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Overhaul mode A/C matching to be much cheaper.

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The old matching process which tracked mode A values as pseudo-aircraft
got very, very expensive with a large number of mode A/C messages (and
with lots of single-bit errors, which seems common with a Beast doing
the reception)

Instead just count A/C messages directly into a 4096-entry array (which
is very fast) and periodically scan the mode S aircraft list to see if
we can match anything up (which is fixed overhead + cost proportional
to the number of mode S aircraft)
This commit is contained in:
Oliver Jowett 2016-10-11 18:00:11 +01:00
parent 60f1f3bcb6
commit 25ea6d398b
6 changed files with 111 additions and 140 deletions
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8
net_io.c
View file

@ -710,7 +710,7 @@ static void send_sbs_heartbeat(struct net_service *service)
void modesQueueOutput(struct modesMessage *mm, struct aircraft *a) {
int is_mlat = (mm->source == SOURCE_MLAT);
if (!is_mlat && mm->correctedbits < 2) {
if (a && !is_mlat && mm->correctedbits < 2) {
// Don't ever forward 2-bit-corrected messages via SBS output.
// Don't ever forward mlat messages via SBS output.
modesSendSBSOutput(mm, a);
@ -728,7 +728,7 @@ void modesQueueOutput(struct modesMessage *mm, struct aircraft *a) {
modesSendBeastOutput(mm);
}
if (!is_mlat) {
if (a && !is_mlat) {
writeFATSVEvent(mm, a);
}
}
@ -1027,10 +1027,6 @@ char *generateAircraftJson(const char *url_path, int *len) {
Modes.stats_current.messages_total + Modes.stats_alltime.messages_total);
for (a = Modes.aircrafts; a; a = a->next) {
if (a->modeACflags & MODEAC_MSG_FLAG) { // skip any fudged ICAO records Mode A/C
continue;
}
if (a->messages < 2) { // basic filter for bad decodes
continue;
}