iraf.net

I may have found a bug in IRAF's [i:d8167a55da]copy[/i:d8167a55da] command. I've noticed that [i:d8167a55da]copy[/i:d8167a55da] corrupts some gzipped files. For instance, try downloading and [i:d8167a55da]copy[/i:d8167a55da]'ing [b:d8167a55da]table.2.gz[/b:d8167a55da] fromhttp://vizier.cfa.harvard.edu/viz-bin/ftp-index?/ftp/cats/J/A%2bA/424/919/x70z02Notice the file size increases by 1 after a copy. The UNIX [i:d8167a55da]cp[/i:d8167a55da] command does not corrupt the file allowing [i:d8167a55da]gunzip[/i:d8167a55da] to run without a premature end of file error. Some of the other files from the URL such as [b:d8167a55da]table.10.gz[/b:d8167a55da] and [b:d8167a55da]table.16.gz[/b:d8167a55da] exhibit the same behavior. Ideas?Jason

This is a side-effect of the size of an SPP character (two bytes) meaning that iraf file i/o can't write an odd number of bytes to a file. In most cases the extra NULL is harmless but this is one case where a host program doesn't like it (another being some tasks reading the GIF images produced by EXPORT, however there a "null extension" is actually in the gif spec but rarely implemented as legal). Changing the size of an spp char is a one-line change, but after 20 years there may be untold numbers of unintended consequences in other tasks. OTOH, we're in good shape to start using unicode chars in the system 8-) Simplest thing is to just use 'cp' for binary files, it's a default foreign task and is readily available.-MikeP.S. Note: This isn't a file corruption of any kind, it is just that there is an extra NULL byte on the file in the event the input file was an odd size.

[quote:98a543410c="fitz"]This is a side-effect of the size of an SPP character (two bytes) meaning that iraf file i/o can't write an odd number of bytes to a file. [/quote:98a543410c] Thank you, Mike. Wow! I consider myself pretty good at IRAF and I can't believe that I never noticed this or that it never caused me a problem before. Hmmm... I better doublecheck some of my scripts.[quote:98a543410c="fitz"]we're in good shape to start using unicode chars in the system[/quote:98a543410c] Until that happens, perhaps the help file for [i:98a543410c]copy[/i:98a543410c] should include a BUGS section.Big thanks,
Jason