World: r3wp

In cases like this, Robert, I usually use somthing like

>> pass: func [value] [any [value []]]

which makes code somewhat readable

>> a: compose [ (pass if 0 > 1 ["b"]) ]

Clean and simple solution.

a: compose [(pick [["b"][]] 0 > 1)]

If I wish to compute a checksum on an image file, I can do this

checksum read/binary %image.png


but how do I get the same result when I have the image as image data 
?

eg. i: load %image.png

and to compute the checksm on i ?

guess I can't

convert it to binary first

or if you want to avoid loading the image twice:

i: read/binary %image.png
checksum i
i: load i

Since I might be grabbing the image as jpg and then saving it to 
png, I guess I should save it to memory as binary and do the calculation 
that way.

I use these quite often:

ifs: func [c b][either c [do b][""]] ;like if but return empty string

ifb: func [c b][either c [do b][[]]] ;like if but return empty block

my bad, thanks Dock, I can refactor to
ifs: func [c b][either c b [""]] ;like if but return empty string
ifb: func [c b][either c b [[]]] ;like if but return empty block
so ifs is like your if* 8)

Which version of rebol allows for evaluation in paths?  (i.e. block/(1+i): 
"hello" )  Or am I not remembering this correctly?

Nevermind, I think I just had a typo in my code. :)

What is the limitation on file size that REBOL 7.6 can handle?

I'm assuming there must be a iimit that open/direct can't just mount 
any file size.  I'm assuming that the limitation is roughly 2 Gigs.

I'm also assuming since a port/size is integer! that the file size 
can be no greater than 2099999999 bytes.

Since integers greater than that number cause errors.

Ok, I checked for a file size limitation in REBOL but haven't found 
one.  I noticed the documentation for open/direct for example says 
that /direct can be used for files of any size.  I don't see how 
that can be if it is calculating the size as an integer and integer 
has a limitations.

Largest 32-bit signed int is 2 ** 31 - 1 = 2'147'483'647

If REBOL internally use 32-bit unsigned, it's 2 ** 32 - 1 = 4'294'967'295

If REBOL internally use 64-bit unsigned, it's 2 ** 64 - 1 ca. = 
1.845E+19

I'm actually running an experiment now.  I'm going to write a file 
that will attempt to exceed those sizes.

:-) Be sure, you have enough HD space!

The file system might have max-size for files. I remember something 
about 2 or 4GB for some file systems.

FAT32 is the one with that limit.

Yep, hit it today on FAT32 - 4GB file was produced.

I'm on NTFS.  I'll post what I find out.

currently still writing a file which is only at 668 Megs at the moment.

Anton, you created a 4GB file using REBOL or was reading one when 
you got the error?

Sorry, not using Rebol, but in Linux, creating a file in a FAT32 
partition.

ahhh ok.

I was curious because I'm interested in what happens when I hit 2099999999 
size.

Actually a bit larger than that.

I don't know where you got that number from; If I remember correctly 
the first time you can get a problem with rebol file size is at 2 
^ 31 - 1

Oh it was a generic range number based on a algorithm I was running. 
 I expect the number to be the 32 bit signed number that John posted.

Maybe it was 2 ^ 31 - your buffer size ?

That number I posted is the highest in my algorithm I could hit.

Ok, that makes sense.

p: open/direct/write/new %/k/test.bin

b: make binary! 1000000 insert/dup b #{00} 1000000 i: 0 while [not 
error? try [insert tail p b]][i: i + 1]

created file ower 5GB here... than I stoped it.

what OS?

WIN/ ntfs

ok cool.

I want to be able to do some probes on the file once I get it to 
size.

on the port rather.

The problem is with reading anyway

You having problem reading that file now?

But not impossible I guess. Using such a big files is not practical 
imho.

I think it's when you want to seek to a position greater than 2 ^ 
31 - 1

you run into a problem then.

I'm not going to read such a file if I have only 1GB memory:)

Well I'm testing a new indexing system for TRETBASE and need to know 
some significant data to fine tune it.

That is where my interest lies Anton.