just stumbled over this description of the Buf type in perl 6. may be of interest to someone
http://perlcabal.org/syn/S02.html#Built-In_Data_Types
A Buf is a stringish view of an array of integers, and has no Unicode or character properties without explicit conversion to some kind of Str. (A buf is the native counterpart.) Typically it's an array of bytes serving as a buffer. Bitwise operations on a Buf treat the entire buffer as a single large integer. Bitwise operations on a Str generally fail unless the Str in question can provide an abstract Buf interface somehow. Coercion to Buf should generally invalidate the Str interface. As a generic type Buf may be instantiated as (or bound to) any of buf8, buf16, or buf32 (or to any type that provides the appropriate Buf interface), but when used to create a buffer Buf defaults to buf8.
Unlike Str types, Buf types prefer to deal with integer string positions, and map these directly to the underlying compact array as indices. That is, these are not necessarily byte positions--an integer position just counts over the number of underlying positions, where one position means one cell of the underlying integer type. Builtin string operations on Buf types return integers and expect integers when dealing with positions. As a limiting case, buf8 is just an old-school byte string, and the positions are byte positions. Note, though, that if you remap a section of buf32 memory to be buf8, you'll have to multiply all your positions by 4.
greetings, martin.