Initial commit

Torque/SDK/engine/core/bitTables.h

@@ -0,0 +1,42 @@
+//-----------------------------------------------------------------------------
+// Torque Game Engine
+// Copyright (C) GarageGames.com, Inc.
+//-----------------------------------------------------------------------------
+
+#ifndef _BITTABLES_H_
+#define _BITTABLES_H_
+
+#ifndef _PLATFORM_H_
+#include "platform/platform.h"
+#endif
+
+class BitTables
+{
+  private:
+   static bool mTablesBuilt;        ///< For first time build
+   static S8   mHighBit[256];       ///< I.e. crude logarithm
+   static S8   mWhichOn[256][8];    ///< Unroll a bitset collection (note
+   static S8   mNumOn[256];         //    ptr table wastes same amt.)
+
+  public:
+   BitTables();
+
+   /// How many bits are on?
+   static const S32   numOn(U8 b)       {  return mNumOn[b];      }
+
+   /// Return a pointer to 8 S8's, which are set according to which bits are set in the passed value.
+   static const S8 *  whichOn(U8 b)     {  return mWhichOn[b];    }
+
+   static const S32   highBit(U8 b)     {  return mHighBit[b];    }
+
+
+   static S32 getPower16(U16 x)   { return x<256 ? mHighBit[x] : mHighBit[x>>8]+8; }
+   static S32 getPower32(U32 x){
+                  if( x < (1<<16) )
+                     return( x < (1<<8)  ? mHighBit[x] : mHighBit[x>>8]+8 );
+                  else
+                     return( x < (1<<24) ? mHighBit[x>>16]+16 : mHighBit[x>>24]+24 );
+                 }
+};
+
+#endif