------------------------------------*/
void CFileGZInputStream::close()
{
        if (m_f)
        {
                gzclose(THE_GZFILE);
                m_f = nullptr;
        }
}

/*---------------------------------------------------------------
                                                        Destructor
 ---------------------------------------------------------------*/
CFileGZInputStream::~CFileGZInputStream() { close(); }
/*---------------------------------------------------------------
                                                        Read
                        Reads bytes from the stream into Buffer
 ---------------------------------------------------------------*/
size_t CFileGZInputStream::Read(void* Buffer, size_t Count)
{
        if (!m_f)
        {
                THROW_EXCEPTION("File is not open.");
        }

        return gzread(THE_GZFILE, Buffer, Count);
}

/*---------------------------------------------------------------
                                                        Write
                        Writes a block of bytes to the stream.
 ---------------------------------------------------------------*/
size_t CFileGZInputStream::Write(const void* Buffer, size_t Count)
{
        MRPT_UNUSED_PARAM(Buffer);
        MRPT_UNUSED_PARAM(Count);
        THROW_EXCEPTION("Trying to write to an input file stream.");
}

/*---------------------------------------------------------------
                                                getTotalBytesCount
 ---------------------------------------------------------------*/
uint64_t CFileGZInputStream::getTotalBytesCount()
{
        if (!m_f)
        {
                THROW_EXCEPTION("File is not open.");
        }
        return m_file_size;
}

/*---------------------------------------------------------------
                                                getPosition
 ---------------------------------------------------------------*/
uint64_t CFileGZInputStream::getPosition()
{
        if (!m_f)
        {
                THROW_EXCEPTION("File is not open.");
        }
        return gztell(THE_GZFILE);
}

/*---------------------------------------------------------------
                                                fileOpenCorrectly
 ---------------------------------------------------------------*/
bool CFileGZInputStream::fileOpenCorrectly() { return m_f != nullptr; }
/*---------------------------------------------------------------
                                                checkEOF
 ---------------------------------------------------------------*/
bool CFileGZInputStream::checkEOF()
{
        if (!m_f)
                return true;
        else
                return 0 != gzeof(THE_GZFILE);
}