Method extend

plugins/e57/libE57Format/src/CheckedFile.cpp:566–662

}

void CheckedFile::extend( uint64_t newLength, OffsetMode omode )
{
#ifdef E57_VERBOSE
   // cout << "extend newLength=" << newLength << " omode="<< omode << std::endl;
   // //???
#endif
   if ( readOnly_ )
   {
      throw E57_EXCEPTION2( ErrorFileReadOnly, "fileName=" + fileName_ );
   }

   uint64_t newLogicalLength = 0;

   if ( omode == Physical )
   {
      newLogicalLength = physicalToLogical( newLength );
   }
   else
   {
      newLogicalLength = newLength;
   }

   uint64_t currentLogicalLength = length( Logical );

   // Make sure we are trying to make file longer
   if ( newLogicalLength < currentLogicalLength )
   {
      throw E57_EXCEPTION2( ErrorInternal,
                            "fileName=" + fileName_ + " newLength=" + toString( newLogicalLength ) +
                               " currentLength=" + toString( currentLogicalLength ) );
   }

   // Calc how may zero bytes we have to add to end
   uint64_t nWrite = newLogicalLength - currentLogicalLength;

   // Seek to current end of file
   seek( currentLogicalLength, Logical );

   uint64_t page = 0;
   size_t pageOffset = 0;

   getCurrentPageAndOffset( page, pageOffset );

   // Calc first write size (may be partial page)
   // Watch out for different int sizes here.
   size_t n = 0;

   if ( nWrite < logicalPageSize - pageOffset )
   {
      n = static_cast<size_t>( nWrite );
   }
   else
   {
      n = logicalPageSize - pageOffset;
   }

   // Allocate temp page buffer
   std::vector<char> page_buffer_v( physicalPageSize );