NetBSD/gnu/dist/toolchain/libiberty/strstr.c

52 lines
959 B
C

/* Simple implementation of strstr for systems without it.
This function is in the public domain. */
/*
NAME
strstr -- locate first occurance of a substring
SYNOPSIS
#include <string.h>
char *strstr (char *s1, char *s2)
DESCRIPTION
Locates the first occurance in the string pointed to by S1 of
the string pointed to by S2. Returns a pointer to the substring
found, or a NULL pointer if not found. If S2 points to a string
with zero length, the function returns S1.
BUGS
*/
/* FIXME: The above description is ANSI compiliant. This routine has not
been validated to comply with it. -fnf */
char *
strstr (s1, s2)
char *s1, *s2;
{
register char *p = s1;
extern char *strchr ();
extern int strncmp ();
#if __GNUC__==2
extern __SIZE_TYPE__ strlen ();
#endif
register int len = strlen (s2);
for (; (p = strchr (p, *s2)) != 0; p++)
{
if (strncmp (p, s2, len) == 0)
{
return (p);
}
}
return (0);
}