Re: set-fontset-font is slow if the fontset is specified by a long name

[Kenichi Handa]

In article <address@hidden>, YAMAMOTO Mitsuharu <address@hidden> writes:

> When a fontset name is specified in a long format, set-fontset-font
> takes much time to complete.  For example, the evaluation of the
> following expression terminates instantly.

>   (dotimes (i 100)
>     (set-fontset-font "fontset-default"
>                     'latin-iso8859-1
>                     '("helvetica" . "iso8859-1")))

> But if we replace "fontset-default" with
> "-*-*-*-*-*-*-*-*-*-*-*-*-fontset-default", then it becomes much
> slower.

>   (dotimes (i 100)
>     (set-fontset-font "-*-*-*-*-*-*-*-*-*-*-*-*-fontset-default"
>                     'latin-iso8859-1
>                     '("helvetica" . "iso8859-1")))

set-fontset-font converts NAME into a regular expression
while converting every '*' into '.*'.  So, the above
slowness is because of this regular-expression processing is
slow.

(string-match "-.*-.*-.*-.*-.*-.*-.*-.*-.*-.*-.*-.*-fontset-default"
              "-*-*-*-*-*-*-*-*-*-*-*-*-fontset-default"))

I fixed the code so that convert '*' to "[^-]*" if full XLFD
is given.  This speedups the second example, but still the
first one is faster because it's registered in
fontset-alias-alist.

If you want to make this faster in 21.3, please try


---
Ken'ichi HANDA
address@hidden