Remove ticket_cost member as it is no longer needed

include/ucore/rate_limit.h

@@ -54,15 +54,22 @@ struct RateLimit {
 
     //internal fields:
 
-    //how much each ticket is worth.
-    long ticket_cost;
-
     //money we have to "buy" tickets
     long funds;
     //time of the previos period
     long last_ts;
 };
 
+/** Static initializer for a struct RateLimit
+ *
+ * @param tickets number of tickets (bucket depth)
+ * @param period per this period
+ */
+#define UC_RATELIMIT_INITIALIZER(tickets, period)\
+{ tickets, period, tickets * period, 0}
+
+  
+
 /**
  * Initialize a struct RateLimit, which can hand out @tickets per @period
  * the perioid must be in the same units as the current_ts

src/rate_limit.c

@@ -5,21 +5,19 @@ void uc_ratelimit_init(struct RateLimit *r, long tickets, long period, long curr
 {
     r->tickets = tickets;
 
-    r->ticket_cost = period;
-
     r->period = period;
-    r->funds = r->ticket_cost * tickets;
+    r->funds = r->period * tickets;
     r->last_ts = current_ts;
 
     assert(tickets > 0);
     assert(period > 0);
-    assert(r->ticket_cost > 0);
+    assert(r->period > 0);
     assert(r->funds > 0);
 }
 
 void uc_ratelimit_reset(struct RateLimit *r, long current_ts)
 {
-    r->funds = r->ticket_cost * r->tickets;
+    r->funds = r->period * r->tickets;
 
     if (current_ts) {
         r->last_ts = current_ts;
@@ -46,20 +44,20 @@ int uc_ratelimit_allow(struct RateLimit *r, long current_ts)
     //the last time. 
     r->funds += diff_period * r->tickets;
 
-    //the below is the real algorithm, with ticket_cost = 
+    //the below is the real algorithm, with period = 
     //tickets * period. 
     //we have optimized this to the expression used above
     //r->funds += diff_period  * 
-    //                        ((r->tickets * r->ticket_cost) / r->period);
+    //                        ((r->tickets * r->period) / r->period);
 
     //throttle handing out tickets
-    if (r->funds > r->ticket_cost * r->tickets) {
-        r->funds = r->ticket_cost * r->tickets;
+    if (r->funds > r->period * r->tickets) {
+        r->funds = r->period * r->tickets;
     }
 
     //If we have enough to buy atleast one ticket, we can allow 
-    if (r->funds >=  r->ticket_cost) {
-        r->funds -= r->ticket_cost;
+    if (r->funds >=  r->period) {
+        r->funds -= r->period;
         allowed = 1;
     } else {
         //not enough to buy a ticket