Path: utzoo!utgpu!cs.utexas.edu!qt.cs.utexas.edu!yale.edu!think.com!mintaka!spdcc!dirtydog.ima.isc.com!karl
From: karl@ima.isc.com (Karl Heuer)
Newsgroups: alt.hackers
Subject: Re: Useful string function
Message-ID: <1991Jun27.151946.25284@ima.isc.com>
Date: 27 Jun 91 15:19:46 GMT
References: <27187@ttidca.TTI.COM> <27212@ttidca.TTI.COM>
Sender: usenet@ima.isc.com (news)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 38
Approved: karl@ima.isc.com

In <27212@ttidca.TTI.COM> hollombe@ttidca.TTI.COM (The Polymath) writes:
>In <27187@ttidca.TTI.COM> hollombe@ttidca.TTI.COM (The Polymath) writes:
>}... a function that finds a substring within a string and returns its
>}starting location or -1 if the substring isn't there.  ...
>
>My thanks to all who wrote to tell me about the strstr(3), or equivalent,
>function in their libraries.  [We don't have it here.]
>To all others in my position I say again, enjoy.

To you and all others in your position, I would recommend that you *not* use
Strloc(), because it's better to create your own implementation of strstr()
that agrees with the ANSI specs.  Then when strstr() does become ubiquitous,
you won't have future generations scratching their heads wondering why your
programs use an incompatible variant.

>(And to those who think they can improve on my code -- go for it.  I make
>no claim perfection).

I rather like this implementation, myself; it's small and contains no function
calls.  Speed improvements are possible, but I wouldn't bother with minor
tweaks--if the speed is necessary, just go straight to Boyer-Moore.

Karl W. Z. Heuer (karl@ima.isc.com or uunet!ima!karl), The Walking Lint
________
#if defined(NEED_STRSTR) /* deassert if you already have an ANSI library */
/* Public Domain strstr() implementation by Karl Heuer */
#include <stddef.h> /* for NULL */
char *strstr(register char const *s, register char const *t) {
    do {
	register char const *ss = s;
	register char const *tt = t;
	do {
	    if (*tt == '\0') return ((char *)s);
	} while (*ss++ == *tt++);
    } while (*s++ != '\0');
    return (NULL);
}
#endif