I have a few lines of code I use for byte reversal of some 16mb files. I have got it to convert this byte order in .6 - .8 secs. I was wondering if there is a more faster way than using these two methods I have below. Please feel free to crush my record of 0.68640184402465.

Here is a file to test with ofcourse: Test File

use strict;
use warnings;
use Time::HiRes qw( time );

my $start = time();

open (my $file, '<', $ARGV[0]) or die 'cannot open $file: $!';
binmode($file);

open (my $reversedFile, '+>', "$ARGV[0].swap");
binmode($reversedFile);

my($data, $n);

 while (($n = read $file, $data, 4096) != 0) {
    print $reversedFile pack("v*", unpack("n*", $data));
    }
    
my $end = time();
my $runtime = sprintf("%.16s", $end - $start);
print $runtime;

[download]
And another method which is a little slower it seems: 
use strict;
use warnings;
use Time::HiRes qw( time );

my $start = time();

my $input_file = $ARGV[0];

my $data = do {

    local $/ = undef;
    open (my $fh, "<", $input_file) or die "could not open $input_file
+: $!";
    binmode($fh);
    <$fh>;

};

my $reversed_data = pack( "v*", unpack( "n*", $data ) );

open my $output, '>', "bkpps3.swap.bin";
binmode($output);

print $output $reversed_data;

my $end = time();
my $runtime = sprintf( "%.16s", $end - $start );
print $runtime;

[download]
Like i said, I really am not to sure how to make it faster than it is. Any input is appreciated :)

In reply to Fastest byteswap (little endian to big endian (eg. 34127856 -> 12345678) by james28909

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