CFileInputStream.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/CFileInputStream.h>
#include <mrpt/system/os.h>
#include <mrpt/system/os.h>

using namespace mrpt::utils;
using namespace std;

/*---------------------------------------------------------------
                                                        Constructor
 ---------------------------------------------------------------*/
CFileInputStream::CFileInputStream( const string                &fileName ) : m_if()
{
        MRPT_START

        // Try to open the file:
        // Open for input:
        if (!open(fileName))
                THROW_EXCEPTION_FMT( "Error trying to open file: '%s'",fileName.c_str() );

        MRPT_END
}

/*---------------------------------------------------------------
                                                        Constructor
 ---------------------------------------------------------------*/
CFileInputStream::CFileInputStream() : m_if()
{
}

/*---------------------------------------------------------------
                                                        open
 ---------------------------------------------------------------*/
bool CFileInputStream::open( const string &fileName )
{
        // Try to open the file:
        // Open for input:
        m_if.open(fileName.c_str(), ios_base::binary | ios_base::in );
        return m_if.is_open();
}

/*---------------------------------------------------------------
                                                        close
 ---------------------------------------------------------------*/
void CFileInputStream::close()
{
        if (m_if.is_open()) m_if.close();
}

/*---------------------------------------------------------------
                                                        Destructor
 ---------------------------------------------------------------*/
CFileInputStream::~CFileInputStream()
{
        close();
}

/*---------------------------------------------------------------
                                                        Read
                        Reads bytes from the stream into Buffer
 ---------------------------------------------------------------*/
size_t  CFileInputStream::Read(void *Buffer, size_t Count)
{
        if (!m_if.is_open()) return 0;

        m_if.read(static_cast<char*>(Buffer),Count);
        return m_if.fail() ? 0:Count;
}

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

/*---------------------------------------------------------------
                                                        Seek
        Method for moving to a specified position in the streamed resource.
         See documentation of CStream::Seek
 ---------------------------------------------------------------*/
uint64_t CFileInputStream::Seek(int64_t Offset, CStream::TSeekOrigin Origin)
{
        if (!m_if.is_open()) return 0;

        ifstream::off_type  offset = Offset;
        ifstream::seekdir  way;

        switch(Origin)
        {
        case sFromBeginning: way = ios_base::beg; break;
        case sFromCurrent: way = ios_base::cur; break;
        case sFromEnd: way = ios_base::end; break;
        default: THROW_EXCEPTION("Invalid value for 'Origin'");
        }

        m_if.seekg(offset, way);

        return getPosition();
}

/*---------------------------------------------------------------
                                                getTotalBytesCount
 ---------------------------------------------------------------*/
uint64_t CFileInputStream::getTotalBytesCount()
{
        if (!fileOpenCorrectly()) return 0;

        uint64_t previousPos = getPosition();
        uint64_t fileSize = Seek(0,sFromEnd);
        Seek( previousPos );
        return fileSize;
}

/*---------------------------------------------------------------
                                                getPosition
 ---------------------------------------------------------------*/
uint64_t CFileInputStream::getPosition()
{
        if (m_if.is_open())
                        return m_if.tellg();
        else    return 0;
}

/*---------------------------------------------------------------
                                                fileOpenCorrectly
 ---------------------------------------------------------------*/
bool  CFileInputStream::fileOpenCorrectly()
{
        return m_if.is_open();
}

/*---------------------------------------------------------------
                                                readLine
 ---------------------------------------------------------------*/
bool CFileInputStream::readLine( string &str )
{
        str = string(); // clear() is not defined in VC6
        if (!m_if.is_open()) return false;

        std::getline( m_if, str );
        return !m_if.fail() && !m_if.eof();
}

/*---------------------------------------------------------------
                                                checkEOF
 ---------------------------------------------------------------*/
bool CFileInputStream::checkEOF()
{
        if (!m_if.is_open())
                return true;
        return m_if.eof();
}

void CFileInputStream::clearError()
{
        if (m_if.is_open())
                        m_if.clear();
}