runestrstr.c (1222B)
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(const Rune *s1, const Rune *s2) 25 { 26 const Rune *pa, *pb; 27 Rune *p; 28 int c0, c; 29 30 c0 = *s2; 31 if(c0 == 0) 32 return (Rune*)s1; 33 s2++; 34 for(p=runestrchr(s1, c0); p; p=runestrchr(p+1, c0)) { 35 pa = p; 36 for(pb=s2;; pb++) { 37 c = *pb; 38 if(c == 0) 39 return p; 40 if(c != *++pa) 41 break; 42 } 43 } 44 return 0; 45 }