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Groups > comp.lang.c++ > #82757
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: Can anyone improve this ? |
| Date | 2022-01-12 14:14 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <87ee5d6ny8.fsf@bsb.me.uk> (permalink) |
| References | <srjdtm$d9c$1@dont-email.me> <srkqk6$mtr$1@dont-email.me> <srmkil$pjh$2@dont-email.me> |
Bonita Montero <Bonita.Montero@gmail.com> writes:
> sizes instead of size; corrected:
>
> size_t utf8Strlen( char const *str )
> {
> static size_t const sizes[8] = { 1, 0, 2, 3, 4, 0, 0, 0 };
> size_t len = 0;
> for( unsigned char c; (c = *str); )
> {
> size_t size = sizes[countl_zero<unsigned char>( ~c )];
> if( !size ) [[unlikely]]
> return -1;
> ++len;
> for( char const *cpEnd = str + size; ++str != cpEnd; )
> if( ((unsigned char)*str & 0x0C0) != 0x080 ) [[unlikely]]
> return -1;
> }
> return len;
> }
You reject simpler solutions because they don't detect the one error you
have decided to look for. There are other encoding errors that this
code won't catch. Seems a bit arbitrary to me. I'd want a fast
utf8-strlen for external strings that have been validated and for
strings internally generated by valid code, or a slower one that caught
all invalid encodings.
--
Ben.
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Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-11 09:08 +0100
Re: Can anyone improve this ? Juha Nieminen <nospam@thanks.invalid> - 2022-01-11 09:50 +0000
Re: Can anyone improve this ? Juha Nieminen <nospam@thanks.invalid> - 2022-01-11 11:07 +0000
Re: Can anyone improve this ? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-01-11 11:08 +0000
Re: Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-11 18:28 +0100
Re: Can anyone improve this ? Christian Gollwitzer <auriocus@gmx.de> - 2022-01-11 18:41 +0100
Re: Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-11 19:36 +0100
Re: Can anyone improve this ? Öö Tiib <ootiib@hot.ee> - 2022-01-11 21:54 -0800
Re: Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-11 21:51 +0100
Re: Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-12 14:19 +0100
Re: Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-12 14:20 +0100
Re: Can anyone improve this ? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-01-12 14:14 +0000
Re: Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-12 17:20 +0100
Re: Can anyone improve this ? "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2022-01-12 08:38 -0800
Re: Can anyone improve this ? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-01-12 16:55 +0000
Re: Can anyone improve this ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-16 12:09 -0800
Re: Can anyone improve this ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-16 12:12 -0800
Re: Can anyone improve this ? Öö Tiib <ootiib@hot.ee> - 2022-01-16 13:00 -0800
Re: Can anyone improve this ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-17 10:13 -0800
Re: Can anyone improve this ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-17 10:28 -0800
Re: Can anyone improve this ? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-01-17 21:51 +0100
Re: Can anyone improve this ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-17 16:16 -0800
Re: Can anyone improve this ? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-01-17 22:43 -0800
Re: Can anyone improve this ? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-01-18 12:09 +0100
Re: Can anyone improve this ? Bonita Montero <Bonita.Montero@gmail.com> - 2022-01-18 09:18 +0100
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