firmware/libc/strstr.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id: $
 *
 * Copyright (C) 1991, 1992  Linus Torvalds
 * (from linux/lib/string.c)
 *
 ****************************************************************************/

#include <string.h>

/**
 * strstr - Find the first substring in a %NUL terminated string
 * @s1: The string to be searched
 * @s2: The string to search for
 */
char *strstr(const char *s1, const char *s2)
{
    int l1, l2;

    l2 = strlen(s2);
    if (!l2)
        return (char *)s1;
    l1 = strlen(s1);
    while (l1 >= l2) {
        l1--;
        if (!memcmp(s1, s2, l2))
            return (char *)s1;
        s1++;
    }
    return NULL;
}