[Paraview] Slow XML readers

[Bam Ting]

I have noticed that when saving data from ParaView in the XML binary format,
a binary file is not produced. Please check me on this! I think it is a bug!

 to reproduce:

open ParaView
sources->mandlebrot
dims 205,250,250
File->Save Data-> vti, binary
File->Save Data-> legacy binary

look at the files produced, the XML vti is clearly not a binary file (and by
the way on windows unix line feeds are used, not sure if that is
desireable), while the legacy file clearly is a binary file.

If I underrstand the XML reader/writer tuple correctly here is a potential
performance caveat when using the XML reader/writer tuple: Be sure file is
really binary!!!!

When ParaView saves data as vti XML binary, the file is not really binary at
all but rather base 64 encoded, utf8. This combination could not be slower!
As the reader reads each character writen this way, it first tests to see
how many bytes the character has, then does the base 64 conversion to native
float/double. Operation thus on each character is of course a trerrible idea
if one cares about performance!


delete the pipeline
Open both files
tools->timer log

You will likely see that the binary legacy file loads twice as fast as the
XML.

Experts, plz verify I am not smoking crack
Thx
Bam
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.paraview.org/pipermail/paraview/attachments/20090702/569b5200/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: bin_is_not.vti
Type: application/octet-stream
Size: 1040 bytes
Desc: not available
URL: <http://www.paraview.org/pipermail/paraview/attachments/20090702/569b5200/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: bin_is.vtk
Type: application/octet-stream
Size: 1054 bytes
Desc: not available
URL: <http://www.paraview.org/pipermail/paraview/attachments/20090702/569b5200/attachment-0001.obj>