Convert BufferedSolenoid to use HAL.

Change-Id: Ibb1f5d800923b340a4632ad79611442dc54aec34
diff --git a/frc971/wpilib/buffered_pcm.h b/frc971/wpilib/buffered_pcm.h
index 4ff625b..877e830 100644
--- a/frc971/wpilib/buffered_pcm.h
+++ b/frc971/wpilib/buffered_pcm.h
@@ -3,8 +3,7 @@
 
 #include <memory>
 
-#include "Solenoid.h"
-#undef ERROR
+#include <HAL/HAL.h>
 
 #include "frc971/wpilib/buffered_solenoid.h"
 
@@ -17,24 +16,28 @@
 // The way to use this is to call MakeSolenoid for whichever solenoid numbers
 // you want, call Set on those, and then periodically call Flush on this object
 // to write all of the buffered values out.
-class BufferedPcm : public Solenoid {
+class BufferedPcm {
  public:
-  explicit BufferedPcm() : Solenoid(0) {}
+  explicit BufferedPcm(int module = 0);
 
   // Creates a new BufferedSolenoid for a specified port number.
   ::std::unique_ptr<BufferedSolenoid> MakeSolenoid(int number);
 
+  // Returns a bitmask of the state of all the solenoids.
+  int32_t GetAll();
+
   // Actually sends all of the values out.
   void Flush();
 
  private:
-  // WPILib declares this pure virtual and then never calls it...
-#ifdef WPILIB2015
-  virtual void InitSolenoid() override {}
-#endif
-
   void DoSet(int number, bool value);
 
+  int module_;
+  ::std::array<HAL_SolenoidHandle, 8> solenoid_handles_{
+      {HAL_kInvalidHandle, HAL_kInvalidHandle, HAL_kInvalidHandle,
+       HAL_kInvalidHandle, HAL_kInvalidHandle, HAL_kInvalidHandle,
+       HAL_kInvalidHandle, HAL_kInvalidHandle}};
+
   uint8_t values_ = 0;
 
   friend class BufferedSolenoid;