/* Simple implementation of strstr for systems without it. This function is in the public domain. */ /* @deftypefn Supplemental char* strstr (const char *@var{string}, const char *@var{sub}) This function searches for the substring @var{sub} in the string @var{string}, not including the terminating null characters. A pointer to the first occurrence of @var{sub} is returned, or @code{NULL} if the substring is absent. If @var{sub} points to a string with zero length, the function returns @var{string}. @end deftypefn */ /* FIXME: The above description is ANSI compiliant. This routine has not been validated to comply with it. -fnf */ #include <stddef.h> extern char *strchr (const char *, int); extern int strncmp (const void *, const void *, size_t); extern size_t strlen (const char *); char * strstr (const char *s1, const char *s2) { const char *p = s1; const size_t len = strlen (s2); for (; (p = strchr (p, *s2)) != 0; p++) { if (strncmp (p, s2, len) == 0) return (char *)p; } return (0); }