diff --git a/aos/logging/replay.cc b/aos/logging/replay.cc
new file mode 100644
index 0000000..c58ee8c
--- /dev/null
+++ b/aos/logging/replay.cc
@@ -0,0 +1,49 @@
+#include "aos/logging/replay.h"
+
+#include <chrono>
+
+namespace aos {
+namespace logging {
+namespace linux_code {
+
+namespace chrono = ::std::chrono;
+
+bool LogReplayer::ProcessMessage() {
+  const LogFileMessageHeader *message = reader_->ReadNextMessage(false);
+  if (message == nullptr) return true;
+  if (message->type != LogFileMessageHeader::MessageType::kStruct) return false;
+
+  const char *position = reinterpret_cast<const char *>(message + 1);
+
+  ::std::string process(position, message->name_size);
+  position += message->name_size;
+
+  uint32_t type_id;
+  memcpy(&type_id, position, sizeof(type_id));
+  position += sizeof(type_id);
+
+  uint32_t message_length;
+  memcpy(&message_length, position, sizeof(message_length));
+  position += sizeof(message_length);
+  ::std::string message_text(position, message_length);
+  position += message_length;
+
+  size_t split_index = message_text.find_first_of(':') + 2;
+  split_index = message_text.find_first_of(':', split_index) + 2;
+  message_text = message_text.substr(split_index);
+
+  auto handler = handlers_.find(Key(process, message_text));
+  if (handler == handlers_.end()) return false;
+
+  handler->second->HandleStruct(
+      monotonic_clock::time_point(chrono::seconds(message->time_sec) +
+                                  chrono::nanoseconds(message->time_nsec)),
+      type_id, position,
+      message->message_size -
+          (sizeof(type_id) + sizeof(message_length) + message_length));
+  return false;
+}
+
+}  // namespace linux_code
+}  // namespace logging
+}  // namespace aos