[Insight-users] Two bugs in MetaImageIO

[Luis Ibanez]

Hi Jarek,

Thanks for pointing this out.
We will be making the fixes on the code.

There is noting better than a bug
report with the fix included    :-)

Thanks


    Luis

========================================

Jarek Sacha wrote:
> Just noticed two bugs in itkMetaImageIO.cxx (revision 1.18)
> 
> 1) Once a header is read there is no check if the input steam is fine. 
> In result an incorrect image data can be read, for instance you can load 
> data from a non-existing file without error.
> 
> 2) If a header and image data are in separate files and header name does 
> not start with a path then the name of the image data file gets 
> corrupted (first letter in the name is duplicated)
> 
> Possible fixes:
> Bug 1: Change method MetaImageIO::Read from
> 
>   void MetaImageIO::Read(void* buffer)
>   {
>     unsigned int dimensions = this->GetNumberOfDimensions();
>     unsigned int numberOfPixels = 1;
>     for( unsigned int dim=0; dim< dimensions; dim++ )
>       {
>       numberOfPixels *= m_Dimensions[ dim ];
>       }
> 
>     unsigned int pixelSize =  this->GetComponentSize();
> 
>     char * p = static_cast<char *>(buffer);
>     for( unsigned int pixelnumber = 0; pixelnumber< numberOfPixels; 
> pixelnumber++)
>     {
>       for(unsigned int bytes=0; bytes<pixelSize; bytes++)
>       {
>         *p = m_Ifstream.get();
>         p++;
>       }
>     }
> 
>     SwapBytesIfNecessary( buffer, numberOfPixels );
> 
>   }
> 
> to something like (for clarity ImageIORegion is ignored below):
> 
>   void MetaImageIO::Read(void* buffer)
>   {
>     char * p = static_cast<char *>(buffer);
>     m_Ifstream.read(p, GetImageSizeInBytes());
>     bool success = !m_Ifstream.bad();
>     m_Ifstream.close();
>     if( !success )
>       {
>       itkExceptionMacro("Error reading image data.");
>       }
> 
>     SwapBytesIfNecessary(buffer, GetImageSizeInPixels());
>   }
> 
> Bug 2: In method MetaImageIO::ReadImageInformation, in the "if" 
> statement checking for "ElementDataFile" replace
> 
>       {
>       size_t endOfPath = m_FileName.find_last_of( "\\/" );
>       if( endOfPath > m_FileName.max_size() )
>         {
>         endOfPath = 0; // there is no path
>         }
>       m_Ifstream.close();        // Close the header
>       std::string dataFileName;
>       dataFileName = m_FileName.substr( 0, endOfPath+1 );
>       dataFileName += key;
>       m_FileName = dataFileName;    // Compose the data filename
>       m_Ifstream.open( m_FileName.c_str(), std::ios::in | 
> std::ios::binary );
>       return;
>       }
> 
> with something like:
> 
>       {
>       m_Ifstream.close();        // Close the header
> 
>       std::string dataFileName;
>       size_t endOfPath = m_FileName.find_last_of( "\\/" );
>       if( endOfPath == std::string::npos )
>         {
>         dataFileName = key;     // there is no path
>         }
>       else
>         {
>         dataFileName = m_FileName.substr( 0, endOfPath+1 );
>         dataFileName += key;
>         }
> 
>       m_FileName = dataFileName;    // Compose the data filename
>       m_Ifstream.open( m_FileName.c_str(), std::ios::in | 
> std::ios::binary );
>       if( !m_Ifstream )
>         {
>         itkExceptionMacro("Error opening image data file.");
>         }
> 
>       return;
>       }
> 
> Home this helps,
> 
> Jarek
> 
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