Clamp every elapsed time span at zero, using a set of helper functions

1 files changed, 20 insertions, 4 deletions

diff --git a/src/trackerlogic.h b/src/trackerlogic.h
index 692b6af..c8d859c 100644
--- a/src/trackerlogic.h
+++ b/src/trackerlogic.h
@@ -61,10 +61,10 @@ typedef struct {
 #define OT_PEER_TIMEOUT               45
 
 /* We maintain a list of 1024 pointers to sorted list of ot_torrent structs
- Sort key is, of course, its hash */
-/* Set from the Makefile, 8 to 16. More buckets means shorter vectors and a
-   cheaper insert, which only pays for a tracker carrying millions of
-   torrents; see DESIGN. */
+ Sort key is, of course, its hash.
+ Can be tweked from the Makefile, sensible values are between 8 in 16. More
+ buckets means shorter vectors and a cheaper insert, which only pays for a
+ tracker carrying millions of torrents. Consult the DESIGN document. */
 #ifndef OT_BUCKET_COUNT_BITS
 #define OT_BUCKET_COUNT_BITS          10
 #endif
@@ -95,6 +95,22 @@ static inline ot_time time_now_minutes(void) { return time_now_seconds() / 60; }
 /* For the deadlines the tracker sets on itself, which read better as the
    span they allow than as an addition to the current second */
 static inline ot_time time_future_seconds(int span) { return time_now_seconds() + span; }
+
+/* How long ago a stamp was taken. */
+_Static_assert((ot_time)-1 < 0, "ot_time has to be signed for time_since_* to clamp");
+
+static inline ot_time time_since_seconds(ot_time then) {
+  ot_time now = time_now_seconds();
+  return now > then ? now - then : 0;
+}
+
+static inline ot_time time_since_minutes(ot_time then) {
+  ot_time now = time_now_minutes();
+  return now > then ? now - then : 0;
+}
+
+/* Has a deadline the tracker set on itself gone by? */
+static inline int time_is_past(ot_time deadline) { return time_now_seconds() > deadline; }
 /* Cleared from the interrupt handler and read by every worker */
 extern _Atomic int    g_opentracker_running;