strpos

strpos.c

/* {{{ proto int strpos(string haystack, string needle [, int offset])
   Finds position of first occurrence of a string within another */
PHP_FUNCTION(strpos)
{
	zval *needle;
	char *haystack;
	char *found = NULL;
	char  needle_char[2];
	long  offset = 0;
	int   haystack_len;

	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sz|l", &haystack, &haystack_len, &needle, &offset) == FAILURE) {
		return;
	}

	if (offset < 0 || offset > haystack_len) {
		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Offset not contained in string");
		RETURN_FALSE;
	}

	if (Z_TYPE_P(needle) == IS_STRING) {
		if (!Z_STRLEN_P(needle)) {
			php_error_docref(NULL TSRMLS_CC, E_WARNING, "Empty needle");
			RETURN_FALSE;
		}

		found = php_memnstr(haystack + offset,
			                Z_STRVAL_P(needle),
			                Z_STRLEN_P(needle),
			                haystack + haystack_len);
	} else {
		if (php_needle_char(needle, needle_char TSRMLS_CC) != SUCCESS) {
			RETURN_FALSE;
		}
		needle_char[1] = 0;

		found = php_memnstr(haystack + offset,
							needle_char,
							1,
		                    haystack + haystack_len);
	}

	if (found) {
		RETURN_LONG(found - haystack);
	} else {
		RETURN_FALSE;
	}
}
/* }}} */