1 files changed, 27 insertions, 7 deletions
diff --git a/ARMeilleure/Common/BitMap.cs b/ARMeilleure/Common/BitMap.cs
index 35100536..b1c9a673 100644
--- a/ARMeilleure/Common/BitMap.cs
+++ b/ARMeilleure/Common/BitMap.cs
@@ -4,12 +4,12 @@ using System.Numerics;
 
 namespace ARMeilleure.Common
 {
-    class BitMap : IEnumerator<int>
+    class BitMap : IEnumerator<int>, IEnumerable<int>
     {
         private const int IntSize = 64;
         private const int IntMask = IntSize - 1;
 
-        private List<long> _masks;
+        private readonly List<long> _masks;
 
         private int _enumIndex;
         private long _enumMask;
@@ -57,7 +57,7 @@ namespace ARMeilleure.Common
             EnsureCapacity(bit + 1);
 
             int wordIndex = bit / IntSize;
-            int wordBit   = bit & IntMask;
+            int wordBit = bit & IntMask;
 
             long wordMask = 1L << wordBit;
 
@@ -76,7 +76,7 @@ namespace ARMeilleure.Common
             EnsureCapacity(bit + 1);
 
             int wordIndex = bit / IntSize;
-            int wordBit   = bit & IntMask;
+            int wordBit = bit & IntMask;
 
             long wordMask = 1L << wordBit;
 
@@ -88,11 +88,26 @@ namespace ARMeilleure.Common
             EnsureCapacity(bit + 1);
 
             int wordIndex = bit / IntSize;
-            int wordBit   = bit & IntMask;
+            int wordBit = bit & IntMask;
 
             return (_masks[wordIndex] & (1L << wordBit)) != 0;
         }
 
+        public int FindFirstUnset()
+        {
+            for (int index = 0; index < _masks.Count; index++)
+            {
+                long mask = _masks[index];
+
+                if (mask != -1L)
+                {
+                    return BitOperations.TrailingZeroCount(~mask) + index * IntSize;
+                }
+            }
+
+            return _masks.Count * IntSize;
+        }
+
         public bool Set(BitMap map)
         {
             EnsureCapacity(map._masks.Count * IntSize);
@@ -135,7 +150,7 @@ namespace ARMeilleure.Common
             return modified;
         }
 
- #region IEnumerable<long> Methods
+        #region IEnumerable<long> Methods
 
         // Note: The bit enumerator is embedded in this class to avoid creating garbage when enumerating.
 
@@ -147,6 +162,11 @@ namespace ARMeilleure.Common
             }
         }
 
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
         public IEnumerator<int> GetEnumerator()
         {
             Reset();
@@ -180,6 +200,6 @@ namespace ARMeilleure.Common
 
         public void Dispose() { }
 
-#endregion
+        #endregion
     }
 }
 \ No newline at end of file