This benchmarks as around %1500 quicker than the original. 

     s/iter   org   new  best
org    5.62    --  -78%  -94%
new    1.26  346%    --  -73%
best  0.345 1529%  266%    --
The results are the same

[download]

It'll probably be deemed unreadble, but it is a bit quick. 

sub ba2bi2 {
    my @ba = reverse (@_, (0) x (4 - ( @_%4 || 4 ) ) );
    my $result = Math::BigInt->new(0);
    $result *= 4294967296
    , $result += $_
        for map{
                unpack 'N'
                , pack 'C4'
                , @ba[4*$_ .. 4*$_+3]
            } 0 .. ($#ba/4);
    return $result;
}

[download]

Examine what is said, not who speaks.

The 7th Rule of perl club is -- pearl clubs are easily damaged. Use a diamond club instead.

In reply to Re: Converting an array of bytes into a BigInt - 1500% quicker. by BrowserUk
in thread Converting an array of bytes into a BigInt - speed considerations by dempa

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