[Sbcl-help] help with octets-to-string and string-to-octets

[Russell M. <rus...@ya...>]

I'm attempting to write a subclass of sb-gray:fundamental-stream with
the following properties:

1. at make-instance time you must supply :external-format.

2. one can read and write strings to/from it.

3. it transparently converts these strings into bytes for you with
calls to the above functions, and directly calls unix-read and
unix-write at the proper times.

4. it buffers input and output intelligently.

5. it supports read-n-bytes with the nifto-matic ability to not block
if the requested number of bytes is not available.

Given all of that, here is my question.

Assume I've read some data from the network as bytes, and stored it
into a (vector (unsigned-byte 8) *).  To implement read-char, I need
to call sb-ext:octets-to-string.  But here I need to know how many
bytes will make up a character, which I don't know how to figure out
in general.

From reading octets.lisp, I think that I can assume that 1 byte = 1
char at this time, but I know that this isn't right in general.  I'm
not very well read in the character encoding department, so any ideas
you might have here would help.

-russ