On Mon, 14 Mar 2005 xxxxxx@philips.com wrote:

> Then I would like to support and Taylor's proposal of having a COPY!
> operation, for example with the following specification:
>
> (BYTE-VECTOR-COPY! lhs i-lhs rhs i-rhs n)
>
>         copies n bytes from the byte-vector rhs (starting at index i-rhs)
> into
>         the byte-vector lhs (starting at index i-lhs). The exact integers
> n, i-rhs,
>         and i-lhs satisfy
>
>                 0 <= i-rhs <= i-rhs + n <= (byte-vector-length rhs),
>                 0 <= i-lhs <= i-lhs + n <= (byte-vector-length lhs).
>
>         The procedure makes sure the elements are properly copied, even if
>         lhs and rhs refer to the same byte-vector object.
>
> (Warning to implementors in C: Use memmove, not memcpy!)
>
> In addition, I am frequently missing VECTOR-COPY, and this will likely
> also be the case for byte vectors. So I propose to include also:
>
> (BYTE-VECTOR-COPY byte-vector)

I'd like to suggest generalizing this to something like:

  (BYTE-VECTOR-SUBSEQUENCE byte-vector [start-offset [end-offset]])

or maybe just adding:

  (BYTE-VECTOR-SUBSEQUENCE byte-vector start-offset [end-offset])

which granted is implemented in two lines with a CREATE and a COPY!, but
neverthess I find it a quite common operation worthy of a common name.

> Concerning the /fill/ argument in MAKE-BYTE-VECTOR: It is optional in
> R5RS, but I would be in favour of having it mandatory here.

I would like to additionally suggest:

  (BYTE-VECTOR-FILL! byte-vector start-offset end-offset(or length?) value)

for the many times I find myself needing to fill just a portion of a byte
vector.

--
-- Donovan Kolbly                    (  xxxxxx@rscheme.org
				     (  http://www.rscheme.org/~donovan/