[iproute PATCH 2/4] tc: util: bore up action_a2n()

[Phil Sutter]

It's a pitty this function is used nowhere, so let's polish it for use:

* Loop over branch names, makes it clear that every former conditional
  was exactly identical.
* Support 'pipe' branch name, too.
* Make number parsing optional.

Signed-off-by: Phil Sutter <p...@nwl.cc>
---
 tc/tc_util.c | 56 +++++++++++++++++++++++++++++++++++---------------------
 tc/tc_util.h |  2 +-
 2 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/tc/tc_util.c b/tc/tc_util.c
index fd6669f281cc1..cd7b40b0afe48 100644
--- a/tc/tc_util.c
+++ b/tc/tc_util.c
@@ -435,29 +435,43 @@ char *action_n2a(int action, char *buf, int len)
        }
 }
 
-int action_a2n(char *arg, int *result)
+/* Convert action branch name into numeric format.
+ *
+ * Parameters:
+ * @arg - string to parse
+ * @result - pointer to output variable
+ * @allow_num - whether @arg may be in numeric format already
+ *
+ * In error case, returns -1 and does not touch @result. Otherwise returns 0.
+ */
+int action_a2n(char *arg, int *result, bool allow_num)
 {
-       int res;
-
-       if (matches(arg, "continue") == 0)
-               res = -1;
-       else if (matches(arg, "drop") == 0)
-               res = TC_ACT_SHOT;
-       else if (matches(arg, "shot") == 0)
-               res = TC_ACT_SHOT;
-       else if (matches(arg, "pass") == 0)
-               res = TC_ACT_OK;
-       else if (strcmp(arg, "ok") == 0)
-               res = TC_ACT_OK;
-       else if (matches(arg, "reclassify") == 0)
-               res = TC_ACT_RECLASSIFY;
-       else {
-               char dummy;
-
-               if (sscanf(arg, "%d%c", &res, &dummy) != 1)
-                       return -1;
+       int n;
+       char dummy;
+       struct {
+               const char *a;
+               int n;
+       } a2n[] = {
+               {"continue", TC_ACT_UNSPEC},
+               {"drop", TC_ACT_SHOT},
+               {"shot", TC_ACT_SHOT},
+               {"pass", TC_ACT_OK},
+               {"ok", TC_ACT_OK},
+               {"reclassify", TC_ACT_RECLASSIFY},
+               {"pipe", TC_ACT_PIPE},
+               { NULL },
+       }, *iter;
+
+       for (iter = a2n; iter->a; iter++) {
+               if (matches(arg, iter->a) != 0)
+                       continue;
+               *result = iter->n;
+               return 0;
        }
-       *result = res;
+       if (!allow_num || sscanf(arg, "%d%c", &n, &dummy) != 1)
+               return -1;
+
+       *result = n;
        return 0;
 }
 
diff --git a/tc/tc_util.h b/tc/tc_util.h
index 744f18fdd9117..e7613ab1bd496 100644
--- a/tc/tc_util.h
+++ b/tc/tc_util.h
@@ -100,7 +100,7 @@ int tc_print_police(FILE *f, struct rtattr *tb);
 int parse_police(int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n);
 
 char *action_n2a(int action, char *buf, int len);
-int action_a2n(char *arg, int *result);
+int action_a2n(char *arg, int *result, bool allow_num);
 int act_parse_police(struct action_util *a, int *argc_p,
                     char ***argv_p, int tca_id, struct nlmsghdr *n);
 int print_police(struct action_util *a, FILE *f, struct rtattr *tb);
-- 
2.8.2