CFileGZInputStream.cpp

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/* +---------------------------------------------------------------------------+
   |                     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(NULL)
{
        MRPT_START
        open(fileName);
        MRPT_END
}
/*---------------------------------------------------------------
                                                        Constructor
 ---------------------------------------------------------------*/
CFileGZInputStream::CFileGZInputStream( ) : m_f(NULL)
{
}
 
/*---------------------------------------------------------------
                                                        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 != NULL;
 
        MRPT_END
}
 
/*---------------------------------------------------------------
                                                        close
 ---------------------------------------------------------------*/
void CFileGZInputStream::close()
{
        if (m_f)
        {
                gzclose(THE_GZFILE);
                m_f = NULL;
        }
}
 
/*---------------------------------------------------------------
                                                        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!=NULL;
}
 
/*---------------------------------------------------------------
                                                checkEOF
 ---------------------------------------------------------------*/
bool CFileGZInputStream::checkEOF()
{
        if (!m_f)       return true;
        else            return 0!=gzeof(THE_GZFILE);
}