#!/usr/bin/perl -w
#
# $Id: shaname,v 1.1 2009/01/05 03:41:22 vogelke Exp $
#
# Use SHA512 hash to create 16-character signature for string.

use strict;
use Carp;
use Digest::SHA qw/sha512_hex/;
my $hash;

while (<>) {
    chomp;
    $hash = hash2name($_);
    print "$hash:$_\n";
}

exit(0);

# ------------------------------------------------------------------------
# Use every 8th character from SHA512 as a hash value.
# Yeah, I know you're not supposed to do that because it's not
# "guaranteed unique".  Sue me.

sub hash2name {
    my $data = shift(@_) or croak "no string\n";
    my $name = '';
    my $hash = sha512_hex($data);
    my $max  = 128;   # 512 bits = 128 hex characters

    my $k = 0;
    while ($k < $max) {
        $name .= substr($hash, $k, 1);
        $k += 8;
    }

    return ($name);
}