Experimental Physics and
Industrial Control System

Marty Kraimer <[email protected]> · Wed, 26 Oct 2005 06:55:31 -0500

Benjamin Franksen wrote:

On Wednesday 26 October 2005 00:33, Jeff Hill wrote:

Attached is a rough cut at the EPICS V4 CA protocol specification.

Hi Jeff,

Just one little thought about STRING data type:

UINTN			the number of UTF-8 tokens
OCTET sequence	UTF-8 encoded character string sequence

I take it that 'number of UTF-8 tokens' means 'number of octets', right?

Maybe it would be worthwhile to consider adding a 'number

of /characters/' count in addition to the byte count. This could

improve performance, particularly when converting to other encodings on

the client side. Of course any gain must be offset against the

increased protocol overhead.

The same applies of course to any library string representations.

Ben

Java 5 uses 16 bits for char, which is not sufficient to encode all

uni-code character sets.

It uses 2 consecutive chars to hold a unicode character that does not

fit in 16 bits.

At least some C/C++ implementations use 32 bits for wchar which is

sufficient for all unicode characters.

But what if an implementation uses 16 bits?

Thus how will the number of characters in a UTF-8 string be used?

Better to just let final sender/receiver of the character string handle it.

Marty