1 /* strstr.c -- return the offset of one string within another
2 Copyright (C) 1989, 1990 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
7 any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
17
18 /* Written by Mike Rendell <michael@cs.mun.ca>. */
19
20 /* Return the starting address of string S2 in S1;
21 return 0 if it is not found. */
22
23 char *
strstr(s1,s2)24 strstr (s1, s2)
25 char *s1;
26 char *s2;
27 {
28 int i;
29 char *p1;
30 char *p2;
31 char *s = s1;
32
33 for (p2 = s2, i = 0; *s; p2 = s2, i++, s++)
34 {
35 for (p1 = s; *p1 && *p2 && *p1 == *p2; p1++, p2++)
36 ;
37 if (!*p2)
38 break;
39 }
40 if (!*p2)
41 return s1 + i;
42
43 return 0;
44 }
45