$begin = time();
for( 0 .. 20 ) {
    my @a = reverse map chop( $buffer), 0 .. length( $buffer ) -1;
}
printf( "reverse map chop consumed %.3f seconds\n", time() - $begin );

__END__
C:\test>junk47
split consumed 2.368 second(s)
pack consumed 0.347 seconds
pack and chr in map consumed 4.041 seconds
unpack '{a1)* consumed 2.507 seconds
substr for consumed 1.652 seconds
reverse map chop consumed 0.477 seconds