diff --git a/include/utils/BitSet.h b/include/utils/BitSet.h
index 75abe6c..f1d68a0 100644
--- a/include/utils/BitSet.h
+++ b/include/utils/BitSet.h
@@ -30,72 +30,102 @@
 struct BitSet32 {
     uint32_t value;
 
-    inline BitSet32() : value(0) { }
+    inline BitSet32() : value(0UL) { }
     explicit inline BitSet32(uint32_t value) : value(value) { }
 
     // Gets the value associated with a particular bit index.
-    static inline uint32_t valueForBit(uint32_t n) { return 0x80000000 >> n; }
+    static inline uint32_t valueForBit(uint32_t n) { return 0x80000000UL >> n; }
 
     // Clears the bit set.
-    inline void clear() { value = 0; }
+    inline void clear() { clear(value); }
+
+    static inline void clear(uint32_t& value) { value = 0UL; }
 
     // Returns the number of marked bits in the set.
-    inline uint32_t count() const { return __builtin_popcountl(value); }
+    inline uint32_t count() const { return count(value); }
+
+    static inline uint32_t count(uint32_t value) { return __builtin_popcountl(value); }
 
     // Returns true if the bit set does not contain any marked bits.
-    inline bool isEmpty() const { return ! value; }
+    inline bool isEmpty() const { return isEmpty(value); }
+
+    static inline bool isEmpty(uint32_t value) { return ! value; }
 
     // Returns true if the bit set does not contain any unmarked bits.
-    inline bool isFull() const { return value == 0xffffffff; }
+    inline bool isFull() const { return isFull(value); }
+
+    static inline bool isFull(uint32_t value) { return value == 0xffffffffUL; }
 
     // Returns true if the specified bit is marked.
-    inline bool hasBit(uint32_t n) const { return value & valueForBit(n); }
+    inline bool hasBit(uint32_t n) const { return hasBit(value, n); }
+
+    static inline bool hasBit(uint32_t value, uint32_t n) { return value & valueForBit(n); }
 
     // Marks the specified bit.
-    inline void markBit(uint32_t n) { value |= valueForBit(n); }
+    inline void markBit(uint32_t n) { markBit(value, n); }
+
+    static inline void markBit (uint32_t& value, uint32_t n) { value |= valueForBit(n); }
 
     // Clears the specified bit.
-    inline void clearBit(uint32_t n) { value &= ~ valueForBit(n); }
+    inline void clearBit(uint32_t n) { clearBit(value, n); }
+
+    static inline void clearBit(uint32_t& value, uint32_t n) { value &= ~ valueForBit(n); }
 
     // Finds the first marked bit in the set.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t firstMarkedBit() const { return __builtin_clzl(value); }
+    inline uint32_t firstMarkedBit() const { return firstMarkedBit(value); }
+
+    static uint32_t firstMarkedBit(uint32_t value) { return __builtin_clzl(value); }
 
     // Finds the first unmarked bit in the set.
     // Result is undefined if all bits are marked.
-    inline uint32_t firstUnmarkedBit() const { return __builtin_clzl(~ value); }
+    inline uint32_t firstUnmarkedBit() const { return firstUnmarkedBit(value); }
+
+    static inline uint32_t firstUnmarkedBit(uint32_t value) { return __builtin_clzl(~ value); }
 
     // Finds the last marked bit in the set.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t lastMarkedBit() const { return 31 - __builtin_ctzl(value); }
+    inline uint32_t lastMarkedBit() const { return lastMarkedBit(value); }
+
+    static inline uint32_t lastMarkedBit(uint32_t value) { return 31 - __builtin_ctzl(value); }
 
     // Finds the first marked bit in the set and clears it.  Returns the bit index.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t clearFirstMarkedBit() {
-        uint32_t n = firstMarkedBit();
-        clearBit(n);
+    inline uint32_t clearFirstMarkedBit() { return clearFirstMarkedBit(value); }
+
+    static inline uint32_t clearFirstMarkedBit(uint32_t& value) {
+        uint32_t n = firstMarkedBit(value);
+        clearBit(value, n);
         return n;
     }
 
     // Finds the first unmarked bit in the set and marks it.  Returns the bit index.
     // Result is undefined if all bits are marked.
-    inline uint32_t markFirstUnmarkedBit() {
-        uint32_t n = firstUnmarkedBit();
-        markBit(n);
+    inline uint32_t markFirstUnmarkedBit() { return markFirstUnmarkedBit(value); }
+
+    static inline uint32_t markFirstUnmarkedBit(uint32_t& value) {
+        uint32_t n = firstUnmarkedBit(value);
+        markBit(value, n);
         return n;
     }
 
     // Finds the last marked bit in the set and clears it.  Returns the bit index.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t clearLastMarkedBit() {
-        uint32_t n = lastMarkedBit();
-        clearBit(n);
+    inline uint32_t clearLastMarkedBit() { return clearLastMarkedBit(value); }
+
+    static inline uint32_t clearLastMarkedBit(uint32_t& value) {
+        uint32_t n = lastMarkedBit(value);
+        clearBit(value, n);
         return n;
     }
 
