>perl -wMstrict -le
"use constant S => 'iiMMMMMMMMMMoooooooooooooooooooooooMMMMMMMMMMiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiMMMMM
MMMMMMMMooooooooooooooooooooo';
 print q{'}, S, q{'};
 ;;
 (my $rle = S) =~ s{ ((.) \2{0,254}) }{ chr(length $1) . $2 }xmsge;
 print qq{'$rle'};
 ;;
 (my $s = $rle) =~ s{ (.) (.) }{ $2 x ord $1 }xmsge;
 print qq{'$s'};
 ;;
 die 'encode/decocde failed' if $s ne S;
 print 'encode/decode ok!';
"
'iiMMMMMMMMMMoooooooooooooooooooooooMMMMMMMMMMiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiMMMMMMMMMMMMMooooooooooo
oooooooooo'
'?i
M?o
M§o'
'iiMMMMMMMMMMoooooooooooooooooooooooMMMMMMMMMMiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiMMMMMMMMMMMMMooooooooooo
oooooooooo'
encode/decode ok!