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 /*
20  * Return pointer to first occurrence of s2 in s1,
21  * 0 if none
22  */
23 Rune*
24 runestrstr(Rune *s1, Rune *s2)
25 {
26 	Rune *p, *pa, *pb;
27 	int c0, c;
28 
29 	c0 = *s2;
30 	if(c0 == 0)
31 		return s1;
32 	s2++;
33 	for(p=runestrchr(s1, c0); p; p=runestrchr(p+1, c0)) {
34 		pa = p;
35 		for(pb=s2;; pb++) {
36 			c = *pb;
37 			if(c == 0)
38 				return p;
39 			if(c != *++pa)
40 				break;
41 		}
42 	}
43 	return 0;
44 }