On 09-May-2016 02:38, Jon D wrote:
I did a performance study on speeding up case conversion in
std.uni.asLowerCase. Specifics for asLowerCase have been added to issue
https://issues.dlang.org/show_bug.cgi?id=11229. Publishing here as some
of the more general observations may be of wider interest.
Background - Case conversion can generally be sped up by checking if a
character is ascii before invoking a full unicode case conversion. The
single character std.uni.toLower does this optimization, but
std.uni.asLowerCase does not. asLowerCase does a lazy conversion of a
range. For the test, I created a replacement for asLowerCase which uses
map and toLower. In essence, `map!(x => x.toLower)` or `map!(x =>
x.byDchar.toLower)`.
The only problem is that it should consider multi-codepoint replacements
aka full-case folding in Unicode.
Otherwise - go ahead and issue a pull request to add
special case for < 0x80.
--
Dmitry Olshansky
