vec($_[2], $_ + $step, 1) = vec($_[0], $_, 1) for $fs .. $fs + $l - 1;
} else { # There's a risk of overwriting if $_[0] and $_[2] are the same SV.
vec($_[2], $_ + $step, 1) = vec($_[0], $_, 1) for reverse $fs .. $fs + $l - 1;
vec($_[2], $_ + $step, 1) = vec($_[0], $_, 1) for $fs .. $fs + $l - 1;
} else { # There's a risk of overwriting if $_[0] and $_[2] are the same SV.
vec($_[2], $_ + $step, 1) = vec($_[0], $_, 1) for reverse $fs .. $fs + $l - 1;
-Copyright 2008,2009,2010,2011 Vincent Pit, all rights reserved.
+Copyright 2008,2009,2010,2011,2012 Vincent Pit, all rights reserved.