Re: One example of code I can't understand

["Stephen J. Turnbull" <stephen@xemacs.org>]

Kenichi Handa writes:

 > It is theoretically possible to modify all of them to use a
 > multibyte buffer that contains only ASCII and eight-bit
 > chars.  But, as it may make the operations slow, I don't see
 > a merit in doing that.

XEmacs has always done it this way; it is more than a theoretical
possibility.  In XEmacs it doesn't make much difference for the
operations you describe (less than a factor of 2) because the overhead
of interfacing to the pipes is greater than the overhead of
conversion.  This is based on some profiling Ben did many years ago;
ISTR it was basically linear up to 128MB or maybe 256MB.  I don't
recall the exact numbers, but I do remember being very surprised that
it was substantially less than 2.

In XEmacs, I think it makes a much bigger difference for mail buffers
(VM, or Gnus nnfolder) because of the frequency of byte<->char
conversions in those more or less random access applications.