Engine directory for ticket #1

Engine/source/math/mRandomDeck.h

@@ -0,0 +1,138 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2012 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#ifndef _MRANDOMDECK_H_
+#define _MRANDOMDECK_H_
+
+#ifndef _MRANDOM_H_
+#include "math/mRandom.h"
+#endif
+
+template <class T>
+class MRandomDeck
+{
+protected:
+
+   MRandomLCG *mRandGen;
+
+   Vector<T> mDeck;
+
+   Vector<T> mPile;
+
+public:
+
+   MRandomDeck( MRandomLCG *randGen = &gRandGen );
+
+   void addToPile( const T &item );
+
+   void addToPile( const Vector<T> &items );
+
+   void shuffle();
+
+   S32 draw( T *item, bool reshuffle = true );
+
+   void removeAll( Vector<T> *outItems );
+
+};
+
+template<class T>
+inline MRandomDeck<T>::MRandomDeck( MRandomLCG *randGen )
+   : mRandGen( randGen )
+{
+}
+
+template<class T> 
+inline void MRandomDeck<T>::shuffle()
+{
+   // Move everything to the pile.
+   mPile.merge( mDeck );
+
+   if ( mPile.empty() )
+      return;
+   T& last = mPile.last();
+   mDeck.clear();
+
+   // Randomly draw from the pile
+   // and place them in the deck.
+   while ( !mPile.empty() )
+   {
+      U32 i = mRandGen->randI( 0, mPile.size() - 1 );
+      mDeck.push_back( mPile[i] );
+      mPile.erase_fast( i );
+   }
+
+   // Make sure that the first drawn item
+   // is not the same as the last drawn item.
+   if ( mDeck.last() == last )
+   {
+      mDeck.pop_back();
+      mDeck.push_front( last );
+   }
+}
+
+template<class T> 
+inline S32 MRandomDeck<T>::draw( T *item, bool reshuffle )
+{ 
+   if ( mDeck.size() == 0 )
+   {
+      if ( mPile.size() == 0 )
+         return -1;
+      
+      if ( reshuffle )
+         shuffle();
+      else
+         return -1;
+   }
+
+   *item = mDeck.last();
+   mPile.push_back( *item );
+   mDeck.pop_back();   
+
+   return mDeck.size();
+}
+
+template<class T>
+inline void MRandomDeck<T>::addToPile( const T &item )
+{
+   mPile.push_back( item );
+}
+
+template<class T>
+inline void MRandomDeck<T>::addToPile( const Vector<T> &items )
+{
+   mPile.merge( items );
+}
+
+template<class T>
+inline void MRandomDeck<T>::removeAll( Vector<T> *outItems )
+{
+   if ( outItems )
+   {
+      outItems->merge( mPile );
+      outItems->merge( mDeck );
+   }
+
+   mPile.clear();
+   mDeck.clear();
+}
+
+#endif //_MRANDOMDECK_H_