OpenEuphoria

Re: random filenames

• Posted by Jason Gade <jaygade at yahoo.com> Mar 19, 2007
• 520 views

jacques deschênes wrote:
> 
> Hi Hayden,
> the reason for unprintable character is that rand(125)+1 generate values
> between
> 1 and 126 and codes below 32 are unprintable
> replace rand(125)+1 by   rand(93) + 32
> but beware that some characters like '\' are forbidden in windows filenames
> so a better choice could be rand(26)+'a' (limit to lower case letters)
> But all this is not 100% collision proof.
> 
> regards,
> Jacques D.
> 
> Hayden McKay wrote:
> > 
> > Doe's anyone know how to implement a small runtime cross-platform random
> > filename
> > generator?
> > 
> > I'm currently just adding the '~' char to the filename
> > ie: filename = '~' & filename
> > 
> > I've written a small template but it will return unprintable chars;
> > 
> > }}}
<eucode>
> > function TempFile(sequence mode)
> >     sequence s
> > 
> >     s = repeat(-1, 8)
> >     for j = 1 to 8 do            -- DOS filename compatablity
> >         s[j] = rand(125 + 1)
> >     end for
> > 
> >     s &= ".TMP"
> > 
> >     return OpenFile(s, mode)
> > 
> > end function
> > </eucode>
{{{

> > 
> > Maybee a 'set_rand()' might fix?

Here's an (untested) idea:

constant CHARLIST = "abcdefghijklmnopqrstuvwxyz1234567890"
function TempFile(sequence mode)
    sequence s
    s = repeat(-1, 8)

    integer charcount
    charcount = length(CHARLIST)

    for j = 1 to 8 do -- DOS filename compatibility
        s[j] = CHARLIST[rand(charcount)]
    end for

    s &= ".TMP"

    return OpenFile(s, mode)

end function

I just noticed that Christian Cuvier's upload is showing up, I haven't looked at
it yet.

--
"Any programming problem can be solved by adding a level of indirection."
--anonymous
"Any performance problem can be solved by removing a level of indirection."
--M. Haertel
"Premature optimization is the root of all evil in programming."
--C.A.R. Hoare
j.