xref: /plan9/sys/src/ape/lib/utf/runestrstr.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 /*
20*40ef9009SDavid du Colombier  * Return pointer to first occurrence of s2 in s1,
21*40ef9009SDavid du Colombier  * 0 if none
22*40ef9009SDavid du Colombier  */
23*40ef9009SDavid du Colombier Rune*
runestrstr(Rune * s1,Rune * s2)24*40ef9009SDavid du Colombier runestrstr(Rune *s1, Rune *s2)
25*40ef9009SDavid du Colombier {
26*40ef9009SDavid du Colombier 	Rune *p, *pa, *pb;
27*40ef9009SDavid du Colombier 	int c0, c;
28*40ef9009SDavid du Colombier 
29*40ef9009SDavid du Colombier 	c0 = *s2;
30*40ef9009SDavid du Colombier 	if(c0 == 0)
31*40ef9009SDavid du Colombier 		return s1;
32*40ef9009SDavid du Colombier 	s2++;
33*40ef9009SDavid du Colombier 	for(p=runestrchr(s1, c0); p; p=runestrchr(p+1, c0)) {
34*40ef9009SDavid du Colombier 		pa = p;
35*40ef9009SDavid du Colombier 		for(pb=s2;; pb++) {
36*40ef9009SDavid du Colombier 			c = *pb;
37*40ef9009SDavid du Colombier 			if(c == 0)
38*40ef9009SDavid du Colombier 				return p;
39*40ef9009SDavid du Colombier 			if(c != *++pa)
40*40ef9009SDavid du Colombier 				break;
41*40ef9009SDavid du Colombier 		}
42*40ef9009SDavid du Colombier 	}
43*40ef9009SDavid du Colombier 	return 0;
44*40ef9009SDavid du Colombier }
45