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Merge branch 'dev' of /var/lib/git/libucore into dev

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This commit is contained in:
Nils O. Selåsdal
2013-10-17 21:00:32 +02:00
parent 987db2d096 b91d5870b8
commit 4b13f1f1c9
4 changed files with 50 additions and 50 deletions
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src/rate_limit.c
+39 -38
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@@ -1,18 +1,18 @@
#include <assert.h>
#include <limits.h>
#include "ucore/rate_limit.h"
void uc_ratelimit_init(struct RateLimit *r, long tickets, long period, long current_ts)
void uc_ratelimit_init(struct RateLimit *r, long tickets, long period)
{
r->tickets = tickets;
r->period = period;
r->funds = r->period * tickets;
r->last_ts = current_ts;
r->funds = 0; //we fill it on first _allow call
r->last_ts = -period; //-period ensures the first tick can start
//at >= 0 and still refill the bicket
assert(tickets > 0);
assert(period > 0);
assert(r->period > 0);
assert(r->funds > 0);
}
void uc_ratelimit_reset(struct RateLimit *r, long current_ts)
@@ -29,43 +29,44 @@ int uc_ratelimit_allow(struct RateLimit *r, long current_ts)
int allowed;
long diff_period;
//Find elapsed time
diff_period = current_ts - r->last_ts;
if (diff_period > r->period + 1) {
//help prevent overflow when calculating available_tickets below
diff_period = r->period + 1;
} else if (diff_period < 0) {
//If time went backwards, we halt the time for this round
diff_period = 0;
}
//Calculate the cost of tickets that became available since
//the last time.
r->funds += diff_period * r->tickets;
//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->period) / r->period);
//throttle handing out 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->period) {
if (r->funds >= r->period) {
//we have enough
r->funds -= r->period;
allowed = 1;
} else {
//not enough to buy a ticket
allowed = 0;
} else { //refill
//Find elapsed time
diff_period = current_ts - r->last_ts;
if (diff_period > r->period + 1) {
//help prevent overflow when calculating available_tickets below
diff_period = r->period + 1;
} else if (diff_period < 0) {
//time went backwards, skip this round
diff_period = 0;
}
//Calculate the cost of tickets that became available
r->funds += diff_period * r->tickets;
//throttle handing out 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->period) {
r->funds -= r->period;
allowed = 1;
} else {
//not enough to buy a ticket
allowed = 0;
}
//save this period.
r->last_ts = current_ts;
}
//save this period.
r->last_ts = current_ts;
return allowed;
}