strstr.c

来自「newos is new operation system」· C语言 代码 · 共 25 行

/* 
** Copyright 2001, Travis Geiselbrecht. All rights reserved.
** Distributed under the terms of the NewOS License.
*/
#include <string.h>
#include <sys/types.h>

char *
strstr(char const *s1, char const *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;
}