I need to write a float in big-endian format on a little-endian machine. The only way I found to do it is to pack the number into float format, rip apart the bytes, reverse them, and repack them.
This works fine, but I'm little dizzy from hoop-jumping. Is there a shorter way to get there? Here is my example, in baby Perl to be clear about the steps. Please note: I'm not looking for denser code, I know I can use map to eliminate
temporary variables. I'm looking for a better algorithm.
PackFoo
#!/usr/bin/perl
use strict;
my ($num, $str, @bytes);
$num = -1.18024688796416e+29;
$str = pack('f', $num);
showstring('native', $str);
@bytes = split('', $str);
@bytes = reverse(@bytes);
$str = join('', @bytes);
$str = pack('a4', $str);
showstring('alien ', $str);
#-----------------------------------------------------------
sub showstring {
my ($label, $str) = @_;
my @bytes = unpack('H2H2H2H2', $str);
print "$label 0x", join("", @bytes), "\n";
}