     // Gets the index of the specified bit in the set, which is the number of
     // marked bits that appear before the specified bit.
     inline uint32_t getIndexOfBit(uint32_t n) const {
+        return getIndexOfBit(value, n);
+    }
+
+    static inline uint32_t getIndexOfBit(uint32_t value, uint32_t n) {
         return __builtin_popcountl(value & ~(0xffffffffUL >> n));
     }
 
@@ -130,65 +160,93 @@
     static inline uint64_t valueForBit(uint32_t n) { return 0x8000000000000000ULL >> n; }
 
     // Clears the bit set.
-    inline void clear() { value = 0ULL; }
+    inline void clear() { clear(value); }
+
+    static inline void clear(uint64_t& value) { value = 0ULL; }
 
     // Returns the number of marked bits in the set.
-    inline uint32_t count() const { return __builtin_popcountll(value); }
+    inline uint32_t count() const { return count(value); }
+
+    static inline uint32_t count(uint64_t value) { return __builtin_popcountll(value); }
 
     // Returns true if the bit set does not contain any marked bits.
-    inline bool isEmpty() const { return ! value; }
+    inline bool isEmpty() const { return isEmpty(value); }
+
+    static inline bool isEmpty(uint64_t value) { return ! value; }
 
     // Returns true if the bit set does not contain any unmarked bits.
-    inline bool isFull() const { return value == 0xffffffffffffffffULL; }
+    inline bool isFull() const { return isFull(value); }
+
+    static inline bool isFull(uint64_t value) { return value == 0xffffffffffffffffULL; }
 
     // Returns true if the specified bit is marked.
-    inline bool hasBit(uint32_t n) const { return value & valueForBit(n); }
+    inline bool hasBit(uint32_t n) const { return hasBit(value, n); }
+
+    static inline bool hasBit(uint64_t value, uint32_t n) { return value & valueForBit(n); }
 
     // Marks the specified bit.
-    inline void markBit(uint32_t n) { value |= valueForBit(n); }
+    inline void markBit(uint32_t n) { markBit(value, n); }
+
+    static inline void markBit(uint64_t& value, uint32_t n) { value |= valueForBit(n); }
 
     // Clears the specified bit.
-    inline void clearBit(uint32_t n) { value &= ~ valueForBit(n); }
+    inline void clearBit(uint32_t n) { clearBit(value, n); }
+
+    static inline void clearBit(uint64_t& value, uint32_t n) { value &= ~ valueForBit(n); }
 
     // Finds the first marked bit in the set.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t firstMarkedBit() const { return __builtin_clzll(value); }
+    inline uint32_t firstMarkedBit() const { return firstMarkedBit(value); }
+
+    static inline uint32_t firstMarkedBit(uint64_t value) { return __builtin_clzll(value); }
 
     // Finds the first unmarked bit in the set.
     // Result is undefined if all bits are marked.
-    inline uint32_t firstUnmarkedBit() const { return __builtin_clzll(~ value); }
+    inline uint32_t firstUnmarkedBit() const { return firstUnmarkedBit(value); }
+
+    static inline uint32_t firstUnmarkedBit(uint64_t value) { return __builtin_clzll(~ value); }
 
     // Finds the last marked bit in the set.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t lastMarkedBit() const { return 63 - __builtin_ctzll(value); }
+    inline uint32_t lastMarkedBit() const { return lastMarkedBit(value); }
+
+    static inline uint32_t lastMarkedBit(uint64_t value) { return 63 - __builtin_ctzll(value); }
 
     // Finds the first marked bit in the set and clears it.  Returns the bit index.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t clearFirstMarkedBit() {
-        uint64_t n = firstMarkedBit();
-        clearBit(n);
+    inline uint32_t clearFirstMarkedBit() { return clearFirstMarkedBit(value); }
+
+    static inline uint32_t clearFirstMarkedBit(uint64_t& value) {
+        uint64_t n = firstMarkedBit(value);
+        clearBit(value, n);
         return n;
     }
 
     // Finds the first unmarked bit in the set and marks it.  Returns the bit index.
     // Result is undefined if all bits are marked.
-    inline uint32_t markFirstUnmarkedBit() {
-        uint64_t n = firstUnmarkedBit();
-        markBit(n);
+    inline uint32_t markFirstUnmarkedBit() { return markFirstUnmarkedBit(value); }
+
+    static inline uint32_t markFirstUnmarkedBit(uint64_t& value) {
+        uint64_t n = firstUnmarkedBit(value);
+        markBit(value, n);
         return n;
     }
 
     // Finds the last marked bit in the set and clears it.  Returns the bit index.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t clearLastMarkedBit() {
-        uint64_t n = lastMarkedBit();
-        clearBit(n);
+    inline uint32_t clearLastMarkedBit() { return clearLastMarkedBit(value); }
+
+    static inline uint32_t clearLastMarkedBit(uint64_t& value) {
+        uint64_t n = lastMarkedBit(value);
+        clearBit(value, n);
         return n;
     }
 
     // Gets the index of the specified bit in the set, which is the number of
     // marked bits that appear before the specified bit.
-    inline uint32_t getIndexOfBit(uint32_t n) const {
+    inline uint32_t getIndexOfBit(uint32_t n) const { return getIndexOfBit(value, n); }
+
+    static inline uint32_t getIndexOfBit(uint64_t value, uint32_t n) {
         return __builtin_popcountll(value & ~(0xffffffffffffffffULL >> n));
     }