On Mon, 1 Oct 2012, Max Leske wrote:
Hi guys
Is there a way to find out (from outside of the image), if an image has been
saved with Cog? What I would like to do is something like this:
$ head -20 myImage.image | grep <some expression>
The use case for this is seaside hosting, where we only have squeak VMs to run
images, so when an image is uploaded that was saved with Cog that image cause
trouble.
Any ideas?
Currently there are 3 image formats around 6502 (old interpreter format,
no closures), 6504 (new interpreter format with closures), 6505 (Cog
format). The first two bytes of the image file contain the image format in
little-endian (IIRC) format. So you can decide it by checking the first
byte (head -c 1). If you only support the old interpreter format, then
the following bash expression should work:
[ $(head -c 1 $IMAGE_NAME) == 'f' ]
Levente
Cheers,
Max
