1 /*
2  * The authors of this software are Rob Pike and Ken Thompson.
3  *              Copyright (c) 2002 by Lucent Technologies.
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose without fee is hereby granted, provided that this entire notice
6  * is included in all copies of any software which is or includes a copy
7  * or modification of this software and in all copies of the supporting
8  * documentation for such software.
9  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE
11  * ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13  */
14 #include <stdarg.h>
15 #include <string.h>
16 #include "plan9.h"
17 #include "utf.h"
18 
19 int
20 utfnlen(char *s, long m)
21 {
22 	int c;
23 	long n;
24 	Rune rune;
25 	char *es;
26 
27 	es = s + m;
28 	for(n = 0; s < es; n++) {
29 		c = *(uchar*)s;
30 		if(c < Runeself){
31 			if(c == '\0')
32 				break;
33 			s++;
34 			continue;
35 		}
36 		if(!fullrune(s, es-s))
37 			break;
38 		s += chartorune(&rune, s);
39 	}
40 	return n;
41 }