#include "platform.h"#include "utf.h" intutfnlen(const char *s, long m){	int c;	long n;	Rune rune;	const char *es; 	es = s + m;	for(n = 0; s < es; n++) {		c = *(const u8int*)s;		if(c < Runeself){			if(c == '\0')				break;			s++;			continue;		}		if(!fullrune(s, es-s))			break;		s += chartorune(&rune, s);	}	return n;}