From: torek@horse.ee.lbl.gov (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: HIgher problems at hand. HELP!
Date: 26 Jul 92 02:05:43 GMT
Reply-To: torek@horse.ee.lbl.gov (Chris Torek)
Organization: Lawrence Berkeley Laboratory, Berkeley
NNTP-Posting-Host: 128.3.112.15

In article <1992Jul25.142216.5636@druid.uucp> darcy@druid.uucp
(D'Arcy J.M. Cain) writes:
>... if the Amiga really doesn't have a strstr here it is:
>
>/*
> * strstr - find first occurrence of wanted in s
> *
> * based on code by Henry Spencer
> * modified for ANSI by D'Arcy J.M. Cain
> */

The given strstr() fails to meet the second sentence under `Returns'
in the ANSI C standard description of strstr() (line 25, p. 168):

    If |s2| points to a string with zero length, the function
    returns |s1|.

Thus,

	strstr("foo", "")

must return a pointer to the `f' in "foo".

Other than that, and its peculiar redefinition of `const', it is OK.
Nonetheless, here is my strstr() from the BSD net.2 C library.  Note
that <sys/cdefs.h> is a hack for Classic C compilers, and is not needed
(nor useful) for a Pure ANSI compiler.

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strstr.c	5.2 (Berkeley) 1/26/91";
#endif /* LIBC_SCCS and not lint */

#include <sys/cdefs.h>
#include <string.h>

/*
 * Find the first occurrence of find in s.
 */
char *
strstr(s, find)
	register const char *s, *find;
{
	register char c, sc;
	register size_t len;

	if ((c = *find++) != 0) {
		len = strlen(find);
		do {
			do {
				if ((sc = *s++) == 0)
					return (NULL);
			} while (sc != c);
		} while (strncmp(s, find, len) != 0);
		s--;
	}
	return ((char *)s);
}
-- 
In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 510 486 5427)
Berkeley, CA		Domain:	torek@ee.lbl.gov