Processing speed in large C++ raw strings.

[Alan Mackenzie]

Hello, Dmitry.

Some while ago, you were complaining, justifiably, about the
sluggishness when typing characters into very long C++ raw strings.  To
demonstrate this, you put xdisp.c into C++ mode, and put a raw string
round nearly the entire buffer.

Last week, it was taking over 2 seconds to process a single
self-insert-command into this string, and my machine is not slow.

I have now optimized CC Mode, such that each such self-insert-command
now takes around 0.07s-0.1s.  I used two strategies for this: (i) breaking out
of (expensive) fontification routines early, when the region being
fontified is nothing but a string; (ii) Not fontifying the entire raw
string for a change to only a small part of it.

-- 
Alan Mackenzie (Nuremberg, Germany).