#!/usr/bin/perl -w

#Prints out an ascii map of a file.

use strict;

my ($length) = 15;

if ($ARGV[0]) {

    open (FILE, "$ARGV[0]") || die ("Can't open the file you specified!\n");
    
    my ($count) = 0;
    my ($bytes);
    my ($buffer) = "";
    my (%uniques);
    
    while ( read (FILE, $bytes, $length) ) {
	if ($count % $length == 0) {
	    print ("-------------- ROW: $count --- [$bytes]\n");
	}

	my (@string) = split(//, $bytes);

	foreach my $e (@string) {
	    #Assign this to the unique hash.
	    $uniques{$e} = "";

	    #Print out some warnings regarding invisible chars.
	    my ($info) = "";
	    my ($asciival) = ord $e;

	    ($info, $e) = tweak($e);

	    print "$count:\t$e\t-> ", $asciival, " $info\r\n";
	    $count++;
	}
    }
    
    print ("--------------\nTOTAL BYTES: $count \tUNIQUE CHARS: ", scalar keys %uniques, "\n\n");

    close (FILE);

} else {
    die ("Usage: asciimap.pl filename\n");
}


sub tweak {
    my ($byte)  = @_;
    my ($bytecopy) = $byte;

    my (%invisibles) = (
			chr(8)  => "(Backspace)",
			chr(9)  => "(Horizontal tab)",
			chr(10) => "(Newline)",
			chr(11) => "(Vertical tab)",			
			chr(13) => "(Carriage return)"			
			);
    
    my (@arr) = keys %invisibles;

    foreach my $elem (@arr) {
        if ("$byte" eq "$elem") {
	    return ($invisibles{$elem}, "");
	}
    }
    return ("", "$bytecopy");
}