--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/dancres/struct/BitVisitorImpl.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,67 @@
+package org.dancres.struct;
+
+/**
+   A class to take a bit array and iterate over them reporting offset of
+   each set bit.
+*/
+public class BitVisitorImpl implements BitVisitor {
+    private Object[] theLocks;
+    private long[] theBits;
+
+    private int theBitGroupIndex = 0;
+    private int theBitGroupPtr = 0;
+
+    private int theBase = 0;
+
+    private long theMask = 1L;
+
+    private boolean testZero;
+
+    public BitVisitorImpl(long[] aBits, Object[] aLocks, boolean findZero) {
+        theBits = aBits;
+        theLocks = aLocks;
+        testZero = findZero;
+    }
+
+    /**
+       @return -1 when no bits are left
+     */
+    public int getNext() {
+        while (theBitGroupIndex < theBits.length) {
+            long myLong;
+
+            synchronized(theLocks[theBitGroupIndex]) {
+                myLong = theBits[theBitGroupIndex];
+            }
+
+            if (myLong != 0) {
+                while (theBitGroupPtr < 64) {
+                    ++theBitGroupPtr;
+
+                    if (testZero) {
+                        if ((myLong & theMask) == 0) {
+                            theMask = theMask << 1;
+                            return (theBase + theBitGroupPtr - 1);
+                        } else 
+                            theMask = theMask << 1;
+                    } else {
+                        if ((myLong & theMask) != 0) {
+                            theMask = theMask << 1;
+                            return (theBase + theBitGroupPtr - 1);
+                        } else 
+                            theMask = theMask << 1;
+                    }
+                }
+
+                // Get ready for next block
+                theBitGroupPtr = 0;
+            }
+
+            theBase += 64;
+            ++theBitGroupIndex;
+            theMask = 1L;
+        }
+
+        return -1;
+    }
+}
\ No newline at end of file