xref: /aosp_15_r20/external/libutf/utfnlen.c (revision e72f39528b91793251d8cc21b78f3f8706ae7c47)
1*e72f3952SAlexander Dorokhine /*
2*e72f3952SAlexander Dorokhine  * The authors of this software are Rob Pike and Ken Thompson.
3*e72f3952SAlexander Dorokhine  *              Copyright (c) 2002 by Lucent Technologies.
4*e72f3952SAlexander Dorokhine  * Permission to use, copy, modify, and distribute this software for any
5*e72f3952SAlexander Dorokhine  * purpose without fee is hereby granted, provided that this entire notice
6*e72f3952SAlexander Dorokhine  * is included in all copies of any software which is or includes a copy
7*e72f3952SAlexander Dorokhine  * or modification of this software and in all copies of the supporting
8*e72f3952SAlexander Dorokhine  * documentation for such software.
9*e72f3952SAlexander Dorokhine  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10*e72f3952SAlexander Dorokhine  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
11*e72f3952SAlexander Dorokhine  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12*e72f3952SAlexander Dorokhine  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13*e72f3952SAlexander Dorokhine  */
14*e72f3952SAlexander Dorokhine #include <stdarg.h>
15*e72f3952SAlexander Dorokhine #include <string.h>
16*e72f3952SAlexander Dorokhine #include "utf.h"
17*e72f3952SAlexander Dorokhine #include "utfdef.h"
18*e72f3952SAlexander Dorokhine 
19*e72f3952SAlexander Dorokhine int
utfnlen(const char * s,long m)20*e72f3952SAlexander Dorokhine utfnlen(const char *s, long m)
21*e72f3952SAlexander Dorokhine {
22*e72f3952SAlexander Dorokhine 	int c;
23*e72f3952SAlexander Dorokhine 	long n;
24*e72f3952SAlexander Dorokhine 	Rune rune;
25*e72f3952SAlexander Dorokhine 	const char *es;
26*e72f3952SAlexander Dorokhine 
27*e72f3952SAlexander Dorokhine 	es = s + m;
28*e72f3952SAlexander Dorokhine 	for(n = 0; s < es; n++) {
29*e72f3952SAlexander Dorokhine 		c = *(uchar*)s;
30*e72f3952SAlexander Dorokhine 		if(c < Runeself){
31*e72f3952SAlexander Dorokhine 			if(c == '\0')
32*e72f3952SAlexander Dorokhine 				break;
33*e72f3952SAlexander Dorokhine 			s++;
34*e72f3952SAlexander Dorokhine 			continue;
35*e72f3952SAlexander Dorokhine 		}
36*e72f3952SAlexander Dorokhine 		if(!fullrune(s, es-s))
37*e72f3952SAlexander Dorokhine 			break;
38*e72f3952SAlexander Dorokhine 		s += chartorune(&rune, s);
39*e72f3952SAlexander Dorokhine 	}
40*e72f3952SAlexander Dorokhine 	return n;
41*e72f3952SAlexander Dorokhine }
42