#! perl -slw
use strict;
use Time::HiRes qw[ time ];

my @lookup; $#lookup = 0x3ffff;
$lookup[ $_ ] = [ ( $_ & 0x3f000 ) >> 12, ( $_ & 0xfc0 ) >> 6, $_ & 0x3f ]
    for 0 .. 0x3ffff;

my( @nxt, @mid, @bot );
$nxt[ $_ ] = ( $_ & 0x3f000 ) >> 12,
$mid[ $_ ] = ( $_ & 0xfc0 ) >> 6,
$bot[ $_ ] = $_ & 0x3f
    for 0 .. 0x3ffff;

our $ITERS //= 10e6;

sub stuff{
    #print "@_";
}

my $n = 0x80061861;

my $start = time;
for ( 1 .. $ITERS ) {
    stuff(
        ( $_ & 0xffc00000 ) >> 18,
        ( $_ & 0x0003f000 ) >> 12,
        ( $_ & 0x00000fc0 ) >>  6,
        ( $_ & 0x0000003f )
    );
}
printf "Shift&and took: %.12f seconds\n", ( time() - $start ) / $ITERS;

$start = time;
for ( 1 .. $ITERS ) {
    stuff( $_ >> 18, @{ $lookup[ $_ & 0x3ffff ] } );
}
printf "  Lookup  took: %.12f seconds\n", ( time() - $start ) / $ITERS;

$start = time;
for ( 1 .. $ITERS ) {
    my $i = $_ & 0x3ffff;
    stuff( $_ >> 18, $nxt[ $i ], $mid[ $i ], $bot[ $i ] );
}
printf "  Lookup2 took: %.12f seconds\n", ( time() - $start ) / $ITERS;

$start = time;
for ( 1 .. $ITERS ) {
    stuff( unpack 'vccc', join'',map{ pack'b*', $_ } unpack 'a14a6a6a6', unpack 'B32', pack 'N', $_ );
}
printf "(un)pack  took: %.12f seconds\n", ( time() - $start ) / $ITERS;