MT#55283 change str_token_sep semantics a bit

If there are no more tokens, instead of returning a null string as
remainder, set the remainder to the end of the original string with a
zero length.

Update two places in the code where this makes a difference.

Change-Id: I137fbce3e7d88ccba65f6b23a36aa1dfbbd3867e

daemon/control_ng_flags_parser.c

@@ -255,7 +255,7 @@ void parse_rtpp_flags(const str * rtpp_flags, sdp_ng_flags *out)
 
 generic:
 		/* generic one key flags */
-		if (!val.s)
+		if (!val.len)
 			call_ng_flags_flags(&key, 0, out);
 		/* generic flags with value, but no particular processing */
 		else

lib/str.h

@@ -436,8 +436,11 @@ INLINE unsigned long long str_to_ui(const str *s, unsigned long long def) {
 
 INLINE bool str_token(str *new_token, str *ori_and_remainder, int sep) {
 	*new_token = *ori_and_remainder;
-	if (!str_chr_str(ori_and_remainder, ori_and_remainder, sep))
+	if (!str_chr_str(ori_and_remainder, ori_and_remainder, sep)) {
+		*ori_and_remainder = *new_token;
+		str_shift(ori_and_remainder, ori_and_remainder->len);
 		return false;
+	}
 	new_token->len = ori_and_remainder->s - new_token->s;
 	if (str_shift(ori_and_remainder, 1))
 		return false;
@@ -445,6 +448,10 @@ INLINE bool str_token(str *new_token, str *ori_and_remainder, int sep) {
 }
 
 INLINE bool str_token_sep(str *new_token, str *ori_and_remainder, int sep) {
+	if (ori_and_remainder->len == 0) {
+		*new_token = STR_NULL;
+		return false;
+	}
 	str ori = *ori_and_remainder;
 	if (str_token(new_token, ori_and_remainder, sep))
 		return true;