ref: d76adb110f09d0b3dfdd090f6bd385ebd66b4194
dir: /sys/src/libc/port/utflen.c/
#include <u.h>
#include <libc.h>
int
utflen(char *s)
{
int c;
long n;
Rune rune;
n = 0;
for(;;) {
c = *(uchar*)s;
if(c < Runeself) {
if(c == 0)
return n;
s++;
} else
s += chartorune(&rune, s);
n++;
}
}