There is no need to use s/^\s*//. This will waste time on strings with no leading space. Use s/^\s+// at all times -- it obviously won't do anything if there's no whitespace to match.

A general rule of thumb is that s/X*// is slower than s/X+//, and in cases where the RHS (right-hand side) is something OTHER than "", chances are you really do mean X+.