xref: /plan9/sys/src/ape/lib/utf/utfnlen.c (revision 40ef9009116dd37656783aaadc8782c1d8bfb056)
1*40ef9009SDavid du Colombier /*
2*40ef9009SDavid du Colombier  * The authors of this software are Rob Pike and Ken Thompson.
3*40ef9009SDavid du Colombier  *              Copyright (c) 2002 by Lucent Technologies.
4*40ef9009SDavid du Colombier  * Permission to use, copy, modify, and distribute this software for any
5*40ef9009SDavid du Colombier  * purpose without fee is hereby granted, provided that this entire notice
6*40ef9009SDavid du Colombier  * is included in all copies of any software which is or includes a copy
7*40ef9009SDavid du Colombier  * or modification of this software and in all copies of the supporting
8*40ef9009SDavid du Colombier  * documentation for such software.
9*40ef9009SDavid du Colombier  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10*40ef9009SDavid du Colombier  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
11*40ef9009SDavid du Colombier  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12*40ef9009SDavid du Colombier  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13*40ef9009SDavid du Colombier  */
14*40ef9009SDavid du Colombier #include <stdarg.h>
15*40ef9009SDavid du Colombier #include <string.h>
16*40ef9009SDavid du Colombier #include "utf.h"
17*40ef9009SDavid du Colombier #include "utfdef.h"
18*40ef9009SDavid du Colombier 
19*40ef9009SDavid du Colombier int
utfnlen(char * s,long m)20*40ef9009SDavid du Colombier utfnlen(char *s, long m)
21*40ef9009SDavid du Colombier {
22*40ef9009SDavid du Colombier 	int c;
23*40ef9009SDavid du Colombier 	long n;
24*40ef9009SDavid du Colombier 	Rune rune;
25*40ef9009SDavid du Colombier 	char *es;
26*40ef9009SDavid du Colombier 
27*40ef9009SDavid du Colombier 	es = s + m;
28*40ef9009SDavid du Colombier 	for(n = 0; s < es; n++) {
29*40ef9009SDavid du Colombier 		c = *(uchar*)s;
30*40ef9009SDavid du Colombier 		if(c < Runeself){
31*40ef9009SDavid du Colombier 			if(c == '\0')
32*40ef9009SDavid du Colombier 				break;
33*40ef9009SDavid du Colombier 			s++;
34*40ef9009SDavid du Colombier 			continue;
35*40ef9009SDavid du Colombier 		}
36*40ef9009SDavid du Colombier 		if(!fullrune(s, es-s))
37*40ef9009SDavid du Colombier 			break;
38*40ef9009SDavid du Colombier 		s += chartorune(&rune, s);
39*40ef9009SDavid du Colombier 	}
40*40ef9009SDavid du Colombier 	return n;
41*40ef9009SDavid du Colombier }
42