CFileInputStream.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, 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 "io-precomp.h"  // Precompiled headers
 
#include <mrpt/io/CFileInputStream.h>
#include <mrpt/core/exceptions.h>
 
using namespace mrpt::io;
using namespace std;
 
static_assert(
        !std::is_copy_constructible<CFileInputStream>::value &&
                !std::is_copy_assignable<CFileInputStream>::value,
        "Copy Check");
 
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() const
{
        if (!fileOpenCorrectly()) return 0;
 
        auto& f = const_cast<std::ifstream&>(m_if);
 
        const uint64_t previousPos = f.tellg();
        f.seekg(0, ios_base::end);
        uint64_t fileSize = f.tellg();
        f.seekg(previousPos, ios_base::beg);
        return fileSize;
}
 
/*---------------------------------------------------------------
                                                getPosition
 ---------------------------------------------------------------*/
uint64_t CFileInputStream::getPosition() const
{
        auto& f = const_cast<std::ifstream&>(m_if);
        if (m_if.is_open())
                return f.tellg();
        else
                return 0;
}
 
/*---------------------------------------------------------------
                                                fileOpenCorrectly
 ---------------------------------------------------------------*/
bool CFileInputStream::fileOpenCorrectly() const { 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();
}