[PATCH] Enable input using variable-width encodings

[Pétur Runólfsson]

Nathan Myers wrote:
> Streamsize is conceptually unsigned, but must be signed for conformance.

There are a number of places where streamsize is used to hold the
value -1.

> We should used unsigned values where we can, and accept that casts
> are needed sometimes.  We should _not_ use streamsize to describe buffer
> sizes, but should use it only where the interface requires it, or where
> the use is clearly derived from that interface.
>
> This will matter more, and be more noticeable, when streamsize is
> uniformly 64 bits on all targets, and (possibly) a class object.
> (Soon, I hope.)

Did you mean streamoff here? streamsize is required to be a built-in
type and should be the same size as size_t. I don't see how changing
the type for streamoff affects uses of streamsize.

Regards,
Petur