windows-nt/Source/XPSP1/NT/base/crts/crtw32/string/strstr.c
2020-09-26 16:20:57 +08:00

71 lines
1.4 KiB
C

/***
*strstr.c - search for one string inside another
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines strstr() - search for one string inside another
*
*Revision History:
* 02-27-90 GJF Fixed calling type, #include <cruntime.h>, fixed
* copyright.
* 08-14-90 SBM Removed now redundant #include <stddef.h>
* 10-02-90 GJF New-style function declarator.
* 09-03-93 GJF Replaced _CALLTYPE1 with __cdecl.
* 03-14-94 GJF If string2 is empty, return string1.
* 12-30-94 CFW Avoid 'const' warning.
*
*******************************************************************************/
#include <cruntime.h>
#include <string.h>
/***
*char *strstr(string1, string2) - search for string2 in string1
*
*Purpose:
* finds the first occurrence of string2 in string1
*
*Entry:
* char *string1 - string to search in
* char *string2 - string to search for
*
*Exit:
* returns a pointer to the first occurrence of string2 in
* string1, or NULL if string2 does not occur in string1
*
*Uses:
*
*Exceptions:
*
*******************************************************************************/
char * __cdecl strstr (
const char * str1,
const char * str2
)
{
char *cp = (char *) str1;
char *s1, *s2;
if ( !*str2 )
return((char *)str1);
while (*cp)
{
s1 = cp;
s2 = (char *) str2;
while ( *s1 && *s2 && !(*s1-*s2) )
s1++, s2++;
if (!*s2)
return(cp);
cp++;
}
return(NULL);
}