use strict;
use utf8;     # used only for this SSCCE to set scalar $SGML at line 44
use Devel::Peek qw (Dump);
use Encode qw(encode_utf8);

binmode(STDOUT, ":utf8");

my %_table = ();
# -----------------------------------
sub load_map
{
   while( <DATA> ) {
     chomp;
     my $offset = index($_,' ');
     my $bin    = substr($_,$offset+1);
     my $esc    = substr($_,0,$offset);
     $_table{$bin} = $esc;
   }
}

# -----------------------------------
sub _mapchar
{
   my ($char) = @_;
   if ( $char !~ /[\r\n\s]/) {
        my $nbytes = length encode_utf8($char);
        if ($nbytes > 1) {
        $char = exists $_table{$char} ? $_table{$char} : '?';
        }
   }
   return $char;
}
# -----------------------------------
sub escapeUTF8
{
   my ( $sgml_r) = @_;

   Dump $$sgml_r;
   $$sgml_r =~ s/(.)/_mapchar($1)/eg;
}

load_map();

my $SGML='RÖCHLING';
print "1: $SGML\n";
escapeUTF8(\$SGML);
print "2: $SGML\n";

__DATA__
&dollar; $
&Ouml; Ö
&raquo; »
~