adds a simple rate calculation

src/asynStreamGeneratorDriver.cpp

@@ -359,7 +359,13 @@ void asynStreamGeneratorDriver::receiveUDP() {
     // These messages don't have any obious start or end to synchronise
     // against...
     const std::size_t bufferSize = 1500;
-    char buffer[bufferSize + 1]; // so that \0 can fit
+    char buffer[bufferSize];
+
+    // We have 10 mcpdids
+    uint64_t lastBufferNumber* = new uint64_t[10];
+    for (size_t i = 0; i < 10; ++i) {
+        lastBufferNumber[i] = 0;
+    }
 
     while (true) {
 
@@ -454,6 +460,12 @@ void asynStreamGeneratorDriver::processEvents() {
     // uint32. It does support int64 though.. so we start with that
     epicsInt32 *counts = new epicsInt32[this->num_channels];
 
+    size_t countDiffsPtr = 0;
+    epicsInt32 *rates = new epicsInt32[this->num_channels];
+    epicsInt32 *countDiff = new epicsInt32[this->num_channels];
+    epicsInt32 *countDiffs = new epicsInt32[this->num_channels * 10];
+    epicsTimeStamp lastRateUpdate = epicsTime::getCurrent();
+
     asynStatus status = asynSuccess;
     NormalisedEvent *ne;
     uint64_t newestTimestamp = 0;
@@ -473,6 +485,9 @@ void asynStreamGeneratorDriver::processEvents() {
             // resolution with a uint64_t we will have an overflow after around
             // 4 years
             newestTimestamp = std::max(newestTimestamp, ne->timestamp);
+
+            ++countDiff[ne->source == 0 ? ne->pixelId + 1 : 0];
+
             timeQueue.push(ne);
         }
 
@@ -580,6 +595,34 @@ void asynStreamGeneratorDriver::processEvents() {
                 delete ne;
             }
         }
+
+        // Careful changing any of these magic numbers until I clean this up
+        // as you might end up calculating the wrong rate
+        epicsTimeStamp currentTime = epicsTime::getCurrent();
+        if (epicsTimeDiffInNS(&currentTime, &lastRateUpdate) > 100'000'000ll) {
+            lastRateUpdate = currentTime;
+
+            for (size_t i = 0; i <= this->num_channels; ++i) {
+                countDiffs[i * 10 + countDiffsPtr] = countDiff[i];
+
+                uint64_t cnt = 0;
+                for (size_t j = 0; j <= 10; ++j) {
+                    cnt += countDiffs[i * 10 + j];
+                }
+                rates[i] = cnt / 10.;
+
+                countDiff[i] = 0;
+            }
+
+            countDiffsPtr = (countDiffsPtr + 1) % 10;
+
+            lock();
+            for (size_t i = 0; i < num_channels; ++i) {
+                setIntegerParam(P_Rates[i], rates[i]);
+            }
+            callParamCallbacks();
+            unlock();
+        }
     }
 }