Add sync limit

sf-stream/include/stream_config.hpp

@@ -6,4 +6,6 @@ namespace stream_config
     const size_t STREAM_RCVHWM = 100;
     // Size of buffer between the receiving and sending part.
     const int STREAM_FASTQUEUE_SLOTS = 5;
+    // If the modules are offset more than 1000 pulses, crush.
+    const uint64_t PULSE_OFFSET_LIMIT = 1000;
 }

sf-stream/src/LiveRecvModule.cpp

@@ -105,6 +105,24 @@ uint64_t LiveRecvModule::align_modules(
         max_pulse_id = max(max_pulse_id, module_meta.pulse_id);
     }
 
+    auto max_diff = max_pulse_id - min_pulse_id;
+    if (max_diff > PULSE_OFFSET_LIMIT) {
+        stringstream err_msg;
+
+        err_msg << "[LiveRecvModule::align_modules]";
+        err_msg << " PULSE_OFFSET_LIMIT exceeded.";
+        err_msg << " Modules out of sync for " << max_diff << " pulses.";
+
+        for (auto& module_meta : meta->module) {
+            err_msg << " (" << module_meta.module_id << ", ";
+            err_msg << module_meta.pulse_id << "),";
+        }
+
+        err_msg << endl;
+
+        throw runtime_error(err_msg.str());
+    }
+
     // Second pass - align all receivers to max_pulse_id.
     for (size_t i_module = 0; i_module < n_modules_; i_module++) {
         auto& module_meta = meta->module[i_module];