# Which are the expected Unicode codepoints?
my @expected_codepoints = (9, 10, 13, # newlines+tab
                           32..127,
                           (map { ord } split //, "äöüÄÖÜß"),
                           0x20ac, # euro sign
                          );

# Which are the expected encodings? May be empty, in this case
# all to perl available encodings will be checked.
my @expected_encodings = qw(cp1252 iso-8859-1 utf-8);

# Text to analyze, specify in raw octets:
my $octets_to_analyze = "Bla äöü \x80";

######################################################################
# No user-servicable parts below this point.

use strict;
use Encode;

if (!@expected_encodings) {
    @expected_encodings = Encode->encodings(":all");
}
my %expected_codepoints = map {($_,1)} @expected_codepoints;
my @encoding_result;

for my $encoding (@expected_encodings) {
    my $characters = eval {
        decode($encoding, $octets_to_analyze, Encode::FB_CROAK|Encode::LEAVE_SRC);
    };
    if (!$@) {
        my %got_codepoints;
        for my $codepoint (map { ord } split //, $characters) {
            $got_codepoints{$codepoint}++;
        }
        my $fitting_codepoints = 0;
        while(my($k,$v) = each %got_codepoints) {
            if (exists $expected_codepoints{$k}) {
                $fitting_codepoints++;
            }
        }
        push @encoding_result, [$encoding, $fitting_codepoints*100/keys %got_codepoints];
    }
}

@encoding_result = sort { $b->[1] <=> $a->[1] } @encoding_result;
for my $result (@encoding_result) {
    printf "%-30s: %4.1f%%\n", $result->[0], $result->[1];
}