#!/usr/bin/perl -w
#
# Script for creating a cryptogram out of a plaintext
# ascii file.
#
# By:      Rob Hudson
# Created: 22 Jan 2000
use Text::Wrap;

my $alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
my $inFile = $ARGV[0] if ($ARGV[0] ne "") or die "No file specified\n";

# Read it, Scrunch it, Up it.
open IN, $inFile or die "Can't open input file: $!";
my $text = "";
while (<IN>) {
  s/[\s]+/ /g; 
  $text .= $_;
}
close (IN);
$text = uc($text);

# Build random alphabet string, not allowing repeat letters
my @alpha = split //, $alpha;
my $substit = join '', fisher_yates_shuffle(\@alpha);

# Have to use an eval since $vars don't get interpreted
# inside a tr call.
eval "\$text =~ tr/$alpha/$substit/";
print wrap ("","", $text), "\n";

# Fisher Yates Shuffle algorithm found in perlfaq4
sub fisher_yates_shuffle {
  my $array = shift;
  for (my $i = @$array; --$i; ) {
    my $j = int rand ($i+1);
    next if $i == $j;
    @$array[$i, $j] = @$array[$j, $i];
  }
  return join '', @$array;
}