ref: 4a1fc5ccb596a0f88f465b81a638f0068e82f0b9
dir: /libkern/utflen.c/
#include "lib9.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++; } }