a

libc/utfnlen.c

@@ -0,0 +1,26 @@
+#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;
+}