xref: /netbsd-src/external/bsd/am-utils/dist/libamu/strstr.c (revision 8bae5d409deb915cf7c8f0539fae22ff2cb8a313)
1 /*	$NetBSD: strstr.c,v 1.1.1.3 2015/01/17 16:34:18 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1997-2014 Erez Zadok
5  * Copyright (c) 1990 Jan-Simon Pendry
6  * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
7  * Copyright (c) 1990 The Regents of the University of California.
8  * All rights reserved.
9  *
10  * This code is derived from the Free Software Foundation, Inc. GNU utilities.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *
37  * File: am-utils/libamu/strstr.c
38  *
39  */
40 
41 #ifdef HAVE_CONFIG_H
42 # include <config.h>
43 #endif /* HAVE_CONFIG_H */
44 #include <am_defs.h>
45 #include <amu.h>
46 
47 
48 /* strstr.c -- return the offset of one string within another
49    Copyright (C) 1989, 1990 Free Software Foundation, Inc.
50 
51    This program is free software; you can redistribute it and/or modify
52    it under the terms of the GNU General Public License as published by
53    the Free Software Foundation; either version 2, or (at your option)
54    any later version.
55 
56    This program is distributed in the hope that it will be useful,
57    but WITHOUT ANY WARRANTY; without even the implied warranty of
58    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
59    GNU General Public License for more details.
60 
61    You should have received a copy of the GNU General Public License
62    along with this program; if not, write to the Free Software
63    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
64 
65 /* Author:
66 	Mike Rendell			Department of Computer Science
67 	michael@garfield.mun.edu	Memorial University of Newfoundland
68 	..!uunet!garfield!michael	St. John's, Nfld., Canada
69 	(709) 737-4550			A1C 5S7
70 */
71 
72 
73 /*
74  * Return the starting address of string S2 in S1;
75  * return 0 if it is not found.
76  */
77 char *
strstr(char * s1,char * s2)78 strstr(char *s1, char *s2)
79 {
80   int i;
81   char *p1;
82   char *p2;
83   char *s = s1;
84 
85   for (p2 = s2, i = 0; *s; p2 = s2, i++, s++) {
86     for (p1 = s; *p1 && *p2 && *p1 == *p2; p1++, p2++)
87       ;
88     if (!*p2)
89       break;
90   }
91   if (!*p2)
92     return s1 + i;
93 
94   return 0;
95 }
96