diff --git a/dbus-top/analyzer.hpp b/dbus-top/analyzer.hpp
new file mode 100644
index 0000000..2284c7f
--- /dev/null
+++ b/dbus-top/analyzer.hpp
@@ -0,0 +1,177 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "histogram.hpp"
+
+#include <systemd/sd-bus.h>
+
+#include <atomic>
+#include <map>
+#include <mutex>
+#include <string>
+#include <vector>
+
+enum DBusTopSortField
+{
+    // DBus Message properties
+    kSender,
+    kDestination,
+    kInterface,
+    kPath,
+    kMember,
+    kSenderPID,
+    kSenderCMD,
+    // Computed metrics
+    kMsgPerSec,
+    kAverageLatency,
+};
+
+const std::string FieldNames[] = {"Sender",     "Destination", "Interface",
+                                  "Path",       "Member",      "Sender PID",
+                                  "Sender CMD", "Msg/s",       "Avg Latency"};
+const int FieldPreferredWidths[] = {18, 20, 12, 10, 10, 10, 25, 8, 12};
+bool DBusTopSortFieldIsNumeric(DBusTopSortField field);
+
+struct DBusTopComputedMetrics
+{
+    DBusTopComputedMetrics()
+    {
+        num_signals = 0;
+        num_errors = 0;
+        num_method_returns = 0;
+        num_method_calls = 0;
+        total_latency_usec = 0;
+    }
+    int num_method_returns = 0;
+    int num_errors = 0;
+    int num_signals = 0;
+    int num_method_calls;
+    uint64_t total_latency_usec;
+};
+
+class DBusTopStatistics
+{
+  public:
+    int num_messages_;
+    int num_mc_, num_mr_, num_sig_, num_error_;
+    float seconds_since_last_sample_;
+    std::vector<DBusTopSortField> fields_;
+    std::map<std::vector<std::string>, DBusTopComputedMetrics> stats_;
+    DBusTopStatistics() :
+        num_messages_(0), num_mc_(0), num_mr_(0), num_sig_(0), num_error_(0),
+        seconds_since_last_sample_(0)
+    {
+        fields_ = {kSender, kDestination, kSenderPID, kSenderCMD};
+        stats_.clear();
+    }
+
+    std::vector<DBusTopSortField> GetFields()
+    {
+        return fields_;
+    }
+
+    std::vector<std::string> GetFieldNames()
+    {
+        const int N = fields_.size();
+        std::vector<std::string> ret(N);
+        for (int i = 0; i < static_cast<int>(fields_.size()); i++)
+        {
+            ret[i] = FieldNames[static_cast<int>(fields_[i])];
+        }
+        return ret;
+    }
+
+    std::vector<int> GetFieldPreferredWidths()
+    {
+        const int N = fields_.size();
+        std::vector<int> ret(N);
+        for (int i = 0; i < static_cast<int>(fields_.size()); i++)
+        {
+            ret[i] = FieldPreferredWidths[static_cast<int>(fields_[i])];
+        }
+        return ret;
+    }
+
+    void Reset()
+    {
+        num_messages_ = 0;
+        num_mc_ = 0;
+        num_mr_ = 0;
+        num_sig_ = 0;
+        num_error_ = 0;
+        stats_.clear();
+    }
+    
+    void SetSortFieldsAndReset(const std::vector<DBusTopSortField>& f)
+    {
+        num_messages_ = 0;
+        num_mc_ = 0;
+        num_mr_ = 0;
+        num_sig_ = 0;
+        num_error_ = 0;
+        stats_.clear();
+        fields_ = f;
+    }
+
+    void Assign(DBusTopStatistics* out)
+    {
+        out->num_messages_ = this->num_messages_;
+        out->num_mc_ = this->num_mc_;
+        out->num_mr_ = this->num_mr_;
+        out->num_sig_ = this->num_sig_;
+        out->num_error_ = this->num_error_;
+        out->seconds_since_last_sample_ = this->seconds_since_last_sample_;
+        out->fields_ = this->fields_;
+        out->stats_ = this->stats_;
+    }
+
+    void OnNewDBusMessage(const char* sender, const char* destination,
+                          const char* interface, const char* path,
+                          const char* message, const char type,
+                          sd_bus_message* m);
+    std::string CheckAndFixNullString(const char* x)
+    {
+        if (x == nullptr)
+            return "(null)";
+        else
+            return std::string(x);
+    }
+
+    std::map<std::vector<std::string>, DBusTopComputedMetrics> StatsSnapshot()
+    {
+        std::map<std::vector<std::string>, DBusTopComputedMetrics> ret;
+        ret = stats_;
+        return ret;
+    }
+
+  private:
+    std::mutex mtx_;
+};
+
+int GetSummaryIntervalInMillises();
+// Monitor sensor details-related DBus method calls/replies
+// typedef void (*SetDBusTopConnection)(const char* conn);
+namespace dbus_top_analyzer
+{
+    void Process();
+    void Finish();
+    typedef void (*DBusTopStatisticsCallback)(DBusTopStatistics*,
+                                            Histogram<float>*);
+    void SetDBusTopStatisticsCallback(DBusTopStatisticsCallback cb);
+    void AnalyzerThread();
+    // Methods for sending Object Mapper queries
+    void ListAllSensors();
+} // namespace dbus_top_analyzer