Add a utility Bits class to help work with bit ranges in integers. Ideally we should add a bunch of other classical bitwise operations here

Base/CMakeLists.txt

@@ -80,6 +80,7 @@ SET( SOURCES
 )
 
 SET( HEADERS
+  "include/Bits.h"
   "include/BitStream.h"
   "include/Color.h"
   "include/CompressionJob.h"

Base/include/Bits.h

@@ -0,0 +1,92 @@
+/* FasTC
+ * Copyright (c) 2014 University of North Carolina at Chapel Hill.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for educational, research, and non-profit purposes, without
+ * fee, and without a written agreement is hereby granted, provided that the
+ * above copyright notice, this paragraph, and the following four paragraphs
+ * appear in all copies.
+ *
+ * Permission to incorporate this software into commercial products may be
+ * obtained by contacting the authors or the Office of Technology Development
+ * at the University of North Carolina at Chapel Hill <otd@unc.edu>.
+ *
+ * This software program and documentation are copyrighted by the University of
+ * North Carolina at Chapel Hill. The software program and documentation are
+ * supplied "as is," without any accompanying services from the University of
+ * North Carolina at Chapel Hill or the authors. The University of North
+ * Carolina at Chapel Hill and the authors do not warrant that the operation of
+ * the program will be uninterrupted or error-free. The end-user understands
+ * that the program was developed for research purposes and is advised not to
+ * rely exclusively on the program for any reason.
+ *
+ * IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE
+ * AUTHORS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL,
+ * OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF
+ * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA
+ * AT CHAPEL HILL OR THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY
+ * DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY 
+ * STATUTORY WARRANTY OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON
+ * AN "AS IS" BASIS, AND THE UNIVERSITY  OF NORTH CAROLINA AT CHAPEL HILL AND
+ * THE AUTHORS HAVE NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, 
+ * ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Please send all BUG REPORTS to <pavel@cs.unc.edu>.
+ *
+ * The authors may be contacted via:
+ *
+ * Pavel Krajcevski
+ * Dept of Computer Science
+ * 201 S Columbia St
+ * Frederick P. Brooks, Jr. Computer Science Bldg
+ * Chapel Hill, NC 27599-3175
+ * USA
+ * 
+ * <http://gamma.cs.unc.edu/FasTC/>
+ */
+
+#ifndef __BASE_INCLUDE_BITS_H__
+#define __BASE_INCLUDE_BITS_H__
+
+#include "TexCompTypes.h"
+
+namespace FasTC {
+
+  template<typename IntType>
+  class Bits {
+   private:
+    const IntType &m_Bits;
+
+    // Don't copy
+    Bits() { }
+    Bits(const Bits &) { }
+    Bits &operator=(const Bits &) { }
+
+   public:
+    explicit Bits(IntType &v) : m_Bits(v) { }
+
+    bool operator[](uint32 bitPos) {
+      return (m_Bits >> bitPos) & 1;
+    }
+
+    IntType operator()(uint32 start, uint32 end) {
+      if(start == end) {
+        return (*this)[start];
+      } else if(start > end) {
+        uint32 t = start;
+        start = end;
+        end = t;
+      }
+
+      uint64 mask = (1 << (end - start + 1)) - 1;
+      return (m_Bits >> start) & mask;
+    }
+  };
+
+}  // namespace FasTC
+#endif // __BASE_INCLUDE_BITS_H__