Make Random class serializable, and save to state files.

Changes.txt

@@ -37,6 +37,10 @@
     then back again would pass a 'Tab' key event to the app, which in
     most cases would navigate to the next UI element.
 
+  * Fixed potential issue with state file saving and the debugger; under
+    certain circumstances a rewind would give a different state than
+    before (note that the state file format has changed because of this).
+
   * Fixed lockups when entering the debugger under certain circumstances.
 
   * Reverted joystick changes for Decathlon ROMs from last release, as

src/emucore/Random.hxx

@@ -22,6 +22,7 @@
 
 #include "bspf.hxx"
 #include "OSystem.hxx"
+#include "Serializable.hxx"
 
 /**
   This is a quick-and-dirty random number generator.  It is based on
@@ -30,7 +31,7 @@
 
   @author  Bradford W. Mott
 */
-class Random
+class Random : public Serializable
 {
   public:
     /**
@@ -57,6 +58,59 @@ class Random
       return (myValue = (myValue * 2416 + 374441) % 1771875);
     }
 
+    /**
+      Save the current state of this device to the given Serializer.
+
+      @param out  The Serializer object to use
+      @return  False on any errors, else true
+    */
+    bool save(Serializer& out) const override
+    {
+        try
+        {
+          out.putString(name());
+          out.putInt(myValue);
+        }
+        catch(...)
+        {
+          cerr << "ERROR: Random::save" << endl;
+          return false;
+        }
+
+        return true;
+    }
+
+    /**
+      Load the current state of this device from the given Serializer.
+
+      @param in  The Serializer object to use
+      @return  False on any errors, else true
+    */
+    bool load(Serializer& in) override
+    {
+      try
+      {
+        if(in.getString() != name())
+          return false;
+
+        myValue = in.getInt();
+      }
+      catch(...)
+      {
+        cerr << "ERROR: Random::load" << endl;
+        return false;
+      }
+
+      return true;
+    }
+
+    /**
+      Get a descriptor for the device name (used in error checking).
+
+      @return The name of the object
+    */
+    string name() const override { return "Random"; }
+
   private:
     // Set the OSystem we're using
     const OSystem& myOSystem;

src/emucore/StateManager.cxx

@@ -28,7 +28,7 @@
 
 #include "StateManager.hxx"
 
-#define STATE_HEADER "05000000state"
+#define STATE_HEADER "05000200state"
 #define MOVIE_HEADER "03030000movie"
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

src/emucore/System.cxx

@@ -221,6 +221,8 @@ bool System::save(Serializer& out) const
       return false;
     if(!myCart.save(out))
       return false;
+    if(!randGenerator().save(out))
+      return false;
   }
   catch(...)
   {
@@ -251,6 +253,8 @@ bool System::load(Serializer& in)
       return false;
     if(!myCart.load(in))
       return false;
+    if(!randGenerator().load(in))
+      return false;
   }
   catch(...)
   {