#! perl -slw
use strict;
use Devel::Peek;
use Inline C => Config => BUILD_NOISY => 1;
use Inline C => <<'END_C',  NAME => 'QsortPD', CLEAN_AFTER_BUILD => 0;

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

int compare( const void *arg1, const void *arg2 ) {
    double diff = *(double*)arg1 - *(double*)arg2;
    return diff < 0 ? -1 : diff > 0 ? 1 : 0;
}

int qsortPackedDoubles( SV *data, SV *n ) {
    qsort( (void *)SvPVX( data ), SvUV( n ), sizeof( double ), compare );
}

END_C
our $N ||= 1e6; ## Warning N less that 1000 will give funny results

my $packedDoubles = '';

## Preallocate the scalar and random fill with packed doubles
open RAM, '>', \$packedDoubles;
seek RAM, $N*8, 0;
print RAM chr(0);
seek RAM, 0, 0;
printf RAM "%s", pack 'd1000', map{ rand 32767 } 1 .. 1000 for 1 .. $N / 1000;
close RAM;

print "Starting sort of $N packed doubles: ", time;
qsortPackedDoubles( $packedDoubles, $N );
print "Finished sort of $N packed doubles: ", time;

<>;
print for unpack 'd*', $packedDoubles;