strstr.c

MIPS下的boottloader yamon 的源代码

/************************************************************************
 *
 *  strstr.c
 *
 *  search first occurrence of string in string.
 *
 *
 * ######################################################################
 *
 * Copyright (c) 1999-2000 MIPS Technologies, Inc. All rights reserved. 
 * 
 * Unpublished rights reserved under the Copyright Laws of the United States of 
 * America. 
 * 
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 * Inc. ("MIPS Technologies"). Any copying, modifying or use of this information 
 * (in whole or in part) which is not expressly permitted in writing by MIPS 
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 * prohibited. At a minimum, this information is protected under unfair 
 * competition laws and the expression of the information contained herein is 
 * protected under federal copyright laws. Violations thereof may result in 
 * criminal penalties and fines. 
 * MIPS Technologies or any contractually-authorized third party reserves the 
 * right to change the information contained in this document to improve 
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 ************************************************************************/

#include <string.h>

char *strstr(
	const char 	*s1, 
	const char 	*s2)
{
    const char *s ;
    const char *t ;

    if (!s1 || !s2)
	return (0);

    if (!*s2)
	return ((char*)s1);

    for (; *s1; s1++) 
    {
	if (*s1 == *s2) 
        {
	    t = s1;
	    s = s2;
	    for (; *t; s++, t++) 
            {
		if (*t != *s)
		    break;
	    }
	    if (!*s)
		return ((char*)s1);
	}
    }
    return (0);
}