copied everything over from 2012 and removed all of the actual robot code except the drivetrain stuff


git-svn-id: https://robotics.mvla.net/svn/frc971/2013/trunk/src@4078 f308d9b7-e957-4cde-b6ac-9a88185e7312
diff --git a/aos/common/control_loop/ControlLoop.h b/aos/common/control_loop/ControlLoop.h
new file mode 100644
index 0000000..b69cf01
--- /dev/null
+++ b/aos/common/control_loop/ControlLoop.h
@@ -0,0 +1,133 @@
+#ifndef AOS_CONTROL_LOOP_CONTROL_LOOP_H_
+#define AOS_CONTROL_LOOP_CONTROL_LOOP_H_
+
+#include <cstring>
+
+#include "aos/aos_core.h"
+#include "aos/common/control_loop/Timing.h"
+#include "aos/common/messages/RobotState.q.h"
+#include "aos/common/type_traits.h"
+
+namespace aos {
+namespace control_loops {
+
+// Interface to describe runnable jobs.
+class Runnable {
+ public:
+  virtual ~Runnable() {}
+  // Runs forever.
+  virtual void Run() = 0;
+  // Does one quick piece of work and return.  Does _not_ block.
+  virtual void Iterate() = 0;
+};
+
+class SerializableControlLoop : public Runnable {
+ public:
+  // Returns the size of all the data to be sent when serialized.
+  virtual size_t SeralizedSize() = 0;
+  // Serialize the current data.
+  virtual void Serialize(char *buffer) const = 0;
+  // Serialize zeroed data in case the data is out of date.
+  virtual void SerializeZeroMessage(char *buffer) const = 0;
+  // Deserialize data into the control loop.
+  virtual void Deserialize(const char *buffer) = 0;
+  // Unique identifier for the control loop.
+  // Most likely the hash of the queue group.
+  virtual uint32_t UniqueID() = 0;
+};
+
+// Provides helper methods to assist in writing control loops.
+// This template expects to be constructed with a queue group as an argument
+// that has a goal, position, status, and output queue.
+// It will then call the RunIteration method every cycle that it has enough
+// valid data for the control loop to run.
+// If has_position is false, the control loop will always use NULL as the
+// position and not check the queue.  This is used for "loops" that control
+// motors open loop.
+template <class T, bool has_position = true>
+class ControlLoop : public SerializableControlLoop {
+ public:
+  // Maximum age of position packets before the loop will be disabled due to
+  // invalid position data.
+  static const int kPositionTimeoutMs = 100;
+  // Maximum age of driver station packets before the loop will be disabled.
+  static const int kDSPacketTimeoutMs = 100;
+
+  ControlLoop(T *control_loop) : control_loop_(control_loop) {}
+
+  // Create some convenient typedefs to reference the Goal, Position, Status,
+  // and Output structures.
+  typedef typename std::remove_reference<
+      decltype(*(static_cast<T *>(NULL)->goal.MakeMessage().get()))>::type
+        GoalType;
+  typedef typename std::remove_reference<
+      decltype(*(static_cast<T *>(NULL)->position.MakeMessage().get()))>::type
+        PositionType;
+  typedef typename std::remove_reference<
+    decltype(*(static_cast<T *>(NULL)->status.MakeMessage().get()))>::type
+      StatusType;
+  typedef typename std::remove_reference<
+    decltype(*(static_cast<T *>(NULL)->output.MakeMessage().get()))>::type
+      OutputType;
+
+  // Constructs and sends a message on the output queue which will stop all the
+  // motors.  Calls Zero to clear all the state.
+  void ZeroOutputs();
+
+  // Sets the output to zero.
+  // Over-ride if a value of zero is not "off" for this subsystem.
+  virtual void Zero(OutputType *output) { output->Zero(); }
+
+  // Runs the loop forever.
+  virtual void Run();
+
+  // Runs one cycle of the loop.
+  virtual void Iterate();
+
+  // Returns the name of the queue group.
+  const char *name() { return control_loop_->name(); }
+
+  // Methods to serialize all the data that should be sent over the network.
+  virtual size_t SeralizedSize() { return control_loop_->goal->Size(); }
+  virtual void Serialize(char *buffer) const {
+    control_loop_->goal->Serialize(buffer);
+  }
+  virtual void SerializeZeroMessage(char *buffer) const {
+    GoalType zero_goal;
+    zero_goal.Zero();
+    zero_goal.Serialize(buffer);
+  }
+
+  virtual void Deserialize(const char *buffer) {
+    ScopedMessagePtr<GoalType> new_msg = control_loop_->goal.MakeMessage();
+    new_msg->Deserialize(buffer);
+    new_msg.Send();
+  }
+
+  virtual uint32_t UniqueID() { return control_loop_->hash(); }
+
+ protected:
+  // Runs an iteration of the control loop.
+  // goal is the last goal that was sent.  It might be any number of cycles old.
+  // position is the current position, or NULL if we didn't get a position this
+  // cycle.
+  // output is the values to be sent to the motors.  This is NULL if the output
+  // is going to be ignored and set to 0.
+  // status is the status of the control loop.
+  // Both output and status should be filled in by the implementation.
+  virtual void RunIteration(const GoalType *goal,
+                            const PositionType *position,
+                            OutputType *output,
+                            StatusType *status) = 0;
+
+ private:
+  // Pointer to the queue group
+  T *control_loop_;
+};
+
+}  // namespace control_loops
+}  // namespace aos
+
+#include "aos/common/control_loop/ControlLoop-tmpl.h"  // IWYU pragma: export
+
+#endif