Matt Sergeant writes:
> On Fri, 19 May 2000, David Larkin wrote:
>
> > I require a large array of ints in a real application, just stripped
> > problem down to bear bones for demo.
>
> Is your array sparse by any chance? If not your modperl daemon is going to
> get _much_ larger after you populate that array. If it's sparse, consider
> using a hash - that will give you a slight speed penalty at the benefit of
> not consuming quite so much ram. Other things to consider:
>
> Re-write this critical bit of code in XS (not as hard as it sounds).
> Use a database.
> Use the filesystem.
Simply store them in native form in a big long string, just like C
would do. Pre-extend the string first, if you know how big you want it:
$intsize = 4; # alter if sizeof(int) != 4
$intarray = "\0" x (30000 * $intsize);
Update index $i with
substr($intarray, $i * $intsize, $intsize) = pack("I", $newval);
which assumes an unsigned int, or use "i" for signed.
To retrieve index $i use
$val = unpack("I", substr($intarray, $i * $intsize, $intsize));
You can even retrive a bunch of them faster with
@ten_to_thirty = unpack("I20", substr(...));
or set a bunch with
substr(..., $intsize * 10) = pack("I20", @ten_to_thirty);
For that last bit of extra performance, do
sub INTSIZE () { 4 }; # alter if sizeof(int) != 4
--Malcolm
--
Malcolm Beattie <[EMAIL PROTECTED]>
Unix Systems Programmer
Oxford University Computing Services
