ref: da4e4af4c4d766178e1212baec18c88ce4523ccb
dir: /libc/utfnlen.c/
#include <u.h> #include <libc.h> int utfnlen(char *s, long m) { int c; long n; Rune rune; char *es; es = s + m; for(n = 0; s < es; n++) { c = *(uchar*)s; if(c < Runeself){ if(c == '\0') break; s++; continue; } if(!fullrune(s, es-s)) break; s += chartorune(&rune, s); } return n; }