xref: /plan9/sys/src/cmd/unix/drawterm/libc/utfrune.c (revision 8ccd4a6360d974db7bd7bbd4f37e7018419ea908)
1 #include <u.h>
2 #include <libc.h>
3 
4 char*
utfrune(char * s,long c)5 utfrune(char *s, long c)
6 {
7 	long c1;
8 	Rune r;
9 	int n;
10 
11 	if(c < Runesync)		/* not part of utf sequence */
12 		return strchr(s, c);
13 
14 	for(;;) {
15 		c1 = *(uchar*)s;
16 		if(c1 < Runeself) {	/* one byte rune */
17 			if(c1 == 0)
18 				return 0;
19 			if(c1 == c)
20 				return s;
21 			s++;
22 			continue;
23 		}
24 		n = chartorune(&r, s);
25 		if(r == c)
26 			return s;
27 		s += n;
28 	}
29 	return 0;
30 }
31